ListView.java revision 1ad11b9c6c7b555c27b917f26ecc08446f589284
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.MathUtils; 33import android.util.SparseBooleanArray; 34import android.view.FocusFinder; 35import android.view.KeyEvent; 36import android.view.SoundEffectConstants; 37import android.view.View; 38import android.view.ViewDebug; 39import android.view.ViewGroup; 40import android.view.ViewParent; 41import android.view.ViewRootImpl; 42import android.view.accessibility.AccessibilityEvent; 43import android.view.accessibility.AccessibilityNodeInfo; 44import android.widget.RemoteViews.RemoteView; 45 46import java.util.ArrayList; 47 48/* 49 * Implementation Notes: 50 * 51 * Some terminology: 52 * 53 * index - index of the items that are currently visible 54 * position - index of the items in the cursor 55 */ 56 57 58/** 59 * A view that shows items in a vertically scrolling list. The items 60 * come from the {@link ListAdapter} associated with this view. 61 * 62 * <p>See the <a href="{@docRoot}guide/topics/ui/layout/listview.html">List View</a> 63 * guide.</p> 64 * 65 * @attr ref android.R.styleable#ListView_entries 66 * @attr ref android.R.styleable#ListView_divider 67 * @attr ref android.R.styleable#ListView_dividerHeight 68 * @attr ref android.R.styleable#ListView_headerDividersEnabled 69 * @attr ref android.R.styleable#ListView_footerDividersEnabled 70 */ 71@RemoteView 72public class ListView extends AbsListView { 73 /** 74 * Used to indicate a no preference for a position type. 75 */ 76 static final int NO_POSITION = -1; 77 78 /** 79 * When arrow scrolling, ListView will never scroll more than this factor 80 * times the height of the list. 81 */ 82 private static final float MAX_SCROLL_FACTOR = 0.33f; 83 84 /** 85 * When arrow scrolling, need a certain amount of pixels to preview next 86 * items. This is usually the fading edge, but if that is small enough, 87 * we want to make sure we preview at least this many pixels. 88 */ 89 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 90 91 /** 92 * A class that represents a fixed view in a list, for example a header at the top 93 * or a footer at the bottom. 94 */ 95 public class FixedViewInfo { 96 /** The view to add to the list */ 97 public View view; 98 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 99 public Object data; 100 /** <code>true</code> if the fixed view should be selectable in the list */ 101 public boolean isSelectable; 102 } 103 104 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 105 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 106 107 Drawable mDivider; 108 int mDividerHeight; 109 110 Drawable mOverScrollHeader; 111 Drawable mOverScrollFooter; 112 113 private boolean mIsCacheColorOpaque; 114 private boolean mDividerIsOpaque; 115 116 private boolean mHeaderDividersEnabled; 117 private boolean mFooterDividersEnabled; 118 119 private boolean mAreAllItemsSelectable = true; 120 121 private boolean mItemsCanFocus = false; 122 123 // used for temporary calculations. 124 private final Rect mTempRect = new Rect(); 125 private Paint mDividerPaint; 126 127 // the single allocated result per list view; kinda cheesey but avoids 128 // allocating these thingies too often. 129 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 130 131 // Keeps focused children visible through resizes 132 private FocusSelector mFocusSelector; 133 134 public ListView(Context context) { 135 this(context, null); 136 } 137 138 public ListView(Context context, AttributeSet attrs) { 139 this(context, attrs, com.android.internal.R.attr.listViewStyle); 140 } 141 142 public ListView(Context context, AttributeSet attrs, int defStyle) { 143 super(context, attrs, defStyle); 144 145 TypedArray a = context.obtainStyledAttributes(attrs, 146 com.android.internal.R.styleable.ListView, defStyle, 0); 147 148 CharSequence[] entries = a.getTextArray( 149 com.android.internal.R.styleable.ListView_entries); 150 if (entries != null) { 151 setAdapter(new ArrayAdapter<CharSequence>(context, 152 com.android.internal.R.layout.simple_list_item_1, entries)); 153 } 154 155 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 156 if (d != null) { 157 // If a divider is specified use its intrinsic height for divider height 158 setDivider(d); 159 } 160 161 final Drawable osHeader = a.getDrawable( 162 com.android.internal.R.styleable.ListView_overScrollHeader); 163 if (osHeader != null) { 164 setOverscrollHeader(osHeader); 165 } 166 167 final Drawable osFooter = a.getDrawable( 168 com.android.internal.R.styleable.ListView_overScrollFooter); 169 if (osFooter != null) { 170 setOverscrollFooter(osFooter); 171 } 172 173 // Use the height specified, zero being the default 174 final int dividerHeight = a.getDimensionPixelSize( 175 com.android.internal.R.styleable.ListView_dividerHeight, 0); 176 if (dividerHeight != 0) { 177 setDividerHeight(dividerHeight); 178 } 179 180 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 181 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 182 183 a.recycle(); 184 } 185 186 /** 187 * @return The maximum amount a list view will scroll in response to 188 * an arrow event. 189 */ 190 public int getMaxScrollAmount() { 191 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 192 } 193 194 /** 195 * Make sure views are touching the top or bottom edge, as appropriate for 196 * our gravity 197 */ 198 private void adjustViewsUpOrDown() { 199 final int childCount = getChildCount(); 200 int delta; 201 202 if (childCount > 0) { 203 View child; 204 205 if (!mStackFromBottom) { 206 // Uh-oh -- we came up short. Slide all views up to make them 207 // align with the top 208 child = getChildAt(0); 209 delta = child.getTop() - mListPadding.top; 210 if (mFirstPosition != 0) { 211 // It's OK to have some space above the first item if it is 212 // part of the vertical spacing 213 delta -= mDividerHeight; 214 } 215 if (delta < 0) { 216 // We only are looking to see if we are too low, not too high 217 delta = 0; 218 } 219 } else { 220 // we are too high, slide all views down to align with bottom 221 child = getChildAt(childCount - 1); 222 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 223 224 if (mFirstPosition + childCount < mItemCount) { 225 // It's OK to have some space below the last item if it is 226 // part of the vertical spacing 227 delta += mDividerHeight; 228 } 229 230 if (delta > 0) { 231 delta = 0; 232 } 233 } 234 235 if (delta != 0) { 236 offsetChildrenTopAndBottom(-delta); 237 } 238 } 239 } 240 241 /** 242 * Add a fixed view to appear at the top of the list. If addHeaderView is 243 * called more than once, the views will appear in the order they were 244 * added. Views added using this call can take focus if they want. 245 * <p> 246 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 247 * the supplied cursor with one that will also account for header and footer 248 * views. 249 * 250 * @param v The view to add. 251 * @param data Data to associate with this view 252 * @param isSelectable whether the item is selectable 253 */ 254 public void addHeaderView(View v, Object data, boolean isSelectable) { 255 256 if (mAdapter != null && ! (mAdapter instanceof HeaderViewListAdapter)) { 257 throw new IllegalStateException( 258 "Cannot add header view to list -- setAdapter has already been called."); 259 } 260 261 FixedViewInfo info = new FixedViewInfo(); 262 info.view = v; 263 info.data = data; 264 info.isSelectable = isSelectable; 265 mHeaderViewInfos.add(info); 266 267 // in the case of re-adding a header view, or adding one later on, 268 // we need to notify the observer 269 if (mAdapter != null && mDataSetObserver != null) { 270 mDataSetObserver.onChanged(); 271 } 272 } 273 274 /** 275 * Add a fixed view to appear at the top of the list. If addHeaderView is 276 * called more than once, the views will appear in the order they were 277 * added. Views added using this call can take focus if they want. 278 * <p> 279 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 280 * the supplied cursor with one that will also account for header and footer 281 * views. 282 * 283 * @param v The view to add. 284 */ 285 public void addHeaderView(View v) { 286 addHeaderView(v, null, true); 287 } 288 289 @Override 290 public int getHeaderViewsCount() { 291 return mHeaderViewInfos.size(); 292 } 293 294 /** 295 * Removes a previously-added header view. 296 * 297 * @param v The view to remove 298 * @return true if the view was removed, false if the view was not a header 299 * view 300 */ 301 public boolean removeHeaderView(View v) { 302 if (mHeaderViewInfos.size() > 0) { 303 boolean result = false; 304 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 305 if (mDataSetObserver != null) { 306 mDataSetObserver.onChanged(); 307 } 308 result = true; 309 } 310 removeFixedViewInfo(v, mHeaderViewInfos); 311 return result; 312 } 313 return false; 314 } 315 316 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 317 int len = where.size(); 318 for (int i = 0; i < len; ++i) { 319 FixedViewInfo info = where.get(i); 320 if (info.view == v) { 321 where.remove(i); 322 break; 323 } 324 } 325 } 326 327 /** 328 * Add a fixed view to appear at the bottom of the list. If addFooterView is 329 * called more than once, the views will appear in the order they were 330 * added. Views added using this call can take focus if they want. 331 * <p> 332 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 333 * the supplied cursor with one that will also account for header and footer 334 * views. 335 * 336 * @param v The view to add. 337 * @param data Data to associate with this view 338 * @param isSelectable true if the footer view can be selected 339 */ 340 public void addFooterView(View v, Object data, boolean isSelectable) { 341 342 // NOTE: do not enforce the adapter being null here, since unlike in 343 // addHeaderView, it was never enforced here, and so existing apps are 344 // relying on being able to add a footer and then calling setAdapter to 345 // force creation of the HeaderViewListAdapter wrapper 346 347 FixedViewInfo info = new FixedViewInfo(); 348 info.view = v; 349 info.data = data; 350 info.isSelectable = isSelectable; 351 mFooterViewInfos.add(info); 352 353 // in the case of re-adding a footer view, or adding one later on, 354 // we need to notify the observer 355 if (mAdapter != null && mDataSetObserver != null) { 356 mDataSetObserver.onChanged(); 357 } 358 } 359 360 /** 361 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 362 * than once, the views will appear in the order they were added. Views added using 363 * this call can take focus if they want. 364 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 365 * cursor with one that will also account for header and footer views. 366 * 367 * 368 * @param v The view to add. 369 */ 370 public void addFooterView(View v) { 371 addFooterView(v, null, true); 372 } 373 374 @Override 375 public int getFooterViewsCount() { 376 return mFooterViewInfos.size(); 377 } 378 379 /** 380 * Removes a previously-added footer view. 381 * 382 * @param v The view to remove 383 * @return 384 * true if the view was removed, false if the view was not a footer view 385 */ 386 public boolean removeFooterView(View v) { 387 if (mFooterViewInfos.size() > 0) { 388 boolean result = false; 389 if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 390 if (mDataSetObserver != null) { 391 mDataSetObserver.onChanged(); 392 } 393 result = true; 394 } 395 removeFixedViewInfo(v, mFooterViewInfos); 396 return result; 397 } 398 return false; 399 } 400 401 /** 402 * Returns the adapter currently in use in this ListView. The returned adapter 403 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 404 * might be a {@link WrapperListAdapter}. 405 * 406 * @return The adapter currently used to display data in this ListView. 407 * 408 * @see #setAdapter(ListAdapter) 409 */ 410 @Override 411 public ListAdapter getAdapter() { 412 return mAdapter; 413 } 414 415 /** 416 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 417 * through the specified intent. 418 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 419 */ 420 @android.view.RemotableViewMethod 421 public void setRemoteViewsAdapter(Intent intent) { 422 super.setRemoteViewsAdapter(intent); 423 } 424 425 /** 426 * Sets the data behind this ListView. 427 * 428 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 429 * depending on the ListView features currently in use. For instance, adding 430 * headers and/or footers will cause the adapter to be wrapped. 431 * 432 * @param adapter The ListAdapter which is responsible for maintaining the 433 * data backing this list and for producing a view to represent an 434 * item in that data set. 435 * 436 * @see #getAdapter() 437 */ 438 @Override 439 public void setAdapter(ListAdapter adapter) { 440 if (mAdapter != null && mDataSetObserver != null) { 441 mAdapter.unregisterDataSetObserver(mDataSetObserver); 442 } 443 444 resetList(); 445 mRecycler.clear(); 446 447 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 448 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 449 } else { 450 mAdapter = adapter; 451 } 452 453 mOldSelectedPosition = INVALID_POSITION; 454 mOldSelectedRowId = INVALID_ROW_ID; 455 456 // AbsListView#setAdapter will update choice mode states. 