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