ListView.java revision 1fa179ef41c06bd19da70fd9bf95741238791940
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 17package android.widget; 18 19import com.android.internal.R; 20import com.android.internal.util.Predicate; 21import com.google.android.collect.Lists; 22 23import android.content.Context; 24import android.content.Intent; 25import android.content.res.TypedArray; 26import android.graphics.Canvas; 27import android.graphics.Paint; 28import android.graphics.PixelFormat; 29import android.graphics.Rect; 30import android.graphics.drawable.Drawable; 31import android.util.AttributeSet; 32import android.util.SparseBooleanArray; 33import android.view.FocusFinder; 34import android.view.KeyEvent; 35import android.view.SoundEffectConstants; 36import android.view.View; 37import android.view.ViewDebug; 38import android.view.ViewGroup; 39import android.view.ViewParent; 40import android.view.accessibility.AccessibilityEvent; 41import android.view.accessibility.AccessibilityNodeInfo; 42import android.widget.RemoteViews.RemoteView; 43 44import java.util.ArrayList; 45 46/* 47 * Implementation Notes: 48 * 49 * Some terminology: 50 * 51 * index - index of the items that are currently visible 52 * position - index of the items in the cursor 53 */ 54 55 56/** 57 * A view that shows items in a vertically scrolling list. The items 58 * come from the {@link ListAdapter} associated with this view. 59 * 60 * <p>See the <a href="{@docRoot}resources/tutorials/views/hello-listview.html">List View 61 * tutorial</a>.</p> 62 * 63 * @attr ref android.R.styleable#ListView_entries 64 * @attr ref android.R.styleable#ListView_divider 65 * @attr ref android.R.styleable#ListView_dividerHeight 66 * @attr ref android.R.styleable#ListView_headerDividersEnabled 67 * @attr ref android.R.styleable#ListView_footerDividersEnabled 68 */ 69@RemoteView 70public class ListView extends AbsListView { 71 /** 72 * Used to indicate a no preference for a position type. 73 */ 74 static final int NO_POSITION = -1; 75 76 /** 77 * When arrow scrolling, ListView will never scroll more than this factor 78 * times the height of the list. 79 */ 80 private static final float MAX_SCROLL_FACTOR = 0.33f; 81 82 /** 83 * When arrow scrolling, need a certain amount of pixels to preview next 84 * items. This is usually the fading edge, but if that is small enough, 85 * we want to make sure we preview at least this many pixels. 86 */ 87 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 88 89 /** 90 * A class that represents a fixed view in a list, for example a header at the top 91 * or a footer at the bottom. 92 */ 93 public class FixedViewInfo { 94 /** The view to add to the list */ 95 public View view; 96 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 97 public Object data; 98 /** <code>true</code> if the fixed view should be selectable in the list */ 99 public boolean isSelectable; 100 } 101 102 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 103 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 104 105 Drawable mDivider; 106 int mDividerHeight; 107 108 Drawable mOverScrollHeader; 109 Drawable mOverScrollFooter; 110 111 private boolean mIsCacheColorOpaque; 112 private boolean mDividerIsOpaque; 113 114 private boolean mHeaderDividersEnabled; 115 private boolean mFooterDividersEnabled; 116 117 private boolean mAreAllItemsSelectable = true; 118 119 private boolean mItemsCanFocus = false; 120 121 // used for temporary calculations. 122 private final Rect mTempRect = new Rect(); 123 private Paint mDividerPaint; 124 125 // the single allocated result per list view; kinda cheesey but avoids 126 // allocating these thingies too often. 127 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 128 129 // Keeps focused children visible through resizes 130 private FocusSelector mFocusSelector; 131 132 public ListView(Context context) { 133 this(context, null); 134 } 135 136 public ListView(Context context, AttributeSet attrs) { 137 this(context, attrs, com.android.internal.R.attr.listViewStyle); 138 } 139 140 public ListView(Context context, AttributeSet attrs, int defStyle) { 141 super(context, attrs, defStyle); 142 143 TypedArray a = context.obtainStyledAttributes(attrs, 144 com.android.internal.R.styleable.ListView, defStyle, 0); 145 146 CharSequence[] entries = a.getTextArray( 147 com.android.internal.R.styleable.ListView_entries); 148 if (entries != null) { 149 setAdapter(new ArrayAdapter<CharSequence>(context, 150 com.android.internal.R.layout.simple_list_item_1, entries)); 151 } 152 153 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 154 if (d != null) { 155 // If a divider is specified use its intrinsic height for divider height 156 setDivider(d); 157 } 158 159 final Drawable osHeader = a.getDrawable( 160 com.android.internal.R.styleable.ListView_overScrollHeader); 161 if (osHeader != null) { 162 setOverscrollHeader(osHeader); 163 } 164 165 final Drawable osFooter = a.getDrawable( 166 com.android.internal.R.styleable.ListView_overScrollFooter); 167 if (osFooter != null) { 168 setOverscrollFooter(osFooter); 169 } 170 171 // Use the height specified, zero being the default 172 final int dividerHeight = a.getDimensionPixelSize( 173 com.android.internal.R.styleable.ListView_dividerHeight, 0); 174 if (dividerHeight != 0) { 175 setDividerHeight(dividerHeight); 176 } 177 178 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 179 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 180 181 a.recycle(); 182 } 183 184 /** 185 * @return The maximum amount a list view will scroll in response to 186 * an arrow event. 187 */ 188 public int getMaxScrollAmount() { 189 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 190 } 191 192 /** 193 * Make sure views are touching the top or bottom edge, as appropriate for 194 * our gravity 195 */ 196 private void adjustViewsUpOrDown() { 197 final int childCount = getChildCount(); 198 int delta; 199 200 if (childCount > 0) { 201 View child; 202 203 if (!mStackFromBottom) { 204 // Uh-oh -- we came up short. Slide all views up to make them 205 // align with the top 206 child = getChildAt(0); 207 delta = child.getTop() - mListPadding.top; 208 if (mFirstPosition != 0) { 209 // It's OK to have some space above the first item if it is 210 // part of the vertical spacing 211 delta -= mDividerHeight; 212 } 213 if (delta < 0) { 214 // We only are looking to see if we are too low, not too high 215 delta = 0; 216 } 217 } else { 218 // we are too high, slide all views down to align with bottom 219 child = getChildAt(childCount - 1); 220 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 221 222 if (mFirstPosition + childCount < mItemCount) { 223 // It's OK to have some space below the last item if it is 224 // part of the vertical spacing 225 delta += mDividerHeight; 226 } 227 228 if (delta > 0) { 229 delta = 0; 230 } 231 } 232 233 if (delta != 0) { 234 offsetChildrenTopAndBottom(-delta); 235 } 236 } 237 } 238 239 /** 240 * Add a fixed view to appear at the top of the list. If addHeaderView is 241 * called more than once, the views will appear in the order they were 242 * added. Views added using this call can take focus if they want. 243 * <p> 244 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 245 * the supplied cursor with one that will also account for header and footer 246 * views. 247 * 248 * @param v The view to add. 249 * @param data Data to associate with this view 250 * @param isSelectable whether the item is selectable 251 */ 252 public void addHeaderView(View v, Object data, boolean isSelectable) { 253 254 if (mAdapter != null && ! (mAdapter instanceof HeaderViewListAdapter)) { 255 throw new IllegalStateException( 256 "Cannot add header view to list -- setAdapter has already been called."); 257 } 258 259 FixedViewInfo info = new FixedViewInfo(); 260 info.view = v; 261 info.data = data; 262 info.isSelectable = isSelectable; 263 mHeaderViewInfos.add(info); 264 265 // in the case of re-adding a header view, or adding one later on, 266 // we need to notify the observer 267 if (mAdapter != null && mDataSetObserver != null) { 268 mDataSetObserver.onChanged(); 269 } 270 } 271 272 /** 273 * Add a fixed view to appear at the top of the list. If addHeaderView is 274 * called more than once, the views will appear in the order they were 275 * added. Views added using this call can take focus if they want. 276 * <p> 277 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 278 * the supplied cursor with one that will also account for header and footer 279 * views. 280 * 281 * @param v The view to add. 282 */ 283 public void addHeaderView(View v) { 284 addHeaderView(v, null, true); 285 } 286 287 @Override 288 public int getHeaderViewsCount() { 289 return mHeaderViewInfos.size(); 290 } 291 292 /** 293 * Removes a previously-added header view. 294 * 295 * @param v The view to remove 296 * @return true if the view was removed, false if the view was not a header 297 * view 298 */ 299 public boolean removeHeaderView(View v) { 300 if (mHeaderViewInfos.size() > 0) { 301 boolean result = false; 302 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 303 if (mDataSetObserver != null) { 304 mDataSetObserver.onChanged(); 305 } 306 result = true; 307 } 308 removeFixedViewInfo(v, mHeaderViewInfos); 309 return result; 310 } 311 return false; 312 } 313 314 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 315 int len = where.size(); 316 for (int i = 0; i < len; ++i) { 317 FixedViewInfo info = where.get(i); 318 if (info.view == v) { 319 where.remove(i); 320 break; 321 } 322 } 323 } 324 325 /** 326 * Add a fixed view to appear at the bottom of the list. If addFooterView is 327 * called more than once, the views will appear in the order they were 328 * added. Views added using this call can take focus if they want. 329 * <p> 330 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 331 * the supplied cursor with one that will also account for header and footer 332 * views. 333 * 334 * @param v The view to add. 335 * @param data Data to associate with this view 336 * @param isSelectable true if the footer view can be selected 337 */ 338 public void addFooterView(View v, Object data, boolean isSelectable) { 339 340 // NOTE: do not enforce the adapter being null here, since unlike in 341 // addHeaderView, it was never enforced here, and so existing apps are 342 // relying on being able to add a footer and then calling setAdapter to 343 // force creation of the HeaderViewListAdapter wrapper 344 345 FixedViewInfo info = new FixedViewInfo(); 346 info.view = v; 347 info.data = data; 348 info.isSelectable = isSelectable; 349 mFooterViewInfos.add(info); 350 351 // in the case of re-adding a footer view, or adding one later on, 352 // we need to notify the observer 353 if (mAdapter != null && mDataSetObserver != null) { 354 mDataSetObserver.onChanged(); 355 } 356 } 357 358 /** 359 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 360 * than once, the views will appear in the order they were added. Views added using 361 * this call can take focus if they want. 362 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 363 * cursor with one that will also account for header and footer views. 364 * 365 * 366 * @param v The view to add. 367 */ 368 public void addFooterView(View v) { 369 addFooterView(v, null, true); 370 } 371 372 @Override 373 public int getFooterViewsCount() { 374 return mFooterViewInfos.size(); 375 } 376 377 /** 378 * Removes a previously-added footer view. 379 * 380 * @param v The view to remove 381 * @return 382 * true if the view was removed, false if the view was not a footer view 383 */ 384 public boolean removeFooterView(View v) { 385 if (mFooterViewInfos.size() > 0) { 386 boolean result = false; 387 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 388 if (mDataSetObserver != null) { 389 mDataSetObserver.onChanged(); 390 } 391 result = true; 392 } 393 removeFixedViewInfo(v, mFooterViewInfos); 394 return result; 395 } 396 return false; 397 } 398 399 /** 400 * Returns the adapter currently in use in this ListView. The returned adapter 401 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 402 * might be a {@link WrapperListAdapter}. 403 * 404 * @return The adapter currently used to display data in this ListView. 405 * 406 * @see #setAdapter(ListAdapter) 407 */ 408 @Override 409 public ListAdapter getAdapter() { 410 return mAdapter; 411 } 412 413 /** 414 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 415 * through the specified intent. 416 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 417 */ 418 @android.view.RemotableViewMethod 419 public void setRemoteViewsAdapter(Intent intent) { 420 super.setRemoteViewsAdapter(intent); 421 } 422 423 /** 424 * Sets the data behind this ListView. 425 * 426 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 427 * depending on the ListView features currently in use. For instance, adding 428 * headers and/or footers will cause the adapter to be wrapped. 429 * 430 * @param adapter The ListAdapter which is responsible for maintaining the 431 * data backing this list and for producing a view to represent an 432 * item in that data set. 433 * 434 * @see #getAdapter() 435 */ 436 @Override 437 public void setAdapter(ListAdapter adapter) { 438 if (mAdapter != null && mDataSetObserver != null) { 439 mAdapter.unregisterDataSetObserver(mDataSetObserver); 440 } 441 442 resetList(); 443 mRecycler.clear(); 444 445 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 446 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 447 } else { 448 mAdapter = adapter; 449 } 450 451 mOldSelectedPosition = INVALID_POSITION; 452 mOldSelectedRowId = INVALID_ROW_ID; 453 454 // AbsListView#setAdapter will update choice mode states. 