457 super.setAdapter(adapter); 458 459 if (mAdapter != null) { 460 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 461 mOldItemCount = mItemCount; 462 mItemCount = mAdapter.getCount(); 463 checkFocus(); 464 465 mDataSetObserver = new AdapterDataSetObserver(); 466 mAdapter.registerDataSetObserver(mDataSetObserver); 467 468 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 469 470 int position; 471 if (mStackFromBottom) { 472 position = lookForSelectablePosition(mItemCount - 1, false); 473 } else { 474 position = lookForSelectablePosition(0, true); 475 } 476 setSelectedPositionInt(position); 477 setNextSelectedPositionInt(position); 478 479 if (mItemCount == 0) { 480 // Nothing selected 481 checkSelectionChanged(); 482 } 483 } else { 484 mAreAllItemsSelectable = true; 485 checkFocus(); 486 // Nothing selected 487 checkSelectionChanged(); 488 } 489 490 requestLayout(); 491 } 492 493 494 /** 495 * The list is empty. Clear everything out. 496 */ 497 @Override 498 void resetList() { 499 // The parent's resetList() will remove all views from the layout so we need to 500 // cleanup the state of our footers and headers 501 clearRecycledState(mHeaderViewInfos); 502 clearRecycledState(mFooterViewInfos); 503 504 super.resetList(); 505 506 mLayoutMode = LAYOUT_NORMAL; 507 } 508 509 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 510 if (infos != null) { 511 final int count = infos.size(); 512 513 for (int i = 0; i < count; i++) { 514 final View child = infos.get(i).view; 515 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 516 if (p != null) { 517 p.recycledHeaderFooter = false; 518 } 519 } 520 } 521 } 522 523 /** 524 * @return Whether the list needs to show the top fading edge 525 */ 526 private boolean showingTopFadingEdge() { 527 final int listTop = mScrollY + mListPadding.top; 528 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 529 } 530 531 /** 532 * @return Whether the list needs to show the bottom fading edge 533 */ 534 private boolean showingBottomFadingEdge() { 535 final int childCount = getChildCount(); 536 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 537 final int lastVisiblePosition = mFirstPosition + childCount - 1; 538 539 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 540 541 return (lastVisiblePosition < mItemCount - 1) 542 || (bottomOfBottomChild < listBottom); 543 } 544 545 546 @Override 547 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 548 549 int rectTopWithinChild = rect.top; 550 551 // offset so rect is in coordinates of the this view 552 rect.offset(child.getLeft(), child.getTop()); 553 rect.offset(-child.getScrollX(), -child.getScrollY()); 554 555 final int height = getHeight(); 556 int listUnfadedTop = getScrollY(); 557 int listUnfadedBottom = listUnfadedTop + height; 558 final int fadingEdge = getVerticalFadingEdgeLength(); 559 560 if (showingTopFadingEdge()) { 561 // leave room for top fading edge as long as rect isn't at very top 562 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 563 listUnfadedTop += fadingEdge; 564 } 565 } 566 567 int childCount = getChildCount(); 568 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 569 570 if (showingBottomFadingEdge()) { 571 // leave room for bottom fading edge as long as rect isn't at very bottom 572 if ((mSelectedPosition < mItemCount - 1) 573 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 574 listUnfadedBottom -= fadingEdge; 575 } 576 } 577 578 int scrollYDelta = 0; 579 580 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 581 // need to MOVE DOWN to get it in view: move down just enough so 582 // that the entire rectangle is in view (or at least the first 583 // screen size chunk). 584 585 if (rect.height() > height) { 586 // just enough to get screen size chunk on 587 scrollYDelta += (rect.top - listUnfadedTop); 588 } else { 589 // get entire rect at bottom of screen 590 scrollYDelta += (rect.bottom - listUnfadedBottom); 591 } 592 593 // make sure we aren't scrolling beyond the end of our children 594 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 595 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 596 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 597 // need to MOVE UP to get it in view: move up just enough so that 598 // entire rectangle is in view (or at least the first screen 599 // size chunk of it). 600 601 if (rect.height() > height) { 602 // screen size chunk 603 scrollYDelta -= (listUnfadedBottom - rect.bottom); 604 } else { 605 // entire rect at top 606 scrollYDelta -= (listUnfadedTop - rect.top); 607 } 608 609 // make sure we aren't scrolling any further than the top our children 610 int top = getChildAt(0).getTop(); 611 int deltaToTop = top - listUnfadedTop; 612 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 613 } 614 615 final boolean scroll = scrollYDelta != 0; 616 if (scroll) { 617 scrollListItemsBy(-scrollYDelta); 618 positionSelector(INVALID_POSITION, child); 619 mSelectedTop = child.getTop(); 620 invalidate(); 621 } 622 return scroll; 623 } 624 625 /** 626 * {@inheritDoc} 627 */ 628 @Override 629 void fillGap(boolean down) { 630 final int count = getChildCount(); 631 if (down) { 632 int paddingTop = 0; 633 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 634 paddingTop = getListPaddingTop(); 635 } 636 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 637 paddingTop; 638 fillDown(mFirstPosition + count, startOffset); 639 correctTooHigh(getChildCount()); 640 } else { 641 int paddingBottom = 0; 642 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 643 paddingBottom = getListPaddingBottom(); 644 } 645 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 646 getHeight() - paddingBottom; 647 fillUp(mFirstPosition - 1, startOffset); 648 correctTooLow(getChildCount()); 649 } 650 } 651 652 /** 653 * Fills the list from pos down to the end of the list view. 654 * 655 * @param pos The first position to put in the list 656 * 657 * @param nextTop The location where the top of the item associated with pos 658 * should be drawn 659 * 660 * @return The view that is currently selected, if it happens to be in the 661 * range that we draw. 662 */ 663 private View fillDown(int pos, int nextTop) { 664 View selectedView = null; 665 666 int end = (mBottom - mTop); 667 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 668 end -= mListPadding.bottom; 669 } 670 671 while (nextTop < end && pos < mItemCount) { 672 // is this the selected item? 673 boolean selected = pos == mSelectedPosition; 674 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 675 676 nextTop = child.getBottom() + mDividerHeight; 677 if (selected) { 678 selectedView = child; 679 } 680 pos++; 681 } 682 683 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 684 return selectedView; 685 } 686 687 /** 688 * Fills the list from pos up to the top of the list view. 689 * 690 * @param pos The first position to put in the list 691 * 692 * @param nextBottom The location where the bottom of the item associated 693 * with pos should be drawn 694 * 695 * @return The view that is currently selected 696 */ 697 private View fillUp(int pos, int nextBottom) { 698 View selectedView = null; 699 700 int end = 0; 701 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 702 end = mListPadding.top; 703 } 704 705 while (nextBottom > end && pos >= 0) { 706 // is this the selected item? 707 boolean selected = pos == mSelectedPosition; 708 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 709 nextBottom = child.getTop() - mDividerHeight; 710 if (selected) { 711 selectedView = child; 712 } 713 pos--; 714 } 715 716 mFirstPosition = pos + 1; 717 setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); 718 return selectedView; 719 } 720 721 /** 722 * Fills the list from top to bottom, starting with mFirstPosition 723 * 724 * @param nextTop The location where the top of the first item should be 725 * drawn 726 * 727 * @return The view that is currently selected 728 */ 729 private View fillFromTop(int nextTop) { 730 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 731 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 732 if (mFirstPosition < 0) { 733 mFirstPosition = 0; 734 } 735 return fillDown(mFirstPosition, nextTop); 736 } 737 738 739 /** 740 * Put mSelectedPosition in the middle of the screen and then build up and 741 * down from there. This method forces mSelectedPosition to the center. 742 * 743 * @param childrenTop Top of the area in which children can be drawn, as 744 * measured in pixels 745 * @param childrenBottom Bottom of the area in which children can be drawn, 746 * as measured in pixels 747 * @return Currently selected view 748 */ 749 private View fillFromMiddle(int childrenTop, int childrenBottom) { 750 int height = childrenBottom - childrenTop; 751 752 int position = reconcileSelectedPosition(); 753 754 View sel = makeAndAddView(position, childrenTop, true, 755 mListPadding.left, true); 756 mFirstPosition = position; 757 758 int selHeight = sel.getMeasuredHeight(); 759 if (selHeight <= height) { 760 sel.offsetTopAndBottom((height - selHeight) / 2); 761 } 762 763 fillAboveAndBelow(sel, position); 764 765 if (!mStackFromBottom) { 766 correctTooHigh(getChildCount()); 767 } else { 768 correctTooLow(getChildCount()); 769 } 770 771 return sel; 772 } 773 774 /** 775 * Once the selected view as been placed, fill up the visible area above and 776 * below it. 777 * 778 * @param sel The selected view 779 * @param position The position corresponding to sel 780 */ 781 private void fillAboveAndBelow(View sel, int position) { 782 final int dividerHeight = mDividerHeight; 783 if (!mStackFromBottom) { 784 fillUp(position - 1, sel.getTop() - dividerHeight); 785 adjustViewsUpOrDown(); 786 fillDown(position + 1, sel.getBottom() + dividerHeight); 787 } else { 788 fillDown(position + 1, sel.getBottom() + dividerHeight); 789 adjustViewsUpOrDown(); 790 fillUp(position - 1, sel.getTop() - dividerHeight); 791 } 792 } 793 794 795 /** 796 * Fills the grid based on positioning the new selection at a specific 797 * location. The selection may be moved so that it does not intersect the 798 * faded edges. The grid is then filled upwards and downwards from there. 799 * 800 * @param selectedTop Where the selected item should be 801 * @param childrenTop Where to start drawing children 802 * @param childrenBottom Last pixel where children can be drawn 803 * @return The view that currently has selection 804 */ 805 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 806 int fadingEdgeLength = getVerticalFadingEdgeLength(); 807 final int selectedPosition = mSelectedPosition; 808 809 View sel; 810 811 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 812 selectedPosition); 813 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 814 selectedPosition); 815 816 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 817 818 819 // Some of the newly selected item extends below the bottom of the list 820 if (sel.getBottom() > bottomSelectionPixel) { 821 // Find space available above the selection into which we can scroll 822 // upwards 823 final int spaceAbove = sel.getTop() - topSelectionPixel; 824 825 // Find space required to bring the bottom of the selected item 826 // fully into view 827 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 828 final int offset = Math.min(spaceAbove, spaceBelow); 829 830 // Now offset the selected item to get it into view 831 sel.offsetTopAndBottom(-offset); 832 } else if (sel.getTop() < topSelectionPixel) { 833 // Find space required to bring the top of the selected item fully 834 // into view 835 final int spaceAbove = topSelectionPixel - sel.getTop(); 836 837 // Find space available below the selection into which we can scroll 838 // downwards 839 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 840 final int offset = Math.min(spaceAbove, spaceBelow); 841 842 // Offset the selected item to get it into view 843 sel.offsetTopAndBottom(offset); 844 } 845 846 // Fill in views above and below 847 fillAboveAndBelow(sel, selectedPosition); 848 849 if (!mStackFromBottom) { 850 correctTooHigh(getChildCount()); 851 } else { 852 correctTooLow(getChildCount()); 853 } 854 855 return sel; 856 } 857 858 /** 859 * Calculate the bottom-most pixel we can draw the selection into 860 * 861 * @param childrenBottom Bottom pixel were children can be drawn 862 * @param fadingEdgeLength Length of the fading edge in pixels, if present 863 * @param selectedPosition The position that will be selected 864 * @return The bottom-most pixel we can draw the selection into 865 */ 866 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 867 int selectedPosition) { 868 int bottomSelectionPixel = childrenBottom; 869 if (selectedPosition != mItemCount - 1) { 870 bottomSelectionPixel -= fadingEdgeLength; 871 } 872 return bottomSelectionPixel; 873 } 874 875 /** 876 * Calculate the top-most pixel we can draw the selection into 877 * 878 * @param childrenTop Top pixel were children can be drawn 879 * @param fadingEdgeLength Length of the fading edge in pixels, if present 880 * @param selectedPosition The position that will be selected 881 * @return The top-most pixel we can draw the selection into 882 */ 883 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 884 // first pixel we can draw the selection into 885 int topSelectionPixel = childrenTop; 886 if (selectedPosition > 0) { 887 topSelectionPixel += fadingEdgeLength; 888 } 889 return topSelectionPixel; 890 } 891 892 /** 893 * Smoothly scroll to the specified adapter position. The view will 894 * scroll such that the indicated position is displayed. 895 * @param position Scroll to this adapter position. 896 */ 897 @android.view.RemotableViewMethod 898 public void smoothScrollToPosition(int position) { 899 super.smoothScrollToPosition(position); 900 } 901 902 /** 903 * Smoothly scroll to the specified adapter position offset. The view will 904 * scroll such that the indicated position is displayed. 905 * @param offset The amount to offset from the adapter position to scroll to. 906 */ 907 @android.view.RemotableViewMethod 908 public void smoothScrollByOffset(int offset) { 909 super.smoothScrollByOffset(offset); 910 } 911 912 /** 913 * Fills the list based on positioning the new selection relative to the old 914 * selection. The new selection will be placed at, above, or below the 915 * location of the new selection depending on how the selection is moving. 916 * The selection will then be pinned to the visible part of the screen, 917 * excluding the edges that are faded. The list is then filled upwards and 918 * downwards from there. 