1 /* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.widget; 18 19 import android.annotation.Nullable; 20 import android.os.Bundle; 21 import android.os.Trace; 22 import com.android.internal.R; 23 import com.android.internal.util.Predicate; 24 import com.google.android.collect.Lists; 25 26 import android.annotation.IdRes; 27 import android.annotation.NonNull; 28 import android.content.Context; 29 import android.content.Intent; 30 import android.content.res.TypedArray; 31 import android.graphics.Canvas; 32 import android.graphics.Paint; 33 import android.graphics.PixelFormat; 34 import android.graphics.Rect; 35 import android.graphics.drawable.Drawable; 36 import android.util.AttributeSet; 37 import android.util.MathUtils; 38 import android.util.SparseBooleanArray; 39 import android.view.FocusFinder; 40 import android.view.KeyEvent; 41 import android.view.SoundEffectConstants; 42 import android.view.View; 43 import android.view.ViewDebug; 44 import android.view.ViewGroup; 45 import android.view.ViewHierarchyEncoder; 46 import android.view.ViewParent; 47 import android.view.ViewRootImpl; 48 import android.view.accessibility.AccessibilityNodeInfo; 49 import android.view.accessibility.AccessibilityNodeInfo.AccessibilityAction; 50 import android.view.accessibility.AccessibilityNodeInfo.CollectionInfo; 51 import android.view.accessibility.AccessibilityNodeInfo.CollectionItemInfo; 52 import android.view.accessibility.AccessibilityNodeProvider; 53 import android.widget.RemoteViews.RemoteView; 54 55 import java.util.ArrayList; 56 57 /* 58 * Implementation Notes: 59 * 60 * Some terminology: 61 * 62 * index - index of the items that are currently visible 63 * position - index of the items in the cursor 64 */ 65 66 67 /** 68 * A view that shows items in a vertically scrolling list. The items 69 * come from the {@link ListAdapter} associated with this view. 70 * 71 * <p>See the <a href="{@docRoot}guide/topics/ui/layout/listview.html">List View</a> 72 * guide.</p> 73 * 74 * @attr ref android.R.styleable#ListView_entries 75 * @attr ref android.R.styleable#ListView_divider 76 * @attr ref android.R.styleable#ListView_dividerHeight 77 * @attr ref android.R.styleable#ListView_headerDividersEnabled 78 * @attr ref android.R.styleable#ListView_footerDividersEnabled 79 */ 80 @RemoteView 81 public class ListView extends AbsListView { 82 /** 83 * Used to indicate a no preference for a position type. 84 */ 85 static final int NO_POSITION = -1; 86 87 /** 88 * When arrow scrolling, ListView will never scroll more than this factor 89 * times the height of the list. 90 */ 91 private static final float MAX_SCROLL_FACTOR = 0.33f; 92 93 /** 94 * When arrow scrolling, need a certain amount of pixels to preview next 95 * items. This is usually the fading edge, but if that is small enough, 96 * we want to make sure we preview at least this many pixels. 97 */ 98 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 99 100 /** 101 * A class that represents a fixed view in a list, for example a header at the top 102 * or a footer at the bottom. 103 */ 104 public class FixedViewInfo { 105 /** The view to add to the list */ 106 public View view; 107 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 108 public Object data; 109 /** <code>true</code> if the fixed view should be selectable in the list */ 110 public boolean isSelectable; 111 } 112 113 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 114 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 115 116 Drawable mDivider; 117 int mDividerHeight; 118 119 Drawable mOverScrollHeader; 120 Drawable mOverScrollFooter; 121 122 private boolean mIsCacheColorOpaque; 123 private boolean mDividerIsOpaque; 124 125 private boolean mHeaderDividersEnabled; 126 private boolean mFooterDividersEnabled; 127 128 private boolean mAreAllItemsSelectable = true; 129 130 private boolean mItemsCanFocus = false; 131 132 // used for temporary calculations. 133 private final Rect mTempRect = new Rect(); 134 private Paint mDividerPaint; 135 136 // the single allocated result per list view; kinda cheesey but avoids 137 // allocating these thingies too often. 138 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 139 140 // Keeps focused children visible through resizes 141 private FocusSelector mFocusSelector; 142 143 public ListView(Context context) { 144 this(context, null); 145 } 146 147 public ListView(Context context, AttributeSet attrs) { 148 this(context, attrs, R.attr.listViewStyle); 149 } 150 151 public ListView(Context context, AttributeSet attrs, int defStyleAttr) { 152 this(context, attrs, defStyleAttr, 0); 153 } 154 155 public ListView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { 156 super(context, attrs, defStyleAttr, defStyleRes); 157 158 final TypedArray a = context.obtainStyledAttributes( 159 attrs, R.styleable.ListView, defStyleAttr, defStyleRes); 160 161 final CharSequence[] entries = a.getTextArray(R.styleable.ListView_entries); 162 if (entries != null) { 163 setAdapter(new ArrayAdapter<>(context, R.layout.simple_list_item_1, entries)); 164 } 165 166 final Drawable d = a.getDrawable(R.styleable.ListView_divider); 167 if (d != null) { 168 // Use an implicit divider height which may be explicitly 169 // overridden by android:dividerHeight further down. 170 setDivider(d); 171 } 172 173 final Drawable osHeader = a.getDrawable(R.styleable.ListView_overScrollHeader); 174 if (osHeader != null) { 175 setOverscrollHeader(osHeader); 176 } 177 178 final Drawable osFooter = a.getDrawable(R.styleable.ListView_overScrollFooter); 179 if (osFooter != null) { 180 setOverscrollFooter(osFooter); 181 } 182 183 // Use an explicit divider height, if specified. 184 if (a.hasValueOrEmpty(R.styleable.ListView_dividerHeight)) { 185 final int dividerHeight = a.getDimensionPixelSize( 186 R.styleable.ListView_dividerHeight, 0); 187 if (dividerHeight != 0) { 188 setDividerHeight(dividerHeight); 189 } 190 } 191 192 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 193 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 194 195 a.recycle(); 196 } 197 198 /** 199 * @return The maximum amount a list view will scroll in response to 200 * an arrow event. 201 */ 202 public int getMaxScrollAmount() { 203 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 204 } 205 206 /** 207 * Make sure views are touching the top or bottom edge, as appropriate for 208 * our gravity 209 */ 210 private void adjustViewsUpOrDown() { 211 final int childCount = getChildCount(); 212 int delta; 213 214 if (childCount > 0) { 215 View child; 216 217 if (!mStackFromBottom) { 218 // Uh-oh -- we came up short. Slide all views up to make them 219 // align with the top 220 child = getChildAt(0); 221 delta = child.getTop() - mListPadding.top; 222 if (mFirstPosition != 0) { 223 // It's OK to have some space above the first item if it is 224 // part of the vertical spacing 225 delta -= mDividerHeight; 226 } 227 if (delta < 0) { 228 // We only are looking to see if we are too low, not too high 229 delta = 0; 230 } 231 } else { 232 // we are too high, slide all views down to align with bottom 233 child = getChildAt(childCount - 1); 234 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 235 236 if (mFirstPosition + childCount < mItemCount) { 237 // It's OK to have some space below the last item if it is 238 // part of the vertical spacing 239 delta += mDividerHeight; 240 } 241 242 if (delta > 0) { 243 delta = 0; 244 } 245 } 246 247 if (delta != 0) { 248 offsetChildrenTopAndBottom(-delta); 249 } 250 } 251 } 252 253 /** 254 * Add a fixed view to appear at the top of the list. If this method is 255 * called more than once, the views will appear in the order they were 256 * added. Views added using this call can take focus if they want. 257 * <p> 258 * Note: When first introduced, this method could only be called before 259 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 260 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 261 * called at any time. If the ListView's adapter does not extend 262 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 263 * instance of {@link WrapperListAdapter}. 264 * 265 * @param v The view to add. 266 * @param data Data to associate with this view 267 * @param isSelectable whether the item is selectable 268 */ 269 public void addHeaderView(View v, Object data, boolean isSelectable) { 270 final FixedViewInfo info = new FixedViewInfo(); 271 info.view = v; 272 info.data = data; 273 info.isSelectable = isSelectable; 274 mHeaderViewInfos.add(info); 275 mAreAllItemsSelectable &= isSelectable; 276 277 // Wrap the adapter if it wasn't already wrapped. 278 if (mAdapter != null) { 279 if (!(mAdapter instanceof HeaderViewListAdapter)) { 280 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter); 281 } 282 283 // In the case of re-adding a header view, or adding one later on, 284 // we need to notify the observer. 285 if (mDataSetObserver != null) { 286 mDataSetObserver.onChanged(); 287 } 288 } 289 } 290 291 /** 292 * Add a fixed view to appear at the top of the list. If addHeaderView is 293 * called more than once, the views will appear in the order they were 294 * added. Views added using this call can take focus if they want. 295 * <p> 296 * Note: When first introduced, this method could only be called before 297 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 298 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 299 * called at any time. If the ListView's adapter does not extend 300 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 301 * instance of {@link WrapperListAdapter}. 302 * 303 * @param v The view to add. 304 */ 305 public void addHeaderView(View v) { 306 addHeaderView(v, null, true); 307 } 308 309 @Override 310 public int getHeaderViewsCount() { 311 return mHeaderViewInfos.size(); 312 } 313 314 /** 315 * Removes a previously-added header view. 316 * 317 * @param v The view to remove 318 * @return true if the view was removed, false if the view was not a header 319 * view 320 */ 321 public boolean removeHeaderView(View v) { 322 if (mHeaderViewInfos.size() > 0) { 323 boolean result = false; 324 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 325 if (mDataSetObserver != null) { 326 mDataSetObserver.onChanged(); 327 } 328 result = true; 329 } 330 removeFixedViewInfo(v, mHeaderViewInfos); 331 return result; 332 } 333 return false; 334 } 335 336 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 337 int len = where.size(); 338 for (int i = 0; i < len; ++i) { 339 FixedViewInfo info = where.get(i); 340 if (info.view == v) { 341 where.remove(i); 342 break; 343 } 344 } 345 } 346 347 /** 348 * Add a fixed view to appear at the bottom of the list. If addFooterView is 349 * called more than once, the views will appear in the order they were 350 * added. Views added using this call can take focus if they want. 351 * <p> 352 * Note: When first introduced, this method could only be called before 353 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 354 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 355 * called at any time. If the ListView's adapter does not extend 356 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 357 * instance of {@link WrapperListAdapter}. 358 * 359 * @param v The view to add. 360 * @param data Data to associate with this view 361 * @param isSelectable true if the footer view can be selected 362 */ 363 public void addFooterView(View v, Object data, boolean isSelectable) { 364 final FixedViewInfo info = new FixedViewInfo(); 365 info.view = v; 366 info.data = data; 367 info.isSelectable = isSelectable; 368 mFooterViewInfos.add(info); 369 mAreAllItemsSelectable &= isSelectable; 370 371 // Wrap the adapter if it wasn't already wrapped. 372 if (mAdapter != null) { 373 if (!(mAdapter instanceof HeaderViewListAdapter)) { 374 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter); 375 } 376 377 // In the case of re-adding a footer view, or adding one later on, 378 // we need to notify the observer. 379 if (mDataSetObserver != null) { 380 mDataSetObserver.onChanged(); 381 } 382 } 383 } 384 385 /** 386 * Add a fixed view to appear at the bottom of the list. If addFooterView is 387 * called more than once, the views will appear in the order they were 388 * added. Views added using this call can take focus if they want. 389 * <p> 390 * Note: When first introduced, this method could only be called before 391 * setting the adapter with {@link #setAdapter(ListAdapter)}. Starting with 392 * {@link android.os.Build.VERSION_CODES#KITKAT}, this method may be 393 * called at any time. If the ListView's adapter does not extend 394 * {@link HeaderViewListAdapter}, it will be wrapped with a supporting 395 * instance of {@link WrapperListAdapter}. 396 * 397 * @param v The view to add. 398 */ 399 public void addFooterView(View v) { 400 addFooterView(v, null, true); 401 } 402 403 @Override 404 public int getFooterViewsCount() { 405 return mFooterViewInfos.size(); 406 } 407 408 /** 409 * Removes a previously-added footer view. 410 * 411 * @param v The view to remove 412 * @return 413 * true if the view was removed, false if the view was not a footer view 414 */ 415 public boolean removeFooterView(View v) { 416 if (mFooterViewInfos.size() > 0) { 417 boolean result = false; 418 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 419 if (mDataSetObserver != null) { 420 mDataSetObserver.onChanged(); 421 } 422 result = true; 423 } 424 removeFixedViewInfo(v, mFooterViewInfos); 425 return result; 426 } 427 return false; 428 } 429 430 /** 431 * Returns the adapter currently in use in this ListView. The returned adapter 432 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 433 * might be a {@link WrapperListAdapter}. 434 * 435 * @return The adapter currently used to display data in this ListView. 436 * 437 * @see #setAdapter(ListAdapter) 438 */ 439 @Override 440 public ListAdapter getAdapter() { 441 return mAdapter; 442 } 443 444 /** 445 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 446 * through the specified intent. 447 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 448 */ 449 @android.view.RemotableViewMethod 450 public void setRemoteViewsAdapter(Intent intent) { 451 super.setRemoteViewsAdapter(intent); 452 } 453 454 /** 455 * Sets the data behind this ListView. 456 * 457 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 458 * depending on the ListView features currently in use. For instance, adding 459 * headers and/or footers will cause the adapter to be wrapped. 460 * 461 * @param adapter The ListAdapter which is responsible for maintaining the 462 * data backing this list and for producing a view to represent an 463 * item in that data set. 464 * 465 * @see #getAdapter() 466 */ 467 @Override 468 public void setAdapter(ListAdapter adapter) { 469 if (mAdapter != null && mDataSetObserver != null) { 470 mAdapter.unregisterDataSetObserver(mDataSetObserver); 471 } 472 473 resetList(); 474 mRecycler.clear(); 475 476 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 477 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 478 } else { 479 mAdapter = adapter; 480 } 481 482 mOldSelectedPosition = INVALID_POSITION; 483 mOldSelectedRowId = INVALID_ROW_ID; 484 485 // AbsListView#setAdapter will update choice mode states. 