455 super.setAdapter(adapter); 456 457 if (mAdapter != null) { 458 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 459 mOldItemCount = mItemCount; 460 mItemCount = mAdapter.getCount(); 461 checkFocus(); 462 463 mDataSetObserver = new AdapterDataSetObserver(); 464 mAdapter.registerDataSetObserver(mDataSetObserver); 465 466 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 467 468 int position; 469 if (mStackFromBottom) { 470 position = lookForSelectablePosition(mItemCount - 1, false); 471 } else { 472 position = lookForSelectablePosition(0, true); 473 } 474 setSelectedPositionInt(position); 475 setNextSelectedPositionInt(position); 476 477 if (mItemCount == 0) { 478 // Nothing selected 479 checkSelectionChanged(); 480 } 481 } else { 482 mAreAllItemsSelectable = true; 483 checkFocus(); 484 // Nothing selected 485 checkSelectionChanged(); 486 } 487 488 requestLayout(); 489 } 490 491 492 /** 493 * The list is empty. Clear everything out. 494 */ 495 @Override 496 void resetList() { 497 // The parent's resetList() will remove all views from the layout so we need to 498 // cleanup the state of our footers and headers 499 clearRecycledState(mHeaderViewInfos); 500 clearRecycledState(mFooterViewInfos); 501 502 super.resetList(); 503 504 mLayoutMode = LAYOUT_NORMAL; 505 } 506 507 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 508 if (infos != null) { 509 final int count = infos.size(); 510 511 for (int i = 0; i < count; i++) { 512 final View child = infos.get(i).view; 513 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 514 if (p != null) { 515 p.recycledHeaderFooter = false; 516 } 517 } 518 } 519 } 520 521 /** 522 * @return Whether the list needs to show the top fading edge 523 */ 524 private boolean showingTopFadingEdge() { 525 final int listTop = mScrollY + mListPadding.top; 526 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 527 } 528 529 /** 530 * @return Whether the list needs to show the bottom fading edge 531 */ 532 private boolean showingBottomFadingEdge() { 533 final int childCount = getChildCount(); 534 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 535 final int lastVisiblePosition = mFirstPosition + childCount - 1; 536 537 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 538 539 return (lastVisiblePosition < mItemCount - 1) 540 || (bottomOfBottomChild < listBottom); 541 } 542 543 544 @Override 545 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 546 547 int rectTopWithinChild = rect.top; 548 549 // offset so rect is in coordinates of the this view 550 rect.offset(child.getLeft(), child.getTop()); 551 rect.offset(-child.getScrollX(), -child.getScrollY()); 552 553 final int height = getHeight(); 554 int listUnfadedTop = getScrollY(); 555 int listUnfadedBottom = listUnfadedTop + height; 556 final int fadingEdge = getVerticalFadingEdgeLength(); 557 558 if (showingTopFadingEdge()) { 559 // leave room for top fading edge as long as rect isn't at very top 560 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 561 listUnfadedTop += fadingEdge; 562 } 563 } 564 565 int childCount = getChildCount(); 566 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 567 568 if (showingBottomFadingEdge()) { 569 // leave room for bottom fading edge as long as rect isn't at very bottom 570 if ((mSelectedPosition < mItemCount - 1) 571 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 572 listUnfadedBottom -= fadingEdge; 573 } 574 } 575 576 int scrollYDelta = 0; 577 578 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 579 // need to MOVE DOWN to get it in view: move down just enough so 580 // that the entire rectangle is in view (or at least the first 581 // screen size chunk). 582 583 if (rect.height() > height) { 584 // just enough to get screen size chunk on 585 scrollYDelta += (rect.top - listUnfadedTop); 586 } else { 587 // get entire rect at bottom of screen 588 scrollYDelta += (rect.bottom - listUnfadedBottom); 589 } 590 591 // make sure we aren't scrolling beyond the end of our children 592 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 593 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 594 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 595 // need to MOVE UP to get it in view: move up just enough so that 596 // entire rectangle is in view (or at least the first screen 597 // size chunk of it). 598 599 if (rect.height() > height) { 600 // screen size chunk 601 scrollYDelta -= (listUnfadedBottom - rect.bottom); 602 } else { 603 // entire rect at top 604 scrollYDelta -= (listUnfadedTop - rect.top); 605 } 606 607 // make sure we aren't scrolling any further than the top our children 608 int top = getChildAt(0).getTop(); 609 int deltaToTop = top - listUnfadedTop; 610 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 611 } 612 613 final boolean scroll = scrollYDelta != 0; 614 if (scroll) { 615 scrollListItemsBy(-scrollYDelta); 616 positionSelector(INVALID_POSITION, child); 617 mSelectedTop = child.getTop(); 618 invalidate(); 619 } 620 return scroll; 621 } 622 623 /** 624 * {@inheritDoc} 625 */ 626 @Override 627 void fillGap(boolean down) { 628 final int count = getChildCount(); 629 if (down) { 630 int paddingTop = 0; 631 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 632 paddingTop = getListPaddingTop(); 633 } 634 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 635 paddingTop; 636 fillDown(mFirstPosition + count, startOffset); 637 correctTooHigh(getChildCount()); 638 } else { 639 int paddingBottom = 0; 640 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 641 paddingBottom = getListPaddingBottom(); 642 } 643 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 644 getHeight() - paddingBottom; 645 fillUp(mFirstPosition - 1, startOffset); 646 correctTooLow(getChildCount()); 647 } 648 } 649 650 /** 651 * Fills the list from pos down to the end of the list view. 652 * 653 * @param pos The first position to put in the list 654 * 655 * @param nextTop The location where the top of the item associated with pos 656 * should be drawn 657 * 658 * @return The view that is currently selected, if it happens to be in the 659 * range that we draw. 660 */ 661 private View fillDown(int pos, int nextTop) { 662 View selectedView = null; 663 664 int end = (mBottom - mTop); 665 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 666 end -= mListPadding.bottom; 667 } 668 669 while (nextTop < end && pos < mItemCount) { 670 // is this the selected item? 671 boolean selected = pos == mSelectedPosition; 672 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 673 674 nextTop = child.getBottom() + mDividerHeight; 675 if (selected) { 676 selectedView = child; 677 } 678 pos++; 679 } 680 681 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 682 return selectedView; 683 } 684 685 /** 686 * Fills the list from pos up to the top of the list view. 687 * 688 * @param pos The first position to put in the list 689 * 690 * @param nextBottom The location where the bottom of the item associated 691 * with pos should be drawn 692 * 693 * @return The view that is currently selected 694 */ 695 private View fillUp(int pos, int nextBottom) { 696 View selectedView = null; 697 698 int end = 0; 699 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 700 end = mListPadding.top; 701 } 702 703 while (nextBottom > end && pos >= 0) { 704 // is this the selected item? 705 boolean selected = pos == mSelectedPosition; 706 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 707 nextBottom = child.getTop() - mDividerHeight; 708 if (selected) { 709 selectedView = child; 710 } 711 pos--; 712 } 713 714 mFirstPosition = pos + 1; 715 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 716 return selectedView; 717 } 718 719 /** 720 * Fills the list from top to bottom, starting with mFirstPosition 721 * 722 * @param nextTop The location where the top of the first item should be 723 * drawn 724 * 725 * @return The view that is currently selected 726 */ 727 private View fillFromTop(int nextTop) { 728 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 729 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 730 if (mFirstPosition < 0) { 731 mFirstPosition = 0; 732 } 733 return fillDown(mFirstPosition, nextTop); 734 } 735 736 737 /** 738 * Put mSelectedPosition in the middle of the screen and then build up and 739 * down from there. This method forces mSelectedPosition to the center. 740 * 741 * @param childrenTop Top of the area in which children can be drawn, as 742 * measured in pixels 743 * @param childrenBottom Bottom of the area in which children can be drawn, 744 * as measured in pixels 745 * @return Currently selected view 746 */ 747 private View fillFromMiddle(int childrenTop, int childrenBottom) { 748 int height = childrenBottom - childrenTop; 749 750 int position = reconcileSelectedPosition(); 751 752 View sel = makeAndAddView(position, childrenTop, true, 753 mListPadding.left, true); 754 mFirstPosition = position; 755 756 int selHeight = sel.getMeasuredHeight(); 757 if (selHeight <= height) { 758 sel.offsetTopAndBottom((height - selHeight) / 2); 759 } 760 761 fillAboveAndBelow(sel, position); 762 763 if (!mStackFromBottom) { 764 correctTooHigh(getChildCount()); 765 } else { 766 correctTooLow(getChildCount()); 767 } 768 769 return sel; 770 } 771 772 /** 773 * Once the selected view as been placed, fill up the visible area above and 774 * below it. 775 * 776 * @param sel The selected view 777 * @param position The position corresponding to sel 778 */ 779 private void fillAboveAndBelow(View sel, int position) { 780 final int dividerHeight = mDividerHeight; 781 if (!mStackFromBottom) { 782 fillUp(position - 1, sel.getTop() - dividerHeight); 783 adjustViewsUpOrDown(); 784 fillDown(position + 1, sel.getBottom() + dividerHeight); 785 } else { 786 fillDown(position + 1, sel.getBottom() + dividerHeight); 787 adjustViewsUpOrDown(); 788 fillUp(position - 1, sel.getTop() - dividerHeight); 789 } 790 } 791 792 793 /** 794 * Fills the grid based on positioning the new selection at a specific 795 * location. The selection may be moved so that it does not intersect the 796 * faded edges. The grid is then filled upwards and downwards from there. 797 * 798 * @param selectedTop Where the selected item should be 799 * @param childrenTop Where to start drawing children 800 * @param childrenBottom Last pixel where children can be drawn 801 * @return The view that currently has selection 802 */ 803 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 804 int fadingEdgeLength = getVerticalFadingEdgeLength(); 805 final int selectedPosition = mSelectedPosition; 806 807 View sel; 808 809 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 810 selectedPosition); 811 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 812 selectedPosition); 813 814 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 815 816 817 // Some of the newly selected item extends below the bottom of the list 818 if (sel.getBottom() > bottomSelectionPixel) { 819 // Find space available above the selection into which we can scroll 820 // upwards 821 final int spaceAbove = sel.getTop() - topSelectionPixel; 822 823 // Find space required to bring the bottom of the selected item 824 // fully into view 825 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 826 final int offset = Math.min(spaceAbove, spaceBelow); 827 828 // Now offset the selected item to get it into view 829 sel.offsetTopAndBottom(-offset); 830 } else if (sel.getTop() < topSelectionPixel) { 831 // Find space required to bring the top of the selected item fully 832 // into view 833 final int spaceAbove = topSelectionPixel - sel.getTop(); 834 835 // Find space available below the selection into which we can scroll 836 // downwards 837 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 838 final int offset = Math.min(spaceAbove, spaceBelow); 839 840 // Offset the selected item to get it into view 841 sel.offsetTopAndBottom(offset); 842 } 843 844 // Fill in views above and below 845 fillAboveAndBelow(sel, selectedPosition); 846 847 if (!mStackFromBottom) { 848 correctTooHigh(getChildCount()); 849 } else { 850 correctTooLow(getChildCount()); 851 } 852 853 return sel; 854 } 855 856 /** 857 * Calculate the bottom-most pixel we can draw the selection into 858 * 859 * @param childrenBottom Bottom pixel were children can be drawn 860 * @param fadingEdgeLength Length of the fading edge in pixels, if present 861 * @param selectedPosition The position that will be selected 862 * @return The bottom-most pixel we can draw the selection into 863 */ 864 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 865 int selectedPosition) { 866 int bottomSelectionPixel = childrenBottom; 867 if (selectedPosition != mItemCount - 1) { 868 bottomSelectionPixel -= fadingEdgeLength; 869 } 870 return bottomSelectionPixel; 871 } 872 873 /** 874 * Calculate the top-most pixel we can draw the selection into 875 * 876 * @param childrenTop Top pixel were children can be drawn 877 * @param fadingEdgeLength Length of the fading edge in pixels, if present 878 * @param selectedPosition The position that will be selected 879 * @return The top-most pixel we can draw the selection into 880 */ 881 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 882 // first pixel we can draw the selection into 883 int topSelectionPixel = childrenTop; 884 if (selectedPosition > 0) { 885 topSelectionPixel += fadingEdgeLength; 886 } 887 return topSelectionPixel; 888 } 889 890 /** 891 * Smoothly scroll to the specified adapter position. The view will 892 * scroll such that the indicated position is displayed. 893 * @param position Scroll to this adapter position. 894 */ 895 @android.view.RemotableViewMethod 896 public void smoothScrollToPosition(int position) { 897 super.smoothScrollToPosition(position); 898 } 899 900 /** 901 * Smoothly scroll to the specified adapter position offset. The view will 902 * scroll such that the indicated position is displayed. 903 * @param offset The amount to offset from the adapter position to scroll to. 904 */ 905 @android.view.RemotableViewMethod 906 public void smoothScrollByOffset(int offset) { 907 super.smoothScrollByOffset(offset); 908 } 909 910 /** 911 * Fills the list based on positioning the new selection relative to the old 912 * selection. The new selection will be placed at, above, or below the 913 * location of the new selection depending on how the selection is moving. 914 * The selection will then be pinned to the visible part of the screen, 915 * excluding the edges that are faded. The list is then filled upwards and 916 * downwards from there. 