ListView.java revision a6111377e1edbc5d63fc2a7205d58b2d9c21d978
1/* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.widget; 18 19import com.android.internal.R; 20import com.android.internal.util.Predicate; 21import com.google.android.collect.Lists; 22 23import android.content.Context; 24import android.content.Intent; 25import android.content.res.TypedArray; 26import android.graphics.Canvas; 27import android.graphics.Paint; 28import android.graphics.PixelFormat; 29import android.graphics.Rect; 30import android.graphics.drawable.Drawable; 31import android.util.AttributeSet; 32import android.util.SparseBooleanArray; 33import android.view.FocusFinder; 34import android.view.KeyEvent; 35import android.view.MotionEvent; 36import android.view.SoundEffectConstants; 37import android.view.View; 38import android.view.ViewDebug; 39import android.view.ViewGroup; 40import android.view.ViewParent; 41import android.view.accessibility.AccessibilityEvent; 42import android.widget.RemoteViews.RemoteView; 43 44import java.util.ArrayList; 45 46/* 47 * Implementation Notes: 48 * 49 * Some terminology: 50 * 51 * index - index of the items that are currently visible 52 * position - index of the items in the cursor 53 */ 54 55 56/** 57 * A view that shows items in a vertically scrolling list. The items 58 * come from the {@link ListAdapter} associated with this view. 59 * 60 * <p>See the <a href="{@docRoot}resources/tutorials/views/hello-listview.html">List View 61 * tutorial</a>.</p> 62 * 63 * @attr ref android.R.styleable#ListView_entries 64 * @attr ref android.R.styleable#ListView_divider 65 * @attr ref android.R.styleable#ListView_dividerHeight 66 * @attr ref android.R.styleable#ListView_headerDividersEnabled 67 * @attr ref android.R.styleable#ListView_footerDividersEnabled 68 */ 69@RemoteView 70public class ListView extends AbsListView { 71 /** 72 * Used to indicate a no preference for a position type. 73 */ 74 static final int NO_POSITION = -1; 75 76 /** 77 * When arrow scrolling, ListView will never scroll more than this factor 78 * times the height of the list. 79 */ 80 private static final float MAX_SCROLL_FACTOR = 0.33f; 81 82 /** 83 * When arrow scrolling, need a certain amount of pixels to preview next 84 * items. This is usually the fading edge, but if that is small enough, 85 * we want to make sure we preview at least this many pixels. 86 */ 87 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 88 89 /** 90 * A class that represents a fixed view in a list, for example a header at the top 91 * or a footer at the bottom. 92 */ 93 public class FixedViewInfo { 94 /** The view to add to the list */ 95 public View view; 96 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 97 public Object data; 98 /** <code>true</code> if the fixed view should be selectable in the list */ 99 public boolean isSelectable; 100 } 101 102 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 103 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 104 105 Drawable mDivider; 106 int mDividerHeight; 107 108 Drawable mOverScrollHeader; 109 Drawable mOverScrollFooter; 110 111 private boolean mIsCacheColorOpaque; 112 private boolean mDividerIsOpaque; 113 114 private boolean mHeaderDividersEnabled; 115 private boolean mFooterDividersEnabled; 116 117 private boolean mAreAllItemsSelectable = true; 118 119 private boolean mItemsCanFocus = false; 120 121 // used for temporary calculations. 122 private final Rect mTempRect = new Rect(); 123 private Paint mDividerPaint; 124 125 // the single allocated result per list view; kinda cheesey but avoids 126 // allocating these thingies too often. 127 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 128 129 // Keeps focused children visible through resizes 130 private FocusSelector mFocusSelector; 131 132 public ListView(Context context) { 133 this(context, null); 134 } 135 136 public ListView(Context context, AttributeSet attrs) { 137 this(context, attrs, com.android.internal.R.attr.listViewStyle); 138 } 139 140 public ListView(Context context, AttributeSet attrs, int defStyle) { 141 super(context, attrs, defStyle); 142 143 TypedArray a = context.obtainStyledAttributes(attrs, 144 com.android.internal.R.styleable.ListView, defStyle, 0); 145 146 CharSequence[] entries = a.getTextArray( 147 com.android.internal.R.styleable.ListView_entries); 148 if (entries != null) { 149 setAdapter(new ArrayAdapter<CharSequence>(context, 150 com.android.internal.R.layout.simple_list_item_1, entries)); 151 } 152 153 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 154 if (d != null) { 155 // If a divider is specified use its intrinsic height for divider height 156 setDivider(d); 157 } 158 159 final Drawable osHeader = a.getDrawable( 160 com.android.internal.R.styleable.ListView_overScrollHeader); 161 if (osHeader != null) { 162 setOverscrollHeader(osHeader); 163 } 164 165 final Drawable osFooter = a.getDrawable( 166 com.android.internal.R.styleable.ListView_overScrollFooter); 167 if (osFooter != null) { 168 setOverscrollFooter(osFooter); 169 } 170 171 // Use the height specified, zero being the default 172 final int dividerHeight = a.getDimensionPixelSize( 173 com.android.internal.R.styleable.ListView_dividerHeight, 0); 174 if (dividerHeight != 0) { 175 setDividerHeight(dividerHeight); 176 } 177 178 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 179 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 180 181 a.recycle(); 182 } 183 184 /** 185 * @return The maximum amount a list view will scroll in response to 186 * an arrow event. 187 */ 188 public int getMaxScrollAmount() { 189 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 190 } 191 192 /** 193 * Make sure views are touching the top or bottom edge, as appropriate for 194 * our gravity 195 */ 196 private void adjustViewsUpOrDown() { 197 final int childCount = getChildCount(); 198 int delta; 199 200 if (childCount > 0) { 201 View child; 202 203 if (!mStackFromBottom) { 204 // Uh-oh -- we came up short. Slide all views up to make them 205 // align with the top 206 child = getChildAt(0); 207 delta = child.getTop() - mListPadding.top; 208 if (mFirstPosition != 0) { 209 // It's OK to have some space above the first item if it is 210 // part of the vertical spacing 211 delta -= mDividerHeight; 212 } 213 if (delta < 0) { 214 // We only are looking to see if we are too low, not too high 215 delta = 0; 216 } 217 } else { 218 // we are too high, slide all views down to align with bottom 219 child = getChildAt(childCount - 1); 220 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 221 222 if (mFirstPosition + childCount < mItemCount) { 223 // It's OK to have some space below the last item if it is 224 // part of the vertical spacing 225 delta += mDividerHeight; 226 } 227 228 if (delta > 0) { 229 delta = 0; 230 } 231 } 232 233 if (delta != 0) { 234 offsetChildrenTopAndBottom(-delta); 235 } 236 } 237 } 238 239 /** 240 * Add a fixed view to appear at the top of the list. If addHeaderView is 241 * called more than once, the views will appear in the order they were 242 * added. Views added using this call can take focus if they want. 243 * <p> 244 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 245 * the supplied cursor with one that will also account for header and footer 246 * views. 247 * 248 * @param v The view to add. 249 * @param data Data to associate with this view 250 * @param isSelectable whether the item is selectable 251 */ 252 public void addHeaderView(View v, Object data, boolean isSelectable) { 253 254 if (mAdapter != null && ! (mAdapter instanceof HeaderViewListAdapter)) { 255 throw new IllegalStateException( 256 "Cannot add header view to list -- setAdapter has already been called."); 257 } 258 259 FixedViewInfo info = new FixedViewInfo(); 260 info.view = v; 261 info.data = data; 262 info.isSelectable = isSelectable; 263 mHeaderViewInfos.add(info); 264 265 // in the case of re-adding a header view, or adding one later on, 266 // we need to notify the observer 267 if (mDataSetObserver != null) { 268 mDataSetObserver.onChanged(); 269 } 270 } 271 272 /** 273 * Add a fixed view to appear at the top of the list. If addHeaderView is 274 * called more than once, the views will appear in the order they were 275 * added. Views added using this call can take focus if they want. 276 * <p> 277 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 278 * the supplied cursor with one that will also account for header and footer 279 * views. 