486 super.setAdapter(adapter); 487 488 if (mAdapter != null) { 489 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 490 mOldItemCount = mItemCount; 491 mItemCount = mAdapter.getCount(); 492 checkFocus(); 493 494 mDataSetObserver = new AdapterDataSetObserver(); 495 mAdapter.registerDataSetObserver(mDataSetObserver); 496 497 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 498 499 int position; 500 if (mStackFromBottom) { 501 position = lookForSelectablePosition(mItemCount - 1, false); 502 } else { 503 position = lookForSelectablePosition(0, true); 504 } 505 setSelectedPositionInt(position); 506 setNextSelectedPositionInt(position); 507 508 if (mItemCount == 0) { 509 // Nothing selected 510 checkSelectionChanged(); 511 } 512 } else { 513 mAreAllItemsSelectable = true; 514 checkFocus(); 515 // Nothing selected 516 checkSelectionChanged(); 517 } 518 519 requestLayout(); 520 } 521 522 /** 523 * The list is empty. Clear everything out. 524 */ 525 @Override 526 void resetList() { 527 // The parent's resetList() will remove all views from the layout so we need to 528 // cleanup the state of our footers and headers 529 clearRecycledState(mHeaderViewInfos); 530 clearRecycledState(mFooterViewInfos); 531 532 super.resetList(); 533 534 mLayoutMode = LAYOUT_NORMAL; 535 } 536 537 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 538 if (infos != null) { 539 final int count = infos.size(); 540 541 for (int i = 0; i < count; i++) { 542 final View child = infos.get(i).view; 543 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 544 if (p != null) { 545 p.recycledHeaderFooter = false; 546 } 547 } 548 } 549 } 550 551 /** 552 * @return Whether the list needs to show the top fading edge 553 */ 554 private boolean showingTopFadingEdge() { 555 final int listTop = mScrollY + mListPadding.top; 556 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 557 } 558 559 /** 560 * @return Whether the list needs to show the bottom fading edge 561 */ 562 private boolean showingBottomFadingEdge() { 563 final int childCount = getChildCount(); 564 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 565 final int lastVisiblePosition = mFirstPosition + childCount - 1; 566 567 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 568 569 return (lastVisiblePosition < mItemCount - 1) 570 || (bottomOfBottomChild < listBottom); 571 } 572 573 574 @Override 575 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 576 577 int rectTopWithinChild = rect.top; 578 579 // offset so rect is in coordinates of the this view 580 rect.offset(child.getLeft(), child.getTop()); 581 rect.offset(-child.getScrollX(), -child.getScrollY()); 582 583 final int height = getHeight(); 584 int listUnfadedTop = getScrollY(); 585 int listUnfadedBottom = listUnfadedTop + height; 586 final int fadingEdge = getVerticalFadingEdgeLength(); 587 588 if (showingTopFadingEdge()) { 589 // leave room for top fading edge as long as rect isn't at very top 590 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 591 listUnfadedTop += fadingEdge; 592 } 593 } 594 595 int childCount = getChildCount(); 596 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 597 598 if (showingBottomFadingEdge()) { 599 // leave room for bottom fading edge as long as rect isn't at very bottom 600 if ((mSelectedPosition < mItemCount - 1) 601 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 602 listUnfadedBottom -= fadingEdge; 603 } 604 } 605 606 int scrollYDelta = 0; 607 608 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 609 // need to MOVE DOWN to get it in view: move down just enough so 610 // that the entire rectangle is in view (or at least the first 611 // screen size chunk). 612 613 if (rect.height() > height) { 614 // just enough to get screen size chunk on 615 scrollYDelta += (rect.top - listUnfadedTop); 616 } else { 617 // get entire rect at bottom of screen 618 scrollYDelta += (rect.bottom - listUnfadedBottom); 619 } 620 621 // make sure we aren't scrolling beyond the end of our children 622 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 623 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 624 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 625 // need to MOVE UP to get it in view: move up just enough so that 626 // entire rectangle is in view (or at least the first screen 627 // size chunk of it). 628 629 if (rect.height() > height) { 630 // screen size chunk 631 scrollYDelta -= (listUnfadedBottom - rect.bottom); 632 } else { 633 // entire rect at top 634 scrollYDelta -= (listUnfadedTop - rect.top); 635 } 636 637 // make sure we aren't scrolling any further than the top our children 638 int top = getChildAt(0).getTop(); 639 int deltaToTop = top - listUnfadedTop; 640 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 641 } 642 643 final boolean scroll = scrollYDelta != 0; 644 if (scroll) { 645 scrollListItemsBy(-scrollYDelta); 646 positionSelector(INVALID_POSITION, child); 647 mSelectedTop = child.getTop(); 648 invalidate(); 649 } 650 return scroll; 651 } 652 653 /** 654 * {@inheritDoc} 655 */ 656 @Override 657 void fillGap(boolean down) { 658 final int count = getChildCount(); 659 if (down) { 660 int paddingTop = 0; 661 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 662 paddingTop = getListPaddingTop(); 663 } 664 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 665 paddingTop; 666 fillDown(mFirstPosition + count, startOffset); 667 correctTooHigh(getChildCount()); 668 } else { 669 int paddingBottom = 0; 670 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 671 paddingBottom = getListPaddingBottom(); 672 } 673 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 674 getHeight() - paddingBottom; 675 fillUp(mFirstPosition - 1, startOffset); 676 correctTooLow(getChildCount()); 677 } 678 } 679 680 /** 681 * Fills the list from pos down to the end of the list view. 682 * 683 * @param pos The first position to put in the list 684 * 685 * @param nextTop The location where the top of the item associated with pos 686 * should be drawn 687 * 688 * @return The view that is currently selected, if it happens to be in the 689 * range that we draw. 690 */ 691 private View fillDown(int pos, int nextTop) { 692 View selectedView = null; 693 694 int end = (mBottom - mTop); 695 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 696 end -= mListPadding.bottom; 697 } 698 699 while (nextTop < end && pos < mItemCount) { 700 // is this the selected item? 701 boolean selected = pos == mSelectedPosition; 702 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 703 704 nextTop = child.getBottom() + mDividerHeight; 705 if (selected) { 706 selectedView = child; 707 } 708 pos++; 709 } 710 711 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 712 return selectedView; 713 } 714 715 /** 716 * Fills the list from pos up to the top of the list view. 717 * 718 * @param pos The first position to put in the list 719 * 720 * @param nextBottom The location where the bottom of the item associated 721 * with pos should be drawn 722 * 723 * @return The view that is currently selected 724 */ 725 private View fillUp(int pos, int nextBottom) { 726 View selectedView = null; 727 728 int end = 0; 729 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 730 end = mListPadding.top; 731 } 732 733 while (nextBottom > end && pos >= 0) { 734 // is this the selected item? 735 boolean selected = pos == mSelectedPosition; 736 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 737 nextBottom = child.getTop() - mDividerHeight; 738 if (selected) { 739 selectedView = child; 740 } 741 pos--; 742 } 743 744 mFirstPosition = pos + 1; 745 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 746 return selectedView; 747 } 748 749 /** 750 * Fills the list from top to bottom, starting with mFirstPosition 751 * 752 * @param nextTop The location where the top of the first item should be 753 * drawn 754 * 755 * @return The view that is currently selected 756 */ 757 private View fillFromTop(int nextTop) { 758 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 759 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 760 if (mFirstPosition < 0) { 761 mFirstPosition = 0; 762 } 763 return fillDown(mFirstPosition, nextTop); 764 } 765 766 767 /** 768 * Put mSelectedPosition in the middle of the screen and then build up and 769 * down from there. This method forces mSelectedPosition to the center. 770 * 771 * @param childrenTop Top of the area in which children can be drawn, as 772 * measured in pixels 773 * @param childrenBottom Bottom of the area in which children can be drawn, 774 * as measured in pixels 775 * @return Currently selected view 776 */ 777 private View fillFromMiddle(int childrenTop, int childrenBottom) { 778 int height = childrenBottom - childrenTop; 779 780 int position = reconcileSelectedPosition(); 781 782 View sel = makeAndAddView(position, childrenTop, true, 783 mListPadding.left, true); 784 mFirstPosition = position; 785 786 int selHeight = sel.getMeasuredHeight(); 787 if (selHeight <= height) { 788 sel.offsetTopAndBottom((height - selHeight) / 2); 789 } 790 791 fillAboveAndBelow(sel, position); 792 793 if (!mStackFromBottom) { 794 correctTooHigh(getChildCount()); 795 } else { 796 correctTooLow(getChildCount()); 797 } 798 799 return sel; 800 } 801 802 /** 803 * Once the selected view as been placed, fill up the visible area above and 804 * below it. 805 * 806 * @param sel The selected view 807 * @param position The position corresponding to sel 808 */ 809 private void fillAboveAndBelow(View sel, int position) { 810 final int dividerHeight = mDividerHeight; 811 if (!mStackFromBottom) { 812 fillUp(position - 1, sel.getTop() - dividerHeight); 813 adjustViewsUpOrDown(); 814 fillDown(position + 1, sel.getBottom() + dividerHeight); 815 } else { 816 fillDown(position + 1, sel.getBottom() + dividerHeight); 817 adjustViewsUpOrDown(); 818 fillUp(position - 1, sel.getTop() - dividerHeight); 819 } 820 } 821 822 823 /** 824 * Fills the grid based on positioning the new selection at a specific 825 * location. The selection may be moved so that it does not intersect the 826 * faded edges. The grid is then filled upwards and downwards from there. 827 * 828 * @param selectedTop Where the selected item should be 829 * @param childrenTop Where to start drawing children 830 * @param childrenBottom Last pixel where children can be drawn 831 * @return The view that currently has selection 832 */ 833 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 834 int fadingEdgeLength = getVerticalFadingEdgeLength(); 835 final int selectedPosition = mSelectedPosition; 836 837 View sel; 838 839 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 840 selectedPosition); 841 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 842 selectedPosition); 843 844 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 845 846 847 // Some of the newly selected item extends below the bottom of the list 848 if (sel.getBottom() > bottomSelectionPixel) { 849 // Find space available above the selection into which we can scroll 850 // upwards 851 final int spaceAbove = sel.getTop() - topSelectionPixel; 852 853 // Find space required to bring the bottom of the selected item 854 // fully into view 855 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 856 final int offset = Math.min(spaceAbove, spaceBelow); 857 858 // Now offset the selected item to get it into view 859 sel.offsetTopAndBottom(-offset); 860 } else if (sel.getTop() < topSelectionPixel) { 861 // Find space required to bring the top of the selected item fully 862 // into view 863 final int spaceAbove = topSelectionPixel - sel.getTop(); 864 865 // Find space available below the selection into which we can scroll 866 // downwards 867 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 868 final int offset = Math.min(spaceAbove, spaceBelow); 869 870 // Offset the selected item to get it into view 871 sel.offsetTopAndBottom(offset); 872 } 873 874 // Fill in views above and below 875 fillAboveAndBelow(sel, selectedPosition); 876 877 if (!mStackFromBottom) { 878 correctTooHigh(getChildCount()); 879 } else { 880 correctTooLow(getChildCount()); 881 } 882 883 return sel; 884 } 885 886 /** 887 * Calculate the bottom-most pixel we can draw the selection into 888 * 889 * @param childrenBottom Bottom pixel were children can be drawn 890 * @param fadingEdgeLength Length of the fading edge in pixels, if present 891 * @param selectedPosition The position that will be selected 892 * @return The bottom-most pixel we can draw the selection into 893 */ 894 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 895 int selectedPosition) { 896 int bottomSelectionPixel = childrenBottom; 897 if (selectedPosition != mItemCount - 1) { 898 bottomSelectionPixel -= fadingEdgeLength; 899 } 900 return bottomSelectionPixel; 901 } 902 903 /** 904 * Calculate the top-most pixel we can draw the selection into 905 * 906 * @param childrenTop Top pixel were children can be drawn 907 * @param fadingEdgeLength Length of the fading edge in pixels, if present 908 * @param selectedPosition The position that will be selected 909 * @return The top-most pixel we can draw the selection into 910 */ 911 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 912 // first pixel we can draw the selection into 913 int topSelectionPixel = childrenTop; 914 if (selectedPosition > 0) { 915 topSelectionPixel += fadingEdgeLength; 916 } 917 return topSelectionPixel; 918 } 919 920 /** 921 * Smoothly scroll to the specified adapter position. The view will 922 * scroll such that the indicated position is displayed. 923 * @param position Scroll to this adapter position. 924 */ 925 @android.view.RemotableViewMethod 926 public void smoothScrollToPosition(int position) { 927 super.smoothScrollToPosition(position); 928 } 929 930 /** 931 * Smoothly scroll to the specified adapter position offset. The view will 932 * scroll such that the indicated position is displayed. 933 * @param offset The amount to offset from the adapter position to scroll to. 934 */ 935 @android.view.RemotableViewMethod 936 public void smoothScrollByOffset(int offset) { 937 super.smoothScrollByOffset(offset); 938 } 939 940 /** 941 * Fills the list based on positioning the new selection relative to the old 942 * selection. The new selection will be placed at, above, or below the 943 * location of the new selection depending on how the selection is moving. 944 * The selection will then be pinned to the visible part of the screen, 945 * excluding the edges that are faded. The list is then filled upwards and 946 * downwards from there. 947 * 948 * @param oldSel The old selected view. Useful for trying to put the new 949 * selection in the same place 950 * @param newSel The view that is to become selected. Useful for trying to 951 * put the new selection in the same place 952 * @param delta Which way we are moving 953 * @param childrenTop Where to start drawing children 954 * @param childrenBottom Last pixel where children can be drawn 955 * @return The view that currently has selection 956 */ 957 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 958 int childrenBottom) { 959 int fadingEdgeLength = getVerticalFadingEdgeLength(); 960 final int selectedPosition = mSelectedPosition; 961 962 View sel; 963 964 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 965 selectedPosition); 966 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 967 selectedPosition); 968 969 if (delta > 0) { 970 /* 971 * Case 1: Scrolling down. 972 */ 973 974 /* 975 * Before After 976 * | | | | 977 * +-------+ +-------+ 978 * | A | | A | 979 * | 1 | => +-------+ 980 * +-------+ | B | 981 * | B | | 2 | 982 * +-------+ +-------+ 983 * | | | | 984 * 985 * Try to keep the top of the previously selected item where it was. 986 * oldSel = A 987 * sel = B 988 */ 989 990 // Put oldSel (A) where it belongs 991 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 992 mListPadding.left, false); 993 994 final int dividerHeight = mDividerHeight; 995 996 // Now put the new selection (B) below that 997 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 998 mListPadding.left, true); 999 1000 // Some of the newly selected item extends below the bottom of the list 1001 if (sel.getBottom() > bottomSelectionPixel) { 1002 1003 // Find space available above the selection into which we can scroll upwards 1004 int spaceAbove = sel.getTop() - topSelectionPixel; 1005 1006 // Find space required to bring the bottom of the selected item fully into view 1007 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 1008 1009 // Don't scroll more than half the height of the list 1010 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1011 int offset = Math.min(spaceAbove, spaceBelow); 1012 offset = Math.min(offset, halfVerticalSpace); 1013 1014 // We placed oldSel, so offset that item 1015 oldSel.offsetTopAndBottom(-offset); 1016 // Now offset the selected item to get it into view 1017 sel.offsetTopAndBottom(-offset); 1018 } 1019 1020 // Fill in views above and below 1021 if (!mStackFromBottom) { 1022 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1023 adjustViewsUpOrDown(); 1024 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 1025 } else { 1026 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 1027 adjustViewsUpOrDown(); 1028 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1029 } 1030 } else if (delta < 0) { 1031 /* 1032 * Case 2: Scrolling up. 1033 */ 1034 1035 /* 1036 * Before After 1037 * | | | | 1038 * +-------+ +-------+ 1039 * | A | | A | 1040 * +-------+ => | 1 | 1041 * | B | +-------+ 1042 * | 2 | | B | 1043 * +-------+ +-------+ 1044 * | | | | 1045 * 1046 * Try to keep the top of the item about to become selected where it was. 1047 * newSel = A 1048 * olSel = B 1049 */ 1050 1051 if (newSel != null) { 1052 // Try to position the top of newSel (A) where it was before it was selected 1053 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 1054 true); 1055 } else { 1056 // If (A) was not on screen and so did not have a view, position 1057 // it above the oldSel (B) 1058 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 1059 true); 1060 } 1061 1062 // Some of the newly selected item extends above the top of the list 1063 if (sel.getTop() < topSelectionPixel) { 1064 // Find space required to bring the top of the selected item fully into view 1065 int spaceAbove = topSelectionPixel - sel.getTop(); 1066 1067 // Find space available below the selection into which we can scroll downwards 1068 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 1069 1070 // Don't scroll more than half the height of the list 1071 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1072 int offset = Math.min(spaceAbove, spaceBelow); 1073 offset = Math.min(offset, halfVerticalSpace); 1074 1075 // Offset the selected item to get it into view 1076 sel.offsetTopAndBottom(offset); 1077 } 1078 1079 // Fill in views above and below 1080 fillAboveAndBelow(sel, selectedPosition); 1081 } else { 1082 1083 int oldTop = oldSel.getTop(); 1084 1085 /* 1086 * Case 3: Staying still 1087 */ 1088 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1089 1090 // We're staying still... 