919 * 920 * @param oldSel The old selected view. Useful for trying to put the new 921 * selection in the same place 922 * @param newSel The view that is to become selected. Useful for trying to 923 * put the new selection in the same place 924 * @param delta Which way we are moving 925 * @param childrenTop Where to start drawing children 926 * @param childrenBottom Last pixel where children can be drawn 927 * @return The view that currently has selection 928 */ 929 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 930 int childrenBottom) { 931 int fadingEdgeLength = getVerticalFadingEdgeLength(); 932 final int selectedPosition = mSelectedPosition; 933 934 View sel; 935 936 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 937 selectedPosition); 938 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 939 selectedPosition); 940 941 if (delta > 0) { 942 /* 943 * Case 1: Scrolling down. 944 */ 945 946 /* 947 * Before After 948 * | | | | 949 * +-------+ +-------+ 950 * | A | | A | 951 * | 1 | => +-------+ 952 * +-------+ | B | 953 * | B | | 2 | 954 * +-------+ +-------+ 955 * | | | | 956 * 957 * Try to keep the top of the previously selected item where it was. 958 * oldSel = A 959 * sel = B 960 */ 961 962 // Put oldSel (A) where it belongs 963 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 964 mListPadding.left, false); 965 966 final int dividerHeight = mDividerHeight; 967 968 // Now put the new selection (B) below that 969 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 970 mListPadding.left, true); 971 972 // Some of the newly selected item extends below the bottom of the list 973 if (sel.getBottom() > bottomSelectionPixel) { 974 975 // Find space available above the selection into which we can scroll upwards 976 int spaceAbove = sel.getTop() - topSelectionPixel; 977 978 // Find space required to bring the bottom of the selected item fully into view 979 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 980 981 // Don't scroll more than half the height of the list 982 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 983 int offset = Math.min(spaceAbove, spaceBelow); 984 offset = Math.min(offset, halfVerticalSpace); 985 986 // We placed oldSel, so offset that item 987 oldSel.offsetTopAndBottom(-offset); 988 // Now offset the selected item to get it into view 989 sel.offsetTopAndBottom(-offset); 990 } 991 992 // Fill in views above and below 993 if (!mStackFromBottom) { 994 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 995 adjustViewsUpOrDown(); 996 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 997 } else { 998 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 999 adjustViewsUpOrDown(); 1000 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 1001 } 1002 } else if (delta < 0) { 1003 /* 1004 * Case 2: Scrolling up. 1005 */ 1006 1007 /* 1008 * Before After 1009 * | | | | 1010 * +-------+ +-------+ 1011 * | A | | A | 1012 * +-------+ => | 1 | 1013 * | B | +-------+ 1014 * | 2 | | B | 1015 * +-------+ +-------+ 1016 * | | | | 1017 * 1018 * Try to keep the top of the item about to become selected where it was. 1019 * newSel = A 1020 * olSel = B 1021 */ 1022 1023 if (newSel != null) { 1024 // Try to position the top of newSel (A) where it was before it was selected 1025 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 1026 true); 1027 } else { 1028 // If (A) was not on screen and so did not have a view, position 1029 // it above the oldSel (B) 1030 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 1031 true); 1032 } 1033 1034 // Some of the newly selected item extends above the top of the list 1035 if (sel.getTop() < topSelectionPixel) { 1036 // Find space required to bring the top of the selected item fully into view 1037 int spaceAbove = topSelectionPixel - sel.getTop(); 1038 1039 // Find space available below the selection into which we can scroll downwards 1040 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 1041 1042 // Don't scroll more than half the height of the list 1043 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1044 int offset = Math.min(spaceAbove, spaceBelow); 1045 offset = Math.min(offset, halfVerticalSpace); 1046 1047 // Offset the selected item to get it into view 1048 sel.offsetTopAndBottom(offset); 1049 } 1050 1051 // Fill in views above and below 1052 fillAboveAndBelow(sel, selectedPosition); 1053 } else { 1054 1055 int oldTop = oldSel.getTop(); 1056 1057 /* 1058 * Case 3: Staying still 1059 */ 1060 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1061 1062 // We're staying still... 1063 if (oldTop < childrenTop) { 1064 // ... but the top of the old selection was off screen. 1065 // (This can happen if the data changes size out from under us) 1066 int newBottom = sel.getBottom(); 1067 if (newBottom < childrenTop + 20) { 1068 // Not enough visible -- bring it onscreen 1069 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1070 } 1071 } 1072 1073 // Fill in views above and below 1074 fillAboveAndBelow(sel, selectedPosition); 1075 } 1076 1077 return sel; 1078 } 1079 1080 private class FocusSelector implements Runnable { 1081 private int mPosition; 1082 private int mPositionTop; 1083 1084 public FocusSelector setup(int position, int top) { 1085 mPosition = position; 1086 mPositionTop = top; 1087 return this; 1088 } 1089 1090 public void run() { 1091 setSelectionFromTop(mPosition, mPositionTop); 1092 } 1093 } 1094 1095 @Override 1096 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1097 if (getChildCount() > 0) { 1098 View focusedChild = getFocusedChild(); 1099 if (focusedChild != null) { 1100 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1101 final int childBottom = focusedChild.getBottom(); 1102 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1103 final int top = focusedChild.getTop() - offset; 1104 if (mFocusSelector == null) { 1105 mFocusSelector = new FocusSelector(); 1106 } 1107 post(mFocusSelector.setup(childPosition, top)); 1108 } 1109 } 1110 super.onSizeChanged(w, h, oldw, oldh); 1111 } 1112 1113 @Override 1114 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1115 // Sets up mListPadding 1116 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1117 1118 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1119 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1120 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1121 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1122 1123 int childWidth = 0; 1124 int childHeight = 0; 1125 int childState = 0; 1126 1127 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1128 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1129 heightMode == MeasureSpec.UNSPECIFIED)) { 1130 final View child = obtainView(0, mIsScrap); 1131 1132 measureScrapChild(child, 0, widthMeasureSpec); 1133 1134 childWidth = child.getMeasuredWidth(); 1135 childHeight = child.getMeasuredHeight(); 1136 childState = combineMeasuredStates(childState, child.getMeasuredState()); 1137 1138 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1139 ((LayoutParams) child.getLayoutParams()).viewType)) { 1140 mRecycler.addScrapView(child, -1); 1141 } 1142 } 1143 1144 if (widthMode == MeasureSpec.UNSPECIFIED) { 1145 widthSize = mListPadding.left + mListPadding.right + childWidth + 1146 getVerticalScrollbarWidth(); 1147 } else { 1148 widthSize |= (childState&MEASURED_STATE_MASK); 1149 } 1150 1151 if (heightMode == MeasureSpec.UNSPECIFIED) { 1152 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1153 getVerticalFadingEdgeLength() * 2; 1154 } 1155 1156 if (heightMode == MeasureSpec.AT_MOST) { 1157 // TODO: after first layout we should maybe start at the first visible position, not 0 1158 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1159 } 1160 1161 setMeasuredDimension(widthSize , heightSize); 1162 mWidthMeasureSpec = widthMeasureSpec; 1163 } 1164 1165 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1166 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1167 if (p == null) { 1168 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1169 child.setLayoutParams(p); 1170 } 1171 p.viewType = mAdapter.getItemViewType(position); 1172 p.forceAdd = true; 1173 1174 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1175 mListPadding.left + mListPadding.right, p.width); 1176 int lpHeight = p.height; 1177 int childHeightSpec; 1178 if (lpHeight > 0) { 1179 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1180 } else { 1181 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1182 } 1183 child.measure(childWidthSpec, childHeightSpec); 1184 } 1185 1186 /** 1187 * @return True to recycle the views used to measure this ListView in 1188 * UNSPECIFIED/AT_MOST modes, false otherwise. 1189 * @hide 1190 */ 1191 @ViewDebug.ExportedProperty(category = "list") 1192 protected boolean recycleOnMeasure() { 1193 return true; 1194 } 1195 1196 /** 1197 * Measures the height of the given range of children (inclusive) and 1198 * returns the height with this ListView's padding and divider heights 1199 * included. If maxHeight is provided, the measuring will stop when the 1200 * current height reaches maxHeight. 1201 * 1202 * @param widthMeasureSpec The width measure spec to be given to a child's 1203 * {@link View#measure(int, int)}. 1204 * @param startPosition The position of the first child to be shown. 1205 * @param endPosition The (inclusive) position of the last child to be 1206 * shown. Specify {@link #NO_POSITION} if the last child should be 1207 * the last available child from the adapter. 1208 * @param maxHeight The maximum height that will be returned (if all the 1209 * children don't fit in this value, this value will be 1210 * returned). 1211 * @param disallowPartialChildPosition In general, whether the returned 1212 * height should only contain entire children. This is more 1213 * powerful--it is the first inclusive position at which partial 1214 * children will not be allowed. Example: it looks nice to have 1215 * at least 3 completely visible children, and in portrait this 1216 * will most likely fit; but in landscape there could be times 1217 * when even 2 children can not be completely shown, so a value 1218 * of 2 (remember, inclusive) would be good (assuming 1219 * startPosition is 0). 1220 * @return The height of this ListView with the given children. 1221 */ 1222 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1223 final int maxHeight, int disallowPartialChildPosition) { 1224 1225 final ListAdapter adapter = mAdapter; 1226 if (adapter == null) { 1227 return mListPadding.top + mListPadding.bottom; 1228 } 1229 1230 // Include the padding of the list 1231 int returnedHeight = mListPadding.top + mListPadding.bottom; 1232 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1233 // The previous height value that was less than maxHeight and contained 1234 // no partial children 1235 int prevHeightWithoutPartialChild = 0; 1236 int i; 1237 View child; 1238 1239 // mItemCount - 1 since endPosition parameter is inclusive 1240 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1241 final AbsListView.RecycleBin recycleBin = mRecycler; 1242 final boolean recyle = recycleOnMeasure(); 1243 final boolean[] isScrap = mIsScrap; 1244 1245 for (i = startPosition; i <= endPosition; ++i) { 1246 child = obtainView(i, isScrap); 1247 1248 measureScrapChild(child, i, widthMeasureSpec); 1249 1250 if (i > 0) { 1251 // Count the divider for all but one child 1252 returnedHeight += dividerHeight; 1253 } 1254 1255 // Recycle the view before we possibly return from the method 1256 if (recyle && recycleBin.shouldRecycleViewType( 1257 ((LayoutParams) child.getLayoutParams()).viewType)) { 1258 recycleBin.addScrapView(child, -1); 1259 } 1260 1261 returnedHeight += child.getMeasuredHeight(); 1262 1263 if (returnedHeight >= maxHeight) { 1264 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1265 // then the i'th position did not fit completely. 1266 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1267 && (i > disallowPartialChildPosition) // We've past the min pos 1268 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1269 && (returnedHeight != maxHeight) // i'th child did not fit completely 1270 ? prevHeightWithoutPartialChild 1271 : maxHeight; 1272 } 1273 1274 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1275 prevHeightWithoutPartialChild = returnedHeight; 1276 } 1277 } 1278 1279 // At this point, we went through the range of children, and they each 1280 // completely fit, so return the returnedHeight 1281 return returnedHeight; 1282 } 1283 1284 @Override 1285 int findMotionRow(int y) { 1286 int childCount = getChildCount(); 1287 if (childCount > 0) { 1288 if (!mStackFromBottom) { 1289 for (int i = 0; i < childCount; i++) { 1290 View v = getChildAt(i); 1291 if (y <= v.getBottom()) { 1292 return mFirstPosition + i; 1293 } 1294 } 1295 } else { 1296 for (int i = childCount - 1; i >= 0; i--) { 1297 View v = getChildAt(i); 1298 if (y >= v.getTop()) { 1299 return mFirstPosition + i; 1300 } 1301 } 1302 } 1303 } 1304 return INVALID_POSITION; 1305 } 1306 1307 /** 1308 * Put a specific item at a specific location on the screen and then build 1309 * up and down from there. 1310 * 1311 * @param position The reference view to use as the starting point 1312 * @param top Pixel offset from the top of this view to the top of the 1313 * reference view. 1314 * 1315 * @return The selected view, or null if the selected view is outside the 1316 * visible area. 1317 */ 1318 private View fillSpecific(int position, int top) { 1319 boolean tempIsSelected = position == mSelectedPosition; 1320 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1321 // Possibly changed again in fillUp if we add rows above this one. 1322 mFirstPosition = position; 1323 1324 View above; 1325 View below; 1326 1327 final int dividerHeight = mDividerHeight; 1328 if (!mStackFromBottom) { 1329 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1330 // This will correct for the top of the first view not touching the top of the list 1331 adjustViewsUpOrDown(); 1332 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1333 int childCount = getChildCount(); 1334 if (childCount > 0) { 1335 correctTooHigh(childCount); 1336 } 1337 } else { 1338 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1339 // This will correct for the bottom of the last view not touching the bottom of the list 1340 adjustViewsUpOrDown(); 1341 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1342 int childCount = getChildCount(); 1343 if (childCount > 0) { 1344 correctTooLow(childCount); 1345 } 1346 } 1347 1348 if (tempIsSelected) { 1349 return temp; 1350 } else if (above != null) { 1351 return above; 1352 } else { 1353 return below; 1354 } 1355 } 1356 1357 /** 1358 * Check if we have dragged the bottom of the list too high (we have pushed the 1359 * top element off the top of the screen when we did not need to). Correct by sliding 1360 * everything back down. 1361 * 1362 * @param childCount Number of children 1363 */ 1364 private void correctTooHigh(int childCount) { 1365 // First see if the last item is visible. If it is not, it is OK for the 1366 // top of the list to be pushed up. 1367 int lastPosition = mFirstPosition + childCount - 1; 1368 if (lastPosition == mItemCount - 1 && childCount > 0) { 1369 1370 // Get the last child ... 1371 final View lastChild = getChildAt(childCount - 1); 1372 1373 // ... and its bottom edge 1374 final int lastBottom = lastChild.getBottom(); 1375 1376 // This is bottom of our drawable area 1377 final int end = (mBottom - mTop) - mListPadding.bottom; 1378 1379 // This is how far the bottom edge of the last view is from the bottom of the 1380 // drawable area 1381 int bottomOffset = end - lastBottom; 1382 View firstChild = getChildAt(0); 1383 final int firstTop = firstChild.getTop(); 1384 1385 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1386 // first row or the first row is scrolled off the top of the drawable area 1387 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1388 if (mFirstPosition == 0) { 1389 // Don't pull the top too far down 1390 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1391 } 1392 // Move everything down 1393 offsetChildrenTopAndBottom(bottomOffset); 1394 if (mFirstPosition > 0) { 1395 // Fill the gap that was opened above mFirstPosition with more rows, if 1396 // possible 1397 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1398 // Close up the remaining gap 1399 adjustViewsUpOrDown(); 1400 } 1401 1402 } 1403 } 1404 } 1405 1406 /** 1407 * Check if we have dragged the bottom of the list too low (we have pushed the 1408 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1409 * everything back up. 1410 * 1411 * @param childCount Number of children 1412 */ 1413 private void correctTooLow(int childCount) { 1414 // First see if the first item is visible. If it is not, it is OK for the 1415 // bottom of the list to be pushed down. 1416 if (mFirstPosition == 0 && childCount > 0) { 1417 1418 // Get the first child ... 