280 * 281 * @param v The view to add. 282 */ 283 public void addHeaderView(View v) { 284 addHeaderView(v, null, true); 285 } 286 287 @Override 288 public int getHeaderViewsCount() { 289 return mHeaderViewInfos.size(); 290 } 291 292 /** 293 * Removes a previously-added header view. 294 * 295 * @param v The view to remove 296 * @return true if the view was removed, false if the view was not a header 297 * view 298 */ 299 public boolean removeHeaderView(View v) { 300 if (mHeaderViewInfos.size() > 0) { 301 boolean result = false; 302 if (((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 303 if (mDataSetObserver != null) { 304 mDataSetObserver.onChanged(); 305 } 306 result = true; 307 } 308 removeFixedViewInfo(v, mHeaderViewInfos); 309 return result; 310 } 311 return false; 312 } 313 314 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 315 int len = where.size(); 316 for (int i = 0; i < len; ++i) { 317 FixedViewInfo info = where.get(i); 318 if (info.view == v) { 319 where.remove(i); 320 break; 321 } 322 } 323 } 324 325 /** 326 * Add a fixed view to appear at the bottom of the list. If addFooterView is 327 * called more than once, the views will appear in the order they were 328 * added. Views added using this call can take focus if they want. 329 * <p> 330 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 331 * the supplied cursor with one that will also account for header and footer 332 * views. 333 * 334 * @param v The view to add. 335 * @param data Data to associate with this view 336 * @param isSelectable true if the footer view can be selected 337 */ 338 public void addFooterView(View v, Object data, boolean isSelectable) { 339 340 // NOTE: do not enforce the adapter being null here, since unlike in 341 // addHeaderView, it was never enforced here, and so existing apps are 342 // relying on being able to add a footer and then calling setAdapter to 343 // force creation of the HeaderViewListAdapter wrapper 344 345 FixedViewInfo info = new FixedViewInfo(); 346 info.view = v; 347 info.data = data; 348 info.isSelectable = isSelectable; 349 mFooterViewInfos.add(info); 350 351 // in the case of re-adding a footer view, or adding one later on, 352 // we need to notify the observer 353 if (mDataSetObserver != null) { 354 mDataSetObserver.onChanged(); 355 } 356 } 357 358 /** 359 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 360 * than once, the views will appear in the order they were added. Views added using 361 * this call can take focus if they want. 362 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 363 * cursor with one that will also account for header and footer views. 364 * 365 * 366 * @param v The view to add. 367 */ 368 public void addFooterView(View v) { 369 addFooterView(v, null, true); 370 } 371 372 @Override 373 public int getFooterViewsCount() { 374 return mFooterViewInfos.size(); 375 } 376 377 /** 378 * Removes a previously-added footer view. 379 * 380 * @param v The view to remove 381 * @return 382 * true if the view was removed, false if the view was not a footer view 383 */ 384 public boolean removeFooterView(View v) { 385 if (mFooterViewInfos.size() > 0) { 386 boolean result = false; 387 if (((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 388 if (mDataSetObserver != null) { 389 mDataSetObserver.onChanged(); 390 } 391 result = true; 392 } 393 removeFixedViewInfo(v, mFooterViewInfos); 394 return result; 395 } 396 return false; 397 } 398 399 /** 400 * Returns the adapter currently in use in this ListView. The returned adapter 401 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 402 * might be a {@link WrapperListAdapter}. 403 * 404 * @return The adapter currently used to display data in this ListView. 405 * 406 * @see #setAdapter(ListAdapter) 407 */ 408 @Override 409 public ListAdapter getAdapter() { 410 return mAdapter; 411 } 412 413 /** 414 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 415 * through the specified intent. 416 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 417 */ 418 @android.view.RemotableViewMethod 419 public void setRemoteViewsAdapter(Intent intent) { 420 super.setRemoteViewsAdapter(intent); 421 } 422 423 /** 424 * Sets the data behind this ListView. 425 * 426 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 427 * depending on the ListView features currently in use. For instance, adding 428 * headers and/or footers will cause the adapter to be wrapped. 429 * 430 * @param adapter The ListAdapter which is responsible for maintaining the 431 * data backing this list and for producing a view to represent an 432 * item in that data set. 433 * 434 * @see #getAdapter() 435 */ 436 @Override 437 public void setAdapter(ListAdapter adapter) { 438 if (mAdapter != null && mDataSetObserver != null) { 439 mAdapter.unregisterDataSetObserver(mDataSetObserver); 440 } 441 442 resetList(); 443 mRecycler.clear(); 444 445 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 446 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 447 } else { 448 mAdapter = adapter; 449 } 450 451 mOldSelectedPosition = INVALID_POSITION; 452 mOldSelectedRowId = INVALID_ROW_ID; 453 454 // AbsListView#setAdapter will update choice mode states. 455 super.setAdapter(adapter); 456 457 if (mAdapter != null) { 458 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 459 mOldItemCount = mItemCount; 460 mItemCount = mAdapter.getCount(); 461 checkFocus(); 462 463 mDataSetObserver = new AdapterDataSetObserver(); 464 mAdapter.registerDataSetObserver(mDataSetObserver); 465 466 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 467 468 int position; 469 if (mStackFromBottom) { 470 position = lookForSelectablePosition(mItemCount - 1, false); 471 } else { 472 position = lookForSelectablePosition(0, true); 473 } 474 setSelectedPositionInt(position); 475 setNextSelectedPositionInt(position); 476 477 if (mItemCount == 0) { 478 // Nothing selected 479 checkSelectionChanged(); 480 } 481 } else { 482 mAreAllItemsSelectable = true; 483 checkFocus(); 484 // Nothing selected 485 checkSelectionChanged(); 486 } 487 488 requestLayout(); 489 } 490 491 492 /** 493 * The list is empty. Clear everything out. 494 */ 495 @Override 496 void resetList() { 497 // The parent's resetList() will remove all views from the layout so we need to 498 // cleanup the state of our footers and headers 499 clearRecycledState(mHeaderViewInfos); 500 clearRecycledState(mFooterViewInfos); 501 502 super.resetList(); 503 504 mLayoutMode = LAYOUT_NORMAL; 505 } 506 507 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 508 if (infos != null) { 509 final int count = infos.size(); 510 511 for (int i = 0; i < count; i++) { 512 final View child = infos.get(i).view; 513 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 514 if (p != null) { 515 p.recycledHeaderFooter = false; 516 } 517 } 518 } 519 } 520 521 /** 522 * @return Whether the list needs to show the top fading edge 523 */ 524 private boolean showingTopFadingEdge() { 525 final int listTop = mScrollY + mListPadding.top; 526 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 527 } 528 529 /** 530 * @return Whether the list needs to show the bottom fading edge 531 */ 532 private boolean showingBottomFadingEdge() { 533 final int childCount = getChildCount(); 534 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 535 final int lastVisiblePosition = mFirstPosition + childCount - 1; 536 537 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 538 539 return (lastVisiblePosition < mItemCount - 1) 540 || (bottomOfBottomChild < listBottom); 541 } 542 543 544 @Override 545 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 546 547 int rectTopWithinChild = rect.top; 548 549 // offset so rect is in coordinates of the this view 550 rect.offset(child.getLeft(), child.getTop()); 551 rect.offset(-child.getScrollX(), -child.getScrollY()); 552 553 final int height = getHeight(); 554 int listUnfadedTop = getScrollY(); 555 int listUnfadedBottom = listUnfadedTop + height; 556 final int fadingEdge = getVerticalFadingEdgeLength(); 557 558 if (showingTopFadingEdge()) { 559 // leave room for top fading edge as long as rect isn't at very top 560 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 561 listUnfadedTop += fadingEdge; 562 } 563 } 564 565 int childCount = getChildCount(); 566 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 567 568 if (showingBottomFadingEdge()) { 569 // leave room for bottom fading edge as long as rect isn't at very bottom 570 if ((mSelectedPosition < mItemCount - 1) 571 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 572 listUnfadedBottom -= fadingEdge; 573 } 574 } 575 576 int scrollYDelta = 0; 577 578 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 579 // need to MOVE DOWN to get it in view: move down just enough so 580 // that the entire rectangle is in view (or at least the first 581 // screen size chunk). 