1091 if (oldTop < childrenTop) { 1092 // ... but the top of the old selection was off screen. 1093 // (This can happen if the data changes size out from under us) 1094 int newBottom = sel.getBottom(); 1095 if (newBottom < childrenTop + 20) { 1096 // Not enough visible -- bring it onscreen 1097 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1098 } 1099 } 1100 1101 // Fill in views above and below 1102 fillAboveAndBelow(sel, selectedPosition); 1103 } 1104 1105 return sel; 1106 } 1107 1108 private class FocusSelector implements Runnable { 1109 private int mPosition; 1110 private int mPositionTop; 1111 1112 public FocusSelector setup(int position, int top) { 1113 mPosition = position; 1114 mPositionTop = top; 1115 return this; 1116 } 1117 1118 public void run() { 1119 setSelectionFromTop(mPosition, mPositionTop); 1120 } 1121 } 1122 1123 @Override 1124 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1125 if (getChildCount() > 0) { 1126 View focusedChild = getFocusedChild(); 1127 if (focusedChild != null) { 1128 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1129 final int childBottom = focusedChild.getBottom(); 1130 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1131 final int top = focusedChild.getTop() - offset; 1132 if (mFocusSelector == null) { 1133 mFocusSelector = new FocusSelector(); 1134 } 1135 post(mFocusSelector.setup(childPosition, top)); 1136 } 1137 } 1138 super.onSizeChanged(w, h, oldw, oldh); 1139 } 1140 1141 @Override 1142 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1143 // Sets up mListPadding 1144 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1145 1146 final int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1147 final int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1148 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1149 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1150 1151 int childWidth = 0; 1152 int childHeight = 0; 1153 int childState = 0; 1154 1155 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1156 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED 1157 || heightMode == MeasureSpec.UNSPECIFIED)) { 1158 final View child = obtainView(0, mIsScrap); 1159 1160 // Lay out child directly against the parent measure spec so that 1161 // we can obtain exected minimum width and height. 1162 measureScrapChild(child, 0, widthMeasureSpec, heightSize); 1163 1164 childWidth = child.getMeasuredWidth(); 1165 childHeight = child.getMeasuredHeight(); 1166 childState = combineMeasuredStates(childState, child.getMeasuredState()); 1167 1168 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1169 ((LayoutParams) child.getLayoutParams()).viewType)) { 1170 mRecycler.addScrapView(child, 0); 1171 } 1172 } 1173 1174 if (widthMode == MeasureSpec.UNSPECIFIED) { 1175 widthSize = mListPadding.left + mListPadding.right + childWidth + 1176 getVerticalScrollbarWidth(); 1177 } else { 1178 widthSize |= (childState & MEASURED_STATE_MASK); 1179 } 1180 1181 if (heightMode == MeasureSpec.UNSPECIFIED) { 1182 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1183 getVerticalFadingEdgeLength() * 2; 1184 } 1185 1186 if (heightMode == MeasureSpec.AT_MOST) { 1187 // TODO: after first layout we should maybe start at the first visible position, not 0 1188 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1189 } 1190 1191 setMeasuredDimension(widthSize, heightSize); 1192 1193 mWidthMeasureSpec = widthMeasureSpec; 1194 } 1195 1196 private void measureScrapChild(View child, int position, int widthMeasureSpec, int heightHint) { 1197 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1198 if (p == null) { 1199 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1200 child.setLayoutParams(p); 1201 } 1202 p.viewType = mAdapter.getItemViewType(position); 1203 p.forceAdd = true; 1204 1205 final int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1206 mListPadding.left + mListPadding.right, p.width); 1207 final int lpHeight = p.height; 1208 final int childHeightSpec; 1209 if (lpHeight > 0) { 1210 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1211 } else { 1212 childHeightSpec = MeasureSpec.makeSafeMeasureSpec(heightHint, MeasureSpec.UNSPECIFIED); 1213 } 1214 child.measure(childWidthSpec, childHeightSpec); 1215 1216 // Since this view was measured directly aginst the parent measure 1217 // spec, we must measure it again before reuse. 1218 child.forceLayout(); 1219 } 1220 1221 /** 1222 * @return True to recycle the views used to measure this ListView in 1223 * UNSPECIFIED/AT_MOST modes, false otherwise. 1224 * @hide 1225 */ 1226 @ViewDebug.ExportedProperty(category = "list") 1227 protected boolean recycleOnMeasure() { 1228 return true; 1229 } 1230 1231 /** 1232 * Measures the height of the given range of children (inclusive) and 1233 * returns the height with this ListView's padding and divider heights 1234 * included. If maxHeight is provided, the measuring will stop when the 1235 * current height reaches maxHeight. 1236 * 1237 * @param widthMeasureSpec The width measure spec to be given to a child's 1238 * {@link View#measure(int, int)}. 1239 * @param startPosition The position of the first child to be shown. 1240 * @param endPosition The (inclusive) position of the last child to be 1241 * shown. Specify {@link #NO_POSITION} if the last child should be 1242 * the last available child from the adapter. 1243 * @param maxHeight The maximum height that will be returned (if all the 1244 * children don't fit in this value, this value will be 1245 * returned). 1246 * @param disallowPartialChildPosition In general, whether the returned 1247 * height should only contain entire children. This is more 1248 * powerful--it is the first inclusive position at which partial 1249 * children will not be allowed. Example: it looks nice to have 1250 * at least 3 completely visible children, and in portrait this 1251 * will most likely fit; but in landscape there could be times 1252 * when even 2 children can not be completely shown, so a value 1253 * of 2 (remember, inclusive) would be good (assuming 1254 * startPosition is 0). 1255 * @return The height of this ListView with the given children. 1256 */ 1257 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1258 int maxHeight, int disallowPartialChildPosition) { 1259 final ListAdapter adapter = mAdapter; 1260 if (adapter == null) { 1261 return mListPadding.top + mListPadding.bottom; 1262 } 1263 1264 // Include the padding of the list 1265 int returnedHeight = mListPadding.top + mListPadding.bottom; 1266 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1267 // The previous height value that was less than maxHeight and contained 1268 // no partial children 1269 int prevHeightWithoutPartialChild = 0; 1270 int i; 1271 View child; 1272 1273 // mItemCount - 1 since endPosition parameter is inclusive 1274 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1275 final AbsListView.RecycleBin recycleBin = mRecycler; 1276 final boolean recyle = recycleOnMeasure(); 1277 final boolean[] isScrap = mIsScrap; 1278 1279 for (i = startPosition; i <= endPosition; ++i) { 1280 child = obtainView(i, isScrap); 1281 1282 measureScrapChild(child, i, widthMeasureSpec, maxHeight); 1283 1284 if (i > 0) { 1285 // Count the divider for all but one child 1286 returnedHeight += dividerHeight; 1287 } 1288 1289 // Recycle the view before we possibly return from the method 1290 if (recyle && recycleBin.shouldRecycleViewType( 1291 ((LayoutParams) child.getLayoutParams()).viewType)) { 1292 recycleBin.addScrapView(child, -1); 1293 } 1294 1295 returnedHeight += child.getMeasuredHeight(); 1296 1297 if (returnedHeight >= maxHeight) { 1298 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1299 // then the i'th position did not fit completely. 1300 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1301 && (i > disallowPartialChildPosition) // We've past the min pos 1302 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1303 && (returnedHeight != maxHeight) // i'th child did not fit completely 1304 ? prevHeightWithoutPartialChild 1305 : maxHeight; 1306 } 1307 1308 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1309 prevHeightWithoutPartialChild = returnedHeight; 1310 } 1311 } 1312 1313 // At this point, we went through the range of children, and they each 1314 // completely fit, so return the returnedHeight 1315 return returnedHeight; 1316 } 1317 1318 @Override 1319 int findMotionRow(int y) { 1320 int childCount = getChildCount(); 1321 if (childCount > 0) { 1322 if (!mStackFromBottom) { 1323 for (int i = 0; i < childCount; i++) { 1324 View v = getChildAt(i); 1325 if (y <= v.getBottom()) { 1326 return mFirstPosition + i; 1327 } 1328 } 1329 } else { 1330 for (int i = childCount - 1; i >= 0; i--) { 1331 View v = getChildAt(i); 1332 if (y >= v.getTop()) { 1333 return mFirstPosition + i; 1334 } 1335 } 1336 } 1337 } 1338 return INVALID_POSITION; 1339 } 1340 1341 /** 1342 * Put a specific item at a specific location on the screen and then build 1343 * up and down from there. 1344 * 1345 * @param position The reference view to use as the starting point 1346 * @param top Pixel offset from the top of this view to the top of the 1347 * reference view. 1348 * 1349 * @return The selected view, or null if the selected view is outside the 1350 * visible area. 1351 */ 1352 private View fillSpecific(int position, int top) { 1353 boolean tempIsSelected = position == mSelectedPosition; 1354 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1355 // Possibly changed again in fillUp if we add rows above this one. 1356 mFirstPosition = position; 1357 1358 View above; 1359 View below; 1360 1361 final int dividerHeight = mDividerHeight; 1362 if (!mStackFromBottom) { 1363 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1364 // This will correct for the top of the first view not touching the top of the list 1365 adjustViewsUpOrDown(); 1366 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1367 int childCount = getChildCount(); 1368 if (childCount > 0) { 1369 correctTooHigh(childCount); 1370 } 1371 } else { 1372 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1373 // This will correct for the bottom of the last view not touching the bottom of the list 1374 adjustViewsUpOrDown(); 1375 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1376 int childCount = getChildCount(); 1377 if (childCount > 0) { 1378 correctTooLow(childCount); 1379 } 1380 } 1381 1382 if (tempIsSelected) { 1383 return temp; 1384 } else if (above != null) { 1385 return above; 1386 } else { 1387 return below; 1388 } 1389 } 1390 1391 /** 1392 * Check if we have dragged the bottom of the list too high (we have pushed the 1393 * top element off the top of the screen when we did not need to). Correct by sliding 1394 * everything back down. 1395 * 1396 * @param childCount Number of children 1397 */ 1398 private void correctTooHigh(int childCount) { 1399 // First see if the last item is visible. If it is not, it is OK for the 1400 // top of the list to be pushed up. 1401 int lastPosition = mFirstPosition + childCount - 1; 1402 if (lastPosition == mItemCount - 1 && childCount > 0) { 1403 1404 // Get the last child ... 1405 final View lastChild = getChildAt(childCount - 1); 1406 1407 // ... and its bottom edge 1408 final int lastBottom = lastChild.getBottom(); 1409 1410 // This is bottom of our drawable area 1411 final int end = (mBottom - mTop) - mListPadding.bottom; 1412 1413 // This is how far the bottom edge of the last view is from the bottom of the 1414 // drawable area 1415 int bottomOffset = end - lastBottom; 1416 View firstChild = getChildAt(0); 1417 final int firstTop = firstChild.getTop(); 1418 1419 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1420 // first row or the first row is scrolled off the top of the drawable area 1421 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1422 if (mFirstPosition == 0) { 1423 // Don't pull the top too far down 1424 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1425 } 1426 // Move everything down 1427 offsetChildrenTopAndBottom(bottomOffset); 1428 if (mFirstPosition > 0) { 1429 // Fill the gap that was opened above mFirstPosition with more rows, if 1430 // possible 1431 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1432 // Close up the remaining gap 1433 adjustViewsUpOrDown(); 1434 } 1435 1436 } 1437 } 1438 } 1439 1440 /** 1441 * Check if we have dragged the bottom of the list too low (we have pushed the 1442 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1443 * everything back up. 1444 * 1445 * @param childCount Number of children 1446 */ 1447 private void correctTooLow(int childCount) { 1448 // First see if the first item is visible. If it is not, it is OK for the 1449 // bottom of the list to be pushed down. 1450 if (mFirstPosition == 0 && childCount > 0) { 1451 1452 // Get the first child ... 