1419 final View firstChild = getChildAt(0); 1420 1421 // ... and its top edge 1422 final int firstTop = firstChild.getTop(); 1423 1424 // This is top of our drawable area 1425 final int start = mListPadding.top; 1426 1427 // This is bottom of our drawable area 1428 final int end = (mBottom - mTop) - mListPadding.bottom; 1429 1430 // This is how far the top edge of the first view is from the top of the 1431 // drawable area 1432 int topOffset = firstTop - start; 1433 View lastChild = getChildAt(childCount - 1); 1434 final int lastBottom = lastChild.getBottom(); 1435 int lastPosition = mFirstPosition + childCount - 1; 1436 1437 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1438 // last row or the last row is scrolled off the bottom of the drawable area 1439 if (topOffset > 0) { 1440 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1441 if (lastPosition == mItemCount - 1) { 1442 // Don't pull the bottom too far up 1443 topOffset = Math.min(topOffset, lastBottom - end); 1444 } 1445 // Move everything up 1446 offsetChildrenTopAndBottom(-topOffset); 1447 if (lastPosition < mItemCount - 1) { 1448 // Fill the gap that was opened below the last position with more rows, if 1449 // possible 1450 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1451 // Close up the remaining gap 1452 adjustViewsUpOrDown(); 1453 } 1454 } else if (lastPosition == mItemCount - 1) { 1455 adjustViewsUpOrDown(); 1456 } 1457 } 1458 } 1459 } 1460 1461 @Override 1462 protected void layoutChildren() { 1463 final boolean blockLayoutRequests = mBlockLayoutRequests; 1464 if (!blockLayoutRequests) { 1465 mBlockLayoutRequests = true; 1466 } else { 1467 return; 1468 } 1469 1470 try { 1471 super.layoutChildren(); 1472 1473 invalidate(); 1474 1475 if (mAdapter == null) { 1476 resetList(); 1477 invokeOnItemScrollListener(); 1478 return; 1479 } 1480 1481 int childrenTop = mListPadding.top; 1482 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1483 1484 int childCount = getChildCount(); 1485 int index = 0; 1486 int delta = 0; 1487 1488 View sel; 1489 View oldSel = null; 1490 View oldFirst = null; 1491 View newSel = null; 1492 1493 View focusLayoutRestoreView = null; 1494 1495 AccessibilityNodeInfo accessibilityFocusLayoutRestoreNode = null; 1496 View accessibilityFocusLayoutRestoreView = null; 1497 int accessibilityFocusPosition = INVALID_POSITION; 1498 1499 // Remember stuff we will need down below 1500 switch (mLayoutMode) { 1501 case LAYOUT_SET_SELECTION: 1502 index = mNextSelectedPosition - mFirstPosition; 1503 if (index >= 0 && index < childCount) { 1504 newSel = getChildAt(index); 1505 } 1506 break; 1507 case LAYOUT_FORCE_TOP: 1508 case LAYOUT_FORCE_BOTTOM: 1509 case LAYOUT_SPECIFIC: 1510 case LAYOUT_SYNC: 1511 break; 1512 case LAYOUT_MOVE_SELECTION: 1513 default: 1514 // Remember the previously selected view 1515 index = mSelectedPosition - mFirstPosition; 1516 if (index >= 0 && index < childCount) { 1517 oldSel = getChildAt(index); 1518 } 1519 1520 // Remember the previous first child 1521 oldFirst = getChildAt(0); 1522 1523 if (mNextSelectedPosition >= 0) { 1524 delta = mNextSelectedPosition - mSelectedPosition; 1525 } 1526 1527 // Caution: newSel might be null 1528 newSel = getChildAt(index + delta); 1529 } 1530 1531 1532 boolean dataChanged = mDataChanged; 1533 if (dataChanged) { 1534 handleDataChanged(); 1535 } 1536 1537 // Handle the empty set by removing all views that are visible 1538 // and calling it a day 1539 if (mItemCount == 0) { 1540 resetList(); 1541 invokeOnItemScrollListener(); 1542 return; 1543 } else if (mItemCount != mAdapter.getCount()) { 1544 throw new IllegalStateException("The content of the adapter has changed but " 1545 + "ListView did not receive a notification. Make sure the content of " 1546 + "your adapter is not modified from a background thread, but only " 1547 + "from the UI thread. [in ListView(" + getId() + ", " + getClass() 1548 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1549 } 1550 1551 setSelectedPositionInt(mNextSelectedPosition); 1552 1553 // Remember which child, if any, had accessibility focus. This must 1554 // occur before recycling any views, since that will clear 1555 // accessibility focus. 1556 final ViewRootImpl viewRootImpl = getViewRootImpl(); 1557 if (viewRootImpl != null) { 1558 final View accessFocusedView = viewRootImpl.getAccessibilityFocusedHost(); 1559 if (accessFocusedView != null) { 1560 final View accessFocusedChild = findAccessibilityFocusedChild( 1561 accessFocusedView); 1562 if (accessFocusedChild != null) { 1563 if (!dataChanged || isDirectChildHeaderOrFooter(accessFocusedChild)) { 1564 // If the views won't be changing, try to maintain 1565 // focus on the current view host and (if 1566 // applicable) its virtual view. 1567 accessibilityFocusLayoutRestoreView = accessFocusedView; 1568 accessibilityFocusLayoutRestoreNode = viewRootImpl 1569 .getAccessibilityFocusedVirtualView(); 1570 } else { 1571 // Otherwise, try to maintain focus at the same 1572 // position. 1573 accessibilityFocusPosition = getPositionForView(accessFocusedChild); 1574 } 1575 } 1576 } 1577 } 1578 1579 // Pull all children into the RecycleBin. 1580 // These views will be reused if possible 1581 final int firstPosition = mFirstPosition; 1582 final RecycleBin recycleBin = mRecycler; 1583 1584 // reset the focus restoration 1585 View focusLayoutRestoreDirectChild = null; 1586 1587 // Don't put header or footer views into the Recycler. Those are 1588 // already cached in mHeaderViews; 1589 if (dataChanged) { 1590 for (int i = 0; i < childCount; i++) { 1591 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1592 } 1593 } else { 1594 recycleBin.fillActiveViews(childCount, firstPosition); 1595 } 1596 1597 // take focus back to us temporarily to avoid the eventual 1598 // call to clear focus when removing the focused child below 1599 // from messing things up when ViewAncestor assigns focus back 1600 // to someone else 1601 final View focusedChild = getFocusedChild(); 1602 if (focusedChild != null) { 1603 // TODO: in some cases focusedChild.getParent() == null 1604 1605 // we can remember the focused view to restore after relayout if the 1606 // data hasn't changed, or if the focused position is a header or footer 1607 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1608 focusLayoutRestoreDirectChild = focusedChild; 1609 // remember the specific view that had focus 1610 focusLayoutRestoreView = findFocus(); 1611 if (focusLayoutRestoreView != null) { 1612 // tell it we are going to mess with it 1613 focusLayoutRestoreView.onStartTemporaryDetach(); 1614 } 1615 } 1616 requestFocus(); 1617 } 1618 1619 // Clear out old views 1620 detachAllViewsFromParent(); 1621 recycleBin.removeSkippedScrap(); 1622 1623 switch (mLayoutMode) { 1624 case LAYOUT_SET_SELECTION: 1625 if (newSel != null) { 1626 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1627 } else { 1628 sel = fillFromMiddle(childrenTop, childrenBottom); 1629 } 1630 break; 1631 case LAYOUT_SYNC: 1632 sel = fillSpecific(mSyncPosition, mSpecificTop); 1633 break; 1634 case LAYOUT_FORCE_BOTTOM: 1635 sel = fillUp(mItemCount - 1, childrenBottom); 1636 adjustViewsUpOrDown(); 1637 break; 1638 case LAYOUT_FORCE_TOP: 1639 mFirstPosition = 0; 1640 sel = fillFromTop(childrenTop); 1641 adjustViewsUpOrDown(); 1642 break; 1643 case LAYOUT_SPECIFIC: 1644 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1645 break; 1646 case LAYOUT_MOVE_SELECTION: 1647 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1648 break; 1649 default: 1650 if (childCount == 0) { 1651 if (!mStackFromBottom) { 1652 final int position = lookForSelectablePosition(0, true); 1653 setSelectedPositionInt(position); 1654 sel = fillFromTop(childrenTop); 1655 } else { 1656 final int position = lookForSelectablePosition(mItemCount - 1, false); 1657 setSelectedPositionInt(position); 1658 sel = fillUp(mItemCount - 1, childrenBottom); 1659 } 1660 } else { 1661 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1662 sel = fillSpecific(mSelectedPosition, 1663 oldSel == null ? childrenTop : oldSel.getTop()); 1664 } else if (mFirstPosition < mItemCount) { 1665 sel = fillSpecific(mFirstPosition, 1666 oldFirst == null ? childrenTop : oldFirst.getTop()); 1667 } else { 1668 sel = fillSpecific(0, childrenTop); 1669 } 1670 } 1671 break; 1672 } 1673 1674 // Flush any cached views that did not get reused above 1675 recycleBin.scrapActiveViews(); 1676 1677 if (sel != null) { 1678 // the current selected item should get focus if items 1679 // are focusable 1680 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1681 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1682 focusLayoutRestoreView != null && 1683 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1684 if (!focusWasTaken) { 1685 // selected item didn't take focus, fine, but still want 1686 // to make sure something else outside of the selected view 1687 // has focus 1688 final View focused = getFocusedChild(); 1689 if (focused != null) { 1690 focused.clearFocus(); 1691 } 1692 positionSelector(INVALID_POSITION, sel); 1693 } else { 1694 sel.setSelected(false); 1695 mSelectorRect.setEmpty(); 1696 } 1697 } else { 1698 positionSelector(INVALID_POSITION, sel); 1699 } 1700 mSelectedTop = sel.getTop(); 1701 } else { 1702 if (mTouchMode > TOUCH_MODE_DOWN && mTouchMode < TOUCH_MODE_SCROLL) { 1703 View child = getChildAt(mMotionPosition - mFirstPosition); 1704 if (child != null) positionSelector(mMotionPosition, child); 1705 } else { 1706 mSelectedTop = 0; 1707 mSelectorRect.setEmpty(); 1708 } 1709 1710 // even if there is not selected position, we may need to restore 1711 // focus (i.e. something focusable in touch mode) 1712 if (hasFocus() && focusLayoutRestoreView != null) { 1713 focusLayoutRestoreView.requestFocus(); 1714 } 1715 } 1716 1717 // Attempt to restore accessibility focus. 1718 if (accessibilityFocusLayoutRestoreNode != null) { 1719 accessibilityFocusLayoutRestoreNode.performAction( 1720 AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS); 1721 } else if (accessibilityFocusLayoutRestoreView != null) { 1722 accessibilityFocusLayoutRestoreView.requestAccessibilityFocus(); 1723 } else if (accessibilityFocusPosition != INVALID_POSITION) { 1724 // Bound the position within the visible children. 1725 final int position = MathUtils.constrain( 1726 (accessibilityFocusPosition - mFirstPosition), 0, (getChildCount() - 1)); 1727 final View restoreView = getChildAt(position); 1728 if (restoreView != null) { 1729 restoreView.requestAccessibilityFocus(); 1730 } 1731 } 1732 1733 // tell focus view we are done mucking with it, if it is still in 1734 // our view hierarchy. 1735 if (focusLayoutRestoreView != null 1736 && focusLayoutRestoreView.getWindowToken() != null) { 1737 focusLayoutRestoreView.onFinishTemporaryDetach(); 1738 } 1739 1740 mLayoutMode = LAYOUT_NORMAL; 1741 mDataChanged = false; 1742 if (mPositionScrollAfterLayout != null) { 1743 post(mPositionScrollAfterLayout); 1744 mPositionScrollAfterLayout = null; 1745 } 1746 mNeedSync = false; 1747 setNextSelectedPositionInt(mSelectedPosition); 1748 1749 updateScrollIndicators(); 1750 1751 if (mItemCount > 0) { 1752 checkSelectionChanged(); 1753 } 1754 1755 invokeOnItemScrollListener(); 1756 } finally { 1757 if (!blockLayoutRequests) { 1758 mBlockLayoutRequests = false; 1759 } 1760 } 1761 } 1762 1763 /** 1764 * @param focusedView the view that has accessibility focus. 1765 * @return the direct child that contains accessibility focus. 1766 */ 1767 private View findAccessibilityFocusedChild(View focusedView) { 1768 ViewParent viewParent = focusedView.getParent(); 1769 while ((viewParent instanceof View) && (viewParent != this)) { 1770 focusedView = (View) viewParent; 1771 viewParent = viewParent.getParent(); 1772 } 1773 if (!(viewParent instanceof View)) { 1774 return null; 1775 } 1776 return focusedView; 1777 } 1778 1779 /** 1780 * @param child a direct child of this list. 1781 * @return Whether child is a header or footer view. 1782 */ 1783 private boolean isDirectChildHeaderOrFooter(View child) { 1784 1785 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1786 final int numHeaders = headers.size(); 1787 for (int i = 0; i < numHeaders; i++) { 1788 if (child == headers.get(i).view) { 1789 return true; 1790 } 1791 } 1792 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1793 final int numFooters = footers.size(); 1794 for (int i = 0; i < numFooters; i++) { 1795 if (child == footers.get(i).view) { 1796 return true; 1797 } 1798 } 1799 return false; 1800 } 1801 1802 /** 1803 * Obtain the view and add it to our list of children. The view can be made 1804 * fresh, converted from an unused view, or used as is if it was in the 1805 * recycle bin. 1806 * 1807 * @param position Logical position in the list 1808 * @param y Top or bottom edge of the view to add 1809 * @param flow If flow is true, align top edge to y. If false, align bottom 1810 * edge to y. 1811 * @param childrenLeft Left edge where children should be positioned 1812 * @param selected Is this position selected? 1813 * @return View that was added 1814 */ 1815 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1816 boolean selected) { 1817 View child; 1818 1819 1820 if (!mDataChanged) { 1821 // Try to use an existing view for this position 1822 child = mRecycler.getActiveView(position); 1823 if (child != null) { 1824 // Found it -- we're using an existing child 1825 // This just needs to be positioned 1826 setupChild(child, position, y, flow, childrenLeft, selected, true); 1827 1828 return child; 1829 } 1830 } 1831 1832 // Make a new view for this position, or convert an unused view if possible 1833 child = obtainView(position, mIsScrap); 1834 1835 // This needs to be positioned and measured 1836 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1837 1838 return child; 1839 } 1840 1841 /** 1842 * Add a view as a child and make sure it is measured (if necessary) and 1843 * positioned properly. 1844 * 1845 * @param child The view to add 1846 * @param position The position of this child 1847 * @param y The y position relative to which this view will be positioned 1848 * @param flowDown If true, align top edge to y. If false, align bottom 1849 * edge to y. 1850 * @param childrenLeft Left edge where children should be positioned 1851 * @param selected Is this position selected? 