917 * 918 * @param oldSel The old selected view. Useful for trying to put the new 919 * selection in the same place 920 * @param newSel The view that is to become selected. Useful for trying to 921 * put the new selection in the same place 922 * @param delta Which way we are moving 923 * @param childrenTop Where to start drawing children 924 * @param childrenBottom Last pixel where children can be drawn 925 * @return The view that currently has selection 926 */ 927 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 928 int childrenBottom) { 929 int fadingEdgeLength = getVerticalFadingEdgeLength(); 930 final int selectedPosition = mSelectedPosition; 931 932 View sel; 933 934 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 935 selectedPosition); 936 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 937 selectedPosition); 938 939 if (delta > 0) { 940 /* 941 * Case 1: Scrolling down. 942 */ 943 944 /* 945 * Before After 946 * | | | | 947 * +-------+ +-------+ 948 * | A | | A | 949 * | 1 | => +-------+ 950 * +-------+ | B | 951 * | B | | 2 | 952 * +-------+ +-------+ 953 * | | | | 954 * 955 * Try to keep the top of the previously selected item where it was. 956 * oldSel = A 957 * sel = B 958 */ 959 960 // Put oldSel (A) where it belongs 961 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 962 mListPadding.left, false); 963 964 final int dividerHeight = mDividerHeight; 965 966 // Now put the new selection (B) below that 967 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 968 mListPadding.left, true); 969 970 // Some of the newly selected item extends below the bottom of the list 971 if (sel.getBottom() > bottomSelectionPixel) { 972 973 // Find space available above the selection into which we can scroll upwards 974 int spaceAbove = sel.getTop() - topSelectionPixel; 975 976 // Find space required to bring the bottom of the selected item fully into view 977 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 978 979 // Don't scroll more than half the height of the list 980 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 981 int offset = Math.min(spaceAbove, spaceBelow); 982 offset = Math.min(offset, halfVerticalSpace); 983 984 // We placed oldSel, so offset that item 985 oldSel.offsetTopAndBottom(-offset); 986 // Now offset the selected item to get it into view 987 sel.offsetTopAndBottom(-offset); 988 } 989 990 // Fill in views above and below 991 if (!mStackFromBottom) { 992 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 993 adjustViewsUpOrDown(); 994 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 995 } else { 996 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 997 adjustViewsUpOrDown(); 998 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 999 } 1000 } else if (delta < 0) { 1001 /* 1002 * Case 2: Scrolling up. 1003 */ 1004 1005 /* 1006 * Before After 1007 * | | | | 1008 * +-------+ +-------+ 1009 * | A | | A | 1010 * +-------+ => | 1 | 1011 * | B | +-------+ 1012 * | 2 | | B | 1013 * +-------+ +-------+ 1014 * | | | | 1015 * 1016 * Try to keep the top of the item about to become selected where it was. 1017 * newSel = A 1018 * olSel = B 1019 */ 1020 1021 if (newSel != null) { 1022 // Try to position the top of newSel (A) where it was before it was selected 1023 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 1024 true); 1025 } else { 1026 // If (A) was not on screen and so did not have a view, position 1027 // it above the oldSel (B) 1028 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 1029 true); 1030 } 1031 1032 // Some of the newly selected item extends above the top of the list 1033 if (sel.getTop() < topSelectionPixel) { 1034 // Find space required to bring the top of the selected item fully into view 1035 int spaceAbove = topSelectionPixel - sel.getTop(); 1036 1037 // Find space available below the selection into which we can scroll downwards 1038 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 1039 1040 // Don't scroll more than half the height of the list 1041 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1042 int offset = Math.min(spaceAbove, spaceBelow); 1043 offset = Math.min(offset, halfVerticalSpace); 1044 1045 // Offset the selected item to get it into view 1046 sel.offsetTopAndBottom(offset); 1047 } 1048 1049 // Fill in views above and below 1050 fillAboveAndBelow(sel, selectedPosition); 1051 } else { 1052 1053 int oldTop = oldSel.getTop(); 1054 1055 /* 1056 * Case 3: Staying still 1057 */ 1058 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1059 1060 // We're staying still... 1061 if (oldTop < childrenTop) { 1062 // ... but the top of the old selection was off screen. 1063 // (This can happen if the data changes size out from under us) 1064 int newBottom = sel.getBottom(); 1065 if (newBottom < childrenTop + 20) { 1066 // Not enough visible -- bring it onscreen 1067 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1068 } 1069 } 1070 1071 // Fill in views above and below 1072 fillAboveAndBelow(sel, selectedPosition); 1073 } 1074 1075 return sel; 1076 } 1077 1078 private class FocusSelector implements Runnable { 1079 private int mPosition; 1080 private int mPositionTop; 1081 1082 public FocusSelector setup(int position, int top) { 1083 mPosition = position; 1084 mPositionTop = top; 1085 return this; 1086 } 1087 1088 public void run() { 1089 setSelectionFromTop(mPosition, mPositionTop); 1090 } 1091 } 1092 1093 @Override 1094 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1095 if (getChildCount() > 0) { 1096 View focusedChild = getFocusedChild(); 1097 if (focusedChild != null) { 1098 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1099 final int childBottom = focusedChild.getBottom(); 1100 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1101 final int top = focusedChild.getTop() - offset; 1102 if (mFocusSelector == null) { 1103 mFocusSelector = new FocusSelector(); 1104 } 1105 post(mFocusSelector.setup(childPosition, top)); 1106 } 1107 } 1108 super.onSizeChanged(w, h, oldw, oldh); 1109 } 1110 1111 @Override 1112 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1113 // Sets up mListPadding 1114 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1115 1116 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1117 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1118 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1119 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1120 1121 int childWidth = 0; 1122 int childHeight = 0; 1123 int childState = 0; 1124 1125 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1126 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1127 heightMode == MeasureSpec.UNSPECIFIED)) { 1128 final View child = obtainView(0, mIsScrap); 1129 1130 measureScrapChild(child, 0, widthMeasureSpec); 1131 1132 childWidth = child.getMeasuredWidth(); 1133 childHeight = child.getMeasuredHeight(); 1134 childState = combineMeasuredStates(childState, child.getMeasuredState()); 1135 1136 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1137 ((LayoutParams) child.getLayoutParams()).viewType)) { 1138 mRecycler.addScrapView(child, -1); 1139 } 1140 } 1141 1142 if (widthMode == MeasureSpec.UNSPECIFIED) { 1143 widthSize = mListPadding.left + mListPadding.right + childWidth + 1144 getVerticalScrollbarWidth(); 1145 } else { 1146 widthSize |= (childState&MEASURED_STATE_MASK); 1147 } 1148 1149 if (heightMode == MeasureSpec.UNSPECIFIED) { 1150 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1151 getVerticalFadingEdgeLength() * 2; 1152 } 1153 1154 if (heightMode == MeasureSpec.AT_MOST) { 1155 // TODO: after first layout we should maybe start at the first visible position, not 0 1156 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1157 } 1158 1159 setMeasuredDimension(widthSize , heightSize); 1160 mWidthMeasureSpec = widthMeasureSpec; 1161 } 1162 1163 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1164 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1165 if (p == null) { 1166 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1167 child.setLayoutParams(p); 1168 } 1169 p.viewType = mAdapter.getItemViewType(position); 1170 p.forceAdd = true; 1171 1172 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1173 mListPadding.left + mListPadding.right, p.width); 1174 int lpHeight = p.height; 1175 int childHeightSpec; 1176 if (lpHeight > 0) { 1177 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1178 } else { 1179 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1180 } 1181 child.measure(childWidthSpec, childHeightSpec); 1182 } 1183 1184 /** 1185 * @return True to recycle the views used to measure this ListView in 1186 * UNSPECIFIED/AT_MOST modes, false otherwise. 1187 * @hide 1188 */ 1189 @ViewDebug.ExportedProperty(category = "list") 1190 protected boolean recycleOnMeasure() { 1191 return true; 1192 } 1193 1194 /** 1195 * Measures the height of the given range of children (inclusive) and 1196 * returns the height with this ListView's padding and divider heights 1197 * included. If maxHeight is provided, the measuring will stop when the 1198 * current height reaches maxHeight. 1199 * 1200 * @param widthMeasureSpec The width measure spec to be given to a child's 1201 * {@link View#measure(int, int)}. 1202 * @param startPosition The position of the first child to be shown. 1203 * @param endPosition The (inclusive) position of the last child to be 1204 * shown. Specify {@link #NO_POSITION} if the last child should be 1205 * the last available child from the adapter. 1206 * @param maxHeight The maximum height that will be returned (if all the 1207 * children don't fit in this value, this value will be 1208 * returned). 1209 * @param disallowPartialChildPosition In general, whether the returned 1210 * height should only contain entire children. This is more 1211 * powerful--it is the first inclusive position at which partial 1212 * children will not be allowed. Example: it looks nice to have 1213 * at least 3 completely visible children, and in portrait this 1214 * will most likely fit; but in landscape there could be times 1215 * when even 2 children can not be completely shown, so a value 1216 * of 2 (remember, inclusive) would be good (assuming 1217 * startPosition is 0). 1218 * @return The height of this ListView with the given children. 1219 */ 1220 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1221 final int maxHeight, int disallowPartialChildPosition) { 1222 1223 final ListAdapter adapter = mAdapter; 1224 if (adapter == null) { 1225 return mListPadding.top + mListPadding.bottom; 1226 } 1227 1228 // Include the padding of the list 1229 int returnedHeight = mListPadding.top + mListPadding.bottom; 1230 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1231 // The previous height value that was less than maxHeight and contained 1232 // no partial children 1233 int prevHeightWithoutPartialChild = 0; 1234 int i; 1235 View child; 1236 1237 // mItemCount - 1 since endPosition parameter is inclusive 1238 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1239 final AbsListView.RecycleBin recycleBin = mRecycler; 1240 final boolean recyle = recycleOnMeasure(); 1241 final boolean[] isScrap = mIsScrap; 1242 1243 for (i = startPosition; i <= endPosition; ++i) { 1244 child = obtainView(i, isScrap); 1245 1246 measureScrapChild(child, i, widthMeasureSpec); 1247 1248 if (i > 0) { 1249 // Count the divider for all but one child 1250 returnedHeight += dividerHeight; 1251 } 1252 1253 // Recycle the view before we possibly return from the method 1254 if (recyle && recycleBin.shouldRecycleViewType( 1255 ((LayoutParams) child.getLayoutParams()).viewType)) { 1256 recycleBin.addScrapView(child, -1); 1257 } 1258 1259 returnedHeight += child.getMeasuredHeight(); 1260 1261 if (returnedHeight >= maxHeight) { 1262 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1263 // then the i'th position did not fit completely. 1264 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1265 && (i > disallowPartialChildPosition) // We've past the min pos 1266 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1267 && (returnedHeight != maxHeight) // i'th child did not fit completely 1268 ? prevHeightWithoutPartialChild 1269 : maxHeight; 1270 } 1271 1272 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1273 prevHeightWithoutPartialChild = returnedHeight; 1274 } 1275 } 1276 1277 // At this point, we went through the range of children, and they each 1278 // completely fit, so return the returnedHeight 1279 return returnedHeight; 1280 } 1281 1282 @Override 1283 int findMotionRow(int y) { 1284 int childCount = getChildCount(); 1285 if (childCount > 0) { 1286 if (!mStackFromBottom) { 1287 for (int i = 0; i < childCount; i++) { 1288 View v = getChildAt(i); 1289 if (y <= v.getBottom()) { 1290 return mFirstPosition + i; 1291 } 1292 } 1293 } else { 1294 for (int i = childCount - 1; i >= 0; i--) { 1295 View v = getChildAt(i); 1296 if (y >= v.getTop()) { 1297 return mFirstPosition + i; 1298 } 1299 } 1300 } 1301 } 1302 return INVALID_POSITION; 1303 } 1304 1305 /** 1306 * Put a specific item at a specific location on the screen and then build 1307 * up and down from there. 1308 * 1309 * @param position The reference view to use as the starting point 1310 * @param top Pixel offset from the top of this view to the top of the 1311 * reference view. 1312 * 1313 * @return The selected view, or null if the selected view is outside the 1314 * visible area. 1315 */ 1316 private View fillSpecific(int position, int top) { 1317 boolean tempIsSelected = position == mSelectedPosition; 1318 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1319 // Possibly changed again in fillUp if we add rows above this one. 1320 mFirstPosition = position; 1321 1322 View above; 1323 View below; 1324 1325 final int dividerHeight = mDividerHeight; 1326 if (!mStackFromBottom) { 1327 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1328 // This will correct for the top of the first view not touching the top of the list 1329 adjustViewsUpOrDown(); 1330 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1331 int childCount = getChildCount(); 1332 if (childCount > 0) { 1333 correctTooHigh(childCount); 1334 } 1335 } else { 1336 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1337 // This will correct for the bottom of the last view not touching the bottom of the list 1338 adjustViewsUpOrDown(); 1339 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1340 int childCount = getChildCount(); 1341 if (childCount > 0) { 1342 correctTooLow(childCount); 1343 } 1344 } 1345 1346 if (tempIsSelected) { 1347 return temp; 1348 } else if (above != null) { 1349 return above; 1350 } else { 1351 return below; 1352 } 1353 } 1354 1355 /** 1356 * Check if we have dragged the bottom of the list too high (we have pushed the 1357 * top element off the top of the screen when we did not need to). Correct by sliding 1358 * everything back down. 1359 * 1360 * @param childCount Number of children 1361 */ 1362 private void correctTooHigh(int childCount) { 1363 // First see if the last item is visible. If it is not, it is OK for the 1364 // top of the list to be pushed up. 1365 int lastPosition = mFirstPosition + childCount - 1; 1366 if (lastPosition == mItemCount - 1 && childCount > 0) { 1367 1368 // Get the last child ... 