1453 final View firstChild = getChildAt(0); 1454 1455 // ... and its top edge 1456 final int firstTop = firstChild.getTop(); 1457 1458 // This is top of our drawable area 1459 final int start = mListPadding.top; 1460 1461 // This is bottom of our drawable area 1462 final int end = (mBottom - mTop) - mListPadding.bottom; 1463 1464 // This is how far the top edge of the first view is from the top of the 1465 // drawable area 1466 int topOffset = firstTop - start; 1467 View lastChild = getChildAt(childCount - 1); 1468 final int lastBottom = lastChild.getBottom(); 1469 int lastPosition = mFirstPosition + childCount - 1; 1470 1471 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1472 // last row or the last row is scrolled off the bottom of the drawable area 1473 if (topOffset > 0) { 1474 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1475 if (lastPosition == mItemCount - 1) { 1476 // Don't pull the bottom too far up 1477 topOffset = Math.min(topOffset, lastBottom - end); 1478 } 1479 // Move everything up 1480 offsetChildrenTopAndBottom(-topOffset); 1481 if (lastPosition < mItemCount - 1) { 1482 // Fill the gap that was opened below the last position with more rows, if 1483 // possible 1484 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1485 // Close up the remaining gap 1486 adjustViewsUpOrDown(); 1487 } 1488 } else if (lastPosition == mItemCount - 1) { 1489 adjustViewsUpOrDown(); 1490 } 1491 } 1492 } 1493 } 1494 1495 @Override 1496 protected void layoutChildren() { 1497 final boolean blockLayoutRequests = mBlockLayoutRequests; 1498 if (blockLayoutRequests) { 1499 return; 1500 } 1501 1502 mBlockLayoutRequests = true; 1503 1504 try { 1505 super.layoutChildren(); 1506 1507 invalidate(); 1508 1509 if (mAdapter == null) { 1510 resetList(); 1511 invokeOnItemScrollListener(); 1512 return; 1513 } 1514 1515 final int childrenTop = mListPadding.top; 1516 final int childrenBottom = mBottom - mTop - mListPadding.bottom; 1517 final int childCount = getChildCount(); 1518 1519 int index = 0; 1520 int delta = 0; 1521 1522 View sel; 1523 View oldSel = null; 1524 View oldFirst = null; 1525 View newSel = null; 1526 1527 // Remember stuff we will need down below 1528 switch (mLayoutMode) { 1529 case LAYOUT_SET_SELECTION: 1530 index = mNextSelectedPosition - mFirstPosition; 1531 if (index >= 0 && index < childCount) { 1532 newSel = getChildAt(index); 1533 } 1534 break; 1535 case LAYOUT_FORCE_TOP: 1536 case LAYOUT_FORCE_BOTTOM: 1537 case LAYOUT_SPECIFIC: 1538 case LAYOUT_SYNC: 1539 break; 1540 case LAYOUT_MOVE_SELECTION: 1541 default: 1542 // Remember the previously selected view 1543 index = mSelectedPosition - mFirstPosition; 1544 if (index >= 0 && index < childCount) { 1545 oldSel = getChildAt(index); 1546 } 1547 1548 // Remember the previous first child 1549 oldFirst = getChildAt(0); 1550 1551 if (mNextSelectedPosition >= 0) { 1552 delta = mNextSelectedPosition - mSelectedPosition; 1553 } 1554 1555 // Caution: newSel might be null 1556 newSel = getChildAt(index + delta); 1557 } 1558 1559 1560 boolean dataChanged = mDataChanged; 1561 if (dataChanged) { 1562 handleDataChanged(); 1563 } 1564 1565 // Handle the empty set by removing all views that are visible 1566 // and calling it a day 1567 if (mItemCount == 0) { 1568 resetList(); 1569 invokeOnItemScrollListener(); 1570 return; 1571 } else if (mItemCount != mAdapter.getCount()) { 1572 throw new IllegalStateException("The content of the adapter has changed but " 1573 + "ListView did not receive a notification. Make sure the content of " 1574 + "your adapter is not modified from a background thread, but only from " 1575 + "the UI thread. Make sure your adapter calls notifyDataSetChanged() " 1576 + "when its content changes. [in ListView(" + getId() + ", " + getClass() 1577 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1578 } 1579 1580 setSelectedPositionInt(mNextSelectedPosition); 1581 1582 AccessibilityNodeInfo accessibilityFocusLayoutRestoreNode = null; 1583 View accessibilityFocusLayoutRestoreView = null; 1584 int accessibilityFocusPosition = INVALID_POSITION; 1585 1586 // Remember which child, if any, had accessibility focus. This must 1587 // occur before recycling any views, since that will clear 1588 // accessibility focus. 1589 final ViewRootImpl viewRootImpl = getViewRootImpl(); 1590 if (viewRootImpl != null) { 1591 final View focusHost = viewRootImpl.getAccessibilityFocusedHost(); 1592 if (focusHost != null) { 1593 final View focusChild = getAccessibilityFocusedChild(focusHost); 1594 if (focusChild != null) { 1595 if (!dataChanged || isDirectChildHeaderOrFooter(focusChild) 1596 || focusChild.hasTransientState() || mAdapterHasStableIds) { 1597 // The views won't be changing, so try to maintain 1598 // focus on the current host and virtual view. 1599 accessibilityFocusLayoutRestoreView = focusHost; 1600 accessibilityFocusLayoutRestoreNode = viewRootImpl 1601 .getAccessibilityFocusedVirtualView(); 1602 } 1603 1604 // If all else fails, maintain focus at the same 1605 // position. 1606 accessibilityFocusPosition = getPositionForView(focusChild); 1607 } 1608 } 1609 } 1610 1611 View focusLayoutRestoreDirectChild = null; 1612 View focusLayoutRestoreView = null; 1613 1614 // Take focus back to us temporarily to avoid the eventual call to 1615 // clear focus when removing the focused child below from messing 1616 // things up when ViewAncestor assigns focus back to someone else. 1617 final View focusedChild = getFocusedChild(); 1618 if (focusedChild != null) { 1619 // TODO: in some cases focusedChild.getParent() == null 1620 1621 // We can remember the focused view to restore after re-layout 1622 // if the data hasn't changed, or if the focused position is a 1623 // header or footer. 1624 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild) 1625 || focusedChild.hasTransientState() || mAdapterHasStableIds) { 1626 focusLayoutRestoreDirectChild = focusedChild; 1627 // Remember the specific view that had focus. 1628 focusLayoutRestoreView = findFocus(); 1629 if (focusLayoutRestoreView != null) { 1630 // Tell it we are going to mess with it. 1631 focusLayoutRestoreView.onStartTemporaryDetach(); 1632 } 1633 } 1634 requestFocus(); 1635 } 1636 1637 // Pull all children into the RecycleBin. 1638 // These views will be reused if possible 1639 final int firstPosition = mFirstPosition; 1640 final RecycleBin recycleBin = mRecycler; 1641 if (dataChanged) { 1642 for (int i = 0; i < childCount; i++) { 1643 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1644 } 1645 } else { 1646 recycleBin.fillActiveViews(childCount, firstPosition); 1647 } 1648 1649 // Clear out old views 1650 detachAllViewsFromParent(); 1651 recycleBin.removeSkippedScrap(); 1652 1653 switch (mLayoutMode) { 1654 case LAYOUT_SET_SELECTION: 1655 if (newSel != null) { 1656 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1657 } else { 1658 sel = fillFromMiddle(childrenTop, childrenBottom); 1659 } 1660 break; 1661 case LAYOUT_SYNC: 1662 sel = fillSpecific(mSyncPosition, mSpecificTop); 1663 break; 1664 case LAYOUT_FORCE_BOTTOM: 1665 sel = fillUp(mItemCount - 1, childrenBottom); 1666 adjustViewsUpOrDown(); 1667 break; 1668 case LAYOUT_FORCE_TOP: 1669 mFirstPosition = 0; 1670 sel = fillFromTop(childrenTop); 1671 adjustViewsUpOrDown(); 1672 break; 1673 case LAYOUT_SPECIFIC: 1674 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1675 break; 1676 case LAYOUT_MOVE_SELECTION: 1677 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1678 break; 1679 default: 1680 if (childCount == 0) { 1681 if (!mStackFromBottom) { 1682 final int position = lookForSelectablePosition(0, true); 1683 setSelectedPositionInt(position); 1684 sel = fillFromTop(childrenTop); 1685 } else { 1686 final int position = lookForSelectablePosition(mItemCount - 1, false); 1687 setSelectedPositionInt(position); 1688 sel = fillUp(mItemCount - 1, childrenBottom); 1689 } 1690 } else { 1691 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1692 sel = fillSpecific(mSelectedPosition, 1693 oldSel == null ? childrenTop : oldSel.getTop()); 1694 } else if (mFirstPosition < mItemCount) { 1695 sel = fillSpecific(mFirstPosition, 1696 oldFirst == null ? childrenTop : oldFirst.getTop()); 1697 } else { 1698 sel = fillSpecific(0, childrenTop); 1699 } 1700 } 1701 break; 1702 } 1703 1704 // Flush any cached views that did not get reused above 1705 recycleBin.scrapActiveViews(); 1706 1707 if (sel != null) { 1708 // The current selected item should get focus if items are 1709 // focusable. 1710 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1711 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1712 focusLayoutRestoreView != null && 1713 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1714 if (!focusWasTaken) { 1715 // Selected item didn't take focus, but we still want to 1716 // make sure something else outside of the selected view 1717 // has focus. 1718 final View focused = getFocusedChild(); 1719 if (focused != null) { 1720 focused.clearFocus(); 1721 } 1722 positionSelector(INVALID_POSITION, sel); 1723 } else { 1724 sel.setSelected(false); 1725 mSelectorRect.setEmpty(); 1726 } 1727 } else { 1728 positionSelector(INVALID_POSITION, sel); 1729 } 1730 mSelectedTop = sel.getTop(); 1731 } else { 1732 final boolean inTouchMode = mTouchMode == TOUCH_MODE_TAP 1733 || mTouchMode == TOUCH_MODE_DONE_WAITING; 1734 if (inTouchMode) { 1735 // If the user's finger is down, select the motion position. 1736 final View child = getChildAt(mMotionPosition - mFirstPosition); 1737 if (child != null) { 1738 positionSelector(mMotionPosition, child); 1739 } 1740 } else if (mSelectorPosition != INVALID_POSITION) { 1741 // If we had previously positioned the selector somewhere, 1742 // put it back there. It might not match up with the data, 1743 // but it's transitioning out so it's not a big deal. 1744 final View child = getChildAt(mSelectorPosition - mFirstPosition); 1745 if (child != null) { 1746 positionSelector(mSelectorPosition, child); 1747 } 1748 } else { 1749 // Otherwise, clear selection. 1750 mSelectedTop = 0; 1751 mSelectorRect.setEmpty(); 1752 } 1753 1754 // Even if there is not selected position, we may need to 1755 // restore focus (i.e. something focusable in touch mode). 1756 if (hasFocus() && focusLayoutRestoreView != null) { 1757 focusLayoutRestoreView.requestFocus(); 1758 } 1759 } 1760 1761 // Attempt to restore accessibility focus, if necessary. 1762 if (viewRootImpl != null) { 1763 final View newAccessibilityFocusedView = viewRootImpl.getAccessibilityFocusedHost(); 1764 if (newAccessibilityFocusedView == null) { 1765 if (accessibilityFocusLayoutRestoreView != null 1766 && accessibilityFocusLayoutRestoreView.isAttachedToWindow()) { 1767 final AccessibilityNodeProvider provider = 1768 accessibilityFocusLayoutRestoreView.getAccessibilityNodeProvider(); 1769 if (accessibilityFocusLayoutRestoreNode != null && provider != null) { 1770 final int virtualViewId = AccessibilityNodeInfo.getVirtualDescendantId( 1771 accessibilityFocusLayoutRestoreNode.getSourceNodeId()); 1772 provider.performAction(virtualViewId, 1773 AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS, null); 1774 } else { 1775 accessibilityFocusLayoutRestoreView.requestAccessibilityFocus(); 1776 } 1777 } else if (accessibilityFocusPosition != INVALID_POSITION) { 1778 // Bound the position within the visible children. 1779 final int position = MathUtils.constrain( 1780 accessibilityFocusPosition - mFirstPosition, 0, 1781 getChildCount() - 1); 1782 final View restoreView = getChildAt(position); 1783 if (restoreView != null) { 1784 restoreView.requestAccessibilityFocus(); 1785 } 1786 } 1787 } 1788 } 1789 1790 // Tell focus view we are done mucking with it, if it is still in 1791 // our view hierarchy. 1792 if (focusLayoutRestoreView != null 1793 && focusLayoutRestoreView.getWindowToken() != null) { 1794 focusLayoutRestoreView.onFinishTemporaryDetach(); 1795 } 1796 1797 mLayoutMode = LAYOUT_NORMAL; 1798 mDataChanged = false; 1799 if (mPositionScrollAfterLayout != null) { 1800 post(mPositionScrollAfterLayout); 1801 mPositionScrollAfterLayout = null; 1802 } 1803 mNeedSync = false; 1804 setNextSelectedPositionInt(mSelectedPosition); 1805 1806 updateScrollIndicators(); 1807 1808 if (mItemCount > 0) { 1809 checkSelectionChanged(); 1810 } 1811 1812 invokeOnItemScrollListener(); 1813 } finally { 1814 if (!blockLayoutRequests) { 1815 mBlockLayoutRequests = false; 1816 } 1817 } 1818 } 1819 1820 /** 1821 * @param child a direct child of this list. 1822 * @return Whether child is a header or footer view. 1823 */ 1824 private boolean isDirectChildHeaderOrFooter(View child) { 1825 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1826 final int numHeaders = headers.size(); 1827 for (int i = 0; i < numHeaders; i++) { 1828 if (child == headers.get(i).view) { 1829 return true; 1830 } 1831 } 1832 1833 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1834 final int numFooters = footers.size(); 1835 for (int i = 0; i < numFooters; i++) { 1836 if (child == footers.get(i).view) { 1837 return true; 1838 } 1839 } 1840 1841 return false; 1842 } 1843 1844 /** 1845 * Obtain the view and add it to our list of children. The view can be made 1846 * fresh, converted from an unused view, or used as is if it was in the 1847 * recycle bin. 1848 * 1849 * @param position Logical position in the list 1850 * @param y Top or bottom edge of the view to add 1851 * @param flow If flow is true, align top edge to y. If false, align bottom 1852 * edge to y. 1853 * @param childrenLeft Left edge where children should be positioned 1854 * @param selected Is this position selected? 1855 * @return View that was added 1856 */ 1857 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1858 boolean selected) { 1859 View child; 1860 1861 1862 if (!mDataChanged) { 1863 // Try to use an existing view for this position 1864 child = mRecycler.getActiveView(position); 1865 if (child != null) { 1866 // Found it -- we're using an existing child 1867 // This just needs to be positioned 1868 setupChild(child, position, y, flow, childrenLeft, selected, true); 1869 1870 return child; 1871 } 1872 } 1873 1874 // Make a new view for this position, or convert an unused view if possible 1875 child = obtainView(position, mIsScrap); 1876 1877 // This needs to be positioned and measured 1878 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1879 1880 return child; 1881 } 1882 1883 /** 1884 * Add a view as a child and make sure it is measured (if necessary) and 1885 * positioned properly. 1886 * 1887 * @param child The view to add 1888 * @param position The position of this child 1889 * @param y The y position relative to which this view will be positioned 1890 * @param flowDown If true, align top edge to y. If false, align bottom 1891 * edge to y. 1892 * @param childrenLeft Left edge where children should be positioned 1893 * @param selected Is this position selected? 1894 * @param recycled Has this view been pulled from the recycle bin? If so it 1895 * does not need to be remeasured. 1896 */ 1897 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1898 boolean selected, boolean recycled) { 1899 Trace.traceBegin(Trace.TRACE_TAG_VIEW, "setupListItem"); 1900 1901 final boolean isSelected = selected && shouldShowSelector(); 1902 final boolean updateChildSelected = isSelected != child.isSelected(); 1903 final int mode = mTouchMode; 1904 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1905 mMotionPosition == position; 1906 final boolean updateChildPressed = isPressed != child.isPressed(); 1907 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1908 1909 // Respect layout params that are already in the view. Otherwise make some up... 1910 // noinspection unchecked 1911 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1912 if (p == null) { 1913 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1914 } 1915 p.viewType = mAdapter.getItemViewType(position); 1916 1917 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter 1918 && p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1919 attachViewToParent(child, flowDown ? -1 : 0, p); 1920 } else { 1921 p.forceAdd = false; 1922 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1923 p.recycledHeaderFooter = true; 1924 } 1925 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1926 } 1927 1928 if (updateChildSelected) { 1929 child.setSelected(isSelected); 1930 } 1931 1932 if (updateChildPressed) { 1933 child.setPressed(isPressed); 1934 } 1935 1936 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1937 if (child instanceof Checkable) { 1938 ((Checkable) child).setChecked(mCheckStates.get(position)); 1939 } else if (getContext().getApplicationInfo().targetSdkVersion 1940 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1941 child.setActivated(mCheckStates.get(position)); 1942 } 1943 } 1944 1945 if (needToMeasure) { 1946 final int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1947 mListPadding.left + mListPadding.right, p.width); 1948 final int lpHeight = p.height; 1949 final int childHeightSpec; 1950 if (lpHeight > 0) { 1951 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1952 } else { 1953 childHeightSpec = MeasureSpec.makeSafeMeasureSpec(getMeasuredHeight(), 1954 MeasureSpec.UNSPECIFIED); 1955 } 1956 child.measure(childWidthSpec, childHeightSpec); 1957 } else { 1958 cleanupLayoutState(child); 1959 } 1960 1961 final int w = child.getMeasuredWidth(); 1962 final int h = child.getMeasuredHeight(); 1963 final int childTop = flowDown ? y : y - h; 1964 1965 if (needToMeasure) { 1966 final int childRight = childrenLeft + w; 1967 final int childBottom = childTop + h; 1968 child.layout(childrenLeft, childTop, childRight, childBottom); 1969 } else { 1970 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1971 child.offsetTopAndBottom(childTop - child.getTop()); 1972 } 1973 1974 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1975 child.setDrawingCacheEnabled(true); 1976 } 1977 1978 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1979 != position) { 1980 child.jumpDrawablesToCurrentState(); 1981 } 1982 1983 Trace.traceEnd(Trace.TRACE_TAG_VIEW); 1984 } 1985 1986 @Override 1987 protected boolean canAnimate() { 1988 return super.canAnimate() && mItemCount > 0; 1989 } 1990 1991 /** 1992 * Sets the currently selected item. If in touch mode, the item will not be selected 1993 * but it will still be positioned appropriately. If the specified selection position 1994 * is less than 0, then the item at position 0 will be selected. 