582 583 if (rect.height() > height) { 584 // just enough to get screen size chunk on 585 scrollYDelta += (rect.top - listUnfadedTop); 586 } else { 587 // get entire rect at bottom of screen 588 scrollYDelta += (rect.bottom - listUnfadedBottom); 589 } 590 591 // make sure we aren't scrolling beyond the end of our children 592 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 593 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 594 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 595 // need to MOVE UP to get it in view: move up just enough so that 596 // entire rectangle is in view (or at least the first screen 597 // size chunk of it). 598 599 if (rect.height() > height) { 600 // screen size chunk 601 scrollYDelta -= (listUnfadedBottom - rect.bottom); 602 } else { 603 // entire rect at top 604 scrollYDelta -= (listUnfadedTop - rect.top); 605 } 606 607 // make sure we aren't scrolling any further than the top our children 608 int top = getChildAt(0).getTop(); 609 int deltaToTop = top - listUnfadedTop; 610 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 611 } 612 613 final boolean scroll = scrollYDelta != 0; 614 if (scroll) { 615 scrollListItemsBy(-scrollYDelta); 616 positionSelector(INVALID_POSITION, child); 617 mSelectedTop = child.getTop(); 618 invalidate(); 619 } 620 return scroll; 621 } 622 623 /** 624 * {@inheritDoc} 625 */ 626 @Override 627 void fillGap(boolean down) { 628 final int count = getChildCount(); 629 if (down) { 630 int paddingTop = 0; 631 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 632 paddingTop = getListPaddingTop(); 633 } 634 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 635 paddingTop; 636 fillDown(mFirstPosition + count, startOffset); 637 correctTooHigh(getChildCount()); 638 } else { 639 int paddingBottom = 0; 640 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 641 paddingBottom = getListPaddingBottom(); 642 } 643 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 644 getHeight() - paddingBottom; 645 fillUp(mFirstPosition - 1, startOffset); 646 correctTooLow(getChildCount()); 647 } 648 } 649 650 /** 651 * Fills the list from pos down to the end of the list view. 652 * 653 * @param pos The first position to put in the list 654 * 655 * @param nextTop The location where the top of the item associated with pos 656 * should be drawn 657 * 658 * @return The view that is currently selected, if it happens to be in the 659 * range that we draw. 660 */ 661 private View fillDown(int pos, int nextTop) { 662 View selectedView = null; 663 664 int end = (mBottom - mTop); 665 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 666 end -= mListPadding.bottom; 667 } 668 669 while (nextTop < end && pos < mItemCount) { 670 // is this the selected item? 671 boolean selected = pos == mSelectedPosition; 672 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 673 674 nextTop = child.getBottom() + mDividerHeight; 675 if (selected) { 676 selectedView = child; 677 } 678 pos++; 679 } 680 681 return selectedView; 682 } 683 684 /** 685 * Fills the list from pos up to the top of the list view. 686 * 687 * @param pos The first position to put in the list 688 * 689 * @param nextBottom The location where the bottom of the item associated 690 * with pos should be drawn 691 * 692 * @return The view that is currently selected 693 */ 694 private View fillUp(int pos, int nextBottom) { 695 View selectedView = null; 696 697 int end = 0; 698 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 699 end = mListPadding.top; 700 } 701 702 while (nextBottom > end && pos >= 0) { 703 // is this the selected item? 704 boolean selected = pos == mSelectedPosition; 705 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 706 nextBottom = child.getTop() - mDividerHeight; 707 if (selected) { 708 selectedView = child; 709 } 710 pos--; 711 } 712 713 mFirstPosition = pos + 1; 714 715 return selectedView; 716 } 717 718 /** 719 * Fills the list from top to bottom, starting with mFirstPosition 720 * 721 * @param nextTop The location where the top of the first item should be 722 * drawn 723 * 724 * @return The view that is currently selected 725 */ 726 private View fillFromTop(int nextTop) { 727 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 728 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 729 if (mFirstPosition < 0) { 730 mFirstPosition = 0; 731 } 732 return fillDown(mFirstPosition, nextTop); 733 } 734 735 736 /** 737 * Put mSelectedPosition in the middle of the screen and then build up and 738 * down from there. This method forces mSelectedPosition to the center. 739 * 740 * @param childrenTop Top of the area in which children can be drawn, as 741 * measured in pixels 742 * @param childrenBottom Bottom of the area in which children can be drawn, 743 * as measured in pixels 744 * @return Currently selected view 745 */ 746 private View fillFromMiddle(int childrenTop, int childrenBottom) { 747 int height = childrenBottom - childrenTop; 748 749 int position = reconcileSelectedPosition(); 750 751 View sel = makeAndAddView(position, childrenTop, true, 752 mListPadding.left, true); 753 mFirstPosition = position; 754 755 int selHeight = sel.getMeasuredHeight(); 756 if (selHeight <= height) { 757 sel.offsetTopAndBottom((height - selHeight) / 2); 758 } 759 760 fillAboveAndBelow(sel, position); 761 762 if (!mStackFromBottom) { 763 correctTooHigh(getChildCount()); 764 } else { 765 correctTooLow(getChildCount()); 766 } 767 768 return sel; 769 } 770 771 /** 772 * Once the selected view as been placed, fill up the visible area above and 773 * below it. 774 * 775 * @param sel The selected view 776 * @param position The position corresponding to sel 777 */ 778 private void fillAboveAndBelow(View sel, int position) { 779 final int dividerHeight = mDividerHeight; 780 if (!mStackFromBottom) { 781 fillUp(position - 1, sel.getTop() - dividerHeight); 782 adjustViewsUpOrDown(); 783 fillDown(position + 1, sel.getBottom() + dividerHeight); 784 } else { 785 fillDown(position + 1, sel.getBottom() + dividerHeight); 786 adjustViewsUpOrDown(); 787 fillUp(position - 1, sel.getTop() - dividerHeight); 788 } 789 } 790 791 792 /** 793 * Fills the grid based on positioning the new selection at a specific 794 * location. The selection may be moved so that it does not intersect the 795 * faded edges. The grid is then filled upwards and downwards from there. 796 * 797 * @param selectedTop Where the selected item should be 798 * @param childrenTop Where to start drawing children 799 * @param childrenBottom Last pixel where children can be drawn 800 * @return The view that currently has selection 801 */ 802 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 803 int fadingEdgeLength = getVerticalFadingEdgeLength(); 804 final int selectedPosition = mSelectedPosition; 805 806 View sel; 807 808 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 809 selectedPosition); 810 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 811 selectedPosition); 812 813 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 814 815 816 // Some of the newly selected item extends below the bottom of the list 817 if (sel.getBottom() > bottomSelectionPixel) { 818 // Find space available above the selection into which we can scroll 819 // upwards 820 final int spaceAbove = sel.getTop() - topSelectionPixel; 821 822 // Find space required to bring the bottom of the selected item 823 // fully into view 824 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 825 final int offset = Math.min(spaceAbove, spaceBelow); 826 827 // Now offset the selected item to get it into view 828 sel.offsetTopAndBottom(-offset); 829 } else if (sel.getTop() < topSelectionPixel) { 830 // Find space required to bring the top of the selected item fully 831 // into view 832 final int spaceAbove = topSelectionPixel - sel.getTop(); 833 834 // Find space available below the selection into which we can scroll 835 // downwards 836 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 837 final int offset = Math.min(spaceAbove, spaceBelow); 838 839 // Offset the selected item to get it into view 840 sel.offsetTopAndBottom(offset); 841 } 842 843 // Fill in views above and below 844 fillAboveAndBelow(sel, selectedPosition); 845 846 if (!mStackFromBottom) { 847 correctTooHigh(getChildCount()); 848 } else { 849 correctTooLow(getChildCount()); 850 } 851 852 return sel; 853 } 854 855 /** 856 * Calculate the bottom-most pixel we can draw the selection into 857 * 858 * @param childrenBottom Bottom pixel were children can be drawn 859 * @param fadingEdgeLength Length of the fading edge in pixels, if present 860 * @param selectedPosition The position that will be selected 861 * @return The bottom-most pixel we can draw the selection into 862 */ 863 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 864 int selectedPosition) { 865 int bottomSelectionPixel = childrenBottom; 866 if (selectedPosition != mItemCount - 1) { 867 bottomSelectionPixel -= fadingEdgeLength; 868 } 869 return bottomSelectionPixel; 870 } 871 872 /** 873 * Calculate the top-most pixel we can draw the selection into 874 * 875 * @param childrenTop Top pixel were children can be drawn 876 * @param fadingEdgeLength Length of the fading edge in pixels, if present 877 * @param selectedPosition The position that will be selected 878 * @return The top-most pixel we can draw the selection into 879 */ 880 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 881 // first pixel we can draw the selection into 882 int topSelectionPixel = childrenTop; 883 if (selectedPosition > 0) { 884 topSelectionPixel += fadingEdgeLength; 885 } 886 return topSelectionPixel; 887 } 888 889 /** 890 * Smoothly scroll to the specified adapter position. The view will 891 * scroll such that the indicated position is displayed. 892 * @param position Scroll to this adapter position. 893 */ 894 @android.view.RemotableViewMethod 895 public void smoothScrollToPosition(int position) { 896 super.smoothScrollToPosition(position); 897 } 898 899 /** 900 * Smoothly scroll to the specified adapter position offset. The view will 901 * scroll such that the indicated position is displayed. 902 * @param offset The amount to offset from the adapter position to scroll to. 903 */ 904 @android.view.RemotableViewMethod 905 public void smoothScrollByOffset(int offset) { 906 super.smoothScrollByOffset(offset); 907 } 908 909 /** 910 * Fills the list based on positioning the new selection relative to the old 911 * selection. The new selection will be placed at, above, or below the 912 * location of the new selection depending on how the selection is moving. 913 * The selection will then be pinned to the visible part of the screen, 914 * excluding the edges that are faded. The list is then filled upwards and 915 * downwards from there. 916 * 917 * @param oldSel The old selected view. Useful for trying to put the new 918 * selection in the same place 919 * @param newSel The view that is to become selected. Useful for trying to 920 * put the new selection in the same place 921 * @param delta Which way we are moving 922 * @param childrenTop Where to start drawing children 923 * @param childrenBottom Last pixel where children can be drawn 924 * @return The view that currently has selection 925 */ 926 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 927 int childrenBottom) { 928 int fadingEdgeLength = getVerticalFadingEdgeLength(); 929 final int selectedPosition = mSelectedPosition; 930 931 View sel; 932 933 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 934 selectedPosition); 935 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 936 selectedPosition); 937 938 if (delta > 0) { 939 /* 940 * Case 1: Scrolling down. 941 */ 942 943 /* 944 * Before After 945 * | | | | 946 * +-------+ +-------+ 947 * | A | | A | 948 * | 1 | => +-------+ 949 * +-------+ | B | 950 * | B | | 2 | 951 * +-------+ +-------+ 952 * | | | | 953 * 954 * Try to keep the top of the previously selected item where it was. 955 * oldSel = A 956 * sel = B 957 */ 958 959 // Put oldSel (A) where it belongs 960 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 961 mListPadding.left, false); 962 963 final int dividerHeight = mDividerHeight; 964 965 // Now put the new selection (B) below that 966 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 967 mListPadding.left, true); 968 969 // Some of the newly selected item extends below the bottom of the list 970 if (sel.getBottom() > bottomSelectionPixel) { 971 972 // Find space available above the selection into which we can scroll upwards 973 int spaceAbove = sel.getTop() - topSelectionPixel; 974 975 // Find space required to bring the bottom of the selected item fully into view 976 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 977 978 // Don't scroll more than half the height of the list 979 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 980 int offset = Math.min(spaceAbove, spaceBelow); 981 offset = Math.min(offset, halfVerticalSpace); 982 983 // We placed oldSel, so offset that item 984 oldSel.offsetTopAndBottom(-offset); 985 // Now offset the selected item to get it into view 986 sel.offsetTopAndBottom(-offset); 987 } 988 989 // Fill in views above and below 990 if (!mStackFromBottom) { 991 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 992 adjustViewsUpOrDown(); 993 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 994 } else { 995 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 996 adjustViewsUpOrDown(); 997 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 998 } 999 } else if (delta < 0) { 1000 /* 1001 * Case 2: Scrolling up. 1002 */ 1003 1004 /* 1005 * Before After 1006 * | | | | 1007 * +-------+ +-------+ 1008 * | A | | A | 1009 * +-------+ => | 1 | 1010 * | B | +-------+ 1011 * | 2 | | B | 1012 * +-------+ +-------+ 1013 * | | | | 1014 * 1015 * Try to keep the top of the item about to become selected where it was. 1016 * newSel = A 1017 * olSel = B 1018 */ 1019 1020 if (newSel != null) { 1021 // Try to position the top of newSel (A) where it was before it was selected 1022 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 1023 true); 1024 } else { 1025 // If (A) was not on screen and so did not have a view, position 1026 // it above the oldSel (B) 1027 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 1028 true); 1029 } 1030 1031 // Some of the newly selected item extends above the top of the list 1032 if (sel.getTop() < topSelectionPixel) { 1033 // Find space required to bring the top of the selected item fully into view 1034 int spaceAbove = topSelectionPixel - sel.getTop(); 1035 1036 // Find space available below the selection into which we can scroll downwards 1037 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 1038 1039 // Don't scroll more than half the height of the list 1040 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 1041 int offset = Math.min(spaceAbove, spaceBelow); 1042 offset = Math.min(offset, halfVerticalSpace); 1043 1044 // Offset the selected item to get it into view 1045 sel.offsetTopAndBottom(offset); 1046 } 1047 1048 // Fill in views above and below 1049 fillAboveAndBelow(sel, selectedPosition); 1050 } else { 1051 1052 int oldTop = oldSel.getTop(); 1053 1054 /* 1055 * Case 3: Staying still 1056 */ 1057 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1058 1059 // We're staying still... 1060 if (oldTop < childrenTop) { 1061 // ... but the top of the old selection was off screen. 1062 // (This can happen if the data changes size out from under us) 1063 int newBottom = sel.getBottom(); 1064 if (newBottom < childrenTop + 20) { 1065 // Not enough visible -- bring it onscreen 1066 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1067 } 1068 } 1069 1070 // Fill in views above and below 1071 fillAboveAndBelow(sel, selectedPosition); 1072 } 1073 1074 return sel; 1075 } 1076 1077 private class FocusSelector implements Runnable { 1078 private int mPosition; 1079 private int mPositionTop; 1080 1081 public FocusSelector setup(int position, int top) { 1082 mPosition = position; 1083 mPositionTop = top; 1084 return this; 1085 } 1086 1087 public void run() { 1088 setSelectionFromTop(mPosition, mPositionTop); 1089 } 1090 } 1091 1092 @Override 1093 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1094 if (getChildCount() > 0) { 1095 View focusedChild = getFocusedChild(); 1096 if (focusedChild != null) { 1097 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1098 final int childBottom = focusedChild.getBottom(); 1099 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1100 final int top = focusedChild.getTop() - offset; 1101 if (mFocusSelector == null) { 1102 mFocusSelector = new FocusSelector(); 1103 } 1104 post(mFocusSelector.setup(childPosition, top)); 1105 } 1106 } 1107 