1852 * @param recycled Has this view been pulled from the recycle bin? If so it 1853 * does not need to be remeasured. 1854 */ 1855 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1856 boolean selected, boolean recycled) { 1857 final boolean isSelected = selected && shouldShowSelector(); 1858 final boolean updateChildSelected = isSelected != child.isSelected(); 1859 final int mode = mTouchMode; 1860 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1861 mMotionPosition == position; 1862 final boolean updateChildPressed = isPressed != child.isPressed(); 1863 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1864 1865 // Respect layout params that are already in the view. Otherwise make some up... 1866 // noinspection unchecked 1867 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1868 if (p == null) { 1869 p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); 1870 } 1871 p.viewType = mAdapter.getItemViewType(position); 1872 1873 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1874 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1875 attachViewToParent(child, flowDown ? -1 : 0, p); 1876 } else { 1877 p.forceAdd = false; 1878 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1879 p.recycledHeaderFooter = true; 1880 } 1881 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1882 } 1883 1884 if (updateChildSelected) { 1885 child.setSelected(isSelected); 1886 } 1887 1888 if (updateChildPressed) { 1889 child.setPressed(isPressed); 1890 } 1891 1892 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1893 if (child instanceof Checkable) { 1894 ((Checkable) child).setChecked(mCheckStates.get(position)); 1895 } else if (getContext().getApplicationInfo().targetSdkVersion 1896 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1897 child.setActivated(mCheckStates.get(position)); 1898 } 1899 } 1900 1901 if (needToMeasure) { 1902 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1903 mListPadding.left + mListPadding.right, p.width); 1904 int lpHeight = p.height; 1905 int childHeightSpec; 1906 if (lpHeight > 0) { 1907 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1908 } else { 1909 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1910 } 1911 child.measure(childWidthSpec, childHeightSpec); 1912 } else { 1913 cleanupLayoutState(child); 1914 } 1915 1916 final int w = child.getMeasuredWidth(); 1917 final int h = child.getMeasuredHeight(); 1918 final int childTop = flowDown ? y : y - h; 1919 1920 if (needToMeasure) { 1921 final int childRight = childrenLeft + w; 1922 final int childBottom = childTop + h; 1923 child.layout(childrenLeft, childTop, childRight, childBottom); 1924 } else { 1925 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1926 child.offsetTopAndBottom(childTop - child.getTop()); 1927 } 1928 1929 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1930 child.setDrawingCacheEnabled(true); 1931 } 1932 1933 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1934 != position) { 1935 child.jumpDrawablesToCurrentState(); 1936 } 1937 } 1938 1939 @Override 1940 protected boolean canAnimate() { 1941 return super.canAnimate() && mItemCount > 0; 1942 } 1943 1944 /** 1945 * Sets the currently selected item. If in touch mode, the item will not be selected 1946 * but it will still be positioned appropriately. If the specified selection position 1947 * is less than 0, then the item at position 0 will be selected. 1948 * 1949 * @param position Index (starting at 0) of the data item to be selected. 1950 */ 1951 @Override 1952 public void setSelection(int position) { 1953 setSelectionFromTop(position, 0); 1954 } 1955 1956 /** 1957 * Sets the selected item and positions the selection y pixels from the top edge 1958 * of the ListView. (If in touch mode, the item will not be selected but it will 1959 * still be positioned appropriately.) 1960 * 1961 * @param position Index (starting at 0) of the data item to be selected. 1962 * @param y The distance from the top edge of the ListView (plus padding) that the 1963 * item will be positioned. 1964 */ 1965 public void setSelectionFromTop(int position, int y) { 1966 if (mAdapter == null) { 1967 return; 1968 } 1969 1970 if (!isInTouchMode()) { 1971 position = lookForSelectablePosition(position, true); 1972 if (position >= 0) { 1973 setNextSelectedPositionInt(position); 1974 } 1975 } else { 1976 mResurrectToPosition = position; 1977 } 1978 1979 if (position >= 0) { 1980 mLayoutMode = LAYOUT_SPECIFIC; 1981 mSpecificTop = mListPadding.top + y; 1982 1983 if (mNeedSync) { 1984 mSyncPosition = position; 1985 mSyncRowId = mAdapter.getItemId(position); 1986 } 1987 1988 if (mPositionScroller != null) { 1989 mPositionScroller.stop(); 1990 } 1991 requestLayout(); 1992 } 1993 } 1994 1995 /** 1996 * Makes the item at the supplied position selected. 1997 * 1998 * @param position the position of the item to select 1999 */ 2000 @Override 2001 void setSelectionInt(int position) { 2002 setNextSelectedPositionInt(position); 2003 boolean awakeScrollbars = false; 2004 2005 final int selectedPosition = mSelectedPosition; 2006 2007 if (selectedPosition >= 0) { 2008 if (position == selectedPosition - 1) { 2009 awakeScrollbars = true; 2010 } else if (position == selectedPosition + 1) { 2011 awakeScrollbars = true; 2012 } 2013 } 2014 2015 if (mPositionScroller != null) { 2016 mPositionScroller.stop(); 2017 } 2018 2019 layoutChildren(); 2020 2021 if (awakeScrollbars) { 2022 awakenScrollBars(); 2023 } 2024 } 2025 2026 /** 2027 * Find a position that can be selected (i.e., is not a separator). 2028 * 2029 * @param position The starting position to look at. 2030 * @param lookDown Whether to look down for other positions. 2031 * @return The next selectable position starting at position and then searching either up or 2032 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 2033 */ 2034 @Override 2035 int lookForSelectablePosition(int position, boolean lookDown) { 2036 final ListAdapter adapter = mAdapter; 2037 if (adapter == null || isInTouchMode()) { 2038 return INVALID_POSITION; 2039 } 2040 2041 final int count = adapter.getCount(); 2042 if (!mAreAllItemsSelectable) { 2043 if (lookDown) { 2044 position = Math.max(0, position); 2045 while (position < count && !adapter.isEnabled(position)) { 2046 position++; 2047 } 2048 } else { 2049 position = Math.min(position, count - 1); 2050 while (position >= 0 && !adapter.isEnabled(position)) { 2051 position--; 2052 } 2053 } 2054 2055 if (position < 0 || position >= count) { 2056 return INVALID_POSITION; 2057 } 2058 return position; 2059 } else { 2060 if (position < 0 || position >= count) { 2061 return INVALID_POSITION; 2062 } 2063 return position; 2064 } 2065 } 2066 2067 /** 2068 * setSelectionAfterHeaderView set the selection to be the first list item 2069 * after the header views. 2070 */ 2071 public void setSelectionAfterHeaderView() { 2072 final int count = mHeaderViewInfos.size(); 2073 if (count > 0) { 2074 mNextSelectedPosition = 0; 2075 return; 2076 } 2077 2078 if (mAdapter != null) { 2079 setSelection(count); 2080 } else { 2081 mNextSelectedPosition = count; 2082 mLayoutMode = LAYOUT_SET_SELECTION; 2083 } 2084 2085 } 2086 2087 @Override 2088 public boolean dispatchKeyEvent(KeyEvent event) { 2089 // Dispatch in the normal way 2090 boolean handled = super.dispatchKeyEvent(event); 2091 if (!handled) { 2092 // If we didn't handle it... 2093 View focused = getFocusedChild(); 2094 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2095 // ... and our focused child didn't handle it 2096 // ... give it to ourselves so we can scroll if necessary 2097 handled = onKeyDown(event.getKeyCode(), event); 2098 } 2099 } 2100 return handled; 2101 } 2102 2103 @Override 2104 public boolean onKeyDown(int keyCode, KeyEvent event) { 2105 return commonKey(keyCode, 1, event); 2106 } 2107 2108 @Override 2109 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2110 return commonKey(keyCode, repeatCount, event); 2111 } 2112 2113 @Override 2114 public boolean onKeyUp(int keyCode, KeyEvent event) { 2115 return commonKey(keyCode, 1, event); 2116 } 2117 2118 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2119 if (mAdapter == null || !mIsAttached) { 2120 return false; 2121 } 2122 2123 if (mDataChanged) { 2124 layoutChildren(); 2125 } 2126 2127 boolean handled = false; 2128 int action = event.getAction(); 2129 2130 if (action != KeyEvent.ACTION_UP) { 2131 switch (keyCode) { 2132 case KeyEvent.KEYCODE_DPAD_UP: 2133 if (event.hasNoModifiers()) { 2134 handled = resurrectSelectionIfNeeded(); 2135 if (!handled) { 2136 while (count-- > 0) { 2137 if (arrowScroll(FOCUS_UP)) { 2138 handled = true; 2139 } else { 2140 break; 2141 } 2142 } 2143 } 2144 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2145 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2146 } 2147 break; 2148 2149 case KeyEvent.KEYCODE_DPAD_DOWN: 2150 if (event.hasNoModifiers()) { 2151 handled = resurrectSelectionIfNeeded(); 2152 if (!handled) { 2153 while (count-- > 0) { 2154 if (arrowScroll(FOCUS_DOWN)) { 2155 handled = true; 2156 } else { 2157 break; 2158 } 2159 } 2160 } 2161 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2162 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2163 } 2164 break; 2165 2166 case KeyEvent.KEYCODE_DPAD_LEFT: 2167 if (event.hasNoModifiers()) { 2168 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2169 } 2170 break; 2171 2172 case KeyEvent.KEYCODE_DPAD_RIGHT: 2173 if (event.hasNoModifiers()) { 2174 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2175 } 2176 break; 2177 2178 case KeyEvent.KEYCODE_DPAD_CENTER: 2179 case KeyEvent.KEYCODE_ENTER: 2180 if (event.hasNoModifiers()) { 2181 handled = resurrectSelectionIfNeeded(); 2182 if (!handled 2183 && event.getRepeatCount() == 0 && getChildCount() > 0) { 2184 keyPressed(); 2185 handled = true; 2186 } 2187 } 2188 break; 2189 2190 case KeyEvent.KEYCODE_SPACE: 2191 if (mPopup == null || !mPopup.isShowing()) { 2192 if (event.hasNoModifiers()) { 2193 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2194 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2195 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2196 } 2197 handled = true; 2198 } 2199 break; 2200 2201 case KeyEvent.KEYCODE_PAGE_UP: 2202 if (event.hasNoModifiers()) { 2203 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2204 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2205 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2206 } 2207 break; 2208 2209 case KeyEvent.KEYCODE_PAGE_DOWN: 2210 if (event.hasNoModifiers()) { 2211 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2212 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2213 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2214 } 2215 break; 2216 2217 case KeyEvent.KEYCODE_MOVE_HOME: 2218 if (event.hasNoModifiers()) { 2219 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2220 } 2221 break; 2222 2223 case KeyEvent.KEYCODE_MOVE_END: 2224 if (event.hasNoModifiers()) { 2225 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2226 } 2227 break; 2228 2229 case KeyEvent.KEYCODE_TAB: 2230 // XXX Sometimes it is useful to be able to TAB through the items in 2231 // a ListView sequentially. Unfortunately this can create an 2232 // asymmetry in TAB navigation order unless the list selection 2233 // always reverts to the top or bottom when receiving TAB focus from 2234 // another widget. Leaving this behavior disabled for now but 2235 // perhaps it should be configurable (and more comprehensive). 2236 if (false) { 2237 if (event.hasNoModifiers()) { 2238 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_DOWN); 2239 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2240 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_UP); 2241 } 2242 } 2243 break; 2244 } 2245 } 2246 2247 if (handled) { 2248 return true; 2249 } 2250 2251 if (sendToTextFilter(keyCode, count, event)) { 2252 return true; 2253 } 2254 2255 switch (action) { 2256 case KeyEvent.ACTION_DOWN: 2257 return super.onKeyDown(keyCode, event); 2258 2259 case KeyEvent.ACTION_UP: 2260 return super.onKeyUp(keyCode, event); 2261 2262 case KeyEvent.ACTION_MULTIPLE: 2263 return super.onKeyMultiple(keyCode, count, event); 2264 2265 default: // shouldn't happen 2266 return false; 2267 } 2268 } 2269 2270 /** 2271 * Scrolls up or down by the number of items currently present on screen. 2272 * 2273 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2274 * @return whether selection was moved 2275 */ 2276 boolean pageScroll(int direction) { 2277 int nextPage = -1; 2278 boolean down = false; 2279 2280 if (direction == FOCUS_UP) { 2281 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2282 } else if (direction == FOCUS_DOWN) { 2283 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2284 down = true; 2285 } 2286 2287 if (nextPage >= 0) { 2288 int position = lookForSelectablePosition(nextPage, down); 2289 if (position >= 0) { 2290 mLayoutMode = LAYOUT_SPECIFIC; 2291 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2292 2293 if (down && position > mItemCount - getChildCount()) { 2294 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2295 } 2296 2297 if (!down && position < getChildCount()) { 2298 mLayoutMode = LAYOUT_FORCE_TOP; 2299 } 2300 2301 setSelectionInt(position); 2302 invokeOnItemScrollListener(); 2303 if (!awakenScrollBars()) { 2304 invalidate(); 2305 } 2306 2307 return true; 2308 } 2309 } 2310 2311 return false; 2312 } 2313 2314 /** 2315 * Go to the last or first item if possible (not worrying about panning across or navigating 2316 * within the internal focus of the currently selected item.) 2317 * 2318 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2319 * 2320 * @return whether selection was moved 2321 */ 2322 boolean fullScroll(int direction) { 2323 boolean moved = false; 2324 if (direction == FOCUS_UP) { 2325 if (mSelectedPosition != 0) { 2326 int position = lookForSelectablePosition(0, true); 2327 if (position >= 0) { 2328 mLayoutMode = LAYOUT_FORCE_TOP; 2329 setSelectionInt(position); 2330 invokeOnItemScrollListener(); 2331 } 2332 moved = true; 2333 } 2334 } else if (direction == FOCUS_DOWN) { 2335 if (mSelectedPosition < mItemCount - 1) { 2336 int position = lookForSelectablePosition(mItemCount - 1, true); 2337 if (position >= 0) { 2338 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2339 setSelectionInt(position); 2340 invokeOnItemScrollListener(); 2341 } 2342 moved = true; 2343 } 2344 } 2345 2346 if (moved && !awakenScrollBars()) { 2347 awakenScrollBars(); 2348 invalidate(); 2349 } 2350 2351 return moved; 2352 } 2353 2354 /** 2355 * To avoid horizontal focus searches changing the selected item, we 2356 * manually focus search within the selected item (as applicable), and 2357 * prevent focus from jumping to something within another item. 2358 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2359 * @return Whether this consumes the key event. 