1995 * 1996 * @param position Index (starting at 0) of the data item to be selected. 1997 */ 1998 @Override 1999 public void setSelection(int position) { 2000 setSelectionFromTop(position, 0); 2001 } 2002 2003 /** 2004 * Makes the item at the supplied position selected. 2005 * 2006 * @param position the position of the item to select 2007 */ 2008 @Override 2009 void setSelectionInt(int position) { 2010 setNextSelectedPositionInt(position); 2011 boolean awakeScrollbars = false; 2012 2013 final int selectedPosition = mSelectedPosition; 2014 2015 if (selectedPosition >= 0) { 2016 if (position == selectedPosition - 1) { 2017 awakeScrollbars = true; 2018 } else if (position == selectedPosition + 1) { 2019 awakeScrollbars = true; 2020 } 2021 } 2022 2023 if (mPositionScroller != null) { 2024 mPositionScroller.stop(); 2025 } 2026 2027 layoutChildren(); 2028 2029 if (awakeScrollbars) { 2030 awakenScrollBars(); 2031 } 2032 } 2033 2034 /** 2035 * Find a position that can be selected (i.e., is not a separator). 2036 * 2037 * @param position The starting position to look at. 2038 * @param lookDown Whether to look down for other positions. 2039 * @return The next selectable position starting at position and then searching either up or 2040 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 2041 */ 2042 @Override 2043 int lookForSelectablePosition(int position, boolean lookDown) { 2044 final ListAdapter adapter = mAdapter; 2045 if (adapter == null || isInTouchMode()) { 2046 return INVALID_POSITION; 2047 } 2048 2049 final int count = adapter.getCount(); 2050 if (!mAreAllItemsSelectable) { 2051 if (lookDown) { 2052 position = Math.max(0, position); 2053 while (position < count && !adapter.isEnabled(position)) { 2054 position++; 2055 } 2056 } else { 2057 position = Math.min(position, count - 1); 2058 while (position >= 0 && !adapter.isEnabled(position)) { 2059 position--; 2060 } 2061 } 2062 } 2063 2064 if (position < 0 || position >= count) { 2065 return INVALID_POSITION; 2066 } 2067 2068 return position; 2069 } 2070 2071 /** 2072 * Find a position that can be selected (i.e., is not a separator). If there 2073 * are no selectable positions in the specified direction from the starting 2074 * position, searches in the opposite direction from the starting position 2075 * to the current position. 2076 * 2077 * @param current the current position 2078 * @param position the starting position 2079 * @param lookDown whether to look down for other positions 2080 * @return the next selectable position, or {@link #INVALID_POSITION} if 2081 * nothing can be found 2082 */ 2083 int lookForSelectablePositionAfter(int current, int position, boolean lookDown) { 2084 final ListAdapter adapter = mAdapter; 2085 if (adapter == null || isInTouchMode()) { 2086 return INVALID_POSITION; 2087 } 2088 2089 // First check after the starting position in the specified direction. 2090 final int after = lookForSelectablePosition(position, lookDown); 2091 if (after != INVALID_POSITION) { 2092 return after; 2093 } 2094 2095 // Then check between the starting position and the current position. 2096 final int count = adapter.getCount(); 2097 current = MathUtils.constrain(current, -1, count - 1); 2098 if (lookDown) { 2099 position = Math.min(position - 1, count - 1); 2100 while ((position > current) && !adapter.isEnabled(position)) { 2101 position--; 2102 } 2103 if (position <= current) { 2104 return INVALID_POSITION; 2105 } 2106 } else { 2107 position = Math.max(0, position + 1); 2108 while ((position < current) && !adapter.isEnabled(position)) { 2109 position++; 2110 } 2111 if (position >= current) { 2112 return INVALID_POSITION; 2113 } 2114 } 2115 2116 return position; 2117 } 2118 2119 /** 2120 * setSelectionAfterHeaderView set the selection to be the first list item 2121 * after the header views. 2122 */ 2123 public void setSelectionAfterHeaderView() { 2124 final int count = mHeaderViewInfos.size(); 2125 if (count > 0) { 2126 mNextSelectedPosition = 0; 2127 return; 2128 } 2129 2130 if (mAdapter != null) { 2131 setSelection(count); 2132 } else { 2133 mNextSelectedPosition = count; 2134 mLayoutMode = LAYOUT_SET_SELECTION; 2135 } 2136 2137 } 2138 2139 @Override 2140 public boolean dispatchKeyEvent(KeyEvent event) { 2141 // Dispatch in the normal way 2142 boolean handled = super.dispatchKeyEvent(event); 2143 if (!handled) { 2144 // If we didn't handle it... 2145 View focused = getFocusedChild(); 2146 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2147 // ... and our focused child didn't handle it 2148 // ... give it to ourselves so we can scroll if necessary 2149 handled = onKeyDown(event.getKeyCode(), event); 2150 } 2151 } 2152 return handled; 2153 } 2154 2155 @Override 2156 public boolean onKeyDown(int keyCode, KeyEvent event) { 2157 return commonKey(keyCode, 1, event); 2158 } 2159 2160 @Override 2161 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2162 return commonKey(keyCode, repeatCount, event); 2163 } 2164 2165 @Override 2166 public boolean onKeyUp(int keyCode, KeyEvent event) { 2167 return commonKey(keyCode, 1, event); 2168 } 2169 2170 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2171 if (mAdapter == null || !isAttachedToWindow()) { 2172 return false; 2173 } 2174 2175 if (mDataChanged) { 2176 layoutChildren(); 2177 } 2178 2179 boolean handled = false; 2180 int action = event.getAction(); 2181 2182 if (action != KeyEvent.ACTION_UP) { 2183 switch (keyCode) { 2184 case KeyEvent.KEYCODE_DPAD_UP: 2185 if (event.hasNoModifiers()) { 2186 handled = resurrectSelectionIfNeeded(); 2187 if (!handled) { 2188 while (count-- > 0) { 2189 if (arrowScroll(FOCUS_UP)) { 2190 handled = true; 2191 } else { 2192 break; 2193 } 2194 } 2195 } 2196 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2197 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2198 } 2199 break; 2200 2201 case KeyEvent.KEYCODE_DPAD_DOWN: 2202 if (event.hasNoModifiers()) { 2203 handled = resurrectSelectionIfNeeded(); 2204 if (!handled) { 2205 while (count-- > 0) { 2206 if (arrowScroll(FOCUS_DOWN)) { 2207 handled = true; 2208 } else { 2209 break; 2210 } 2211 } 2212 } 2213 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2214 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2215 } 2216 break; 2217 2218 case KeyEvent.KEYCODE_DPAD_LEFT: 2219 if (event.hasNoModifiers()) { 2220 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2221 } 2222 break; 2223 2224 case KeyEvent.KEYCODE_DPAD_RIGHT: 2225 if (event.hasNoModifiers()) { 2226 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2227 } 2228 break; 2229 2230 case KeyEvent.KEYCODE_DPAD_CENTER: 2231 case KeyEvent.KEYCODE_ENTER: 2232 if (event.hasNoModifiers()) { 2233 handled = resurrectSelectionIfNeeded(); 2234 if (!handled 2235 && event.getRepeatCount() == 0 && getChildCount() > 0) { 2236 keyPressed(); 2237 handled = true; 2238 } 2239 } 2240 break; 2241 2242 case KeyEvent.KEYCODE_SPACE: 2243 if (mPopup == null || !mPopup.isShowing()) { 2244 if (event.hasNoModifiers()) { 2245 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2246 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2247 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2248 } 2249 handled = true; 2250 } 2251 break; 2252 2253 case KeyEvent.KEYCODE_PAGE_UP: 2254 if (event.hasNoModifiers()) { 2255 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2256 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2257 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2258 } 2259 break; 2260 2261 case KeyEvent.KEYCODE_PAGE_DOWN: 2262 if (event.hasNoModifiers()) { 2263 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2264 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2265 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2266 } 2267 break; 2268 2269 case KeyEvent.KEYCODE_MOVE_HOME: 2270 if (event.hasNoModifiers()) { 2271 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2272 } 2273 break; 2274 2275 case KeyEvent.KEYCODE_MOVE_END: 2276 if (event.hasNoModifiers()) { 2277 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2278 } 2279 break; 2280 2281 case KeyEvent.KEYCODE_TAB: 2282 // XXX Sometimes it is useful to be able to TAB through the items in 2283 // a ListView sequentially. Unfortunately this can create an 2284 // asymmetry in TAB navigation order unless the list selection 2285 // always reverts to the top or bottom when receiving TAB focus from 2286 // another widget. Leaving this behavior disabled for now but 2287 // perhaps it should be configurable (and more comprehensive). 2288 if (false) { 2289 if (event.hasNoModifiers()) { 2290 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_DOWN); 2291 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2292 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_UP); 2293 } 2294 } 2295 break; 2296 } 2297 } 2298 2299 if (handled) { 2300 return true; 2301 } 2302 2303 if (sendToTextFilter(keyCode, count, event)) { 2304 return true; 2305 } 2306 2307 switch (action) { 2308 case KeyEvent.ACTION_DOWN: 2309 return super.onKeyDown(keyCode, event); 2310 2311 case KeyEvent.ACTION_UP: 2312 return super.onKeyUp(keyCode, event); 2313 2314 case KeyEvent.ACTION_MULTIPLE: 2315 return super.onKeyMultiple(keyCode, count, event); 2316 2317 default: // shouldn't happen 2318 return false; 2319 } 2320 } 2321 2322 /** 2323 * Scrolls up or down by the number of items currently present on screen. 2324 * 2325 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2326 * @return whether selection was moved 2327 */ 2328 boolean pageScroll(int direction) { 2329 final int nextPage; 2330 final boolean down; 2331 2332 if (direction == FOCUS_UP) { 2333 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2334 down = false; 2335 } else if (direction == FOCUS_DOWN) { 2336 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2337 down = true; 2338 } else { 2339 return false; 2340 } 2341 2342 if (nextPage >= 0) { 2343 final int position = lookForSelectablePositionAfter(mSelectedPosition, nextPage, down); 2344 if (position >= 0) { 2345 mLayoutMode = LAYOUT_SPECIFIC; 2346 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2347 2348 if (down && (position > (mItemCount - getChildCount()))) { 2349 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2350 } 2351 2352 if (!down && (position < getChildCount())) { 2353 mLayoutMode = LAYOUT_FORCE_TOP; 2354 } 2355 2356 setSelectionInt(position); 2357 invokeOnItemScrollListener(); 2358 if (!awakenScrollBars()) { 2359 invalidate(); 2360 } 2361 2362 return true; 2363 } 2364 } 2365 2366 return false; 2367 } 2368 2369 /** 2370 * Go to the last or first item if possible (not worrying about panning 2371 * across or navigating within the internal focus of the currently selected 2372 * item.) 2373 * 2374 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2375 * @return whether selection was moved 2376 */ 2377 boolean fullScroll(int direction) { 2378 boolean moved = false; 2379 if (direction == FOCUS_UP) { 2380 if (mSelectedPosition != 0) { 2381 final int position = lookForSelectablePositionAfter(mSelectedPosition, 0, true); 2382 if (position >= 0) { 2383 mLayoutMode = LAYOUT_FORCE_TOP; 2384 setSelectionInt(position); 2385 invokeOnItemScrollListener(); 2386 } 2387 moved = true; 2388 } 2389 } else if (direction == FOCUS_DOWN) { 2390 final int lastItem = (mItemCount - 1); 2391 if (mSelectedPosition < lastItem) { 2392 final int position = lookForSelectablePositionAfter( 2393 mSelectedPosition, lastItem, false); 2394 if (position >= 0) { 2395 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2396 setSelectionInt(position); 2397 invokeOnItemScrollListener(); 2398 } 2399 moved = true; 2400 } 2401 } 2402 2403 if (moved && !awakenScrollBars()) { 2404 awakenScrollBars(); 2405 invalidate(); 2406 } 2407 2408 return moved; 2409 } 2410 2411 /** 2412 * To avoid horizontal focus searches changing the selected item, we 2413 * manually focus search within the selected item (as applicable), and 2414 * prevent focus from jumping to something within another item. 2415 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2416 * @return Whether this consumes the key event. 2417 */ 2418 private boolean handleHorizontalFocusWithinListItem(int direction) { 2419 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2420 throw new IllegalArgumentException("direction must be one of" 2421 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2422 } 2423 2424 final int numChildren = getChildCount(); 2425 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2426 final View selectedView = getSelectedView(); 2427 if (selectedView != null && selectedView.hasFocus() && 2428 selectedView instanceof ViewGroup) { 2429 2430 final View currentFocus = selectedView.findFocus(); 2431 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2432 (ViewGroup) selectedView, currentFocus, direction); 2433 if (nextFocus != null) { 2434 // do the math to get interesting rect in next focus' coordinates 2435 Rect focusedRect = mTempRect; 2436 if (currentFocus != null) { 2437 currentFocus.getFocusedRect(focusedRect); 2438 offsetDescendantRectToMyCoords(currentFocus, focusedRect); 2439 offsetRectIntoDescendantCoords(nextFocus, focusedRect); 2440 } else { 2441 focusedRect = null; 2442 } 2443 if (nextFocus.requestFocus(direction, focusedRect)) { 2444 return true; 2445 } 2446 } 2447 // we are blocking the key from being handled (by returning true) 2448 // if the global result is going to be some other view within this 2449 // list. this is to acheive the overall goal of having 2450 // horizontal d-pad navigation remain in the current item. 2451 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2452 (ViewGroup) getRootView(), currentFocus, direction); 2453 if (globalNextFocus != null) { 2454 return isViewAncestorOf(globalNextFocus, this); 2455 } 2456 } 2457 } 2458 return false; 2459 } 2460 2461 /** 2462 * Scrolls to the next or previous item if possible. 2463 * 2464 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2465 * 2466 * @return whether selection was moved 2467 */ 2468 boolean arrowScroll(int direction) { 2469 try { 2470 mInLayout = true; 2471 final boolean handled = arrowScrollImpl(direction); 2472 if (handled) { 2473 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2474 } 2475 return handled; 2476 } finally { 2477 mInLayout = false; 2478 } 2479 } 2480 2481 /** 2482 * Used by {@link #arrowScrollImpl(int)} to help determine the next selected position 2483 * to move to. This return a position in the direction given if the selected item 2484 * is fully visible. 2485 * 2486 * @param selectedView Current selected view to move from 2487 * @param selectedPos Current selected position to move from 2488 * @param direction Direction to move in 2489 * @return Desired selected position after moving in the given direction 2490 */ 2491 private final int nextSelectedPositionForDirection( 2492 View selectedView, int selectedPos, int direction) { 2493 int nextSelected; 2494 2495 if (direction == View.FOCUS_DOWN) { 2496 final int listBottom = getHeight() - mListPadding.bottom; 2497 if (selectedView != null && selectedView.getBottom() <= listBottom) { 2498 nextSelected = selectedPos != INVALID_POSITION && selectedPos >= mFirstPosition ? 