super.onSizeChanged(w, h, oldw, oldh); 1108 } 1109 1110 @Override 1111 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1112 // Sets up mListPadding 1113 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1114 1115 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1116 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1117 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1118 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1119 1120 int childWidth = 0; 1121 int childHeight = 0; 1122 int childState = 0; 1123 1124 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1125 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1126 heightMode == MeasureSpec.UNSPECIFIED)) { 1127 final View child = obtainView(0, mIsScrap); 1128 1129 measureScrapChild(child, 0, widthMeasureSpec); 1130 1131 childWidth = child.getMeasuredWidth(); 1132 childHeight = child.getMeasuredHeight(); 1133 childState = combineMeasuredStates(childState, child.getMeasuredState()); 1134 1135 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1136 ((LayoutParams) child.getLayoutParams()).viewType)) { 1137 mRecycler.addScrapView(child, -1); 1138 } 1139 } 1140 1141 if (widthMode == MeasureSpec.UNSPECIFIED) { 1142 widthSize = mListPadding.left + mListPadding.right + childWidth + 1143 getVerticalScrollbarWidth(); 1144 } else { 1145 widthSize |= (childState&MEASURED_STATE_MASK); 1146 } 1147 1148 if (heightMode == MeasureSpec.UNSPECIFIED) { 1149 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1150 getVerticalFadingEdgeLength() * 2; 1151 } 1152 1153 if (heightMode == MeasureSpec.AT_MOST) { 1154 // TODO: after first layout we should maybe start at the first visible position, not 0 1155 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1156 } 1157 1158 setMeasuredDimension(widthSize , heightSize); 1159 mWidthMeasureSpec = widthMeasureSpec; 1160 } 1161 1162 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1163 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1164 if (p == null) { 1165 p = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1166 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1167 child.setLayoutParams(p); 1168 } 1169 p.viewType = mAdapter.getItemViewType(position); 1170 p.forceAdd = true; 1171 1172 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1173 mListPadding.left + mListPadding.right, p.width); 1174 int lpHeight = p.height; 1175 int childHeightSpec; 1176 if (lpHeight > 0) { 1177 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1178 } else { 1179 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1180 } 1181 child.measure(childWidthSpec, childHeightSpec); 1182 } 1183 1184 /** 1185 * @return True to recycle the views used to measure this ListView in 1186 * UNSPECIFIED/AT_MOST modes, false otherwise. 1187 * @hide 1188 */ 1189 @ViewDebug.ExportedProperty(category = "list") 1190 protected boolean recycleOnMeasure() { 1191 return true; 1192 } 1193 1194 /** 1195 * Measures the height of the given range of children (inclusive) and 1196 * returns the height with this ListView's padding and divider heights 1197 * included. If maxHeight is provided, the measuring will stop when the 1198 * current height reaches maxHeight. 1199 * 1200 * @param widthMeasureSpec The width measure spec to be given to a child's 1201 * {@link View#measure(int, int)}. 1202 * @param startPosition The position of the first child to be shown. 1203 * @param endPosition The (inclusive) position of the last child to be 1204 * shown. Specify {@link #NO_POSITION} if the last child should be 1205 * the last available child from the adapter. 1206 * @param maxHeight The maximum height that will be returned (if all the 1207 * children don't fit in this value, this value will be 1208 * returned). 1209 * @param disallowPartialChildPosition In general, whether the returned 1210 * height should only contain entire children. This is more 1211 * powerful--it is the first inclusive position at which partial 1212 * children will not be allowed. Example: it looks nice to have 1213 * at least 3 completely visible children, and in portrait this 1214 * will most likely fit; but in landscape there could be times 1215 * when even 2 children can not be completely shown, so a value 1216 * of 2 (remember, inclusive) would be good (assuming 1217 * startPosition is 0). 1218 * @return The height of this ListView with the given children. 1219 */ 1220 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1221 final int maxHeight, int disallowPartialChildPosition) { 1222 1223 final ListAdapter adapter = mAdapter; 1224 if (adapter == null) { 1225 return mListPadding.top + mListPadding.bottom; 1226 } 1227 1228 // Include the padding of the list 1229 int returnedHeight = mListPadding.top + mListPadding.bottom; 1230 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1231 // The previous height value that was less than maxHeight and contained 1232 // no partial children 1233 int prevHeightWithoutPartialChild = 0; 1234 int i; 1235 View child; 1236 1237 // mItemCount - 1 since endPosition parameter is inclusive 1238 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1239 final AbsListView.RecycleBin recycleBin = mRecycler; 1240 final boolean recyle = recycleOnMeasure(); 1241 final boolean[] isScrap = mIsScrap; 1242 1243 for (i = startPosition; i <= endPosition; ++i) { 1244 child = obtainView(i, isScrap); 1245 1246 measureScrapChild(child, i, widthMeasureSpec); 1247 1248 if (i > 0) { 1249 // Count the divider for all but one child 1250 returnedHeight += dividerHeight; 1251 } 1252 1253 // Recycle the view before we possibly return from the method 1254 if (recyle && recycleBin.shouldRecycleViewType( 1255 ((LayoutParams) child.getLayoutParams()).viewType)) { 1256 recycleBin.addScrapView(child, -1); 1257 } 1258 1259 returnedHeight += child.getMeasuredHeight(); 1260 1261 if (returnedHeight >= maxHeight) { 1262 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1263 // then the i'th position did not fit completely. 1264 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1265 && (i > disallowPartialChildPosition) // We've past the min pos 1266 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1267 && (returnedHeight != maxHeight) // i'th child did not fit completely 1268 ? prevHeightWithoutPartialChild 1269 : maxHeight; 1270 } 1271 1272 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1273 prevHeightWithoutPartialChild = returnedHeight; 1274 } 1275 } 1276 1277 // At this point, we went through the range of children, and they each 1278 // completely fit, so return the returnedHeight 1279 return returnedHeight; 1280 } 1281 1282 @Override 1283 int findMotionRow(int y) { 1284 int childCount = getChildCount(); 1285 if (childCount > 0) { 1286 if (!mStackFromBottom) { 1287 for (int i = 0; i < childCount; i++) { 1288 View v = getChildAt(i); 1289 if (y <= v.getBottom()) { 1290 return mFirstPosition + i; 1291 } 1292 } 1293 } else { 1294 for (int i = childCount - 1; i >= 0; i--) { 1295 View v = getChildAt(i); 1296 if (y >= v.getTop()) { 1297 return mFirstPosition + i; 1298 } 1299 } 1300 } 1301 } 1302 return INVALID_POSITION; 1303 } 1304 1305 /** 1306 * Put a specific item at a specific location on the screen and then build 1307 * up and down from there. 1308 * 1309 * @param position The reference view to use as the starting point 1310 * @param top Pixel offset from the top of this view to the top of the 1311 * reference view. 1312 * 1313 * @return The selected view, or null if the selected view is outside the 1314 * visible area. 1315 */ 1316 private View fillSpecific(int position, int top) { 1317 boolean tempIsSelected = position == mSelectedPosition; 1318 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1319 // Possibly changed again in fillUp if we add rows above this one. 1320 mFirstPosition = position; 1321 1322 View above; 1323 View below; 1324 1325 final int dividerHeight = mDividerHeight; 1326 if (!mStackFromBottom) { 1327 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1328 // This will correct for the top of the first view not touching the top of the list 1329 adjustViewsUpOrDown(); 1330 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1331 int childCount = getChildCount(); 1332 if (childCount > 0) { 1333 correctTooHigh(childCount); 1334 } 1335 } else { 1336 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1337 // This will correct for the bottom of the last view not touching the bottom of the list 1338 adjustViewsUpOrDown(); 1339 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1340 int childCount = getChildCount(); 1341 if (childCount > 0) { 1342 correctTooLow(childCount); 1343 } 1344 } 1345 1346 if (tempIsSelected) { 1347 return temp; 1348 } else if (above != null) { 1349 return above; 1350 } else { 1351 return below; 1352 } 1353 } 1354 1355 /** 1356 * Check if we have dragged the bottom of the list too high (we have pushed the 1357 * top element off the top of the screen when we did not need to). Correct by sliding 1358 * everything back down. 1359 * 1360 * @param childCount Number of children 1361 */ 1362 private void correctTooHigh(int childCount) { 1363 // First see if the last item is visible. If it is not, it is OK for the 1364 // top of the list to be pushed up. 1365 int lastPosition = mFirstPosition + childCount - 1; 1366 if (lastPosition == mItemCount - 1 && childCount > 0) { 1367 1368 // Get the last child ... 