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