2360 */ 2361 private boolean handleHorizontalFocusWithinListItem(int direction) { 2362 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2363 throw new IllegalArgumentException("direction must be one of" 2364 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2365 } 2366 2367 final int numChildren = getChildCount(); 2368 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2369 final View selectedView = getSelectedView(); 2370 if (selectedView != null && selectedView.hasFocus() && 2371 selectedView instanceof ViewGroup) { 2372 2373 final View currentFocus = selectedView.findFocus(); 2374 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2375 (ViewGroup) selectedView, currentFocus, direction); 2376 if (nextFocus != null) { 2377 // do the math to get interesting rect in next focus' coordinates 2378 currentFocus.getFocusedRect(mTempRect); 2379 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2380 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2381 if (nextFocus.requestFocus(direction, mTempRect)) { 2382 return true; 2383 } 2384 } 2385 // we are blocking the key from being handled (by returning true) 2386 // if the global result is going to be some other view within this 2387 // list. this is to acheive the overall goal of having 2388 // horizontal d-pad navigation remain in the current item. 2389 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2390 (ViewGroup) getRootView(), currentFocus, direction); 2391 if (globalNextFocus != null) { 2392 return isViewAncestorOf(globalNextFocus, this); 2393 } 2394 } 2395 } 2396 return false; 2397 } 2398 2399 /** 2400 * Scrolls to the next or previous item if possible. 2401 * 2402 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2403 * 2404 * @return whether selection was moved 2405 */ 2406 boolean arrowScroll(int direction) { 2407 try { 2408 mInLayout = true; 2409 final boolean handled = arrowScrollImpl(direction); 2410 if (handled) { 2411 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2412 } 2413 return handled; 2414 } finally { 2415 mInLayout = false; 2416 } 2417 } 2418 2419 /** 2420 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2421 * whether there are focusable items etc. 2422 * 2423 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2424 * @return Whether any scrolling, selection or focus change occured. 2425 */ 2426 private boolean arrowScrollImpl(int direction) { 2427 if (getChildCount() <= 0) { 2428 return false; 2429 } 2430 2431 View selectedView = getSelectedView(); 2432 int selectedPos = mSelectedPosition; 2433 2434 int nextSelectedPosition = (direction == View.FOCUS_DOWN) ? 2435 lookForSelectablePosition(selectedPos + 1, true) : 2436 lookForSelectablePosition(selectedPos - 1, false); 2437 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2438 2439 // if we are moving focus, we may OVERRIDE the default behavior 2440 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2441 if (focusResult != null) { 2442 nextSelectedPosition = focusResult.getSelectedPosition(); 2443 amountToScroll = focusResult.getAmountToScroll(); 2444 } 2445 2446 boolean needToRedraw = focusResult != null; 2447 if (nextSelectedPosition != INVALID_POSITION) { 2448 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2449 setSelectedPositionInt(nextSelectedPosition); 2450 setNextSelectedPositionInt(nextSelectedPosition); 2451 selectedView = getSelectedView(); 2452 selectedPos = nextSelectedPosition; 2453 if (mItemsCanFocus && focusResult == null) { 2454 // there was no new view found to take focus, make sure we 2455 // don't leave focus with the old selection 2456 final View focused = getFocusedChild(); 2457 if (focused != null) { 2458 focused.clearFocus(); 2459 } 2460 } 2461 needToRedraw = true; 2462 checkSelectionChanged(); 2463 } 2464 2465 if (amountToScroll > 0) { 2466 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2467 needToRedraw = true; 2468 } 2469 2470 // if we didn't find a new focusable, make sure any existing focused 2471 // item that was panned off screen gives up focus. 2472 if (mItemsCanFocus && (focusResult == null) 2473 && selectedView != null && selectedView.hasFocus()) { 2474 final View focused = selectedView.findFocus(); 2475 if (!isViewAncestorOf(focused, this) || distanceToView(focused) > 0) { 2476 focused.clearFocus(); 2477 } 2478 } 2479 2480 // if the current selection is panned off, we need to remove the selection 2481 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2482 && !isViewAncestorOf(selectedView, this)) { 2483 selectedView = null; 2484 hideSelector(); 2485 2486 // but we don't want to set the ressurect position (that would make subsequent 2487 // unhandled key events bring back the item we just scrolled off!) 2488 mResurrectToPosition = INVALID_POSITION; 2489 } 2490 2491 if (needToRedraw) { 2492 if (selectedView != null) { 2493 positionSelector(selectedPos, selectedView); 2494 mSelectedTop = selectedView.getTop(); 2495 } 2496 if (!awakenScrollBars()) { 2497 invalidate(); 2498 } 2499 invokeOnItemScrollListener(); 2500 return true; 2501 } 2502 2503 return false; 2504 } 2505 2506 /** 2507 * When selection changes, it is possible that the previously selected or the 2508 * next selected item will change its size. If so, we need to offset some folks, 2509 * and re-layout the items as appropriate. 2510 * 2511 * @param selectedView The currently selected view (before changing selection). 2512 * should be <code>null</code> if there was no previous selection. 2513 * @param direction Either {@link android.view.View#FOCUS_UP} or 2514 * {@link android.view.View#FOCUS_DOWN}. 2515 * @param newSelectedPosition The position of the next selection. 2516 * @param newFocusAssigned whether new focus was assigned. This matters because 2517 * when something has focus, we don't want to show selection (ugh). 2518 */ 2519 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2520 boolean newFocusAssigned) { 2521 if (newSelectedPosition == INVALID_POSITION) { 2522 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2523 } 2524 2525 // whether or not we are moving down or up, we want to preserve the 2526 // top of whatever view is on top: 2527 // - moving down: the view that had selection 2528 // - moving up: the view that is getting selection 2529 View topView; 2530 View bottomView; 2531 int topViewIndex, bottomViewIndex; 2532 boolean topSelected = false; 2533 final int selectedIndex = mSelectedPosition - mFirstPosition; 2534 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2535 if (direction == View.FOCUS_UP) { 2536 topViewIndex = nextSelectedIndex; 2537 bottomViewIndex = selectedIndex; 2538 topView = getChildAt(topViewIndex); 2539 bottomView = selectedView; 2540 topSelected = true; 2541 } else { 2542 topViewIndex = selectedIndex; 2543 bottomViewIndex = nextSelectedIndex; 2544 topView = selectedView; 2545 bottomView = getChildAt(bottomViewIndex); 2546 } 2547 2548 final int numChildren = getChildCount(); 2549 2550 // start with top view: is it changing size? 2551 if (topView != null) { 2552 topView.setSelected(!newFocusAssigned && topSelected); 2553 measureAndAdjustDown(topView, topViewIndex, numChildren); 2554 } 2555 2556 // is the bottom view changing size? 2557 if (bottomView != null) { 2558 bottomView.setSelected(!newFocusAssigned && !topSelected); 2559 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2560 } 2561 } 2562 2563 /** 2564 * Re-measure a child, and if its height changes, lay it out preserving its 2565 * top, and adjust the children below it appropriately. 2566 * @param child The child 2567 * @param childIndex The view group index of the child. 2568 * @param numChildren The number of children in the view group. 2569 */ 2570 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2571 int oldHeight = child.getHeight(); 2572 measureItem(child); 2573 if (child.getMeasuredHeight() != oldHeight) { 2574 // lay out the view, preserving its top 2575 relayoutMeasuredItem(child); 2576 2577 // adjust views below appropriately 2578 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2579 for (int i = childIndex + 1; i < numChildren; i++) { 2580 getChildAt(i).offsetTopAndBottom(heightDelta); 2581 } 2582 } 2583 } 2584 2585 /** 2586 * Measure a particular list child. 2587 * TODO: unify with setUpChild. 2588 * @param child The child. 2589 */ 2590 private void measureItem(View child) { 2591 ViewGroup.LayoutParams p = child.getLayoutParams(); 2592 if (p == null) { 2593 p = new ViewGroup.LayoutParams( 2594 ViewGroup.LayoutParams.MATCH_PARENT, 2595 ViewGroup.LayoutParams.WRAP_CONTENT); 2596 } 2597 2598 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2599 mListPadding.left + mListPadding.right, p.width); 2600 int lpHeight = p.height; 2601 int childHeightSpec; 2602 if (lpHeight > 0) { 2603 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2604 } else { 2605 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2606 } 2607 child.measure(childWidthSpec, childHeightSpec); 2608 } 2609 2610 /** 2611 * Layout a child that has been measured, preserving its top position. 2612 * TODO: unify with setUpChild. 2613 * @param child The child. 2614 */ 2615 private void relayoutMeasuredItem(View child) { 2616 final int w = child.getMeasuredWidth(); 2617 final int h = child.getMeasuredHeight(); 2618 final int childLeft = mListPadding.left; 2619 final int childRight = childLeft + w; 2620 final int childTop = child.getTop(); 2621 final int childBottom = childTop + h; 2622 child.layout(childLeft, childTop, childRight, childBottom); 2623 } 2624 2625 /** 2626 * @return The amount to preview next items when arrow srolling. 2627 */ 2628 private int getArrowScrollPreviewLength() { 2629 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2630 } 2631 2632 /** 2633 * Determine how much we need to scroll in order to get the next selected view 2634 * visible, with a fading edge showing below as applicable. The amount is 2635 * capped at {@link #getMaxScrollAmount()} . 2636 * 2637 * @param direction either {@link android.view.View#FOCUS_UP} or 2638 * {@link android.view.View#FOCUS_DOWN}. 2639 * @param nextSelectedPosition The position of the next selection, or 2640 * {@link #INVALID_POSITION} if there is no next selectable position 2641 * @return The amount to scroll. Note: this is always positive! Direction 2642 * needs to be taken into account when actually scrolling. 2643 */ 2644 private int amountToScroll(int direction, int nextSelectedPosition) { 2645 final int listBottom = getHeight() - mListPadding.bottom; 2646 final int listTop = mListPadding.top; 2647 2648 int numChildren = getChildCount(); 2649 2650 if (direction == View.FOCUS_DOWN) { 2651 int indexToMakeVisible = numChildren - 1; 2652 if (nextSelectedPosition != INVALID_POSITION) { 2653 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2654 } 2655 while (numChildren <= indexToMakeVisible) { 2656 // Child to view is not attached yet. 2657 addViewBelow(getChildAt(numChildren - 1), mFirstPosition + numChildren - 1); 2658 numChildren++; 2659 } 2660 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2661 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2662 2663 int goalBottom = listBottom; 2664 if (positionToMakeVisible < mItemCount - 1) { 2665 goalBottom -= getArrowScrollPreviewLength(); 2666 } 2667 2668 if (viewToMakeVisible.getBottom() <= goalBottom) { 2669 // item is fully visible. 2670 return 0; 2671 } 2672 2673 if (nextSelectedPosition != INVALID_POSITION 2674 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2675 // item already has enough of it visible, changing selection is good enough 2676 return 0; 2677 } 2678 2679 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2680 2681 if ((mFirstPosition + numChildren) == mItemCount) { 2682 // last is last in list -> make sure we don't scroll past it 2683 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2684 amountToScroll = Math.min(amountToScroll, max); 2685 } 2686 2687 return Math.min(amountToScroll, getMaxScrollAmount()); 2688 } else { 2689 int indexToMakeVisible = 0; 2690 if (nextSelectedPosition != INVALID_POSITION) { 2691 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2692 } 2693 while (indexToMakeVisible < 0) { 2694 // Child to view is not attached yet. 2695 addViewAbove(getChildAt(0), mFirstPosition); 2696 mFirstPosition--; 2697 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2698 } 2699 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2700 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2701 int goalTop = listTop; 2702 if (positionToMakeVisible > 0) { 2703 goalTop += getArrowScrollPreviewLength(); 2704 } 2705 if (viewToMakeVisible.getTop() >= goalTop) { 2706 // item is fully visible. 2707 return 0; 2708 } 2709 2710 if (nextSelectedPosition != INVALID_POSITION && 2711 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2712 // item already has enough of it visible, changing selection is good enough 2713 return 0; 2714 } 2715 2716 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2717 if (mFirstPosition == 0) { 2718 // first is first in list -> make sure we don't scroll past it 2719 final int max = listTop - getChildAt(0).getTop(); 2720 amountToScroll = Math.min(amountToScroll, max); 2721 } 2722 return Math.min(amountToScroll, getMaxScrollAmount()); 2723 } 2724 } 2725 2726 /** 2727 * Holds results of focus aware arrow scrolling. 2728 */ 2729 static private class ArrowScrollFocusResult { 2730 private int mSelectedPosition; 2731 private int mAmountToScroll; 2732 2733 /** 2734 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2735 */ 2736 void populate(int selectedPosition, int amountToScroll) { 2737 mSelectedPosition = selectedPosition; 2738 mAmountToScroll = amountToScroll; 2739 } 2740 2741 public int getSelectedPosition() { 2742 return mSelectedPosition; 2743 } 2744 2745 public int getAmountToScroll() { 2746 return mAmountToScroll; 2747 } 2748 } 2749 2750 /** 2751 * @param direction either {@link android.view.View#FOCUS_UP} or 2752 * {@link android.view.View#FOCUS_DOWN}. 2753 * @return The position of the next selectable position of the views that 2754 * are currently visible, taking into account the fact that there might 2755 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2756 * selectable view on screen in the given direction. 