1369 final View lastChild = getChildAt(childCount - 1); 1370 1371 // ... and its bottom edge 1372 final int lastBottom = lastChild.getBottom(); 1373 1374 // This is bottom of our drawable area 1375 final int end = (mBottom - mTop) - mListPadding.bottom; 1376 1377 // This is how far the bottom edge of the last view is from the bottom of the 1378 // drawable area 1379 int bottomOffset = end - lastBottom; 1380 View firstChild = getChildAt(0); 1381 final int firstTop = firstChild.getTop(); 1382 1383 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1384 // first row or the first row is scrolled off the top of the drawable area 1385 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1386 if (mFirstPosition == 0) { 1387 // Don't pull the top too far down 1388 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1389 } 1390 // Move everything down 1391 offsetChildrenTopAndBottom(bottomOffset); 1392 if (mFirstPosition > 0) { 1393 // Fill the gap that was opened above mFirstPosition with more rows, if 1394 // possible 1395 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1396 // Close up the remaining gap 1397 adjustViewsUpOrDown(); 1398 } 1399 1400 } 1401 } 1402 } 1403 1404 /** 1405 * Check if we have dragged the bottom of the list too low (we have pushed the 1406 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1407 * everything back up. 1408 * 1409 * @param childCount Number of children 1410 */ 1411 private void correctTooLow(int childCount) { 1412 // First see if the first item is visible. If it is not, it is OK for the 1413 // bottom of the list to be pushed down. 1414 if (mFirstPosition == 0 && childCount > 0) { 1415 1416 // Get the first child ... 1417 final View firstChild = getChildAt(0); 1418 1419 // ... and its top edge 1420 final int firstTop = firstChild.getTop(); 1421 1422 // This is top of our drawable area 1423 final int start = mListPadding.top; 1424 1425 // This is bottom of our drawable area 1426 final int end = (mBottom - mTop) - mListPadding.bottom; 1427 1428 // This is how far the top edge of the first view is from the top of the 1429 // drawable area 1430 int topOffset = firstTop - start; 1431 View lastChild = getChildAt(childCount - 1); 1432 final int lastBottom = lastChild.getBottom(); 1433 int lastPosition = mFirstPosition + childCount - 1; 1434 1435 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1436 // last row or the last row is scrolled off the bottom of the drawable area 1437 if (topOffset > 0) { 1438 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1439 if (lastPosition == mItemCount - 1) { 1440 // Don't pull the bottom too far up 1441 topOffset = Math.min(topOffset, lastBottom - end); 1442 } 1443 // Move everything up 1444 offsetChildrenTopAndBottom(-topOffset); 1445 if (lastPosition < mItemCount - 1) { 1446 // Fill the gap that was opened below the last position with more rows, if 1447 // possible 1448 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1449 // Close up the remaining gap 1450 adjustViewsUpOrDown(); 1451 } 1452 } else if (lastPosition == mItemCount - 1) { 1453 adjustViewsUpOrDown(); 1454 } 1455 } 1456 } 1457 } 1458 1459 @Override 1460 protected void layoutChildren() { 1461 final boolean blockLayoutRequests = mBlockLayoutRequests; 1462 if (!blockLayoutRequests) { 1463 mBlockLayoutRequests = true; 1464 } else { 1465 return; 1466 } 1467 1468 try { 1469 super.layoutChildren(); 1470 1471 invalidate(); 1472 1473 if (mAdapter == null) { 1474 resetList(); 1475 invokeOnItemScrollListener(); 1476 return; 1477 } 1478 1479 int childrenTop = mListPadding.top; 1480 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1481 1482 int childCount = getChildCount(); 1483 int index = 0; 1484 int delta = 0; 1485 1486 View sel; 1487 View oldSel = null; 1488 View oldFirst = null; 1489 View newSel = null; 1490 1491 View focusLayoutRestoreView = null; 1492 1493 // Remember stuff we will need down below 1494 switch (mLayoutMode) { 1495 case LAYOUT_SET_SELECTION: 1496 index = mNextSelectedPosition - mFirstPosition; 1497 if (index >= 0 && index < childCount) { 1498 newSel = getChildAt(index); 1499 } 1500 break; 1501 case LAYOUT_FORCE_TOP: 1502 case LAYOUT_FORCE_BOTTOM: 1503 case LAYOUT_SPECIFIC: 1504 case LAYOUT_SYNC: 1505 break; 1506 case LAYOUT_MOVE_SELECTION: 1507 default: 1508 // Remember the previously selected view 1509 index = mSelectedPosition - mFirstPosition; 1510 if (index >= 0 && index < childCount) { 1511 oldSel = getChildAt(index); 1512 } 1513 1514 // Remember the previous first child 1515 oldFirst = getChildAt(0); 1516 1517 if (mNextSelectedPosition >= 0) { 1518 delta = mNextSelectedPosition - mSelectedPosition; 1519 } 1520 1521 // Caution: newSel might be null 1522 newSel = getChildAt(index + delta); 1523 } 1524 1525 1526 boolean dataChanged = mDataChanged; 1527 if (dataChanged) { 1528 handleDataChanged(); 1529 } 1530 1531 // Handle the empty set by removing all views that are visible 1532 // and calling it a day 1533 if (mItemCount == 0) { 1534 resetList(); 1535 invokeOnItemScrollListener(); 1536 return; 1537 } else if (mItemCount != mAdapter.getCount()) { 1538 throw new IllegalStateException("The content of the adapter has changed but " 1539 + "ListView did not receive a notification. Make sure the content of " 1540 + "your adapter is not modified from a background thread, but only " 1541 + "from the UI thread. [in ListView(" + getId() + ", " + getClass() 1542 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1543 } 1544 1545 setSelectedPositionInt(mNextSelectedPosition); 1546 1547 // Pull all children into the RecycleBin. 1548 // These views will be reused if possible 1549 final int firstPosition = mFirstPosition; 1550 final RecycleBin recycleBin = mRecycler; 1551 1552 // reset the focus restoration 1553 View focusLayoutRestoreDirectChild = null; 1554 1555 // Don't put header or footer views into the Recycler. Those are 1556 // already cached in mHeaderViews; 1557 if (dataChanged) { 1558 for (int i = 0; i < childCount; i++) { 1559 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1560 if (ViewDebug.TRACE_RECYCLER) { 1561 ViewDebug.trace(getChildAt(i), 1562 ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i); 1563 } 1564 } 1565 } else { 1566 recycleBin.fillActiveViews(childCount, firstPosition); 1567 } 1568 1569 // take focus back to us temporarily to avoid the eventual 1570 // call to clear focus when removing the focused child below 1571 // from messing things up when ViewAncestor assigns focus back 1572 // to someone else 1573 final View focusedChild = getFocusedChild(); 1574 if (focusedChild != null) { 1575 // TODO: in some cases focusedChild.getParent() == null 1576 1577 // we can remember the focused view to restore after relayout if the 1578 // data hasn't changed, or if the focused position is a header or footer 1579 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1580 focusLayoutRestoreDirectChild = focusedChild; 1581 // remember the specific view that had focus 1582 focusLayoutRestoreView = findFocus(); 1583 if (focusLayoutRestoreView != null) { 1584 // tell it we are going to mess with it 1585 focusLayoutRestoreView.onStartTemporaryDetach(); 1586 } 1587 } 1588 requestFocus(); 1589 } 1590 1591 // Clear out old views 1592 detachAllViewsFromParent(); 1593 recycleBin.removeSkippedScrap(); 1594 1595 switch (mLayoutMode) { 1596 case LAYOUT_SET_SELECTION: 1597 if (newSel != null) { 1598 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1599 } else { 1600 sel = fillFromMiddle(childrenTop, childrenBottom); 1601 } 1602 break; 1603 case LAYOUT_SYNC: 1604 sel = fillSpecific(mSyncPosition, mSpecificTop); 1605 break; 1606 case LAYOUT_FORCE_BOTTOM: 1607 sel = fillUp(mItemCount - 1, childrenBottom); 1608 adjustViewsUpOrDown(); 1609 break; 1610 case LAYOUT_FORCE_TOP: 1611 mFirstPosition = 0; 1612 sel = fillFromTop(childrenTop); 1613 adjustViewsUpOrDown(); 1614 break; 1615 case LAYOUT_SPECIFIC: 1616 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1617 break; 1618 case LAYOUT_MOVE_SELECTION: 1619 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1620 break; 1621 default: 1622 if (childCount == 0) { 1623 if (!mStackFromBottom) { 1624 final int position = lookForSelectablePosition(0, true); 1625 setSelectedPositionInt(position); 1626 sel = fillFromTop(childrenTop); 1627 } else { 1628 final int position = lookForSelectablePosition(mItemCount - 1, false); 1629 setSelectedPositionInt(position); 1630 sel = fillUp(mItemCount - 1, childrenBottom); 1631 } 1632 } else { 1633 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1634 sel = fillSpecific(mSelectedPosition, 1635 oldSel == null ? childrenTop : oldSel.getTop()); 1636 } else if (mFirstPosition < mItemCount) { 1637 sel = fillSpecific(mFirstPosition, 1638 oldFirst == null ? childrenTop : oldFirst.getTop()); 1639 } else { 1640 sel = fillSpecific(0, childrenTop); 1641 } 1642 } 1643 break; 1644 } 1645 1646 // Flush any cached views that did not get reused above 1647 recycleBin.scrapActiveViews(); 1648 1649 if (sel != null) { 1650 // the current selected item should get focus if items 1651 // are focusable 1652 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1653 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1654 focusLayoutRestoreView != null && 1655 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1656 if (!focusWasTaken) { 1657 // selected item didn't take focus, fine, but still want 1658 // to make sure something else outside of the selected view 1659 // has focus 1660 final View focused = getFocusedChild(); 1661 if (focused != null) { 1662 focused.clearFocus(); 1663 } 1664 positionSelector(INVALID_POSITION, sel); 1665 } else { 1666 sel.setSelected(false); 1667 mSelectorRect.setEmpty(); 1668 } 1669 } else { 1670 positionSelector(INVALID_POSITION, sel); 1671 } 1672 mSelectedTop = sel.getTop(); 1673 } else { 1674 if (mTouchMode > TOUCH_MODE_DOWN && mTouchMode < TOUCH_MODE_SCROLL) { 1675 View child = getChildAt(mMotionPosition - mFirstPosition); 1676 if (child != null) positionSelector(mMotionPosition, child); 1677 } else { 1678 mSelectedTop = 0; 1679 mSelectorRect.setEmpty(); 1680 } 1681 1682 // even if there is not selected position, we may need to restore 1683 // focus (i.e. something focusable in touch mode) 1684 if (hasFocus() && focusLayoutRestoreView != null) { 1685 focusLayoutRestoreView.requestFocus(); 1686 } 1687 } 1688 1689 // tell focus view we are done mucking with it, if it is still in 1690 // our view hierarchy. 1691 if (focusLayoutRestoreView != null 1692 && focusLayoutRestoreView.getWindowToken() != null) { 1693 focusLayoutRestoreView.onFinishTemporaryDetach(); 1694 } 1695 1696 mLayoutMode = LAYOUT_NORMAL; 1697 mDataChanged = false; 1698 mNeedSync = false; 1699 setNextSelectedPositionInt(mSelectedPosition); 1700 1701 updateScrollIndicators(); 1702 1703 if (mItemCount > 0) { 1704 checkSelectionChanged(); 1705 } 1706 1707 invokeOnItemScrollListener(); 1708 } finally { 1709 if (!blockLayoutRequests) { 1710 mBlockLayoutRequests = false; 1711 } 1712 } 1713 } 1714 1715 /** 1716 * @param child a direct child of this list. 1717 * @return Whether child is a header or footer view. 1718 */ 1719 private boolean isDirectChildHeaderOrFooter(View child) { 1720 1721 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1722 final int numHeaders = headers.size(); 1723 for (int i = 0; i < numHeaders; i++) { 1724 if (child == headers.get(i).view) { 1725 return true; 1726 } 1727 } 1728 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1729 final int numFooters = footers.size(); 1730 for (int i = 0; i < numFooters; i++) { 1731 if (child == footers.get(i).view) { 1732 return true; 1733 } 1734 } 1735 return false; 1736 } 1737 1738 /** 1739 * Obtain the view and add it to our list of children. The view can be made 1740 * fresh, converted from an unused view, or used as is if it was in the 1741 * recycle bin. 1742 * 1743 * @param position Logical position in the list 1744 * @param y Top or bottom edge of the view to add 1745 * @param flow If flow is true, align top edge to y. If false, align bottom 1746 * edge to y. 1747 * @param childrenLeft Left edge where children should be positioned 1748 * @param selected Is this position selected? 1749 * @return View that was added 1750 */ 1751 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1752 boolean selected) { 1753 View child; 1754 1755 1756 if (!mDataChanged) { 1757 // Try to use an existing view for this position 1758 child = mRecycler.getActiveView(position); 1759 if (child != null) { 1760 if (ViewDebug.TRACE_RECYCLER) { 1761 ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, 1762 position, getChildCount()); 1763 } 1764 1765 // Found it -- we're using an existing child 1766 // This just needs to be positioned 1767 setupChild(child, position, y, flow, childrenLeft, selected, true); 1768 1769 return child; 1770 } 1771 } 1772 1773 // Make a new view for this position, or convert an unused view if possible 1774 child = obtainView(position, mIsScrap); 1775 1776 // This needs to be positioned and measured 1777 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1778 1779 return child; 1780 } 1781 1782 /** 1783 * Add a view as a child and make sure it is measured (if necessary) and 1784 * positioned properly. 1785 * 1786 * @param child The view to add 1787 * @param position The position of this child 1788 * @param y The y position relative to which this view will be positioned 1789 * @param flowDown If true, align top edge to y. If false, align bottom 1790 * edge to y. 1791 * @param childrenLeft Left edge where children should be positioned 1792 * @param selected Is this position selected? 1793 * @param recycled Has this view been pulled from the recycle bin? If so it 1794 * does not need to be remeasured. 