2499 selectedPos + 1 : 2500 mFirstPosition; 2501 } else { 2502 return INVALID_POSITION; 2503 } 2504 } else { 2505 final int listTop = mListPadding.top; 2506 if (selectedView != null && selectedView.getTop() >= listTop) { 2507 final int lastPos = mFirstPosition + getChildCount() - 1; 2508 nextSelected = selectedPos != INVALID_POSITION && selectedPos <= lastPos ? 2509 selectedPos - 1 : 2510 lastPos; 2511 } else { 2512 return INVALID_POSITION; 2513 } 2514 } 2515 2516 if (nextSelected < 0 || nextSelected >= mAdapter.getCount()) { 2517 return INVALID_POSITION; 2518 } 2519 return lookForSelectablePosition(nextSelected, direction == View.FOCUS_DOWN); 2520 } 2521 2522 /** 2523 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2524 * whether there are focusable items etc. 2525 * 2526 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2527 * @return Whether any scrolling, selection or focus change occured. 2528 */ 2529 private boolean arrowScrollImpl(int direction) { 2530 if (getChildCount() <= 0) { 2531 return false; 2532 } 2533 2534 View selectedView = getSelectedView(); 2535 int selectedPos = mSelectedPosition; 2536 2537 int nextSelectedPosition = nextSelectedPositionForDirection(selectedView, selectedPos, direction); 2538 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2539 2540 // if we are moving focus, we may OVERRIDE the default behavior 2541 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2542 if (focusResult != null) { 2543 nextSelectedPosition = focusResult.getSelectedPosition(); 2544 amountToScroll = focusResult.getAmountToScroll(); 2545 } 2546 2547 boolean needToRedraw = focusResult != null; 2548 if (nextSelectedPosition != INVALID_POSITION) { 2549 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2550 setSelectedPositionInt(nextSelectedPosition); 2551 setNextSelectedPositionInt(nextSelectedPosition); 2552 selectedView = getSelectedView(); 2553 selectedPos = nextSelectedPosition; 2554 if (mItemsCanFocus && focusResult == null) { 2555 // there was no new view found to take focus, make sure we 2556 // don't leave focus with the old selection 2557 final View focused = getFocusedChild(); 2558 if (focused != null) { 2559 focused.clearFocus(); 2560 } 2561 } 2562 needToRedraw = true; 2563 checkSelectionChanged(); 2564 } 2565 2566 if (amountToScroll > 0) { 2567 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2568 needToRedraw = true; 2569 } 2570 2571 // if we didn't find a new focusable, make sure any existing focused 2572 // item that was panned off screen gives up focus. 2573 if (mItemsCanFocus && (focusResult == null) 2574 && selectedView != null && selectedView.hasFocus()) { 2575 final View focused = selectedView.findFocus(); 2576 if (focused != null) { 2577 if (!isViewAncestorOf(focused, this) || distanceToView(focused) > 0) { 2578 focused.clearFocus(); 2579 } 2580 } 2581 } 2582 2583 // if the current selection is panned off, we need to remove the selection 2584 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2585 && !isViewAncestorOf(selectedView, this)) { 2586 selectedView = null; 2587 hideSelector(); 2588 2589 // but we don't want to set the ressurect position (that would make subsequent 2590 // unhandled key events bring back the item we just scrolled off!) 2591 mResurrectToPosition = INVALID_POSITION; 2592 } 2593 2594 if (needToRedraw) { 2595 if (selectedView != null) { 2596 positionSelectorLikeFocus(selectedPos, selectedView); 2597 mSelectedTop = selectedView.getTop(); 2598 } 2599 if (!awakenScrollBars()) { 2600 invalidate(); 2601 } 2602 invokeOnItemScrollListener(); 2603 return true; 2604 } 2605 2606 return false; 2607 } 2608 2609 /** 2610 * When selection changes, it is possible that the previously selected or the 2611 * next selected item will change its size. If so, we need to offset some folks, 2612 * and re-layout the items as appropriate. 2613 * 2614 * @param selectedView The currently selected view (before changing selection). 2615 * should be <code>null</code> if there was no previous selection. 2616 * @param direction Either {@link android.view.View#FOCUS_UP} or 2617 * {@link android.view.View#FOCUS_DOWN}. 2618 * @param newSelectedPosition The position of the next selection. 2619 * @param newFocusAssigned whether new focus was assigned. This matters because 2620 * when something has focus, we don't want to show selection (ugh). 2621 */ 2622 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2623 boolean newFocusAssigned) { 2624 if (newSelectedPosition == INVALID_POSITION) { 2625 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2626 } 2627 2628 // whether or not we are moving down or up, we want to preserve the 2629 // top of whatever view is on top: 2630 // - moving down: the view that had selection 2631 // - moving up: the view that is getting selection 2632 View topView; 2633 View bottomView; 2634 int topViewIndex, bottomViewIndex; 2635 boolean topSelected = false; 2636 final int selectedIndex = mSelectedPosition - mFirstPosition; 2637 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2638 if (direction == View.FOCUS_UP) { 2639 topViewIndex = nextSelectedIndex; 2640 bottomViewIndex = selectedIndex; 2641 topView = getChildAt(topViewIndex); 2642 bottomView = selectedView; 2643 topSelected = true; 2644 } else { 2645 topViewIndex = selectedIndex; 2646 bottomViewIndex = nextSelectedIndex; 2647 topView = selectedView; 2648 bottomView = getChildAt(bottomViewIndex); 2649 } 2650 2651 final int numChildren = getChildCount(); 2652 2653 // start with top view: is it changing size? 2654 if (topView != null) { 2655 topView.setSelected(!newFocusAssigned && topSelected); 2656 measureAndAdjustDown(topView, topViewIndex, numChildren); 2657 } 2658 2659 // is the bottom view changing size? 2660 if (bottomView != null) { 2661 bottomView.setSelected(!newFocusAssigned && !topSelected); 2662 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2663 } 2664 } 2665 2666 /** 2667 * Re-measure a child, and if its height changes, lay it out preserving its 2668 * top, and adjust the children below it appropriately. 2669 * @param child The child 2670 * @param childIndex The view group index of the child. 2671 * @param numChildren The number of children in the view group. 2672 */ 2673 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2674 int oldHeight = child.getHeight(); 2675 measureItem(child); 2676 if (child.getMeasuredHeight() != oldHeight) { 2677 // lay out the view, preserving its top 2678 relayoutMeasuredItem(child); 2679 2680 // adjust views below appropriately 2681 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2682 for (int i = childIndex + 1; i < numChildren; i++) { 2683 getChildAt(i).offsetTopAndBottom(heightDelta); 2684 } 2685 } 2686 } 2687 2688 /** 2689 * Measure a particular list child. 2690 * TODO: unify with setUpChild. 2691 * @param child The child. 2692 */ 2693 private void measureItem(View child) { 2694 ViewGroup.LayoutParams p = child.getLayoutParams(); 2695 if (p == null) { 2696 p = new ViewGroup.LayoutParams( 2697 ViewGroup.LayoutParams.MATCH_PARENT, 2698 ViewGroup.LayoutParams.WRAP_CONTENT); 2699 } 2700 2701 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2702 mListPadding.left + mListPadding.right, p.width); 2703 int lpHeight = p.height; 2704 int childHeightSpec; 2705 if (lpHeight > 0) { 2706 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2707 } else { 2708 childHeightSpec = MeasureSpec.makeSafeMeasureSpec(getMeasuredHeight(), 2709 MeasureSpec.UNSPECIFIED); 2710 } 2711 child.measure(childWidthSpec, childHeightSpec); 2712 } 2713 2714 /** 2715 * Layout a child that has been measured, preserving its top position. 2716 * TODO: unify with setUpChild. 2717 * @param child The child. 2718 */ 2719 private void relayoutMeasuredItem(View child) { 2720 final int w = child.getMeasuredWidth(); 2721 final int h = child.getMeasuredHeight(); 2722 final int childLeft = mListPadding.left; 2723 final int childRight = childLeft + w; 2724 final int childTop = child.getTop(); 2725 final int childBottom = childTop + h; 2726 child.layout(childLeft, childTop, childRight, childBottom); 2727 } 2728 2729 /** 2730 * @return The amount to preview next items when arrow srolling. 2731 */ 2732 private int getArrowScrollPreviewLength() { 2733 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2734 } 2735 2736 /** 2737 * Determine how much we need to scroll in order to get the next selected view 2738 * visible, with a fading edge showing below as applicable. The amount is 2739 * capped at {@link #getMaxScrollAmount()} . 2740 * 2741 * @param direction either {@link android.view.View#FOCUS_UP} or 2742 * {@link android.view.View#FOCUS_DOWN}. 2743 * @param nextSelectedPosition The position of the next selection, or 2744 * {@link #INVALID_POSITION} if there is no next selectable position 2745 * @return The amount to scroll. Note: this is always positive! Direction 2746 * needs to be taken into account when actually scrolling. 2747 */ 2748 private int amountToScroll(int direction, int nextSelectedPosition) { 2749 final int listBottom = getHeight() - mListPadding.bottom; 2750 final int listTop = mListPadding.top; 2751 2752 int numChildren = getChildCount(); 2753 2754 if (direction == View.FOCUS_DOWN) { 2755 int indexToMakeVisible = numChildren - 1; 2756 if (nextSelectedPosition != INVALID_POSITION) { 2757 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2758 } 2759 while (numChildren <= indexToMakeVisible) { 2760 // Child to view is not attached yet. 2761 addViewBelow(getChildAt(numChildren - 1), mFirstPosition + numChildren - 1); 2762 numChildren++; 2763 } 2764 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2765 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2766 2767 int goalBottom = listBottom; 2768 if (positionToMakeVisible < mItemCount - 1) { 2769 goalBottom -= getArrowScrollPreviewLength(); 2770 } 2771 2772 if (viewToMakeVisible.getBottom() <= goalBottom) { 2773 // item is fully visible. 2774 return 0; 2775 } 2776 2777 if (nextSelectedPosition != INVALID_POSITION 2778 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2779 // item already has enough of it visible, changing selection is good enough 2780 return 0; 2781 } 2782 2783 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2784 2785 if ((mFirstPosition + numChildren) == mItemCount) { 2786 // last is last in list -> make sure we don't scroll past it 2787 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2788 amountToScroll = Math.min(amountToScroll, max); 2789 } 2790 2791 return Math.min(amountToScroll, getMaxScrollAmount()); 2792 } else { 2793 int indexToMakeVisible = 0; 2794 if (nextSelectedPosition != INVALID_POSITION) { 2795 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2796 } 2797 while (indexToMakeVisible < 0) { 2798 // Child to view is not attached yet. 2799 addViewAbove(getChildAt(0), mFirstPosition); 2800 mFirstPosition--; 2801 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2802 } 2803 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2804 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2805 int goalTop = listTop; 2806 if (positionToMakeVisible > 0) { 2807 goalTop += getArrowScrollPreviewLength(); 2808 } 2809 if (viewToMakeVisible.getTop() >= goalTop) { 2810 // item is fully visible. 2811 return 0; 2812 } 2813 2814 if (nextSelectedPosition != INVALID_POSITION && 2815 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2816 // item already has enough of it visible, changing selection is good enough 2817 return 0; 2818 } 2819 2820 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2821 if (mFirstPosition == 0) { 2822 // first is first in list -> make sure we don't scroll past it 2823 final int max = listTop - getChildAt(0).getTop(); 2824 amountToScroll = Math.min(amountToScroll, max); 2825 } 2826 return Math.min(amountToScroll, getMaxScrollAmount()); 2827 } 2828 } 2829 2830 /** 2831 * Holds results of focus aware arrow scrolling. 2832 */ 2833 static private class ArrowScrollFocusResult { 2834 private int mSelectedPosition; 2835 private int mAmountToScroll; 2836 2837 /** 2838 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2839 */ 2840 void populate(int selectedPosition, int amountToScroll) { 2841 mSelectedPosition = selectedPosition; 2842 mAmountToScroll = amountToScroll; 2843 } 2844 2845 public int getSelectedPosition() { 2846 return mSelectedPosition; 2847 } 2848 2849 public int getAmountToScroll() { 2850 return mAmountToScroll; 2851 } 2852 } 2853 2854 /** 2855 * @param direction either {@link android.view.View#FOCUS_UP} or 2856 * {@link android.view.View#FOCUS_DOWN}. 2857 * @return The position of the next selectable position of the views that 2858 * are currently visible, taking into account the fact that there might 2859 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2860 * selectable view on screen in the given direction. 2861 */ 2862 private int lookForSelectablePositionOnScreen(int direction) { 2863 final int firstPosition = mFirstPosition; 2864 if (direction == View.FOCUS_DOWN) { 2865 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2866 mSelectedPosition + 1 : 2867 firstPosition; 2868 if (startPos >= mAdapter.getCount()) { 2869 return INVALID_POSITION; 2870 } 2871 if (startPos < firstPosition) { 2872 startPos = firstPosition; 2873 } 2874 2875 final int lastVisiblePos = getLastVisiblePosition(); 2876 final ListAdapter adapter = getAdapter(); 2877 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2878 if (adapter.isEnabled(pos) 2879 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2880 return pos; 2881 } 2882 } 2883 } else { 2884 int last = firstPosition + getChildCount() - 1; 2885 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2886 mSelectedPosition - 1 : 2887 firstPosition + getChildCount() - 1; 2888 if (startPos < 0 || startPos >= mAdapter.getCount()) { 2889 return INVALID_POSITION; 2890 } 2891 if (startPos > last) { 2892 startPos = last; 2893 } 2894 2895 final ListAdapter adapter = getAdapter(); 2896 for (int pos = startPos; pos >= firstPosition; pos--) { 2897 if (adapter.isEnabled(pos) 2898 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2899 return pos; 2900 } 2901 } 2902 } 2903 return INVALID_POSITION; 2904 } 2905 2906 /** 2907 * Do an arrow scroll based on focus searching. If a new view is 2908 * given focus, return the selection delta and amount to scroll via 2909 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2910 * 2911 * @param direction either {@link android.view.View#FOCUS_UP} or 2912 * {@link android.view.View#FOCUS_DOWN}. 2913 * @return The result if focus has changed, or <code>null</code>. 2914 */ 2915 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2916 final View selectedView = getSelectedView(); 2917 View newFocus; 2918 if (selectedView != null && selectedView.hasFocus()) { 2919 View oldFocus = selectedView.findFocus(); 2920 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2921 } else { 2922 if (direction == View.FOCUS_DOWN) { 2923 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2924 final int listTop = mListPadding.top + 2925 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2926 final int ySearchPoint = 2927 (selectedView != null && selectedView.getTop() > listTop) ? 2928 selectedView.getTop() : 2929 listTop; 2930 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2931 } else { 2932 final boolean bottomFadingEdgeShowing = 2933 (mFirstPosition + getChildCount() - 1) < mItemCount; 2934 final int listBottom = getHeight() - mListPadding.bottom - 2935 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2936 final int ySearchPoint = 2937 (selectedView != null && selectedView.getBottom() < listBottom) ? 