2757 */ 2758 private int lookForSelectablePositionOnScreen(int direction) { 2759 final int firstPosition = mFirstPosition; 2760 if (direction == View.FOCUS_DOWN) { 2761 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2762 mSelectedPosition + 1 : 2763 firstPosition; 2764 if (startPos >= mAdapter.getCount()) { 2765 return INVALID_POSITION; 2766 } 2767 if (startPos < firstPosition) { 2768 startPos = firstPosition; 2769 } 2770 2771 final int lastVisiblePos = getLastVisiblePosition(); 2772 final ListAdapter adapter = getAdapter(); 2773 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2774 if (adapter.isEnabled(pos) 2775 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2776 return pos; 2777 } 2778 } 2779 } else { 2780 int last = firstPosition + getChildCount() - 1; 2781 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2782 mSelectedPosition - 1 : 2783 firstPosition + getChildCount() - 1; 2784 if (startPos < 0 || startPos >= mAdapter.getCount()) { 2785 return INVALID_POSITION; 2786 } 2787 if (startPos > last) { 2788 startPos = last; 2789 } 2790 2791 final ListAdapter adapter = getAdapter(); 2792 for (int pos = startPos; pos >= firstPosition; pos--) { 2793 if (adapter.isEnabled(pos) 2794 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2795 return pos; 2796 } 2797 } 2798 } 2799 return INVALID_POSITION; 2800 } 2801 2802 /** 2803 * Do an arrow scroll based on focus searching. If a new view is 2804 * given focus, return the selection delta and amount to scroll via 2805 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2806 * 2807 * @param direction either {@link android.view.View#FOCUS_UP} or 2808 * {@link android.view.View#FOCUS_DOWN}. 2809 * @return The result if focus has changed, or <code>null</code>. 2810 */ 2811 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2812 final View selectedView = getSelectedView(); 2813 View newFocus; 2814 if (selectedView != null && selectedView.hasFocus()) { 2815 View oldFocus = selectedView.findFocus(); 2816 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2817 } else { 2818 if (direction == View.FOCUS_DOWN) { 2819 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2820 final int listTop = mListPadding.top + 2821 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2822 final int ySearchPoint = 2823 (selectedView != null && selectedView.getTop() > listTop) ? 2824 selectedView.getTop() : 2825 listTop; 2826 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2827 } else { 2828 final boolean bottomFadingEdgeShowing = 2829 (mFirstPosition + getChildCount() - 1) < mItemCount; 2830 final int listBottom = getHeight() - mListPadding.bottom - 2831 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2832 final int ySearchPoint = 2833 (selectedView != null && selectedView.getBottom() < listBottom) ? 2834 selectedView.getBottom() : 2835 listBottom; 2836 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2837 } 2838 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2839 } 2840 2841 if (newFocus != null) { 2842 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2843 2844 // if the focus change is in a different new position, make sure 2845 // we aren't jumping over another selectable position 2846 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2847 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2848 if (selectablePosition != INVALID_POSITION && 2849 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2850 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2851 return null; 2852 } 2853 } 2854 2855 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2856 2857 final int maxScrollAmount = getMaxScrollAmount(); 2858 if (focusScroll < maxScrollAmount) { 2859 // not moving too far, safe to give next view focus 2860 newFocus.requestFocus(direction); 2861 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2862 return mArrowScrollFocusResult; 2863 } else if (distanceToView(newFocus) < maxScrollAmount){ 2864 // Case to consider: 2865 // too far to get entire next focusable on screen, but by going 2866 // max scroll amount, we are getting it at least partially in view, 2867 // so give it focus and scroll the max ammount. 2868 newFocus.requestFocus(direction); 2869 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2870 return mArrowScrollFocusResult; 2871 } 2872 } 2873 return null; 2874 } 2875 2876 /** 2877 * @param newFocus The view that would have focus. 2878 * @return the position that contains newFocus 2879 */ 2880 private int positionOfNewFocus(View newFocus) { 2881 final int numChildren = getChildCount(); 2882 for (int i = 0; i < numChildren; i++) { 2883 final View child = getChildAt(i); 2884 if (isViewAncestorOf(newFocus, child)) { 2885 return mFirstPosition + i; 2886 } 2887 } 2888 throw new IllegalArgumentException("newFocus is not a child of any of the" 2889 + " children of the list!"); 2890 } 2891 2892 /** 2893 * Return true if child is an ancestor of parent, (or equal to the parent). 2894 */ 2895 private boolean isViewAncestorOf(View child, View parent) { 2896 if (child == parent) { 2897 return true; 2898 } 2899 2900 final ViewParent theParent = child.getParent(); 2901 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2902 } 2903 2904 /** 2905 * Determine how much we need to scroll in order to get newFocus in view. 2906 * @param direction either {@link android.view.View#FOCUS_UP} or 2907 * {@link android.view.View#FOCUS_DOWN}. 2908 * @param newFocus The view that would take focus. 2909 * @param positionOfNewFocus The position of the list item containing newFocus 2910 * @return The amount to scroll. Note: this is always positive! Direction 2911 * needs to be taken into account when actually scrolling. 2912 */ 2913 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2914 int amountToScroll = 0; 2915 newFocus.getDrawingRect(mTempRect); 2916 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2917 if (direction == View.FOCUS_UP) { 2918 if (mTempRect.top < mListPadding.top) { 2919 amountToScroll = mListPadding.top - mTempRect.top; 2920 if (positionOfNewFocus > 0) { 2921 amountToScroll += getArrowScrollPreviewLength(); 2922 } 2923 } 2924 } else { 2925 final int listBottom = getHeight() - mListPadding.bottom; 2926 if (mTempRect.bottom > listBottom) { 2927 amountToScroll = mTempRect.bottom - listBottom; 2928 if (positionOfNewFocus < mItemCount - 1) { 2929 amountToScroll += getArrowScrollPreviewLength(); 2930 } 2931 } 2932 } 2933 return amountToScroll; 2934 } 2935 2936 /** 2937 * Determine the distance to the nearest edge of a view in a particular 2938 * direction. 2939 * 2940 * @param descendant A descendant of this list. 2941 * @return The distance, or 0 if the nearest edge is already on screen. 2942 */ 2943 private int distanceToView(View descendant) { 2944 int distance = 0; 2945 descendant.getDrawingRect(mTempRect); 2946 offsetDescendantRectToMyCoords(descendant, mTempRect); 2947 final int listBottom = mBottom - mTop - mListPadding.bottom; 2948 if (mTempRect.bottom < mListPadding.top) { 2949 distance = mListPadding.top - mTempRect.bottom; 2950 } else if (mTempRect.top > listBottom) { 2951 distance = mTempRect.top - listBottom; 2952 } 2953 return distance; 2954 } 2955 2956 2957 /** 2958 * Scroll the children by amount, adding a view at the end and removing 2959 * views that fall off as necessary. 2960 * 2961 * @param amount The amount (positive or negative) to scroll. 2962 */ 2963 private void scrollListItemsBy(int amount) { 2964 offsetChildrenTopAndBottom(amount); 2965 2966 final int listBottom = getHeight() - mListPadding.bottom; 2967 final int listTop = mListPadding.top; 2968 final AbsListView.RecycleBin recycleBin = mRecycler; 2969 2970 if (amount < 0) { 2971 // shifted items up 2972 2973 // may need to pan views into the bottom space 2974 int numChildren = getChildCount(); 2975 View last = getChildAt(numChildren - 1); 2976 while (last.getBottom() < listBottom) { 2977 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2978 if (lastVisiblePosition < mItemCount - 1) { 2979 last = addViewBelow(last, lastVisiblePosition); 2980 numChildren++; 2981 } else { 2982 break; 2983 } 2984 } 2985 2986 // may have brought in the last child of the list that is skinnier 2987 // than the fading edge, thereby leaving space at the end. need 2988 // to shift back 2989 if (last.getBottom() < listBottom) { 2990 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2991 } 2992 2993 // top views may be panned off screen 2994 View first = getChildAt(0); 2995 while (first.getBottom() < listTop) { 2996 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2997 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2998 recycleBin.addScrapView(first, mFirstPosition); 2999 } 3000 detachViewFromParent(first); 3001 first = getChildAt(0); 3002 mFirstPosition++; 3003 } 3004 } else { 3005 // shifted items down 3006 View first = getChildAt(0); 3007 3008 // may need to pan views into top 3009 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 3010 first = addViewAbove(first, mFirstPosition); 3011 mFirstPosition--; 3012 } 3013 3014 // may have brought the very first child of the list in too far and 3015 // need to shift it back 3016 if (first.getTop() > listTop) { 3017 offsetChildrenTopAndBottom(listTop - first.getTop()); 3018 } 3019 3020 int lastIndex = getChildCount() - 1; 3021 View last = getChildAt(lastIndex); 3022 3023 // bottom view may be panned off screen 3024 while (last.getTop() > listBottom) { 3025 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 3026 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 3027 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 3028 } 3029 detachViewFromParent(last); 3030 last = getChildAt(--lastIndex); 3031 } 3032 } 3033 } 3034 3035 private View addViewAbove(View theView, int position) { 3036 int abovePosition = position - 1; 3037 View view = obtainView(abovePosition, mIsScrap); 3038 int edgeOfNewChild = theView.getTop() - mDividerHeight; 3039 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 3040 false, mIsScrap[0]); 3041 return view; 3042 } 3043 3044 private View addViewBelow(View theView, int position) { 3045 int belowPosition = position + 1; 3046 View view = obtainView(belowPosition, mIsScrap); 3047 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 3048 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 3049 false, mIsScrap[0]); 3050 return view; 3051 } 3052 3053 /** 3054 * Indicates that the views created by the ListAdapter can contain focusable 3055 * items. 3056 * 3057 * @param itemsCanFocus true if items can get focus, false otherwise 3058 */ 3059 public void setItemsCanFocus(boolean itemsCanFocus) { 3060 mItemsCanFocus = itemsCanFocus; 3061 if (!itemsCanFocus) { 3062 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 3063 } 3064 } 3065 3066 /** 3067 * @return Whether the views created by the ListAdapter can contain focusable 3068 * items. 3069 */ 3070 public boolean getItemsCanFocus() { 3071 return mItemsCanFocus; 3072 } 3073 3074 @Override 3075 public boolean isOpaque() { 3076 boolean retValue = (mCachingActive && mIsCacheColorOpaque && mDividerIsOpaque && 3077 hasOpaqueScrollbars()) || super.isOpaque(); 3078 if (retValue) { 3079 // only return true if the list items cover the entire area of the view 3080 final int listTop = mListPadding != null ? mListPadding.top : mPaddingTop; 3081 View first = getChildAt(0); 3082 if (first == null || first.getTop() > listTop) { 3083 return false; 3084 } 3085 final int listBottom = getHeight() - 3086 (mListPadding != null ? mListPadding.bottom : mPaddingBottom); 3087 View last = getChildAt(getChildCount() - 1); 3088 if (last == null || last.getBottom() < listBottom) { 3089 return false; 3090 } 3091 } 3092 return retValue; 3093 } 3094 3095 @Override 3096 public void setCacheColorHint(int color) { 3097 final boolean opaque = (color >>> 24) == 0xFF; 3098 mIsCacheColorOpaque = opaque; 3099 if (opaque) { 3100 if (mDividerPaint == null) { 3101 mDividerPaint = new Paint(); 3102 } 3103 mDividerPaint.setColor(color); 3104 } 3105 super.setCacheColorHint(color); 3106 } 3107 3108 void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) { 3109 final int height = drawable.getMinimumHeight(); 3110 3111 canvas.save(); 3112 canvas.clipRect(bounds); 3113 3114 final int span = bounds.bottom - bounds.top; 3115 if (span < height) { 3116 bounds.top = bounds.bottom - height; 3117 } 3118 3119 drawable.setBounds(bounds); 3120 drawable.draw(canvas); 3121 3122 canvas.restore(); 3123 } 3124 3125 void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) { 3126 final int height = drawable.getMinimumHeight(); 3127 3128 canvas.save(); 3129 canvas.clipRect(bounds); 3130 3131 final int span = bounds.bottom - bounds.top; 3132 if (span < height) { 3133 bounds.bottom = bounds.top + height; 3134 } 3135 3136 drawable.setBounds(bounds); 3137 drawable.draw(canvas); 3138 3139 canvas.restore(); 3140 } 3141 3142 @Override 3143 protected void dispatchDraw(Canvas canvas) { 3144 if (mCachingStarted) { 3145 mCachingActive = true; 3146 } 3147 3148 // Draw the dividers 3149 final int dividerHeight = mDividerHeight; 3150 final Drawable overscrollHeader = mOverScrollHeader; 3151 final Drawable overscrollFooter = mOverScrollFooter; 3152 final boolean drawOverscrollHeader = overscrollHeader != null; 3153 final boolean drawOverscrollFooter = overscrollFooter != null; 3154 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3155 3156 if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) { 3157 // Only modify the top and bottom in the loop, we set the left and right here 3158 final Rect bounds = mTempRect; 3159 bounds.left = mPaddingLeft; 3160 bounds.right = mRight - mLeft - mPaddingRight; 3161 3162 final int count = getChildCount(); 3163 final int headerCount = mHeaderViewInfos.size(); 3164 final int itemCount = mItemCount; 3165 final int footerLimit = itemCount - mFooterViewInfos.size() - 1; 3166 final boolean headerDividers = mHeaderDividersEnabled; 3167 final boolean footerDividers = mFooterDividersEnabled; 3168 final int first = mFirstPosition; 3169 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 3170 final ListAdapter adapter = mAdapter; 3171 // If the list is opaque *and* the background is not, we want to 3172 // fill a rect where the dividers would be for non-selectable items 3173 // If the list is opaque and the background is also opaque, we don't 3174 // need to draw anything since the background will do it for us 3175 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3176 3177 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 3178 mDividerPaint = new Paint(); 3179 mDividerPaint.setColor(getCacheColorHint()); 3180 } 3181 final Paint paint = mDividerPaint; 3182 3183 int effectivePaddingTop = 0; 3184 int effectivePaddingBottom = 0; 3185 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 3186 effectivePaddingTop = mListPadding.top; 3187 effectivePaddingBottom = mListPadding.bottom; 3188 } 3189 3190 final int listBottom = mBottom - mTop - effectivePaddingBottom + mScrollY; 3191 if (!mStackFromBottom) { 3192 int bottom = 0; 3193 3194 // Draw top divider or header for overscroll 3195 final int scrollY = mScrollY; 3196 if (count > 0 && scrollY < 0) { 3197 if (drawOverscrollHeader) { 3198 bounds.bottom = 0; 3199 bounds.top = scrollY; 3200 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3201 } else if (drawDividers) { 3202 bounds.bottom = 0; 3203 bounds.top = -dividerHeight; 3204 drawDivider(canvas, bounds, -1); 3205 } 3206 } 3207 3208 for (int i = 0; i < count; i++) { 3209 if ((headerDividers || first + i >= headerCount) && 3210 (footerDividers || first + i < footerLimit)) { 3211 View child = getChildAt(i); 3212 bottom = child.getBottom(); 3213 // Don't draw dividers next to items that are not enabled 3214 3215 if (drawDividers && 3216 (bottom < listBottom && !