1795 */ 1796 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1797 boolean selected, boolean recycled) { 1798 final boolean isSelected = selected && shouldShowSelector(); 1799 final boolean updateChildSelected = isSelected != child.isSelected(); 1800 final int mode = mTouchMode; 1801 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1802 mMotionPosition == position; 1803 final boolean updateChildPressed = isPressed != child.isPressed(); 1804 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1805 1806 // Respect layout params that are already in the view. Otherwise make some up... 1807 // noinspection unchecked 1808 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1809 if (p == null) { 1810 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1811 } 1812 p.viewType = mAdapter.getItemViewType(position); 1813 1814 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1815 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1816 attachViewToParent(child, flowDown ? -1 : 0, p); 1817 } else { 1818 p.forceAdd = false; 1819 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1820 p.recycledHeaderFooter = true; 1821 } 1822 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1823 } 1824 1825 if (updateChildSelected) { 1826 child.setSelected(isSelected); 1827 } 1828 1829 if (updateChildPressed) { 1830 child.setPressed(isPressed); 1831 } 1832 1833 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1834 if (child instanceof Checkable) { 1835 ((Checkable) child).setChecked(mCheckStates.get(position)); 1836 } else if (getContext().getApplicationInfo().targetSdkVersion 1837 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1838 child.setActivated(mCheckStates.get(position)); 1839 } 1840 } 1841 1842 if (needToMeasure) { 1843 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1844 mListPadding.left + mListPadding.right, p.width); 1845 int lpHeight = p.height; 1846 int childHeightSpec; 1847 if (lpHeight > 0) { 1848 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1849 } else { 1850 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1851 } 1852 child.measure(childWidthSpec, childHeightSpec); 1853 } else { 1854 cleanupLayoutState(child); 1855 } 1856 1857 final int w = child.getMeasuredWidth(); 1858 final int h = child.getMeasuredHeight(); 1859 final int childTop = flowDown ? y : y - h; 1860 1861 if (needToMeasure) { 1862 final int childRight = childrenLeft + w; 1863 final int childBottom = childTop + h; 1864 child.layout(childrenLeft, childTop, childRight, childBottom); 1865 } else { 1866 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1867 child.offsetTopAndBottom(childTop - child.getTop()); 1868 } 1869 1870 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1871 child.setDrawingCacheEnabled(true); 1872 } 1873 1874 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1875 != position) { 1876 child.jumpDrawablesToCurrentState(); 1877 } 1878 } 1879 1880 @Override 1881 protected boolean canAnimate() { 1882 return super.canAnimate() && mItemCount > 0; 1883 } 1884 1885 /** 1886 * Sets the currently selected item. If in touch mode, the item will not be selected 1887 * but it will still be positioned appropriately. If the specified selection position 1888 * is less than 0, then the item at position 0 will be selected. 1889 * 1890 * @param position Index (starting at 0) of the data item to be selected. 1891 */ 1892 @Override 1893 public void setSelection(int position) { 1894 setSelectionFromTop(position, 0); 1895 } 1896 1897 /** 1898 * Sets the selected item and positions the selection y pixels from the top edge 1899 * of the ListView. (If in touch mode, the item will not be selected but it will 1900 * still be positioned appropriately.) 1901 * 1902 * @param position Index (starting at 0) of the data item to be selected. 1903 * @param y The distance from the top edge of the ListView (plus padding) that the 1904 * item will be positioned. 1905 */ 1906 public void setSelectionFromTop(int position, int y) { 1907 if (mAdapter == null) { 1908 return; 1909 } 1910 1911 if (!isInTouchMode()) { 1912 position = lookForSelectablePosition(position, true); 1913 if (position >= 0) { 1914 setNextSelectedPositionInt(position); 1915 } 1916 } else { 1917 mResurrectToPosition = position; 1918 } 1919 1920 if (position >= 0) { 1921 mLayoutMode = LAYOUT_SPECIFIC; 1922 mSpecificTop = mListPadding.top + y; 1923 1924 if (mNeedSync) { 1925 mSyncPosition = position; 1926 mSyncRowId = mAdapter.getItemId(position); 1927 } 1928 1929 if (mPositionScroller != null) { 1930 mPositionScroller.stop(); 1931 } 1932 requestLayout(); 1933 } 1934 } 1935 1936 /** 1937 * Makes the item at the supplied position selected. 1938 * 1939 * @param position the position of the item to select 1940 */ 1941 @Override 1942 void setSelectionInt(int position) { 1943 setNextSelectedPositionInt(position); 1944 boolean awakeScrollbars = false; 1945 1946 final int selectedPosition = mSelectedPosition; 1947 1948 if (selectedPosition >= 0) { 1949 if (position == selectedPosition - 1) { 1950 awakeScrollbars = true; 1951 } else if (position == selectedPosition + 1) { 1952 awakeScrollbars = true; 1953 } 1954 } 1955 1956 if (mPositionScroller != null) { 1957 mPositionScroller.stop(); 1958 } 1959 1960 layoutChildren(); 1961 1962 if (awakeScrollbars) { 1963 awakenScrollBars(); 1964 } 1965 } 1966 1967 /** 1968 * Find a position that can be selected (i.e., is not a separator). 1969 * 1970 * @param position The starting position to look at. 1971 * @param lookDown Whether to look down for other positions. 1972 * @return The next selectable position starting at position and then searching either up or 1973 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1974 */ 1975 @Override 1976 int lookForSelectablePosition(int position, boolean lookDown) { 1977 final ListAdapter adapter = mAdapter; 1978 if (adapter == null || isInTouchMode()) { 1979 return INVALID_POSITION; 1980 } 1981 1982 final int count = adapter.getCount(); 1983 if (!mAreAllItemsSelectable) { 1984 if (lookDown) { 1985 position = Math.max(0, position); 1986 while (position < count && !adapter.isEnabled(position)) { 1987 position++; 1988 } 1989 } else { 1990 position = Math.min(position, count - 1); 1991 while (position >= 0 && !adapter.isEnabled(position)) { 1992 position--; 1993 } 1994 } 1995 1996 if (position < 0 || position >= count) { 1997 return INVALID_POSITION; 1998 } 1999 return position; 2000 } else { 2001 if (position < 0 || position >= count) { 2002 return INVALID_POSITION; 2003 } 2004 return position; 2005 } 2006 } 2007 2008 /** 2009 * setSelectionAfterHeaderView set the selection to be the first list item 2010 * after the header views. 2011 */ 2012 public void setSelectionAfterHeaderView() { 2013 final int count = mHeaderViewInfos.size(); 2014 if (count > 0) { 2015 mNextSelectedPosition = 0; 2016 return; 2017 } 2018 2019 if (mAdapter != null) { 2020 setSelection(count); 2021 } else { 2022 mNextSelectedPosition = count; 2023 mLayoutMode = LAYOUT_SET_SELECTION; 2024 } 2025 2026 } 2027 2028 @Override 2029 public boolean dispatchKeyEvent(KeyEvent event) { 2030 // Dispatch in the normal way 2031 boolean handled = super.dispatchKeyEvent(event); 2032 if (!handled) { 2033 // If we didn't handle it... 2034 View focused = getFocusedChild(); 2035 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2036 // ... and our focused child didn't handle it 2037 // ... give it to ourselves so we can scroll if necessary 2038 handled = onKeyDown(event.getKeyCode(), event); 2039 } 2040 } 2041 return handled; 2042 } 2043 2044 @Override 2045 public boolean onKeyDown(int keyCode, KeyEvent event) { 2046 return commonKey(keyCode, 1, event); 2047 } 2048 2049 @Override 2050 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2051 return commonKey(keyCode, repeatCount, event); 2052 } 2053 2054 @Override 2055 public boolean onKeyUp(int keyCode, KeyEvent event) { 2056 return commonKey(keyCode, 1, event); 2057 } 2058 2059 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2060 if (mAdapter == null || !mIsAttached) { 2061 return false; 2062 } 2063 2064 if (mDataChanged) { 2065 layoutChildren(); 2066 } 2067 2068 boolean handled = false; 2069 int action = event.getAction(); 2070 2071 if (action != KeyEvent.ACTION_UP) { 2072 switch (keyCode) { 2073 case KeyEvent.KEYCODE_DPAD_UP: 2074 if (event.hasNoModifiers()) { 2075 handled = resurrectSelectionIfNeeded(); 2076 if (!handled) { 2077 while (count-- > 0) { 2078 if (arrowScroll(FOCUS_UP)) { 2079 handled = true; 2080 } else { 2081 break; 2082 } 2083 } 2084 } 2085 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2086 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2087 } 2088 break; 2089 2090 case KeyEvent.KEYCODE_DPAD_DOWN: 2091 if (event.hasNoModifiers()) { 2092 handled = resurrectSelectionIfNeeded(); 2093 if (!handled) { 2094 while (count-- > 0) { 2095 if (arrowScroll(FOCUS_DOWN)) { 2096 handled = true; 2097 } else { 2098 break; 2099 } 2100 } 2101 } 2102 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2103 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2104 } 2105 break; 2106 2107 case KeyEvent.KEYCODE_DPAD_LEFT: 2108 if (event.hasNoModifiers()) { 2109 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2110 } 2111 break; 2112 2113 case KeyEvent.KEYCODE_DPAD_RIGHT: 2114 if (event.hasNoModifiers()) { 2115 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2116 } 2117 break; 2118 2119 case KeyEvent.KEYCODE_DPAD_CENTER: 2120 case KeyEvent.KEYCODE_ENTER: 2121 if (event.hasNoModifiers()) { 2122 handled = resurrectSelectionIfNeeded(); 2123 if (!handled 2124 && event.getRepeatCount() == 0 && getChildCount() > 0) { 2125 keyPressed(); 2126 handled = true; 2127 } 2128 } 2129 break; 2130 2131 case KeyEvent.KEYCODE_SPACE: 2132 if (mPopup == null || !mPopup.isShowing()) { 2133 if (event.hasNoModifiers()) { 2134 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2135 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2136 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2137 } 2138 handled = true; 2139 } 2140 break; 2141 2142 case KeyEvent.KEYCODE_PAGE_UP: 2143 if (event.hasNoModifiers()) { 2144 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2145 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2146 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2147 } 2148 break; 2149 2150 case KeyEvent.KEYCODE_PAGE_DOWN: 2151 if (event.hasNoModifiers()) { 2152 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2153 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2154 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2155 } 2156 break; 2157 2158 case KeyEvent.KEYCODE_MOVE_HOME: 2159 if (event.hasNoModifiers()) { 2160 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2161 } 2162 break; 2163 2164 case KeyEvent.KEYCODE_MOVE_END: 2165 if (event.hasNoModifiers()) { 2166 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2167 } 2168 break; 2169 2170 case KeyEvent.KEYCODE_TAB: 2171 // XXX Sometimes it is useful to be able to TAB through the items in 2172 // a ListView sequentially. Unfortunately this can create an 2173 // asymmetry in TAB navigation order unless the list selection 2174 // always reverts to the top or bottom when receiving TAB focus from 2175 // another widget. Leaving this behavior disabled for now but 2176 // perhaps it should be configurable (and more comprehensive). 2177 if (false) { 2178 if (event.hasNoModifiers()) { 2179 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_DOWN); 2180 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2181 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_UP); 2182 } 2183 } 2184 break; 2185 } 2186 } 2187 2188 if (handled) { 2189 return true; 2190 } 2191 2192 if (sendToTextFilter(keyCode, count, event)) { 2193 return true; 2194 } 2195 2196 switch (action) { 2197 case KeyEvent.ACTION_DOWN: 2198 return super.onKeyDown(keyCode, event); 2199 2200 case KeyEvent.ACTION_UP: 2201 return super.onKeyUp(keyCode, event); 2202 2203 case KeyEvent.ACTION_MULTIPLE: 2204 return super.onKeyMultiple(keyCode, count, event); 2205 2206 default: // shouldn't happen 2207 return false; 2208 } 2209 } 2210 2211 /** 2212 * Scrolls up or down by the number of items currently present on screen. 2213 * 2214 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2215 * @return whether selection was moved 2216 */ 2217 boolean pageScroll(int direction) { 2218 int nextPage = -1; 2219 boolean down = false; 2220 2221 if (direction == FOCUS_UP) { 2222 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2223 } else if (direction == FOCUS_DOWN) { 2224 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2225 down = true; 2226 } 2227 2228 if (nextPage >= 0) { 2229 int position = lookForSelectablePosition(nextPage, down); 2230 if (position >= 0) { 2231 mLayoutMode = LAYOUT_SPECIFIC; 2232 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2233 2234 if (down && position > mItemCount - getChildCount()) { 2235 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2236 } 2237 2238 if (!down && position < getChildCount()) { 2239 mLayoutMode = LAYOUT_FORCE_TOP; 2240 } 2241 2242 setSelectionInt(position); 2243 invokeOnItemScrollListener(); 2244 if (!awakenScrollBars()) { 2245 invalidate(); 2246 } 2247 2248 return true; 2249 } 2250 } 2251 2252 return false; 2253 } 2254 2255 /** 2256 * Go to the last or first item if possible (not worrying about panning across or navigating 2257 * within the internal focus of the currently selected item.) 2258 * 2259 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2260 * 2261 * @return whether selection was moved 2262 */ 2263 boolean fullScroll(int direction) { 2264 boolean moved = false; 2265 if (direction == FOCUS_UP) { 2266 if (mSelectedPosition != 0) { 2267 int position = lookForSelectablePosition(0, true); 2268 if (position >= 0) { 2269 mLayoutMode = LAYOUT_FORCE_TOP; 2270 setSelectionInt(position); 2271 invokeOnItemScrollListener(); 2272 } 2273 moved = true; 2274 } 2275 } else if (direction == FOCUS_DOWN) { 2276 if (mSelectedPosition < mItemCount - 1) { 2277 int position = lookForSelectablePosition(mItemCount - 1, true); 2278 if (position >= 0) { 2279 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2280 setSelectionInt(position); 2281 invokeOnItemScrollListener(); 2282 } 2283 moved = true; 2284 } 2285 } 2286 2287 if (moved && !awakenScrollBars()) { 2288 awakenScrollBars(); 2289 invalidate(); 2290 } 2291 2292 return moved; 2293 } 2294 2295 /** 2296 * To avoid horizontal focus searches changing the selected item, we 2297 * manually focus search within the selected item (as applicable), and 2298 * prevent focus from jumping to something within another item. 2299 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2300 * @return Whether this consumes the key event. 