2938 selectedView.getBottom() : 2939 listBottom; 2940 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2941 } 2942 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2943 } 2944 2945 if (newFocus != null) { 2946 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2947 2948 // if the focus change is in a different new position, make sure 2949 // we aren't jumping over another selectable position 2950 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2951 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2952 if (selectablePosition != INVALID_POSITION && 2953 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2954 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2955 return null; 2956 } 2957 } 2958 2959 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2960 2961 final int maxScrollAmount = getMaxScrollAmount(); 2962 if (focusScroll < maxScrollAmount) { 2963 // not moving too far, safe to give next view focus 2964 newFocus.requestFocus(direction); 2965 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2966 return mArrowScrollFocusResult; 2967 } else if (distanceToView(newFocus) < maxScrollAmount){ 2968 // Case to consider: 2969 // too far to get entire next focusable on screen, but by going 2970 // max scroll amount, we are getting it at least partially in view, 2971 // so give it focus and scroll the max ammount. 2972 newFocus.requestFocus(direction); 2973 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2974 return mArrowScrollFocusResult; 2975 } 2976 } 2977 return null; 2978 } 2979 2980 /** 2981 * @param newFocus The view that would have focus. 2982 * @return the position that contains newFocus 2983 */ 2984 private int positionOfNewFocus(View newFocus) { 2985 final int numChildren = getChildCount(); 2986 for (int i = 0; i < numChildren; i++) { 2987 final View child = getChildAt(i); 2988 if (isViewAncestorOf(newFocus, child)) { 2989 return mFirstPosition + i; 2990 } 2991 } 2992 throw new IllegalArgumentException("newFocus is not a child of any of the" 2993 + " children of the list!"); 2994 } 2995 2996 /** 2997 * Return true if child is an ancestor of parent, (or equal to the parent). 2998 */ 2999 private boolean isViewAncestorOf(View child, View parent) { 3000 if (child == parent) { 3001 return true; 3002 } 3003 3004 final ViewParent theParent = child.getParent(); 3005 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 3006 } 3007 3008 /** 3009 * Determine how much we need to scroll in order to get newFocus in view. 3010 * @param direction either {@link android.view.View#FOCUS_UP} or 3011 * {@link android.view.View#FOCUS_DOWN}. 3012 * @param newFocus The view that would take focus. 3013 * @param positionOfNewFocus The position of the list item containing newFocus 3014 * @return The amount to scroll. Note: this is always positive! Direction 3015 * needs to be taken into account when actually scrolling. 3016 */ 3017 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 3018 int amountToScroll = 0; 3019 newFocus.getDrawingRect(mTempRect); 3020 offsetDescendantRectToMyCoords(newFocus, mTempRect); 3021 if (direction == View.FOCUS_UP) { 3022 if (mTempRect.top < mListPadding.top) { 3023 amountToScroll = mListPadding.top - mTempRect.top; 3024 if (positionOfNewFocus > 0) { 3025 amountToScroll += getArrowScrollPreviewLength(); 3026 } 3027 } 3028 } else { 3029 final int listBottom = getHeight() - mListPadding.bottom; 3030 if (mTempRect.bottom > listBottom) { 3031 amountToScroll = mTempRect.bottom - listBottom; 3032 if (positionOfNewFocus < mItemCount - 1) { 3033 amountToScroll += getArrowScrollPreviewLength(); 3034 } 3035 } 3036 } 3037 return amountToScroll; 3038 } 3039 3040 /** 3041 * Determine the distance to the nearest edge of a view in a particular 3042 * direction. 3043 * 3044 * @param descendant A descendant of this list. 3045 * @return The distance, or 0 if the nearest edge is already on screen. 3046 */ 3047 private int distanceToView(View descendant) { 3048 int distance = 0; 3049 descendant.getDrawingRect(mTempRect); 3050 offsetDescendantRectToMyCoords(descendant, mTempRect); 3051 final int listBottom = mBottom - mTop - mListPadding.bottom; 3052 if (mTempRect.bottom < mListPadding.top) { 3053 distance = mListPadding.top - mTempRect.bottom; 3054 } else if (mTempRect.top > listBottom) { 3055 distance = mTempRect.top - listBottom; 3056 } 3057 return distance; 3058 } 3059 3060 3061 /** 3062 * Scroll the children by amount, adding a view at the end and removing 3063 * views that fall off as necessary. 3064 * 3065 * @param amount The amount (positive or negative) to scroll. 3066 */ 3067 private void scrollListItemsBy(int amount) { 3068 offsetChildrenTopAndBottom(amount); 3069 3070 final int listBottom = getHeight() - mListPadding.bottom; 3071 final int listTop = mListPadding.top; 3072 final AbsListView.RecycleBin recycleBin = mRecycler; 3073 3074 if (amount < 0) { 3075 // shifted items up 3076 3077 // may need to pan views into the bottom space 3078 int numChildren = getChildCount(); 3079 View last = getChildAt(numChildren - 1); 3080 while (last.getBottom() < listBottom) { 3081 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 3082 if (lastVisiblePosition < mItemCount - 1) { 3083 last = addViewBelow(last, lastVisiblePosition); 3084 numChildren++; 3085 } else { 3086 break; 3087 } 3088 } 3089 3090 // may have brought in the last child of the list that is skinnier 3091 // than the fading edge, thereby leaving space at the end. need 3092 // to shift back 3093 if (last.getBottom() < listBottom) { 3094 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 3095 } 3096 3097 // top views may be panned off screen 3098 View first = getChildAt(0); 3099 while (first.getBottom() < listTop) { 3100 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 3101 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3102 recycleBin.addScrapView(first, mFirstPosition); 3103 } 3104 detachViewFromParent(first); 3105 first = getChildAt(0); 3106 mFirstPosition++; 3107 } 3108 } else { 3109 // shifted items down 3110 View first = getChildAt(0); 3111 3112 // may need to pan views into top 3113 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 3114 first = addViewAbove(first, mFirstPosition); 3115 mFirstPosition--; 3116 } 3117 3118 // may have brought the very first child of the list in too far and 3119 // need to shift it back 3120 if (first.getTop() > listTop) { 3121 offsetChildrenTopAndBottom(listTop - first.getTop()); 3122 } 3123 3124 int lastIndex = getChildCount() - 1; 3125 View last = getChildAt(lastIndex); 3126 3127 // bottom view may be panned off screen 3128 while (last.getTop() > listBottom) { 3129 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 3130 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3131 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 3132 } 3133 detachViewFromParent(last); 3134 last = getChildAt(--lastIndex); 3135 } 3136 } 3137 } 3138 3139 private View addViewAbove(View theView, int position) { 3140 int abovePosition = position - 1; 3141 View view = obtainView(abovePosition, mIsScrap); 3142 int edgeOfNewChild = theView.getTop() - mDividerHeight; 3143 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 3144 false, mIsScrap[0]); 3145 return view; 3146 } 3147 3148 private View addViewBelow(View theView, int position) { 3149 int belowPosition = position + 1; 3150 View view = obtainView(belowPosition, mIsScrap); 3151 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 3152 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 3153 false, mIsScrap[0]); 3154 return view; 3155 } 3156 3157 /** 3158 * Indicates that the views created by the ListAdapter can contain focusable 3159 * items. 3160 * 3161 * @param itemsCanFocus true if items can get focus, false otherwise 3162 */ 3163 public void setItemsCanFocus(boolean itemsCanFocus) { 3164 mItemsCanFocus = itemsCanFocus; 3165 if (!itemsCanFocus) { 3166 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 3167 } 3168 } 3169 3170 /** 3171 * @return Whether the views created by the ListAdapter can contain focusable 3172 * items. 3173 */ 3174 public boolean getItemsCanFocus() { 3175 return mItemsCanFocus; 3176 } 3177 3178 @Override 3179 public boolean isOpaque() { 3180 boolean retValue = (mCachingActive && mIsCacheColorOpaque && mDividerIsOpaque && 3181 hasOpaqueScrollbars()) || super.isOpaque(); 3182 if (retValue) { 3183 // only return true if the list items cover the entire area of the view 3184 final int listTop = mListPadding != null ? mListPadding.top : mPaddingTop; 3185 View first = getChildAt(0); 3186 if (first == null || first.getTop() > listTop) { 3187 return false; 3188 } 3189 final int listBottom = getHeight() - 3190 (mListPadding != null ? mListPadding.bottom : mPaddingBottom); 3191 View last = getChildAt(getChildCount() - 1); 3192 if (last == null || last.getBottom() < listBottom) { 3193 return false; 3194 } 3195 } 3196 return retValue; 3197 } 3198 3199 @Override 3200 public void setCacheColorHint(int color) { 3201 final boolean opaque = (color >>> 24) == 0xFF; 3202 mIsCacheColorOpaque = opaque; 3203 if (opaque) { 3204 if (mDividerPaint == null) { 3205 mDividerPaint = new Paint(); 3206 } 3207 mDividerPaint.setColor(color); 3208 } 3209 super.setCacheColorHint(color); 3210 } 3211 3212 void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) { 3213 final int height = drawable.getMinimumHeight(); 3214 3215 canvas.save(); 3216 canvas.clipRect(bounds); 3217 3218 final int span = bounds.bottom - bounds.top; 3219 if (span < height) { 3220 bounds.top = bounds.bottom - height; 3221 } 3222 3223 drawable.setBounds(bounds); 3224 drawable.draw(canvas); 3225 3226 canvas.restore(); 3227 } 3228 3229 void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) { 3230 final int height = drawable.getMinimumHeight(); 3231 3232 canvas.save(); 3233 canvas.clipRect(bounds); 3234 3235 final int span = bounds.bottom - bounds.top; 3236 if (span < height) { 3237 bounds.bottom = bounds.top + height; 3238 } 3239 3240 drawable.setBounds(bounds); 3241 drawable.draw(canvas); 3242 3243 canvas.restore(); 3244 } 3245 3246 @Override 3247 protected void dispatchDraw(Canvas canvas) { 3248 if (mCachingStarted) { 3249 mCachingActive = true; 3250 } 3251 3252 // Draw the dividers 3253 final int dividerHeight = mDividerHeight; 3254 final Drawable overscrollHeader = mOverScrollHeader; 3255 final Drawable overscrollFooter = mOverScrollFooter; 3256 final boolean drawOverscrollHeader = overscrollHeader != null; 3257 final boolean drawOverscrollFooter = overscrollFooter != null; 3258 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3259 3260 if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) { 3261 // Only modify the top and bottom in the loop, we set the left and right here 3262 final Rect bounds = mTempRect; 3263 bounds.left = mPaddingLeft; 3264 bounds.right = mRight - mLeft - mPaddingRight; 3265 3266 final int count = getChildCount(); 3267 final int headerCount = mHeaderViewInfos.size(); 3268 final int itemCount = mItemCount; 3269 final int footerLimit = (itemCount - mFooterViewInfos.size()); 3270 final boolean headerDividers = mHeaderDividersEnabled; 3271 final boolean footerDividers = mFooterDividersEnabled; 3272 final int first = mFirstPosition; 3273 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 3274 final ListAdapter adapter = mAdapter; 3275 // If the list is opaque *and* the background is not, we want to 3276 // fill a rect where the dividers would be for non-selectable items 3277 // If the list is opaque and the background is also opaque, we don't 3278 // need to draw anything since the background will do it for us 3279 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3280 3281 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 3282 mDividerPaint = new Paint(); 3283 mDividerPaint.setColor(getCacheColorHint()); 3284 } 3285 final Paint paint = mDividerPaint; 3286 3287 int effectivePaddingTop = 0; 3288 int effectivePaddingBottom = 0; 3289 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 3290 effectivePaddingTop = mListPadding.top; 3291 effectivePaddingBottom = mListPadding.bottom; 3292 } 3293 3294 final int listBottom = mBottom - mTop - effectivePaddingBottom + mScrollY; 3295 if (!mStackFromBottom) { 3296 int bottom = 0; 3297 3298 // Draw top divider or header for overscroll 3299 final int scrollY = mScrollY; 3300 if (count > 0 && scrollY < 0) { 3301 if (drawOverscrollHeader) { 3302 bounds.bottom = 0; 3303 bounds.top = scrollY; 3304 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3305 } else if (drawDividers) { 3306 bounds.bottom = 0; 3307 bounds.top = -dividerHeight; 3308 drawDivider(canvas, bounds, -1); 3309 } 3310 } 3311 3312 for (int i = 0; i < count; i++) { 3313 final int itemIndex = (first + i); 3314 final boolean isHeader = (itemIndex < headerCount); 3315 final boolean isFooter = (itemIndex >= footerLimit); 3316 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3317 final View child = getChildAt(i); 3318 bottom = child.getBottom(); 3319 final boolean isLastItem = (i == (count - 1)); 3320 3321 if (drawDividers && (bottom < listBottom) 3322 && !(drawOverscrollFooter && isLastItem)) { 3323 final int nextIndex = (itemIndex + 1); 3324 // Draw dividers between enabled items, headers 3325 // and/or footers when enabled and requested, and 3326 // after the last enabled item. 3327 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3328 && (nextIndex >= headerCount)) && (isLastItem 3329 || adapter.isEnabled(nextIndex) && (footerDividers || !isFooter 3330 && (nextIndex < footerLimit)))) { 3331 bounds.top = bottom; 3332 bounds.bottom = bottom + dividerHeight; 3333 drawDivider(canvas, bounds, i); 3334 } else if (fillForMissingDividers) { 3335 bounds.top = bottom; 3336 bounds.bottom = bottom + dividerHeight; 3337 canvas.drawRect(bounds, paint); 3338 } 3339 } 3340 } 3341 } 3342 3343 final int overFooterBottom = mBottom + mScrollY; 3344 if (drawOverscrollFooter && first + count == itemCount && 3345 overFooterBottom > bottom) { 3346 bounds.top = bottom; 3347 bounds.bottom = overFooterBottom; 3348 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3349 } 3350 } else { 3351 int top; 3352 3353 final int scrollY = mScrollY; 3354 3355 if (count > 0 && drawOverscrollHeader) { 3356 bounds.top = scrollY; 3357 bounds.bottom = getChildAt(0).getTop(); 3358 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3359 } 3360 3361 final int start = drawOverscrollHeader ? 1 : 0; 3362 for (int i = start; i < count; i++) { 3363 final int itemIndex = (first + i); 3364 final boolean isHeader = (itemIndex < headerCount); 3365 final boolean isFooter = (itemIndex >= footerLimit); 3366 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3367 final View child = getChildAt(i); 3368 top = child.getTop(); 3369 if (drawDividers && (top > effectivePaddingTop)) { 3370 final boolean isFirstItem = (i == start); 3371 final int previousIndex = (itemIndex - 1); 3372 // Draw dividers between enabled items, headers 3373 // and/or footers when enabled and requested, and 3374 // before the first enabled item. 3375 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3376 && (previousIndex >= headerCount)) && (isFirstItem || 3377 adapter.isEnabled(previousIndex) && (footerDividers || !isFooter 3378 && (previousIndex < footerLimit)))) { 3379 bounds.top = top - dividerHeight; 3380 bounds.bottom = top; 3381 // Give the method the child ABOVE the divider, 3382 // so we subtract one from our child position. 3383 // Give -1 when there is no child above the 3384 // divider. 3385 drawDivider(canvas, bounds, i - 1); 3386 } else if (fillForMissingDividers) { 3387 bounds.top = top - dividerHeight; 3388 bounds.bottom = top; 3389 canvas.drawRect(bounds, paint); 3390 } 3391 } 3392 } 3393 } 3394 3395 if (count > 0 && scrollY > 0) { 3396 if (drawOverscrollFooter) { 3397 final int absListBottom = mBottom; 3398 bounds.top = absListBottom; 3399 bounds.bottom = absListBottom + scrollY; 3400 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3401 } else if (drawDividers) { 3402 bounds.top = listBottom; 3403 bounds.bottom = listBottom + dividerHeight; 3404 drawDivider(canvas, bounds, -1); 3405 } 3406 } 3407 } 3408 } 3409 3410 // Draw the indicators (these should be drawn above the dividers) and children 3411 super.dispatchDraw(canvas); 3412 } 3413 3414 @Override 3415 protected boolean drawChild(Canvas canvas, View child, long drawingTime) { 3416 boolean more = super.drawChild(canvas, child, drawingTime); 3417 if (mCachingActive && child.mCachingFailed) { 3418 mCachingActive = false; 3419 } 3420 return more; 3421 } 3422 3423 /** 3424 * Draws a divider for the given child in the given bounds. 3425 * 3426 * @param canvas The canvas to draw to. 3427 * @param bounds The bounds of the divider. 3428 * @param childIndex The index of child (of the View) above the divider. 