(drawOverscrollFooter && i == count - 1))) { 3217 if ((areAllItemsSelectable || 3218 (adapter.isEnabled(first + i) && (i == count - 1 || 3219 adapter.isEnabled(first + i + 1))))) { 3220 bounds.top = bottom; 3221 bounds.bottom = bottom + dividerHeight; 3222 drawDivider(canvas, bounds, i); 3223 } else if (fillForMissingDividers) { 3224 bounds.top = bottom; 3225 bounds.bottom = bottom + dividerHeight; 3226 canvas.drawRect(bounds, paint); 3227 } 3228 } 3229 } 3230 } 3231 3232 final int overFooterBottom = mBottom + mScrollY; 3233 if (drawOverscrollFooter && first + count == itemCount && 3234 overFooterBottom > bottom) { 3235 bounds.top = bottom; 3236 bounds.bottom = overFooterBottom; 3237 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3238 } 3239 } else { 3240 int top; 3241 3242 final int scrollY = mScrollY; 3243 3244 if (count > 0 && drawOverscrollHeader) { 3245 bounds.top = scrollY; 3246 bounds.bottom = getChildAt(0).getTop(); 3247 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3248 } 3249 3250 final int start = drawOverscrollHeader ? 1 : 0; 3251 for (int i = start; i < count; i++) { 3252 if ((headerDividers || first + i >= headerCount) && 3253 (footerDividers || first + i < footerLimit)) { 3254 View child = getChildAt(i); 3255 top = child.getTop(); 3256 // Don't draw dividers next to items that are not enabled 3257 if (top > effectivePaddingTop) { 3258 if ((areAllItemsSelectable || 3259 (adapter.isEnabled(first + i) && (i == count - 1 || 3260 adapter.isEnabled(first + i + 1))))) { 3261 bounds.top = top - dividerHeight; 3262 bounds.bottom = top; 3263 // Give the method the child ABOVE the divider, so we 3264 // subtract one from our child 3265 // position. Give -1 when there is no child above the 3266 // divider. 3267 drawDivider(canvas, bounds, i - 1); 3268 } else if (fillForMissingDividers) { 3269 bounds.top = top - dividerHeight; 3270 bounds.bottom = top; 3271 canvas.drawRect(bounds, paint); 3272 } 3273 } 3274 } 3275 } 3276 3277 if (count > 0 && scrollY > 0) { 3278 if (drawOverscrollFooter) { 3279 final int absListBottom = mBottom; 3280 bounds.top = absListBottom; 3281 bounds.bottom = absListBottom + scrollY; 3282 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3283 } else if (drawDividers) { 3284 bounds.top = listBottom; 3285 bounds.bottom = listBottom + dividerHeight; 3286 drawDivider(canvas, bounds, -1); 3287 } 3288 } 3289 } 3290 } 3291 3292 // Draw the indicators (these should be drawn above the dividers) and children 3293 super.dispatchDraw(canvas); 3294 } 3295 3296 @Override 3297 protected boolean drawChild(Canvas canvas, View child, long drawingTime) { 3298 boolean more = super.drawChild(canvas, child, drawingTime); 3299 if (mCachingActive && child.mCachingFailed) { 3300 mCachingActive = false; 3301 } 3302 return more; 3303 } 3304 3305 /** 3306 * Draws a divider for the given child in the given bounds. 3307 * 3308 * @param canvas The canvas to draw to. 3309 * @param bounds The bounds of the divider. 3310 * @param childIndex The index of child (of the View) above the divider. 3311 * This will be -1 if there is no child above the divider to be 3312 * drawn. 3313 */ 3314 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3315 // This widget draws the same divider for all children 3316 final Drawable divider = mDivider; 3317 3318 divider.setBounds(bounds); 3319 divider.draw(canvas); 3320 } 3321 3322 /** 3323 * Returns the drawable that will be drawn between each item in the list. 3324 * 3325 * @return the current drawable drawn between list elements 3326 */ 3327 public Drawable getDivider() { 3328 return mDivider; 3329 } 3330 3331 /** 3332 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3333 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3334 * 3335 * @param divider The drawable to use. 3336 */ 3337 public void setDivider(Drawable divider) { 3338 if (divider != null) { 3339 mDividerHeight = divider.getIntrinsicHeight(); 3340 } else { 3341 mDividerHeight = 0; 3342 } 3343 mDivider = divider; 3344 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3345 requestLayout(); 3346 invalidate(); 3347 } 3348 3349 /** 3350 * @return Returns the height of the divider that will be drawn between each item in the list. 3351 */ 3352 public int getDividerHeight() { 3353 return mDividerHeight; 3354 } 3355 3356 /** 3357 * Sets the height of the divider that will be drawn between each item in the list. Calling 3358 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3359 * 3360 * @param height The new height of the divider in pixels. 3361 */ 3362 public void setDividerHeight(int height) { 3363 mDividerHeight = height; 3364 requestLayout(); 3365 invalidate(); 3366 } 3367 3368 /** 3369 * Enables or disables the drawing of the divider for header views. 3370 * 3371 * @param headerDividersEnabled True to draw the headers, false otherwise. 3372 * 3373 * @see #setFooterDividersEnabled(boolean) 3374 * @see #addHeaderView(android.view.View) 3375 */ 3376 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3377 mHeaderDividersEnabled = headerDividersEnabled; 3378 invalidate(); 3379 } 3380 3381 /** 3382 * Enables or disables the drawing of the divider for footer views. 3383 * 3384 * @param footerDividersEnabled True to draw the footers, false otherwise. 3385 * 3386 * @see #setHeaderDividersEnabled(boolean) 3387 * @see #addFooterView(android.view.View) 3388 */ 3389 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3390 mFooterDividersEnabled = footerDividersEnabled; 3391 invalidate(); 3392 } 3393 3394 /** 3395 * Sets the drawable that will be drawn above all other list content. 3396 * This area can become visible when the user overscrolls the list. 3397 * 3398 * @param header The drawable to use 3399 */ 3400 public void setOverscrollHeader(Drawable header) { 3401 mOverScrollHeader = header; 3402 if (mScrollY < 0) { 3403 invalidate(); 3404 } 3405 } 3406 3407 /** 3408 * @return The drawable that will be drawn above all other list content 3409 */ 3410 public Drawable getOverscrollHeader() { 3411 return mOverScrollHeader; 3412 } 3413 3414 /** 3415 * Sets the drawable that will be drawn below all other list content. 3416 * This area can become visible when the user overscrolls the list, 3417 * or when the list's content does not fully fill the container area. 3418 * 3419 * @param footer The drawable to use 3420 */ 3421 public void setOverscrollFooter(Drawable footer) { 3422 mOverScrollFooter = footer; 3423 invalidate(); 3424 } 3425 3426 /** 3427 * @return The drawable that will be drawn below all other list content 3428 */ 3429 public Drawable getOverscrollFooter() { 3430 return mOverScrollFooter; 3431 } 3432 3433 @Override 3434 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3435 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3436 3437 final ListAdapter adapter = mAdapter; 3438 int closetChildIndex = -1; 3439 int closestChildTop = 0; 3440 if (adapter != null && gainFocus && previouslyFocusedRect != null) { 3441 previouslyFocusedRect.offset(mScrollX, mScrollY); 3442 3443 // Don't cache the result of getChildCount or mFirstPosition here, 3444 // it could change in layoutChildren. 3445 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3446 mLayoutMode = LAYOUT_NORMAL; 3447 layoutChildren(); 3448 } 3449 3450 // figure out which item should be selected based on previously 3451 // focused rect 3452 Rect otherRect = mTempRect; 3453 int minDistance = Integer.MAX_VALUE; 3454 final int childCount = getChildCount(); 3455 final int firstPosition = mFirstPosition; 3456 3457 for (int i = 0; i < childCount; i++) { 3458 // only consider selectable views 3459 if (!adapter.isEnabled(firstPosition + i)) { 3460 continue; 3461 } 3462 3463 View other = getChildAt(i); 3464 other.getDrawingRect(otherRect); 3465 offsetDescendantRectToMyCoords(other, otherRect); 3466 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3467 3468 if (distance < minDistance) { 3469 minDistance = distance; 3470 closetChildIndex = i; 3471 closestChildTop = other.getTop(); 3472 } 3473 } 3474 } 3475 3476 if (closetChildIndex >= 0) { 3477 setSelectionFromTop(closetChildIndex + mFirstPosition, closestChildTop); 3478 } else { 3479 requestLayout(); 3480 } 3481 } 3482 3483 3484 /* 3485 * (non-Javadoc) 3486 * 3487 * Children specified in XML are assumed to be header views. After we have 3488 * parsed them move them out of the children list and into mHeaderViews. 3489 */ 3490 @Override 3491 protected void onFinishInflate() { 3492 super.onFinishInflate(); 3493 3494 int count = getChildCount(); 3495 if (count > 0) { 3496 for (int i = 0; i < count; ++i) { 3497 addHeaderView(getChildAt(i)); 3498 } 3499 removeAllViews(); 3500 } 3501 } 3502 3503 /* (non-Javadoc) 3504 * @see android.view.View#findViewById(int) 3505 * First look in our children, then in any header and footer views that may be scrolled off. 3506 */ 3507 @Override 3508 protected View findViewTraversal(int id) { 3509 View v; 3510 v = super.findViewTraversal(id); 3511 if (v == null) { 3512 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3513 if (v != null) { 3514 return v; 3515 } 3516 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3517 if (v != null) { 3518 return v; 3519 } 3520 } 3521 return v; 3522 } 3523 3524 /* (non-Javadoc) 3525 * 3526 * Look in the passed in list of headers or footers for the view. 3527 */ 3528 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3529 if (where != null) { 3530 int len = where.size(); 3531 View v; 3532 3533 for (int i = 0; i < len; i++) { 3534 v = where.get(i).view; 3535 3536 if (!v.isRootNamespace()) { 3537 v = v.findViewById(id); 3538 3539 if (v != null) { 3540 return v; 3541 } 3542 } 3543 } 3544 } 3545 return null; 3546 } 3547 3548 /* (non-Javadoc) 3549 * @see android.view.View#findViewWithTag(Object) 3550 * First look in our children, then in any header and footer views that may be scrolled off. 3551 */ 3552 @Override 3553 protected View findViewWithTagTraversal(Object tag) { 3554 View v; 3555 v = super.findViewWithTagTraversal(tag); 3556 if (v == null) { 3557 v = findViewWithTagInHeadersOrFooters(mHeaderViewInfos, tag); 3558 if (v != null) { 3559 return v; 3560 } 3561 3562 v = findViewWithTagInHeadersOrFooters(mFooterViewInfos, tag); 3563 if (v != null) { 3564 return v; 3565 } 3566 } 3567 return v; 3568 } 3569 3570 /* (non-Javadoc) 3571 * 3572 * Look in the passed in list of headers or footers for the view with the tag. 3573 */ 3574 View findViewWithTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3575 if (where != null) { 3576 int len = where.size(); 3577 View v; 3578 3579 for (int i = 0; i < len; i++) { 3580 v = where.get(i).view; 3581 3582 if (!v.isRootNamespace()) { 3583 v = v.findViewWithTag(tag); 3584 3585 if (v != null) { 3586 return v; 3587 } 3588 } 3589 } 3590 } 3591 return null; 3592 } 3593 3594 /** 3595 * @hide 3596 * @see android.view.View#findViewByPredicate(Predicate) 3597 * First look in our children, then in any header and footer views that may be scrolled off. 3598 */ 3599 @Override 3600 protected View findViewByPredicateTraversal(Predicate<View> predicate, View childToSkip) { 3601 View v; 3602 v = super.findViewByPredicateTraversal(predicate, childToSkip); 3603 if (v == null) { 3604 v = findViewByPredicateInHeadersOrFooters(mHeaderViewInfos, predicate, childToSkip); 3605 if (v != null) { 3606 return v; 3607 } 3608 3609 v = findViewByPredicateInHeadersOrFooters(mFooterViewInfos, predicate, childToSkip); 3610 if (v != null) { 3611 return v; 3612 } 3613 } 3614 return v; 3615 } 3616 3617 /* (non-Javadoc) 3618 * 3619 * Look in the passed in list of headers or footers for the first view that matches 3620 * the predicate. 3621 */ 3622 View findViewByPredicateInHeadersOrFooters(ArrayList<FixedViewInfo> where, 3623 Predicate<View> predicate, View childToSkip) { 3624 if (where != null) { 3625 int len = where.size(); 3626 View v; 3627 3628 for (int i = 0; i < len; i++) { 3629 v = where.get(i).view; 3630 3631 if (v != childToSkip && !v.isRootNamespace()) { 3632 v = v.findViewByPredicate(predicate); 3633 3634 if (v != null) { 3635 return v; 3636 } 3637 } 3638 } 3639 } 3640 return null; 3641 } 3642 3643 /** 3644 * Returns the set of checked items ids. The result is only valid if the 3645 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3646 * 3647 * @return A new array which contains the id of each checked item in the 3648 * list. 3649 * 3650 * @deprecated Use {@link #getCheckedItemIds()} instead. 3651 */ 3652 @Deprecated 3653 public long[] getCheckItemIds() { 3654 // Use new behavior that correctly handles stable ID mapping. 3655 if (mAdapter != null && mAdapter.hasStableIds()) { 3656 return getCheckedItemIds(); 3657 } 3658 3659 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3660 // Fall back to it to support legacy apps. 3661 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3662 final SparseBooleanArray states = mCheckStates; 3663 final int count = states.size(); 3664 final long[] ids = new long[count]; 3665 final ListAdapter adapter = mAdapter; 3666 3667 int checkedCount = 0; 3668 for (int i = 0; i < count; i++) { 3669 if (states.valueAt(i)) { 3670 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3671 } 3672 } 3673 3674 // Trim array if needed. mCheckStates may contain false values 3675 // resulting in checkedCount being smaller than count. 3676 if (checkedCount == count) { 3677 return ids; 3678 } else { 3679 final long[] result = new long[checkedCount]; 3680 System.arraycopy(ids, 0, result, 0, checkedCount); 3681 3682 return result; 3683 } 3684 } 3685 return new long[0]; 3686 } 3687 3688 @Override 3689 public void onInitializeAccessibilityEvent(AccessibilityEvent event) { 3690 super.onInitializeAccessibilityEvent(event); 3691 event.setClassName(ListView.class.getName()); 3692 } 3693 3694 @Override 3695 public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { 3696 super.onInitializeAccessibilityNodeInfo(info); 3697 info.setClassName(ListView.class.getName()); 3698 } 3699} 3700