2301 */ 2302 private boolean handleHorizontalFocusWithinListItem(int direction) { 2303 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2304 throw new IllegalArgumentException("direction must be one of" 2305 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2306 } 2307 2308 final int numChildren = getChildCount(); 2309 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2310 final View selectedView = getSelectedView(); 2311 if (selectedView != null && selectedView.hasFocus() && 2312 selectedView instanceof ViewGroup) { 2313 2314 final View currentFocus = selectedView.findFocus(); 2315 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2316 (ViewGroup) selectedView, currentFocus, direction); 2317 if (nextFocus != null) { 2318 // do the math to get interesting rect in next focus' coordinates 2319 currentFocus.getFocusedRect(mTempRect); 2320 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2321 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2322 if (nextFocus.requestFocus(direction, mTempRect)) { 2323 return true; 2324 } 2325 } 2326 // we are blocking the key from being handled (by returning true) 2327 // if the global result is going to be some other view within this 2328 // list. this is to acheive the overall goal of having 2329 // horizontal d-pad navigation remain in the current item. 2330 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2331 (ViewGroup) getRootView(), currentFocus, direction); 2332 if (globalNextFocus != null) { 2333 return isViewAncestorOf(globalNextFocus, this); 2334 } 2335 } 2336 } 2337 return false; 2338 } 2339 2340 /** 2341 * Scrolls to the next or previous item if possible. 2342 * 2343 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2344 * 2345 * @return whether selection was moved 2346 */ 2347 boolean arrowScroll(int direction) { 2348 try { 2349 mInLayout = true; 2350 final boolean handled = arrowScrollImpl(direction); 2351 if (handled) { 2352 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2353 } 2354 return handled; 2355 } finally { 2356 mInLayout = false; 2357 } 2358 } 2359 2360 /** 2361 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2362 * whether there are focusable items etc. 2363 * 2364 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2365 * @return Whether any scrolling, selection or focus change occured. 2366 */ 2367 private boolean arrowScrollImpl(int direction) { 2368 if (getChildCount() <= 0) { 2369 return false; 2370 } 2371 2372 View selectedView = getSelectedView(); 2373 int selectedPos = mSelectedPosition; 2374 2375 int nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 2376 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2377 2378 // if we are moving focus, we may OVERRIDE the default behavior 2379 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2380 if (focusResult != null) { 2381 nextSelectedPosition = focusResult.getSelectedPosition(); 2382 amountToScroll = focusResult.getAmountToScroll(); 2383 } 2384 2385 boolean needToRedraw = focusResult != null; 2386 if (nextSelectedPosition != INVALID_POSITION) { 2387 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2388 setSelectedPositionInt(nextSelectedPosition); 2389 setNextSelectedPositionInt(nextSelectedPosition); 2390 selectedView = getSelectedView(); 2391 selectedPos = nextSelectedPosition; 2392 if (mItemsCanFocus && focusResult == null) { 2393 // there was no new view found to take focus, make sure we 2394 // don't leave focus with the old selection 2395 final View focused = getFocusedChild(); 2396 if (focused != null) { 2397 focused.clearFocus(); 2398 } 2399 } 2400 needToRedraw = true; 2401 checkSelectionChanged(); 2402 } 2403 2404 if (amountToScroll > 0) { 2405 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2406 needToRedraw = true; 2407 } 2408 2409 // if we didn't find a new focusable, make sure any existing focused 2410 // item that was panned off screen gives up focus. 2411 if (mItemsCanFocus && (focusResult == null) 2412 && selectedView != null && selectedView.hasFocus()) { 2413 final View focused = selectedView.findFocus(); 2414 if (!isViewAncestorOf(focused, this) || distanceToView(focused) > 0) { 2415 focused.clearFocus(); 2416 } 2417 } 2418 2419 // if the current selection is panned off, we need to remove the selection 2420 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2421 && !isViewAncestorOf(selectedView, this)) { 2422 selectedView = null; 2423 hideSelector(); 2424 2425 // but we don't want to set the ressurect position (that would make subsequent 2426 // unhandled key events bring back the item we just scrolled off!) 2427 mResurrectToPosition = INVALID_POSITION; 2428 } 2429 2430 if (needToRedraw) { 2431 if (selectedView != null) { 2432 positionSelector(selectedPos, selectedView); 2433 mSelectedTop = selectedView.getTop(); 2434 } 2435 if (!awakenScrollBars()) { 2436 invalidate(); 2437 } 2438 invokeOnItemScrollListener(); 2439 return true; 2440 } 2441 2442 return false; 2443 } 2444 2445 /** 2446 * When selection changes, it is possible that the previously selected or the 2447 * next selected item will change its size. If so, we need to offset some folks, 2448 * and re-layout the items as appropriate. 2449 * 2450 * @param selectedView The currently selected view (before changing selection). 2451 * should be <code>null</code> if there was no previous selection. 2452 * @param direction Either {@link android.view.View#FOCUS_UP} or 2453 * {@link android.view.View#FOCUS_DOWN}. 2454 * @param newSelectedPosition The position of the next selection. 2455 * @param newFocusAssigned whether new focus was assigned. This matters because 2456 * when something has focus, we don't want to show selection (ugh). 2457 */ 2458 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2459 boolean newFocusAssigned) { 2460 if (newSelectedPosition == INVALID_POSITION) { 2461 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2462 } 2463 2464 // whether or not we are moving down or up, we want to preserve the 2465 // top of whatever view is on top: 2466 // - moving down: the view that had selection 2467 // - moving up: the view that is getting selection 2468 View topView; 2469 View bottomView; 2470 int topViewIndex, bottomViewIndex; 2471 boolean topSelected = false; 2472 final int selectedIndex = mSelectedPosition - mFirstPosition; 2473 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2474 if (direction == View.FOCUS_UP) { 2475 topViewIndex = nextSelectedIndex; 2476 bottomViewIndex = selectedIndex; 2477 topView = getChildAt(topViewIndex); 2478 bottomView = selectedView; 2479 topSelected = true; 2480 } else { 2481 topViewIndex = selectedIndex; 2482 bottomViewIndex = nextSelectedIndex; 2483 topView = selectedView; 2484 bottomView = getChildAt(bottomViewIndex); 2485 } 2486 2487 final int numChildren = getChildCount(); 2488 2489 // start with top view: is it changing size? 2490 if (topView != null) { 2491 topView.setSelected(!newFocusAssigned && topSelected); 2492 measureAndAdjustDown(topView, topViewIndex, numChildren); 2493 } 2494 2495 // is the bottom view changing size? 2496 if (bottomView != null) { 2497 bottomView.setSelected(!newFocusAssigned && !topSelected); 2498 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2499 } 2500 } 2501 2502 /** 2503 * Re-measure a child, and if its height changes, lay it out preserving its 2504 * top, and adjust the children below it appropriately. 2505 * @param child The child 2506 * @param childIndex The view group index of the child. 2507 * @param numChildren The number of children in the view group. 2508 */ 2509 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2510 int oldHeight = child.getHeight(); 2511 measureItem(child); 2512 if (child.getMeasuredHeight() != oldHeight) { 2513 // lay out the view, preserving its top 2514 relayoutMeasuredItem(child); 2515 2516 // adjust views below appropriately 2517 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2518 for (int i = childIndex + 1; i < numChildren; i++) { 2519 getChildAt(i).offsetTopAndBottom(heightDelta); 2520 } 2521 } 2522 } 2523 2524 /** 2525 * Measure a particular list child. 2526 * TODO: unify with setUpChild. 2527 * @param child The child. 2528 */ 2529 private void measureItem(View child) { 2530 ViewGroup.LayoutParams p = child.getLayoutParams(); 2531 if (p == null) { 2532 p = new ViewGroup.LayoutParams( 2533 ViewGroup.LayoutParams.MATCH_PARENT, 2534 ViewGroup.LayoutParams.WRAP_CONTENT); 2535 } 2536 2537 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2538 mListPadding.left + mListPadding.right, p.width); 2539 int lpHeight = p.height; 2540 int childHeightSpec; 2541 if (lpHeight > 0) { 2542 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2543 } else { 2544 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2545 } 2546 child.measure(childWidthSpec, childHeightSpec); 2547 } 2548 2549 /** 2550 * Layout a child that has been measured, preserving its top position. 2551 * TODO: unify with setUpChild. 2552 * @param child The child. 2553 */ 2554 private void relayoutMeasuredItem(View child) { 2555 final int w = child.getMeasuredWidth(); 2556 final int h = child.getMeasuredHeight(); 2557 final int childLeft = mListPadding.left; 2558 final int childRight = childLeft + w; 2559 final int childTop = child.getTop(); 2560 final int childBottom = childTop + h; 2561 child.layout(childLeft, childTop, childRight, childBottom); 2562 } 2563 2564 /** 2565 * @return The amount to preview next items when arrow srolling. 2566 */ 2567 private int getArrowScrollPreviewLength() { 2568 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2569 } 2570 2571 /** 2572 * Determine how much we need to scroll in order to get the next selected view 2573 * visible, with a fading edge showing below as applicable. The amount is 2574 * capped at {@link #getMaxScrollAmount()} . 2575 * 2576 * @param direction either {@link android.view.View#FOCUS_UP} or 2577 * {@link android.view.View#FOCUS_DOWN}. 2578 * @param nextSelectedPosition The position of the next selection, or 2579 * {@link #INVALID_POSITION} if there is no next selectable position 2580 * @return The amount to scroll. Note: this is always positive! Direction 2581 * needs to be taken into account when actually scrolling. 2582 */ 2583 private int amountToScroll(int direction, int nextSelectedPosition) { 2584 final int listBottom = getHeight() - mListPadding.bottom; 2585 final int listTop = mListPadding.top; 2586 2587 final int numChildren = getChildCount(); 2588 2589 if (direction == View.FOCUS_DOWN) { 2590 int indexToMakeVisible = numChildren - 1; 2591 if (nextSelectedPosition != INVALID_POSITION) { 2592 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2593 } 2594 2595 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2596 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2597 2598 int goalBottom = listBottom; 2599 if (positionToMakeVisible < mItemCount - 1) { 2600 goalBottom -= getArrowScrollPreviewLength(); 2601 } 2602 2603 if (viewToMakeVisible.getBottom() <= goalBottom) { 2604 // item is fully visible. 2605 return 0; 2606 } 2607 2608 if (nextSelectedPosition != INVALID_POSITION 2609 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2610 // item already has enough of it visible, changing selection is good enough 2611 return 0; 2612 } 2613 2614 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2615 2616 if ((mFirstPosition + numChildren) == mItemCount) { 2617 // last is last in list -> make sure we don't scroll past it 2618 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2619 amountToScroll = Math.min(amountToScroll, max); 2620 } 2621 2622 return Math.min(amountToScroll, getMaxScrollAmount()); 2623 } else { 2624 int indexToMakeVisible = 0; 2625 if (nextSelectedPosition != INVALID_POSITION) { 2626 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2627 } 2628 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2629 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2630 int goalTop = listTop; 2631 if (positionToMakeVisible > 0) { 2632 goalTop += getArrowScrollPreviewLength(); 2633 } 2634 if (viewToMakeVisible.getTop() >= goalTop) { 2635 // item is fully visible. 2636 return 0; 2637 } 2638 2639 if (nextSelectedPosition != INVALID_POSITION && 2640 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2641 // item already has enough of it visible, changing selection is good enough 2642 return 0; 2643 } 2644 2645 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2646 if (mFirstPosition == 0) { 2647 // first is first in list -> make sure we don't scroll past it 2648 final int max = listTop - getChildAt(0).getTop(); 2649 amountToScroll = Math.min(amountToScroll, max); 2650 } 2651 return Math.min(amountToScroll, getMaxScrollAmount()); 2652 } 2653 } 2654 2655 /** 2656 * Holds results of focus aware arrow scrolling. 2657 */ 2658 static private class ArrowScrollFocusResult { 2659 private int mSelectedPosition; 2660 private int mAmountToScroll; 2661 2662 /** 2663 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2664 */ 2665 void populate(int selectedPosition, int amountToScroll) { 2666 mSelectedPosition = selectedPosition; 2667 mAmountToScroll = amountToScroll; 2668 } 2669 2670 public int getSelectedPosition() { 2671 return mSelectedPosition; 2672 } 2673 2674 public int getAmountToScroll() { 2675 return mAmountToScroll; 2676 } 2677 } 2678 2679 /** 2680 * @param direction either {@link android.view.View#FOCUS_UP} or 2681 * {@link android.view.View#FOCUS_DOWN}. 2682 * @return The position of the next selectable position of the views that 2683 * are currently visible, taking into account the fact that there might 2684 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2685 * selectable view on screen in the given direction. 2686 */ 2687 private int lookForSelectablePositionOnScreen(int direction) { 2688 final int firstPosition = mFirstPosition; 2689 if (direction == View.FOCUS_DOWN) { 2690 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2691 mSelectedPosition + 1 : 2692 firstPosition; 2693 if (startPos >= mAdapter.getCount()) { 2694 return INVALID_POSITION; 2695 } 2696 if (startPos < firstPosition) { 2697 startPos = firstPosition; 2698 } 2699 2700 final int lastVisiblePos = getLastVisiblePosition(); 2701 final ListAdapter adapter = getAdapter(); 2702 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2703 if (adapter.isEnabled(pos) 2704 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2705 return pos; 2706 } 2707 } 2708 } else { 2709 int last = firstPosition + getChildCount() - 1; 2710 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2711 mSelectedPosition - 1 : 2712 firstPosition + getChildCount() - 1; 2713 if (startPos < 0 || startPos >= mAdapter.getCount()) { 2714 return INVALID_POSITION; 2715 } 2716 if (startPos > last) { 2717 startPos = last; 2718 } 2719 2720 final ListAdapter adapter = getAdapter(); 2721 for (int pos = startPos; pos >= firstPosition; pos--) { 2722 if (adapter.isEnabled(pos) 2723 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2724 return pos; 2725 } 2726 } 2727 } 2728 return INVALID_POSITION; 2729 } 2730 2731 /** 2732 * Do an arrow scroll based on focus searching. If a new view is 2733 * given focus, return the selection delta and amount to scroll via 2734 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2735 * 2736 * @param direction either {@link android.view.View#FOCUS_UP} or 2737 * {@link android.view.View#FOCUS_DOWN}. 