3429 * This will be -1 if there is no child above the divider to be 3430 * drawn. 3431 */ 3432 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3433 // This widget draws the same divider for all children 3434 final Drawable divider = mDivider; 3435 3436 divider.setBounds(bounds); 3437 divider.draw(canvas); 3438 } 3439 3440 /** 3441 * Returns the drawable that will be drawn between each item in the list. 3442 * 3443 * @return the current drawable drawn between list elements 3444 * @attr ref R.styleable#ListView_divider 3445 */ 3446 @Nullable 3447 public Drawable getDivider() { 3448 return mDivider; 3449 } 3450 3451 /** 3452 * Sets the drawable that will be drawn between each item in the list. 3453 * <p> 3454 * <strong>Note:</strong> If the drawable does not have an intrinsic 3455 * height, you should also call {@link #setDividerHeight(int)}. 3456 * 3457 * @param divider the drawable to use 3458 * @attr ref R.styleable#ListView_divider 3459 */ 3460 public void setDivider(@Nullable Drawable divider) { 3461 if (divider != null) { 3462 mDividerHeight = divider.getIntrinsicHeight(); 3463 } else { 3464 mDividerHeight = 0; 3465 } 3466 mDivider = divider; 3467 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3468 requestLayout(); 3469 invalidate(); 3470 } 3471 3472 /** 3473 * @return Returns the height of the divider that will be drawn between each item in the list. 3474 */ 3475 public int getDividerHeight() { 3476 return mDividerHeight; 3477 } 3478 3479 /** 3480 * Sets the height of the divider that will be drawn between each item in the list. Calling 3481 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3482 * 3483 * @param height The new height of the divider in pixels. 3484 */ 3485 public void setDividerHeight(int height) { 3486 mDividerHeight = height; 3487 requestLayout(); 3488 invalidate(); 3489 } 3490 3491 /** 3492 * Enables or disables the drawing of the divider for header views. 3493 * 3494 * @param headerDividersEnabled True to draw the headers, false otherwise. 3495 * 3496 * @see #setFooterDividersEnabled(boolean) 3497 * @see #areHeaderDividersEnabled() 3498 * @see #addHeaderView(android.view.View) 3499 */ 3500 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3501 mHeaderDividersEnabled = headerDividersEnabled; 3502 invalidate(); 3503 } 3504 3505 /** 3506 * @return Whether the drawing of the divider for header views is enabled 3507 * 3508 * @see #setHeaderDividersEnabled(boolean) 3509 */ 3510 public boolean areHeaderDividersEnabled() { 3511 return mHeaderDividersEnabled; 3512 } 3513 3514 /** 3515 * Enables or disables the drawing of the divider for footer views. 3516 * 3517 * @param footerDividersEnabled True to draw the footers, false otherwise. 3518 * 3519 * @see #setHeaderDividersEnabled(boolean) 3520 * @see #areFooterDividersEnabled() 3521 * @see #addFooterView(android.view.View) 3522 */ 3523 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3524 mFooterDividersEnabled = footerDividersEnabled; 3525 invalidate(); 3526 } 3527 3528 /** 3529 * @return Whether the drawing of the divider for footer views is enabled 3530 * 3531 * @see #setFooterDividersEnabled(boolean) 3532 */ 3533 public boolean areFooterDividersEnabled() { 3534 return mFooterDividersEnabled; 3535 } 3536 3537 /** 3538 * Sets the drawable that will be drawn above all other list content. 3539 * This area can become visible when the user overscrolls the list. 3540 * 3541 * @param header The drawable to use 3542 */ 3543 public void setOverscrollHeader(Drawable header) { 3544 mOverScrollHeader = header; 3545 if (mScrollY < 0) { 3546 invalidate(); 3547 } 3548 } 3549 3550 /** 3551 * @return The drawable that will be drawn above all other list content 3552 */ 3553 public Drawable getOverscrollHeader() { 3554 return mOverScrollHeader; 3555 } 3556 3557 /** 3558 * Sets the drawable that will be drawn below all other list content. 3559 * This area can become visible when the user overscrolls the list, 3560 * or when the list's content does not fully fill the container area. 3561 * 3562 * @param footer The drawable to use 3563 */ 3564 public void setOverscrollFooter(Drawable footer) { 3565 mOverScrollFooter = footer; 3566 invalidate(); 3567 } 3568 3569 /** 3570 * @return The drawable that will be drawn below all other list content 3571 */ 3572 public Drawable getOverscrollFooter() { 3573 return mOverScrollFooter; 3574 } 3575 3576 @Override 3577 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3578 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3579 3580 final ListAdapter adapter = mAdapter; 3581 int closetChildIndex = -1; 3582 int closestChildTop = 0; 3583 if (adapter != null && gainFocus && previouslyFocusedRect != null) { 3584 previouslyFocusedRect.offset(mScrollX, mScrollY); 3585 3586 // Don't cache the result of getChildCount or mFirstPosition here, 3587 // it could change in layoutChildren. 3588 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3589 mLayoutMode = LAYOUT_NORMAL; 3590 layoutChildren(); 3591 } 3592 3593 // figure out which item should be selected based on previously 3594 // focused rect 3595 Rect otherRect = mTempRect; 3596 int minDistance = Integer.MAX_VALUE; 3597 final int childCount = getChildCount(); 3598 final int firstPosition = mFirstPosition; 3599 3600 for (int i = 0; i < childCount; i++) { 3601 // only consider selectable views 3602 if (!adapter.isEnabled(firstPosition + i)) { 3603 continue; 3604 } 3605 3606 View other = getChildAt(i); 3607 other.getDrawingRect(otherRect); 3608 offsetDescendantRectToMyCoords(other, otherRect); 3609 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3610 3611 if (distance < minDistance) { 3612 minDistance = distance; 3613 closetChildIndex = i; 3614 closestChildTop = other.getTop(); 3615 } 3616 } 3617 } 3618 3619 if (closetChildIndex >= 0) { 3620 setSelectionFromTop(closetChildIndex + mFirstPosition, closestChildTop); 3621 } else { 3622 requestLayout(); 3623 } 3624 } 3625 3626 3627 /* 3628 * (non-Javadoc) 3629 * 3630 * Children specified in XML are assumed to be header views. After we have 3631 * parsed them move them out of the children list and into mHeaderViews. 3632 */ 3633 @Override 3634 protected void onFinishInflate() { 3635 super.onFinishInflate(); 3636 3637 int count = getChildCount(); 3638 if (count > 0) { 3639 for (int i = 0; i < count; ++i) { 3640 addHeaderView(getChildAt(i)); 3641 } 3642 removeAllViews(); 3643 } 3644 } 3645 3646 /* (non-Javadoc) 3647 * @see android.view.View#findViewById(int) 3648 * First look in our children, then in any header and footer views that may be scrolled off. 3649 */ 3650 @Override 3651 protected View findViewTraversal(@IdRes int id) { 3652 View v; 3653 v = super.findViewTraversal(id); 3654 if (v == null) { 3655 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3656 if (v != null) { 3657 return v; 3658 } 3659 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3660 if (v != null) { 3661 return v; 3662 } 3663 } 3664 return v; 3665 } 3666 3667 /* (non-Javadoc) 3668 * 3669 * Look in the passed in list of headers or footers for the view. 3670 */ 3671 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3672 if (where != null) { 3673 int len = where.size(); 3674 View v; 3675 3676 for (int i = 0; i < len; i++) { 3677 v = where.get(i).view; 3678 3679 if (!v.isRootNamespace()) { 3680 v = v.findViewById(id); 3681 3682 if (v != null) { 3683 return v; 3684 } 3685 } 3686 } 3687 } 3688 return null; 3689 } 3690 3691 /* (non-Javadoc) 3692 * @see android.view.View#findViewWithTag(Object) 3693 * First look in our children, then in any header and footer views that may be scrolled off. 3694 */ 3695 @Override 3696 protected View findViewWithTagTraversal(Object tag) { 3697 View v; 3698 v = super.findViewWithTagTraversal(tag); 3699 if (v == null) { 3700 v = findViewWithTagInHeadersOrFooters(mHeaderViewInfos, tag); 3701 if (v != null) { 3702 return v; 3703 } 3704 3705 v = findViewWithTagInHeadersOrFooters(mFooterViewInfos, tag); 3706 if (v != null) { 3707 return v; 3708 } 3709 } 3710 return v; 3711 } 3712 3713 /* (non-Javadoc) 3714 * 3715 * Look in the passed in list of headers or footers for the view with the tag. 3716 */ 3717 View findViewWithTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3718 if (where != null) { 3719 int len = where.size(); 3720 View v; 3721 3722 for (int i = 0; i < len; i++) { 3723 v = where.get(i).view; 3724 3725 if (!v.isRootNamespace()) { 3726 v = v.findViewWithTag(tag); 3727 3728 if (v != null) { 3729 return v; 3730 } 3731 } 3732 } 3733 } 3734 return null; 3735 } 3736 3737 /** 3738 * @hide 3739 * @see android.view.View#findViewByPredicate(Predicate) 3740 * First look in our children, then in any header and footer views that may be scrolled off. 3741 */ 3742 @Override 3743 protected View findViewByPredicateTraversal(Predicate<View> predicate, View childToSkip) { 3744 View v; 3745 v = super.findViewByPredicateTraversal(predicate, childToSkip); 3746 if (v == null) { 3747 v = findViewByPredicateInHeadersOrFooters(mHeaderViewInfos, predicate, childToSkip); 3748 if (v != null) { 3749 return v; 3750 } 3751 3752 v = findViewByPredicateInHeadersOrFooters(mFooterViewInfos, predicate, childToSkip); 3753 if (v != null) { 3754 return v; 3755 } 3756 } 3757 return v; 3758 } 3759 3760 /* (non-Javadoc) 3761 * 3762 * Look in the passed in list of headers or footers for the first view that matches 3763 * the predicate. 3764 */ 3765 View findViewByPredicateInHeadersOrFooters(ArrayList<FixedViewInfo> where, 3766 Predicate<View> predicate, View childToSkip) { 3767 if (where != null) { 3768 int len = where.size(); 3769 View v; 3770 3771 for (int i = 0; i < len; i++) { 3772 v = where.get(i).view; 3773 3774 if (v != childToSkip && !v.isRootNamespace()) { 3775 v = v.findViewByPredicate(predicate); 3776 3777 if (v != null) { 3778 return v; 3779 } 3780 } 3781 } 3782 } 3783 return null; 3784 } 3785 3786 /** 3787 * Returns the set of checked items ids. The result is only valid if the 3788 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3789 * 3790 * @return A new array which contains the id of each checked item in the 3791 * list. 3792 * 3793 * @deprecated Use {@link #getCheckedItemIds()} instead. 3794 */ 3795 @Deprecated 3796 public long[] getCheckItemIds() { 3797 // Use new behavior that correctly handles stable ID mapping. 3798 if (mAdapter != null && mAdapter.hasStableIds()) { 3799 return getCheckedItemIds(); 3800 } 3801 3802 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3803 // Fall back to it to support legacy apps. 3804 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3805 final SparseBooleanArray states = mCheckStates; 3806 final int count = states.size(); 3807 final long[] ids = new long[count]; 3808 final ListAdapter adapter = mAdapter; 3809 3810 int checkedCount = 0; 3811 for (int i = 0; i < count; i++) { 3812 if (states.valueAt(i)) { 3813 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3814 } 3815 } 3816 3817 // Trim array if needed. mCheckStates may contain false values 3818 // resulting in checkedCount being smaller than count. 3819 if (checkedCount == count) { 3820 return ids; 3821 } else { 3822 final long[] result = new long[checkedCount]; 3823 System.arraycopy(ids, 0, result, 0, checkedCount); 3824 3825 return result; 3826 } 3827 } 3828 return new long[0]; 3829 } 3830 3831 @Override 3832 int getHeightForPosition(int position) { 3833 final int height = super.getHeightForPosition(position); 3834 if (shouldAdjustHeightForDivider(position)) { 3835 return height + mDividerHeight; 3836 } 3837 return height; 3838 } 3839 3840 private boolean shouldAdjustHeightForDivider(int itemIndex) { 3841 final int dividerHeight = mDividerHeight; 3842 final Drawable overscrollHeader = mOverScrollHeader; 3843 final Drawable overscrollFooter = mOverScrollFooter; 3844 final boolean drawOverscrollHeader = overscrollHeader != null; 3845 final boolean drawOverscrollFooter = overscrollFooter != null; 3846 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3847 3848 if (drawDividers) { 3849 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3850 final int itemCount = mItemCount; 3851 final int headerCount = mHeaderViewInfos.size(); 3852 final int footerLimit = (itemCount - mFooterViewInfos.size()); 3853 final boolean isHeader = (itemIndex < headerCount); 3854 final boolean isFooter = (itemIndex >= footerLimit); 3855 final boolean headerDividers = mHeaderDividersEnabled; 3856 final boolean footerDividers = mFooterDividersEnabled; 3857 if ((headerDividers || !isHeader) && (footerDividers || !isFooter)) { 3858 final ListAdapter adapter = mAdapter; 3859 if (!mStackFromBottom) { 3860 final boolean isLastItem = (itemIndex == (itemCount - 1)); 3861 if (!drawOverscrollFooter || !isLastItem) { 3862 final int nextIndex = itemIndex + 1; 3863 // Draw dividers between enabled items, headers 3864 // and/or footers when enabled and requested, and 3865 // after the last enabled item. 3866 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3867 && (nextIndex >= headerCount)) && (isLastItem 3868 || adapter.isEnabled(nextIndex) && (footerDividers || !isFooter 3869 && (nextIndex < footerLimit)))) { 3870 return true; 3871 } else if (fillForMissingDividers) { 3872 return true; 3873 } 3874 } 3875 } else { 3876 final int start = drawOverscrollHeader ? 1 : 0; 3877 final boolean isFirstItem = (itemIndex == start); 3878 if (!isFirstItem) { 3879 final int previousIndex = (itemIndex - 1); 3880 // Draw dividers between enabled items, headers 3881 // and/or footers when enabled and requested, and 3882 // before the first enabled item. 3883 if (adapter.isEnabled(itemIndex) && (headerDividers || !isHeader 3884 && (previousIndex >= headerCount)) && (isFirstItem || 3885 adapter.isEnabled(previousIndex) && (footerDividers || !isFooter 3886 && (previousIndex < footerLimit)))) { 3887 return true; 3888 } else if (fillForMissingDividers) { 3889 return true; 3890 } 3891 } 3892 } 3893 } 3894 } 3895 3896 return false; 3897 } 3898 3899 @Override 3900 public CharSequence getAccessibilityClassName() { 3901 return ListView.class.getName(); 3902 } 3903 3904 /** @hide */ 3905 @Override 3906 public void onInitializeAccessibilityNodeInfoInternal(AccessibilityNodeInfo info) { 3907 super.onInitializeAccessibilityNodeInfoInternal(info); 3908 3909 final int rowsCount = getCount(); 3910 final int selectionMode = getSelectionModeForAccessibility(); 3911 final CollectionInfo collectionInfo = CollectionInfo.obtain( 3912 rowsCount, 1, false, selectionMode); 3913 info.setCollectionInfo(collectionInfo); 3914 3915 if (rowsCount > 0) { 3916 info.addAction(AccessibilityAction.ACTION_SCROLL_TO_POSITION); 3917 } 3918 } 3919 3920 /** @hide */ 3921 @Override 3922 public boolean performAccessibilityActionInternal(int action, Bundle arguments) { 3923 if (super.performAccessibilityActionInternal(action, arguments)) { 3924 return true; 3925 } 3926 3927 switch (action) { 3928 case R.id.accessibilityActionScrollToPosition: { 3929 final int row = arguments.getInt(AccessibilityNodeInfo.ACTION_ARGUMENT_ROW_INT, -1); 3930 final int position = Math.min(row, getCount() - 1); 3931 if (row >= 0) { 3932 // The accessibility service gets data asynchronously, so 3933 // we'll be a little lenient by clamping the last position. 3934 smoothScrollToPosition(position); 3935 return true; 3936 } 3937 } break; 3938 } 3939 3940 return false; 3941 } 3942 3943 @Override 3944 public void onInitializeAccessibilityNodeInfoForItem( 3945 View view, int position, AccessibilityNodeInfo info) { 3946 super.onInitializeAccessibilityNodeInfoForItem(view, position, info); 3947 3948 final LayoutParams lp = (LayoutParams) view.getLayoutParams(); 3949 final boolean isHeading = lp != null && lp.viewType != ITEM_VIEW_TYPE_HEADER_OR_FOOTER; 3950 final boolean isSelected = isItemChecked(position); 3951 final CollectionItemInfo itemInfo = CollectionItemInfo.obtain( 3952 position, 1, 0, 1, isHeading, isSelected); 3953 info.setCollectionItemInfo(itemInfo); 3954 } 3955 3956 /** @hide */ 3957 @Override 3958 protected void encodeProperties(@NonNull ViewHierarchyEncoder encoder) { 3959 super.encodeProperties(encoder); 3960 3961 encoder.addProperty("recycleOnMeasure", recycleOnMeasure()); 3962 } 3963 } 3964