1369 final View lastChild = getChildAt(childCount - 1); 1370 1371 // ... and its bottom edge 1372 final int lastBottom = lastChild.getBottom(); 1373 1374 // This is bottom of our drawable area 1375 final int end = (mBottom - mTop) - mListPadding.bottom; 1376 1377 // This is how far the bottom edge of the last view is from the bottom of the 1378 // drawable area 1379 int bottomOffset = end - lastBottom; 1380 View firstChild = getChildAt(0); 1381 final int firstTop = firstChild.getTop(); 1382 1383 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1384 // first row or the first row is scrolled off the top of the drawable area 1385 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1386 if (mFirstPosition == 0) { 1387 // Don't pull the top too far down 1388 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1389 } 1390 // Move everything down 1391 offsetChildrenTopAndBottom(bottomOffset); 1392 if (mFirstPosition > 0) { 1393 // Fill the gap that was opened above mFirstPosition with more rows, if 1394 // possible 1395 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1396 // Close up the remaining gap 1397 adjustViewsUpOrDown(); 1398 } 1399 1400 } 1401 } 1402 } 1403 1404 /** 1405 * Check if we have dragged the bottom of the list too low (we have pushed the 1406 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1407 * everything back up. 1408 * 1409 * @param childCount Number of children 1410 */ 1411 private void correctTooLow(int childCount) { 1412 // First see if the first item is visible. If it is not, it is OK for the 1413 // bottom of the list to be pushed down. 1414 if (mFirstPosition == 0 && childCount > 0) { 1415 1416 // Get the first child ... 1417 final View firstChild = getChildAt(0); 1418 1419 // ... and its top edge 1420 final int firstTop = firstChild.getTop(); 1421 1422 // This is top of our drawable area 1423 final int start = mListPadding.top; 1424 1425 // This is bottom of our drawable area 1426 final int end = (mBottom - mTop) - mListPadding.bottom; 1427 1428 // This is how far the top edge of the first view is from the top of the 1429 // drawable area 1430 int topOffset = firstTop - start; 1431 View lastChild = getChildAt(childCount - 1); 1432 final int lastBottom = lastChild.getBottom(); 1433 int lastPosition = mFirstPosition + childCount - 1; 1434 1435 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1436 // last row or the last row is scrolled off the bottom of the drawable area 1437 if (topOffset > 0) { 1438 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1439 if (lastPosition == mItemCount - 1) { 1440 // Don't pull the bottom too far up 1441 topOffset = Math.min(topOffset, lastBottom - end); 1442 } 1443 // Move everything up 1444 offsetChildrenTopAndBottom(-topOffset); 1445 if (lastPosition < mItemCount - 1) { 1446 // Fill the gap that was opened below the last position with more rows, if 1447 // possible 1448 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1449 // Close up the remaining gap 1450 adjustViewsUpOrDown(); 1451 } 1452 } else if (lastPosition == mItemCount - 1) { 1453 adjustViewsUpOrDown(); 1454 } 1455 } 1456 } 1457 } 1458 1459 @Override 1460 protected void layoutChildren() { 1461 final boolean blockLayoutRequests = mBlockLayoutRequests; 1462 if (!blockLayoutRequests) { 1463 mBlockLayoutRequests = true; 1464 } else { 1465 return; 1466 } 1467 1468 try { 1469 super.layoutChildren(); 1470 1471 invalidate(); 1472 1473 if (mAdapter == null) { 1474 resetList(); 1475 invokeOnItemScrollListener(); 1476 return; 1477 } 1478 1479 int childrenTop = mListPadding.top; 1480 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1481 1482 int childCount = getChildCount(); 1483 int index = 0; 1484 int delta = 0; 1485 1486 View sel; 1487 View oldSel = null; 1488 View oldFirst = null; 1489 View newSel = null; 1490 1491 View focusLayoutRestoreView = null; 1492 1493 // Remember stuff we will need down below 1494 switch (mLayoutMode) { 1495 case LAYOUT_SET_SELECTION: 1496 index = mNextSelectedPosition - mFirstPosition; 1497 if (index >= 0 && index < childCount) { 1498 newSel = getChildAt(index); 1499 } 1500 break; 1501 case LAYOUT_FORCE_TOP: 1502 case LAYOUT_FORCE_BOTTOM: 1503 case LAYOUT_SPECIFIC: 1504 case LAYOUT_SYNC: 1505 break; 1506 case LAYOUT_MOVE_SELECTION: 1507 default: 1508 // Remember the previously selected view 1509 index = mSelectedPosition - mFirstPosition; 1510 if (index >= 0 && index < childCount) { 1511 oldSel = getChildAt(index); 1512 } 1513 1514 // Remember the previous first child 1515 oldFirst = getChildAt(0); 1516 1517 if (mNextSelectedPosition >= 0) { 1518 delta = mNextSelectedPosition - mSelectedPosition; 1519 } 1520 1521 // Caution: newSel might be null 1522 newSel = getChildAt(index + delta); 1523 } 1524 1525 1526 boolean dataChanged = mDataChanged; 1527 if (dataChanged) { 1528 handleDataChanged(); 1529 } 1530 1531 // Handle the empty set by removing all views that are visible 1532 // and calling it a day 1533 if (mItemCount == 0) { 1534 resetList(); 1535 invokeOnItemScrollListener(); 1536 return; 1537 } else if (mItemCount != mAdapter.getCount()) { 1538 throw new IllegalStateException("The content of the adapter has changed but " 1539 + "ListView did not receive a notification. Make sure the content of " 1540 + "your adapter is not modified from a background thread, but only " 1541 + "from the UI thread. [in ListView(" + getId() + ", " + getClass() 1542 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1543 } 1544 1545 setSelectedPositionInt(mNextSelectedPosition); 1546 1547 // Pull all children into the RecycleBin. 1548 // These views will be reused if possible 1549 final int firstPosition = mFirstPosition; 1550 final RecycleBin recycleBin = mRecycler; 1551 1552 // reset the focus restoration 1553 View focusLayoutRestoreDirectChild = null; 1554 1555 // Don't put header or footer views into the Recycler. Those are 1556 // already cached in mHeaderViews; 1557 if (dataChanged) { 1558 for (int i = 0; i < childCount; i++) { 1559 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1560 if (ViewDebug.TRACE_RECYCLER) { 1561 ViewDebug.trace(getChildAt(i), 1562 ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i); 1563 } 1564 } 1565 } else { 1566 recycleBin.fillActiveViews(childCount, firstPosition); 1567 } 1568 1569 // take focus back to us temporarily to avoid the eventual 1570 // call to clear focus when removing the focused child below 1571 // from messing things up when ViewAncestor assigns focus back 1572 // to someone else 1573 final View focusedChild = getFocusedChild(); 1574 if (focusedChild != null) { 1575 // TODO: in some cases focusedChild.getParent() == null 1576 1577 // we can remember the focused view to restore after relayout if the 1578 // data hasn't changed, or if the focused position is a header or footer 1579 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1580 focusLayoutRestoreDirectChild = focusedChild; 1581 // remember the specific view that had focus 1582 focusLayoutRestoreView = findFocus(); 1583 if (focusLayoutRestoreView != null) { 1584 // tell it we are going to mess with it 1585 focusLayoutRestoreView.onStartTemporaryDetach(); 1586 } 1587 } 1588 requestFocus(); 1589 } 1590 1591 // Clear out old views 1592 detachAllViewsFromParent(); 1593 1594 switch (mLayoutMode) { 1595 case LAYOUT_SET_SELECTION: 1596 if (newSel != null) { 1597 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1598 } else { 1599 sel = fillFromMiddle(childrenTop, childrenBottom); 1600 } 1601 break; 1602 case LAYOUT_SYNC: 1603 sel = fillSpecific(mSyncPosition, mSpecificTop); 1604 break; 1605 case LAYOUT_FORCE_BOTTOM: 1606 sel = fillUp(mItemCount - 1, childrenBottom); 