2738 * @return The result if focus has changed, or <code>null</code>. 2739 */ 2740 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2741 final View selectedView = getSelectedView(); 2742 View newFocus; 2743 if (selectedView != null && selectedView.hasFocus()) { 2744 View oldFocus = selectedView.findFocus(); 2745 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2746 } else { 2747 if (direction == View.FOCUS_DOWN) { 2748 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2749 final int listTop = mListPadding.top + 2750 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2751 final int ySearchPoint = 2752 (selectedView != null && selectedView.getTop() > listTop) ? 2753 selectedView.getTop() : 2754 listTop; 2755 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2756 } else { 2757 final boolean bottomFadingEdgeShowing = 2758 (mFirstPosition + getChildCount() - 1) < mItemCount; 2759 final int listBottom = getHeight() - mListPadding.bottom - 2760 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2761 final int ySearchPoint = 2762 (selectedView != null && selectedView.getBottom() < listBottom) ? 2763 selectedView.getBottom() : 2764 listBottom; 2765 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2766 } 2767 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2768 } 2769 2770 if (newFocus != null) { 2771 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2772 2773 // if the focus change is in a different new position, make sure 2774 // we aren't jumping over another selectable position 2775 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2776 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2777 if (selectablePosition != INVALID_POSITION && 2778 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2779 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2780 return null; 2781 } 2782 } 2783 2784 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2785 2786 final int maxScrollAmount = getMaxScrollAmount(); 2787 if (focusScroll < maxScrollAmount) { 2788 // not moving too far, safe to give next view focus 2789 newFocus.requestFocus(direction); 2790 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2791 return mArrowScrollFocusResult; 2792 } else if (distanceToView(newFocus) < maxScrollAmount){ 2793 // Case to consider: 2794 // too far to get entire next focusable on screen, but by going 2795 // max scroll amount, we are getting it at least partially in view, 2796 // so give it focus and scroll the max ammount. 2797 newFocus.requestFocus(direction); 2798 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2799 return mArrowScrollFocusResult; 2800 } 2801 } 2802 return null; 2803 } 2804 2805 /** 2806 * @param newFocus The view that would have focus. 2807 * @return the position that contains newFocus 2808 */ 2809 private int positionOfNewFocus(View newFocus) { 2810 final int numChildren = getChildCount(); 2811 for (int i = 0; i < numChildren; i++) { 2812 final View child = getChildAt(i); 2813 if (isViewAncestorOf(newFocus, child)) { 2814 return mFirstPosition + i; 2815 } 2816 } 2817 throw new IllegalArgumentException("newFocus is not a child of any of the" 2818 + " children of the list!"); 2819 } 2820 2821 /** 2822 * Return true if child is an ancestor of parent, (or equal to the parent). 2823 */ 2824 private boolean isViewAncestorOf(View child, View parent) { 2825 if (child == parent) { 2826 return true; 2827 } 2828 2829 final ViewParent theParent = child.getParent(); 2830 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2831 } 2832 2833 /** 2834 * Determine how much we need to scroll in order to get newFocus in view. 2835 * @param direction either {@link android.view.View#FOCUS_UP} or 2836 * {@link android.view.View#FOCUS_DOWN}. 2837 * @param newFocus The view that would take focus. 2838 * @param positionOfNewFocus The position of the list item containing newFocus 2839 * @return The amount to scroll. Note: this is always positive! Direction 2840 * needs to be taken into account when actually scrolling. 2841 */ 2842 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2843 int amountToScroll = 0; 2844 newFocus.getDrawingRect(mTempRect); 2845 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2846 if (direction == View.FOCUS_UP) { 2847 if (mTempRect.top < mListPadding.top) { 2848 amountToScroll = mListPadding.top - mTempRect.top; 2849 if (positionOfNewFocus > 0) { 2850 amountToScroll += getArrowScrollPreviewLength(); 2851 } 2852 } 2853 } else { 2854 final int listBottom = getHeight() - mListPadding.bottom; 2855 if (mTempRect.bottom > listBottom) { 2856 amountToScroll = mTempRect.bottom - listBottom; 2857 if (positionOfNewFocus < mItemCount - 1) { 2858 amountToScroll += getArrowScrollPreviewLength(); 2859 } 2860 } 2861 } 2862 return amountToScroll; 2863 } 2864 2865 /** 2866 * Determine the distance to the nearest edge of a view in a particular 2867 * direction. 2868 * 2869 * @param descendant A descendant of this list. 2870 * @return The distance, or 0 if the nearest edge is already on screen. 2871 */ 2872 private int distanceToView(View descendant) { 2873 int distance = 0; 2874 descendant.getDrawingRect(mTempRect); 2875 offsetDescendantRectToMyCoords(descendant, mTempRect); 2876 final int listBottom = mBottom - mTop - mListPadding.bottom; 2877 if (mTempRect.bottom < mListPadding.top) { 2878 distance = mListPadding.top - mTempRect.bottom; 2879 } else if (mTempRect.top > listBottom) { 2880 distance = mTempRect.top - listBottom; 2881 } 2882 return distance; 2883 } 2884 2885 2886 /** 2887 * Scroll the children by amount, adding a view at the end and removing 2888 * views that fall off as necessary. 2889 * 2890 * @param amount The amount (positive or negative) to scroll. 2891 */ 2892 private void scrollListItemsBy(int amount) { 2893 offsetChildrenTopAndBottom(amount); 2894 2895 final int listBottom = getHeight() - mListPadding.bottom; 2896 final int listTop = mListPadding.top; 2897 final AbsListView.RecycleBin recycleBin = mRecycler; 2898 2899 if (amount < 0) { 2900 // shifted items up 2901 2902 // may need to pan views into the bottom space 2903 int numChildren = getChildCount(); 2904 View last = getChildAt(numChildren - 1); 2905 while (last.getBottom() < listBottom) { 2906 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2907 if (lastVisiblePosition < mItemCount - 1) { 2908 last = addViewBelow(last, lastVisiblePosition); 2909 numChildren++; 2910 } else { 2911 break; 2912 } 2913 } 2914 2915 // may have brought in the last child of the list that is skinnier 2916 // than the fading edge, thereby leaving space at the end. need 2917 // to shift back 2918 if (last.getBottom() < listBottom) { 2919 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2920 } 2921 2922 // top views may be panned off screen 2923 View first = getChildAt(0); 2924 while (first.getBottom() < listTop) { 2925 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2926 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2927 detachViewFromParent(first); 2928 recycleBin.addScrapView(first, mFirstPosition); 2929 } else { 2930 removeViewInLayout(first); 2931 } 2932 first = getChildAt(0); 2933 mFirstPosition++; 2934 } 2935 } else { 2936 // shifted items down 2937 View first = getChildAt(0); 2938 2939 // may need to pan views into top 2940 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2941 first = addViewAbove(first, mFirstPosition); 2942 mFirstPosition--; 2943 } 2944 2945 // may have brought the very first child of the list in too far and 2946 // need to shift it back 2947 if (first.getTop() > listTop) { 2948 offsetChildrenTopAndBottom(listTop - first.getTop()); 2949 } 2950 2951 int lastIndex = getChildCount() - 1; 2952 View last = getChildAt(lastIndex); 2953 2954 // bottom view may be panned off screen 2955 while (last.getTop() > listBottom) { 2956 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 2957 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2958 detachViewFromParent(last); 2959 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 2960 } else { 2961 removeViewInLayout(last); 2962 } 2963 last = getChildAt(--lastIndex); 2964 } 2965 } 2966 } 2967 2968 private View addViewAbove(View theView, int position) { 2969 int abovePosition = position - 1; 2970 View view = obtainView(abovePosition, mIsScrap); 2971 int edgeOfNewChild = theView.getTop() - mDividerHeight; 2972 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 2973 false, mIsScrap[0]); 2974 return view; 2975 } 2976 2977 private View addViewBelow(View theView, int position) { 2978 int belowPosition = position + 1; 2979 View view = obtainView(belowPosition, mIsScrap); 2980 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 2981 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 2982 false, mIsScrap[0]); 2983 return view; 2984 } 2985 2986 /** 2987 * Indicates that the views created by the ListAdapter can contain focusable 2988 * items. 2989 * 2990 * @param itemsCanFocus true if items can get focus, false otherwise 2991 */ 2992 public void setItemsCanFocus(boolean itemsCanFocus) { 2993 mItemsCanFocus = itemsCanFocus; 2994 if (!itemsCanFocus) { 2995 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 2996 } 2997 } 2998 2999 /** 3000 * @return Whether the views created by the ListAdapter can contain focusable 3001 * items. 3002 */ 3003 public boolean getItemsCanFocus() { 3004 return mItemsCanFocus; 3005 } 3006 3007 @Override 3008 public boolean isOpaque() { 3009 boolean retValue = (mCachingActive && mIsCacheColorOpaque && mDividerIsOpaque && 3010 hasOpaqueScrollbars()) || super.isOpaque(); 3011 if (retValue) { 3012 // only return true if the list items cover the entire area of the view 3013 final int listTop = mListPadding != null ? mListPadding.top : mPaddingTop; 3014 View first = getChildAt(0); 3015 if (first == null || first.getTop() > listTop) { 3016 return false; 3017 } 3018 final int listBottom = getHeight() - 3019 (mListPadding != null ? mListPadding.bottom : mPaddingBottom); 3020 View last = getChildAt(getChildCount() - 1); 3021 if (last == null || last.getBottom() < listBottom) { 3022 return false; 3023 } 3024 } 3025 return retValue; 3026 } 3027 3028 @Override 3029 public void setCacheColorHint(int color) { 3030 final boolean opaque = (color >>> 24) == 0xFF; 3031 mIsCacheColorOpaque = opaque; 3032 if (opaque) { 3033 if (mDividerPaint == null) { 3034 mDividerPaint = new Paint(); 3035 } 3036 mDividerPaint.setColor(color); 3037 } 3038 super.setCacheColorHint(color); 3039 } 3040 3041 void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) { 3042 final int height = drawable.getMinimumHeight(); 3043 3044 canvas.save(); 3045 canvas.clipRect(bounds); 3046 3047 final int span = bounds.bottom - bounds.top; 3048 if (span < height) { 3049 bounds.top = bounds.bottom - height; 3050 } 3051 3052 drawable.setBounds(bounds); 3053 drawable.draw(canvas); 3054 3055 canvas.restore(); 3056 } 3057 3058 void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) { 3059 final int height = drawable.getMinimumHeight(); 3060 3061 canvas.save(); 3062 canvas.clipRect(bounds); 3063 3064 final int span = bounds.bottom - bounds.top; 3065 if (span < height) { 3066 bounds.bottom = bounds.top + height; 3067 } 3068 3069 drawable.setBounds(bounds); 3070 drawable.draw(canvas); 3071 3072 canvas.restore(); 3073 } 3074 3075 @Override 3076 protected void dispatchDraw(Canvas canvas) { 3077 if (mCachingStarted) { 3078 mCachingActive = true; 3079 } 3080 3081 // Draw the dividers 3082 final int dividerHeight = mDividerHeight; 3083 final Drawable overscrollHeader = mOverScrollHeader; 3084 final Drawable overscrollFooter = mOverScrollFooter; 3085 final boolean drawOverscrollHeader = overscrollHeader != null; 3086 final boolean drawOverscrollFooter = overscrollFooter != null; 3087 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3088 3089 if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) { 3090 // Only modify the top and bottom in the loop, we set the left and right here 3091 final Rect bounds = mTempRect; 3092 bounds.left = mPaddingLeft; 3093 bounds.right = mRight - mLeft - mPaddingRight; 3094 3095 final int count = getChildCount(); 3096 final int headerCount = mHeaderViewInfos.size(); 3097 final int itemCount = mItemCount; 3098 final int footerLimit = itemCount - mFooterViewInfos.size() - 1; 3099 final boolean headerDividers = mHeaderDividersEnabled; 3100 final boolean footerDividers = mFooterDividersEnabled; 3101 final int first = mFirstPosition; 3102 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 3103 final ListAdapter adapter = mAdapter; 3104 // If the list is opaque *and* the background is not, we want to 3105 // fill a rect where the dividers would be for non-selectable items 3106 // If the list is opaque and the background is also opaque, we don't 3107 // need to draw anything since the background will do it for us 3108 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3109 3110 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 3111 mDividerPaint = new Paint(); 3112 mDividerPaint.setColor(getCacheColorHint()); 3113 } 3114 final Paint paint = mDividerPaint; 3115 3116 int effectivePaddingTop = 0; 3117 int effectivePaddingBottom = 0; 3118 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 3119 effectivePaddingTop = mListPadding.top; 3120 effectivePaddingBottom = mListPadding.bottom; 3121 } 3122 3123 final int listBottom = mBottom - mTop - effectivePaddingBottom + mScrollY; 3124 if (!mStackFromBottom) { 3125 int bottom = 0; 3126 3127 // Draw top divider or header for overscroll 3128 final int scrollY = mScrollY; 3129 if (count > 0 && scrollY < 0) { 3130 if (drawOverscrollHeader) { 3131 bounds.bottom = 0; 3132 bounds.top = scrollY; 3133 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3134 } else if (drawDividers) { 3135 bounds.bottom = 0; 3136 bounds.top = -dividerHeight; 3137 drawDivider(canvas, bounds, -1); 3138 } 3139 } 3140 3141 for (int i = 0; i < count; i++) { 3142 if ((headerDividers || first + i >= headerCount) && 3143 (footerDividers || first + i < footerLimit)) { 3144 View child = getChildAt(i); 3145 bottom = child.getBottom(); 3146 // Don't draw dividers next to items that are not enabled 3147 3148 if (drawDividers && 3149 (bottom < listBottom && !(drawOverscrollFooter && i == count - 1))) { 3150 if ((areAllItemsSelectable || 3151 (adapter.isEnabled(first + i) && (i == count - 1 || 3152 adapter.isEnabled(first + i + 1))))) { 3153 bounds.top = bottom; 3154 bounds.bottom = bottom + dividerHeight; 3155 drawDivider(canvas, bounds, i); 3156 } else if (fillForMissingDividers) { 3157 bounds.top = bottom; 3158 bounds.bottom = bottom + dividerHeight; 3159 canvas.drawRect(bounds, paint); 3160 } 3161 } 3162 } 3163 } 3164 3165 final int overFooterBottom = mBottom + mScrollY; 3166 if (drawOverscrollFooter && first + count == itemCount && 3167 overFooterBottom > bottom) { 3168 bounds.top = bottom; 3169 bounds.bottom = overFooterBottom; 3170 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3171 } 3172 } else { 3173 int top; 3174 3175 final int scrollY = mScrollY; 3176 3177 if (count > 0 && drawOverscrollHeader) { 3178 bounds.top = scrollY; 3179 bounds.bottom = getChildAt(0).getTop(); 3180 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3181 } 3182 3183 final int start = drawOverscrollHeader ? 1 : 0; 3184 for (int i = start; i < count; i++) { 3185 if ((headerDividers || first + i >= headerCount) && 3186 (footerDividers || first + i < footerLimit)) { 3187 View child = getChildAt(i); 3188 top = child.getTop(); 3189 // Don't draw dividers next to items that are not enabled 3190 if (top > effectivePaddingTop) { 3191 if ((areAllItemsSelectable || 3192 (adapter.isEnabled(first + i) && (i == count - 1 || 3193 adapter.isEnabled(first + i + 1))))) { 3194 bounds.top = top - dividerHeight; 3195 bounds.bottom = top; 3196 // Give the method the child ABOVE the divider, so we 3197 // subtract one from our child 3198 // position. Give -1 when there is no child above the 3199 // divider. 3200 drawDivider(canvas, bounds, i - 1); 3201 } else if (fillForMissingDividers) { 3202 bounds.top = top - dividerHeight; 3203 bounds.bottom = top; 3204 canvas.drawRect(bounds, paint); 3205 } 3206 } 3207 } 3208 } 3209 3210 if (count > 0 && scrollY > 0) { 3211 if (drawOverscrollFooter) { 3212 final int absListBottom = mBottom; 3213 bounds.top = absListBottom; 3214 bounds.bottom = absListBottom + scrollY; 3215 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3216 } else if (drawDividers) { 3217 bounds.top = listBottom; 3218 bounds.bottom = listBottom + dividerHeight; 3219 drawDivider(canvas, bounds, -1); 3220 } 3221 } 3222 } 3223 } 3224 3225 // Draw the indicators (these should be drawn above the dividers) and children 3226 super.dispatchDraw(canvas); 3227 } 3228 3229 @Override 3230 protected boolean drawChild(Canvas canvas, View child, long drawingTime) { 3231 boolean more = super.drawChild(canvas, child, drawingTime); 3232 if (mCachingActive && child.mCachingFailed) { 3233 mCachingActive = false; 3234 } 3235 return more; 3236 } 3237 3238 /** 3239 * Draws a divider for the given child in the given bounds. 3240 * 3241 * @param canvas The canvas to draw to. 3242 * @param bounds The bounds of the divider. 3243 * @param childIndex The index of child (of the View) above the divider. 3244 * This will be -1 if there is no child above the divider to be 3245 * drawn. 3246 */ 3247 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3248 // This widget draws the same divider for all children 3249 final Drawable divider = mDivider; 3250 3251 divider.setBounds(bounds); 3252 divider.draw(canvas); 3253 } 3254 3255 /** 3256 * Returns the drawable that will be drawn between each item in the list. 3257 * 3258 * @return the current drawable drawn between list elements 3259 */ 3260 public Drawable getDivider() { 3261 return mDivider; 3262 } 3263 3264 /** 3265 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3266 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3267 * 3268 * @param divider The drawable to use. 3269 */ 3270 public void setDivider(Drawable divider) { 3271 if (divider != null) { 3272 mDividerHeight = divider.getIntrinsicHeight(); 3273 } else { 3274 mDividerHeight = 0; 3275 } 3276 mDivider = divider; 3277 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3278 requestLayout(); 3279 invalidate(); 3280 } 3281 3282 /** 3283 * @return Returns the height of the divider that will be drawn between each item in the list. 3284 */ 3285 public int getDividerHeight() { 3286 return mDividerHeight; 3287 } 3288 3289 /** 3290 * Sets the height of the divider that will be drawn between each item in the list. Calling 3291 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3292 * 3293 * @param height The new height of the divider in pixels. 3294 */ 3295 public void setDividerHeight(int height) { 3296 mDividerHeight = height; 3297 requestLayout(); 3298 invalidate(); 3299 } 3300 3301 /** 3302 * Enables or disables the drawing of the divider for header views. 3303 * 3304 * @param headerDividersEnabled True to draw the headers, false otherwise. 3305 * 3306 * @see #setFooterDividersEnabled(boolean) 3307 * @see #addHeaderView(android.view.View) 3308 */ 3309 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3310 mHeaderDividersEnabled = headerDividersEnabled; 3311 invalidate(); 3312 } 3313 3314 /** 3315 * Enables or disables the drawing of the divider for footer views. 3316 * 3317 * @param footerDividersEnabled True to draw the footers, false otherwise. 3318 * 3319 * @see #setHeaderDividersEnabled(boolean) 3320 * @see #addFooterView(android.view.View) 3321 */ 3322 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3323 mFooterDividersEnabled = footerDividersEnabled; 3324 invalidate(); 3325 } 3326 3327 /** 3328 * Sets the drawable that will be drawn above all other list content. 3329 * This area can become visible when the user overscrolls the list. 3330 * 3331 * @param header The drawable to use 3332 */ 3333 public void setOverscrollHeader(Drawable header) { 3334 mOverScrollHeader = header; 3335 if (mScrollY < 0) { 3336 invalidate(); 3337 } 3338 } 3339 3340 /** 3341 * @return The drawable that will be drawn above all other list content 3342 */ 3343 public Drawable getOverscrollHeader() { 3344 return mOverScrollHeader; 3345 } 3346 3347 /** 3348 * Sets the drawable that will be drawn below all other list content. 3349 * This area can become visible when the user overscrolls the list, 3350 * or when the list's content does not fully fill the container area. 3351 * 3352 * @param footer The drawable to use 3353 */ 3354 public void setOverscrollFooter(Drawable footer) { 3355 mOverScrollFooter = footer; 3356 invalidate(); 3357 } 3358 3359 /** 3360 * @return The drawable that will be drawn below all other list content 3361 */ 3362 public Drawable getOverscrollFooter() { 3363 return mOverScrollFooter; 3364 } 3365 3366 @Override 3367 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3368 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3369 3370 final ListAdapter adapter = mAdapter; 3371 int closetChildIndex = -1; 3372 int closestChildTop = 0; 3373 if (adapter != null && gainFocus && previouslyFocusedRect != null) { 3374 previouslyFocusedRect.offset(mScrollX, mScrollY); 3375 3376 // Don't cache the result of getChildCount or mFirstPosition here, 3377 // it could change in layoutChildren. 3378 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3379 mLayoutMode = LAYOUT_NORMAL; 3380 layoutChildren(); 3381 } 3382 3383 // figure out which item should be selected based on previously 3384 // focused rect 3385 Rect otherRect = mTempRect; 3386 int minDistance = Integer.MAX_VALUE; 3387 final int childCount = getChildCount(); 3388 final int firstPosition = mFirstPosition; 3389 3390 for (int i = 0; i < childCount; i++) { 3391 // only consider selectable views 3392 if (!adapter.isEnabled(firstPosition + i)) { 3393 continue; 3394 } 3395 3396 View other = getChildAt(i); 3397 other.getDrawingRect(otherRect); 3398 offsetDescendantRectToMyCoords(other, otherRect); 3399 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3400 3401 if (distance < minDistance) { 3402 minDistance = distance; 3403 closetChildIndex = i; 3404 closestChildTop = other.getTop(); 3405 } 3406 } 3407 } 3408 3409 if (closetChildIndex >= 0) { 3410 setSelectionFromTop(closetChildIndex + mFirstPosition, closestChildTop); 3411 } else { 3412 requestLayout(); 3413 } 3414 } 3415 3416 3417 /* 3418 * (non-Javadoc) 3419 * 3420 * Children specified in XML are assumed to be header views. After we have 3421 * parsed them move them out of the children list and into mHeaderViews. 3422 */ 3423 @Override 3424 protected void onFinishInflate() { 3425 super.onFinishInflate(); 3426 3427 int count = getChildCount(); 3428 if (count > 0) { 3429 for (int i = 0; i < count; ++i) { 3430 addHeaderView(getChildAt(i)); 3431 } 3432 removeAllViews(); 3433 } 3434 } 3435 3436 /* (non-Javadoc) 3437 * @see android.view.View#findViewById(int) 3438 * First look in our children, then in any header and footer views that may be scrolled off. 3439 */ 3440 @Override 3441 protected View findViewTraversal(int id) { 3442 View v; 3443 v = super.findViewTraversal(id); 3444 if (v == null) { 3445 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3446 if (v != null) { 3447 return v; 3448 } 3449 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3450 if (v != null) { 3451 return v; 3452 } 3453 } 3454 return v; 3455 } 3456 3457 /* (non-Javadoc) 3458 * 3459 * Look in the passed in list of headers or footers for the view. 3460 */ 3461 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3462 if (where != null) { 3463 int len = where.size(); 3464 View v; 3465 3466 for (int i = 0; i < len; i++) { 3467 v = where.get(i).view; 3468 3469 if (!v.isRootNamespace()) { 3470 v = v.findViewById(id); 3471 3472 if (v != null) { 3473 return v; 3474 } 3475 } 3476 } 3477 } 3478 return null; 3479 } 3480 3481 /* (non-Javadoc) 3482 * @see android.view.View#findViewWithTag(Object) 3483 * First look in our children, then in any header and footer views that may be scrolled off. 3484 */ 3485 @Override 3486 protected View findViewWithTagTraversal(Object tag) { 3487 View v; 3488 v = super.findViewWithTagTraversal(tag); 3489 if (v == null) { 3490 v = findViewWithTagInHeadersOrFooters(mHeaderViewInfos, tag); 3491 if (v != null) { 3492 return v; 3493 } 3494 3495 v = findViewWithTagInHeadersOrFooters(mFooterViewInfos, tag); 3496 if (v != null) { 3497 return v; 3498 } 3499 } 3500 return v; 3501 } 3502 3503 /* (non-Javadoc) 3504 * 3505 * Look in the passed in list of headers or footers for the view with the tag. 3506 */ 3507 View findViewWithTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3508 if (where != null) { 3509 int len = where.size(); 3510 View v; 3511 3512 for (int i = 0; i < len; i++) { 3513 v = where.get(i).view; 3514 3515 if (!v.isRootNamespace()) { 3516 v = v.findViewWithTag(tag); 3517 3518 if (v != null) { 3519 return v; 3520 } 3521 } 3522 } 3523 } 3524 return null; 3525 } 3526 3527 /** 3528 * @hide 3529 * @see android.view.View#findViewByPredicate(Predicate) 3530 * First look in our children, then in any header and footer views that may be scrolled off. 3531 */ 3532 @Override 3533 protected View findViewByPredicateTraversal(Predicate<View> predicate, View childToSkip) { 3534 View v; 3535 v = super.findViewByPredicateTraversal(predicate, childToSkip); 3536 if (v == null) { 3537 v = findViewByPredicateInHeadersOrFooters(mHeaderViewInfos, predicate, childToSkip); 3538 if (v != null) { 3539 return v; 3540 } 3541 3542 v = findViewByPredicateInHeadersOrFooters(mFooterViewInfos, predicate, childToSkip); 3543 if (v != null) { 3544 return v; 3545 } 3546 } 3547 return v; 3548 } 3549 3550 /* (non-Javadoc) 3551 * 3552 * Look in the passed in list of headers or footers for the first view that matches 3553 * the predicate. 3554 */ 3555 View findViewByPredicateInHeadersOrFooters(ArrayList<FixedViewInfo> where, 3556 Predicate<View> predicate, View childToSkip) { 3557 if (where != null) { 3558 int len = where.size(); 3559 View v; 3560 3561 for (int i = 0; i < len; i++) { 3562 v = where.get(i).view; 3563 3564 if (v != childToSkip && !v.isRootNamespace()) { 3565 v = v.findViewByPredicate(predicate); 3566 3567 if (v != null) { 3568 return v; 3569 } 3570 } 3571 } 3572 } 3573 return null; 3574 } 3575 3576 /** 3577 * Returns the set of checked items ids. The result is only valid if the 3578 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3579 * 3580 * @return A new array which contains the id of each checked item in the 3581 * list. 3582 * 3583 * @deprecated Use {@link #getCheckedItemIds()} instead. 3584 */ 3585 @Deprecated 3586 public long[] getCheckItemIds() { 3587 // Use new behavior that correctly handles stable ID mapping. 3588 if (mAdapter != null && mAdapter.hasStableIds()) { 3589 return getCheckedItemIds(); 3590 } 3591 3592 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3593 // Fall back to it to support legacy apps. 3594 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3595 final SparseBooleanArray states = mCheckStates; 3596 final int count = states.size(); 3597 final long[] ids = new long[count]; 3598 final ListAdapter adapter = mAdapter; 3599 3600 int checkedCount = 0; 3601 for (int i = 0; i < count; i++) { 3602 if (states.valueAt(i)) { 3603 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3604 } 3605 } 3606 3607 // Trim array if needed. mCheckStates may contain false values 3608 // resulting in checkedCount being smaller than count. 3609 if (checkedCount == count) { 3610 return ids; 3611 } else { 3612 final long[] result = new long[checkedCount]; 3613 System.arraycopy(ids, 0, result, 0, checkedCount); 3614 3615 return result; 3616 } 3617 } 3618 return new long[0]; 3619 } 3620 3621 @Override 3622 public void onInitializeAccessibilityEvent(AccessibilityEvent event) { 3623 super.onInitializeAccessibilityEvent(event); 3624 event.setClassName(ListView.class.getName()); 3625 } 3626 3627 @Override 3628 public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { 3629 super.onInitializeAccessibilityNodeInfo(info); 3630 info.setClassName(ListView.class.getName()); 3631 } 3632} 3633