1607 adjustViewsUpOrDown(); 1608 break; 1609 case LAYOUT_FORCE_TOP: 1610 mFirstPosition = 0; 1611 sel = fillFromTop(childrenTop); 1612 adjustViewsUpOrDown(); 1613 break; 1614 case LAYOUT_SPECIFIC: 1615 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1616 break; 1617 case LAYOUT_MOVE_SELECTION: 1618 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1619 break; 1620 default: 1621 if (childCount == 0) { 1622 if (!mStackFromBottom) { 1623 final int position = lookForSelectablePosition(0, true); 1624 setSelectedPositionInt(position); 1625 sel = fillFromTop(childrenTop); 1626 } else { 1627 final int position = lookForSelectablePosition(mItemCount - 1, false); 1628 setSelectedPositionInt(position); 1629 sel = fillUp(mItemCount - 1, childrenBottom); 1630 } 1631 } else { 1632 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1633 sel = fillSpecific(mSelectedPosition, 1634 oldSel == null ? childrenTop : oldSel.getTop()); 1635 } else if (mFirstPosition < mItemCount) { 1636 sel = fillSpecific(mFirstPosition, 1637 oldFirst == null ? childrenTop : oldFirst.getTop()); 1638 } else { 1639 sel = fillSpecific(0, childrenTop); 1640 } 1641 } 1642 break; 1643 } 1644 1645 // Flush any cached views that did not get reused above 1646 recycleBin.scrapActiveViews(); 1647 1648 if (sel != null) { 1649 // the current selected item should get focus if items 1650 // are focusable 1651 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1652 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1653 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1654 if (!focusWasTaken) { 1655 // selected item didn't take focus, fine, but still want 1656 // to make sure something else outside of the selected view 1657 // has focus 1658 final View focused = getFocusedChild(); 1659 if (focused != null) { 1660 focused.clearFocus(); 1661 } 1662 positionSelector(INVALID_POSITION, sel); 1663 } else { 1664 sel.setSelected(false); 1665 mSelectorRect.setEmpty(); 1666 } 1667 } else { 1668 positionSelector(INVALID_POSITION, sel); 1669 } 1670 mSelectedTop = sel.getTop(); 1671 } else { 1672 if (mTouchMode > TOUCH_MODE_DOWN && mTouchMode < TOUCH_MODE_SCROLL) { 1673 View child = getChildAt(mMotionPosition - mFirstPosition); 1674 if (child != null) positionSelector(mMotionPosition, child); 1675 } else { 1676 mSelectedTop = 0; 1677 mSelectorRect.setEmpty(); 1678 } 1679 1680 // even if there is not selected position, we may need to restore 1681 // focus (i.e. something focusable in touch mode) 1682 if (hasFocus() && focusLayoutRestoreView != null) { 1683 focusLayoutRestoreView.requestFocus(); 1684 } 1685 } 1686 1687 // tell focus view we are done mucking with it, if it is still in 1688 // our view hierarchy. 1689 if (focusLayoutRestoreView != null 1690 && focusLayoutRestoreView.getWindowToken() != null) { 1691 focusLayoutRestoreView.onFinishTemporaryDetach(); 1692 } 1693 1694 mLayoutMode = LAYOUT_NORMAL; 1695 mDataChanged = false; 1696 mNeedSync = false; 1697 setNextSelectedPositionInt(mSelectedPosition); 1698 1699 updateScrollIndicators(); 1700 1701 if (mItemCount > 0) { 1702 checkSelectionChanged(); 1703 } 1704 1705 invokeOnItemScrollListener(); 1706 } finally { 1707 if (!blockLayoutRequests) { 1708 mBlockLayoutRequests = false; 1709 } 1710 } 1711 } 1712 1713 /** 1714 * @param child a direct child of this list. 1715 * @return Whether child is a header or footer view. 1716 */ 1717 private boolean isDirectChildHeaderOrFooter(View child) { 1718 1719 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1720 final int numHeaders = headers.size(); 1721 for (int i = 0; i < numHeaders; i++) { 1722 if (child == headers.get(i).view) { 1723 return true; 1724 } 1725 } 1726 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1727 final int numFooters = footers.size(); 1728 for (int i = 0; i < numFooters; i++) { 1729 if (child == footers.get(i).view) { 1730 return true; 1731 } 1732 } 1733 return false; 1734 } 1735 1736 /** 1737 * Obtain the view and add it to our list of children. The view can be made 1738 * fresh, converted from an unused view, or used as is if it was in the 1739 * recycle bin. 1740 * 1741 * @param position Logical position in the list 1742 * @param y Top or bottom edge of the view to add 1743 * @param flow If flow is true, align top edge to y. If false, align bottom 1744 * edge to y. 1745 * @param childrenLeft Left edge where children should be positioned 1746 * @param selected Is this position selected? 1747 * @return View that was added 1748 */ 1749 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1750 boolean selected) { 1751 View child; 1752 1753 1754 if (!mDataChanged) { 1755 // Try to use an existing view for this position 1756 child = mRecycler.getActiveView(position); 1757 if (child != null) { 1758 if (ViewDebug.TRACE_RECYCLER) { 1759 ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, 1760 position, getChildCount()); 1761 } 1762 1763 // Found it -- we're using an existing child 1764 // This just needs to be positioned 1765 setupChild(child, position, y, flow, childrenLeft, selected, true); 1766 1767 return child; 1768 } 1769 } 1770 1771 // Make a new view for this position, or convert an unused view if possible 1772 child = obtainView(position, mIsScrap); 1773 1774 // This needs to be positioned and measured 1775 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1776 1777 return child; 1778 } 1779 1780 /** 1781 * Add a view as a child and make sure it is measured (if necessary) and 1782 * positioned properly. 1783 * 1784 * @param child The view to add 1785 * @param position The position of this child 1786 * @param y The y position relative to which this view will be positioned 1787 * @param flowDown If true, align top edge to y. If false, align bottom 1788 * edge to y. 1789 * @param childrenLeft Left edge where children should be positioned 1790 * @param selected Is this position selected? 1791 * @param recycled Has this view been pulled from the recycle bin? If so it 1792 * does not need to be remeasured. 1793 */ 1794 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1795 boolean selected, boolean recycled) { 1796 final boolean isSelected = selected && shouldShowSelector(); 1797 final boolean updateChildSelected = isSelected != child.isSelected(); 1798 final int mode = mTouchMode; 1799 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1800 mMotionPosition == position; 1801 final boolean updateChildPressed = isPressed != child.isPressed(); 1802 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1803 1804 // Respect layout params that are already in the view. Otherwise make some up... 1805 // noinspection unchecked 1806 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1807 if (p == null) { 1808 p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1809 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1810 } 1811 p.viewType = mAdapter.getItemViewType(position); 1812 1813 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1814 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1815 attachViewToParent(child, flowDown ? -1 : 0, p); 1816 } else { 1817 p.forceAdd = false; 1818 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1819 p.recycledHeaderFooter = true; 1820 } 1821 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1822 } 1823 1824 if (updateChildSelected) { 1825 child.setSelected(isSelected); 1826 } 1827 1828 if (updateChildPressed) { 1829 child.setPressed(isPressed); 1830 } 1831 1832 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1833 if (child instanceof Checkable) { 1834 ((Checkable) child).setChecked(mCheckStates.get(position)); 1835 } else if (getContext().getApplicationInfo().targetSdkVersion 1836 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1837 child.setActivated(mCheckStates.get(position)); 1838 } 1839 } 1840 1841 if (needToMeasure) { 1842 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1843 mListPadding.left + mListPadding.right, p.width); 1844 int lpHeight = p.height; 1845 int childHeightSpec; 1846 if (lpHeight > 0) { 1847 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1848 } else { 1849 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1850 } 1851 child.measure(childWidthSpec, childHeightSpec); 1852 } else { 1853 cleanupLayoutState(child); 1854 } 1855 1856 final int w = child.getMeasuredWidth(); 1857 final int h = child.getMeasuredHeight(); 1858 final int childTop = flowDown ? y : y - h; 1859 1860 if (needToMeasure) { 1861 final int childRight = childrenLeft + w; 1862 final int childBottom = childTop + h; 1863 child.layout(childrenLeft, childTop, childRight, childBottom); 1864 } else { 1865 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1866 child.offsetTopAndBottom(childTop - child.getTop()); 1867 } 1868 1869 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1870 child.setDrawingCacheEnabled(true); 1871 } 1872 1873 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1874 != position) { 1875 child.jumpDrawablesToCurrentState(); 1876 } 1877 } 1878 1879 @Override 1880 protected boolean canAnimate() { 1881 return super.canAnimate() && mItemCount > 0; 1882 } 1883 1884 /** 1885 * Sets the currently selected item. If in touch mode, the item will not be selected 1886 * but it will still be positioned appropriately. If the specified selection position 1887 * is less than 0, then the item at position 0 will be selected. 1888 * 1889 * @param position Index (starting at 0) of the data item to be selected. 1890 */ 1891 @Override 1892 public void setSelection(int position) { 1893 setSelectionFromTop(position, 0); 1894 } 1895 1896 /** 1897 * Sets the selected item and positions the selection y pixels from the top edge 1898 * of the ListView. (If in touch mode, the item will not be selected but it will 1899 * still be positioned appropriately.) 1900 * 1901 * @param position Index (starting at 0) of the data item to be selected. 1902 * @param y The distance from the top edge of the ListView (plus padding) that the 1903 * item will be positioned. 1904 */ 1905 public void setSelectionFromTop(int position, int y) { 1906 if (mAdapter == null) { 1907 return; 1908 } 1909 1910 if (!isInTouchMode()) { 1911 position = lookForSelectablePosition(position, true); 1912 if (position >= 0) { 1913 setNextSelectedPositionInt(position); 1914 } 1915 } else { 1916 mResurrectToPosition = position; 1917 } 1918 1919 if (position >= 0) { 1920 mLayoutMode = LAYOUT_SPECIFIC; 1921 mSpecificTop = mListPadding.top + y; 1922 1923 if (mNeedSync) { 1924 mSyncPosition = position; 1925 mSyncRowId = mAdapter.getItemId(position); 1926 } 1927 1928 requestLayout(); 1929 } 1930 } 1931 1932 /** 1933 * Makes the item at the supplied position selected. 1934 * 1935 * @param position the position of the item to select 1936 */ 1937 @Override 1938 void setSelectionInt(int position) { 1939 setNextSelectedPositionInt(position); 1940 boolean awakeScrollbars = false; 1941 1942 final int selectedPosition = mSelectedPosition; 1943 1944 if (selectedPosition >= 0) { 1945 if (position == selectedPosition - 1) { 1946 awakeScrollbars = true; 1947 } else if (position == selectedPosition + 1) { 1948 awakeScrollbars = true; 1949 } 1950 } 1951 1952 layoutChildren(); 1953 1954 if (awakeScrollbars) { 1955 awakenScrollBars(); 1956 } 1957 } 1958 1959 /** 1960 * Find a position that can be selected (i.e., is not a separator). 1961 * 1962 * @param position The starting position to look at. 1963 * @param lookDown Whether to look down for other positions. 1964 * @return The next selectable position starting at position and then searching either up or 1965 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1966 */ 1967 @Override 1968 int lookForSelectablePosition(int position, boolean lookDown) { 1969 final ListAdapter adapter = mAdapter; 1970 if (adapter == null || isInTouchMode()) { 1971 return INVALID_POSITION; 1972 } 1973 1974 final int count = adapter.getCount(); 1975 if (!mAreAllItemsSelectable) { 1976 if (lookDown) { 1977 position = Math.max(0, position); 1978 while (position < count && !adapter.isEnabled(position)) { 1979 position++; 1980 } 1981 } else { 1982 position = Math.min(position, count - 1); 1983 while (position >= 0 && !adapter.isEnabled(position)) { 1984 position--; 1985 } 1986 } 1987 1988 if (position < 0 || position >= count) { 1989 return INVALID_POSITION; 1990 } 1991 return position; 1992 } else { 1993 if (position < 0 || position >= count) { 1994 return INVALID_POSITION; 1995 } 1996 return position; 1997 } 1998 } 1999 2000 @Override 2001 public void onInitializeAccessibilityEvent(AccessibilityEvent event) { 2002 super.onInitializeAccessibilityEvent(event); 2003 2004 // If the item count is less than 15 then subtract disabled items from the count and 2005 // position. Otherwise ignore disabled items. 2006 int itemCount = 0; 2007 int currentItemIndex = getSelectedItemPosition(); 2008 2009 ListAdapter adapter = getAdapter(); 2010 if (adapter != null) { 2011 final int count = adapter.getCount(); 2012 for (int i = 0; i < count; i++) { 2013 if (adapter.isEnabled(i)) { 2014 itemCount++; 2015 } else if (i <= currentItemIndex) { 2016 currentItemIndex--; 2017 } 2018 } 2019 } 2020 2021 event.setItemCount(itemCount); 2022 event.setCurrentItemIndex(currentItemIndex); 2023 } 2024 2025 /** 2026 * setSelectionAfterHeaderView set the selection to be the first list item 2027 * after the header views. 2028 */ 2029 public void setSelectionAfterHeaderView() { 2030 final int count = mHeaderViewInfos.size(); 2031 if (count > 0) { 2032 mNextSelectedPosition = 0; 2033 return; 2034 } 2035 2036 if (mAdapter != null) { 2037 setSelection(count); 2038 } else { 2039 mNextSelectedPosition = count; 2040 mLayoutMode = LAYOUT_SET_SELECTION; 2041 } 2042 2043 } 2044 2045 @Override 2046 public boolean dispatchKeyEvent(KeyEvent event) { 2047 // Dispatch in the normal way 2048 boolean handled = super.dispatchKeyEvent(event); 2049 if (!handled) { 2050 // If we didn't handle it... 2051 View focused = getFocusedChild(); 2052 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2053 // ... and our focused child didn't handle it 2054 // ... give it to ourselves so we can scroll if necessary 2055 handled = onKeyDown(event.getKeyCode(), event); 2056 } 2057 } 2058 return handled; 2059 } 2060 2061 @Override 2062 public boolean onKeyDown(int keyCode, KeyEvent event) { 2063 return commonKey(keyCode, 1, event); 2064 } 2065 2066 @Override 2067 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2068 return commonKey(keyCode, repeatCount, event); 2069 } 2070 2071 @Override 2072 public boolean onKeyUp(int keyCode, KeyEvent event) { 2073 return commonKey(keyCode, 1, event); 2074 } 2075 2076 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2077 if (mAdapter == null) { 2078 return false; 2079 } 2080 2081 if (mDataChanged) { 2082 layoutChildren(); 2083 } 2084 2085 boolean handled = false; 2086 int action = event.getAction(); 2087 2088 if (action != KeyEvent.ACTION_UP) { 2089 switch (keyCode) { 2090 case KeyEvent.KEYCODE_DPAD_UP: 2091 if (event.hasNoModifiers()) { 2092 handled = resurrectSelectionIfNeeded(); 2093 if (!handled) { 2094 while (count-- > 0) { 2095 if (arrowScroll(FOCUS_UP)) { 2096 handled = true; 2097 } else { 2098 break; 2099 } 2100 } 2101 } 2102 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2103 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2104 } 2105 break; 2106 2107 case KeyEvent.KEYCODE_DPAD_DOWN: 2108 if (event.hasNoModifiers()) { 2109 handled = resurrectSelectionIfNeeded(); 2110 if (!handled) { 2111 while (count-- > 0) { 2112 if (arrowScroll(FOCUS_DOWN)) { 2113 handled = true; 2114 } else { 2115 break; 2116 } 2117 } 2118 } 2119 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2120 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2121 } 2122 break; 2123 2124 case KeyEvent.KEYCODE_DPAD_LEFT: 2125 if (event.hasNoModifiers()) { 2126 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2127 } 2128 break; 2129 2130 case KeyEvent.KEYCODE_DPAD_RIGHT: 2131 if (event.hasNoModifiers()) { 2132 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2133 } 2134 break; 2135 2136 case KeyEvent.KEYCODE_DPAD_CENTER: 2137 case KeyEvent.KEYCODE_ENTER: 2138 if (event.hasNoModifiers()) { 2139 handled = resurrectSelectionIfNeeded(); 2140 if (!handled 2141 && event.getRepeatCount() == 0 && getChildCount() > 0) { 2142 keyPressed(); 2143 handled = true; 2144 } 2145 } 2146 break; 2147 2148 case KeyEvent.KEYCODE_SPACE: 2149 if (mPopup == null || !mPopup.isShowing()) { 2150 if (event.hasNoModifiers()) { 2151 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2152 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2153 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2154 } 2155 handled = true; 2156 } 2157 break; 2158 2159 case KeyEvent.KEYCODE_PAGE_UP: 2160 if (event.hasNoModifiers()) { 2161 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); 2162 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2163 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2164 } 2165 break; 2166 2167 case KeyEvent.KEYCODE_PAGE_DOWN: 2168 if (event.hasNoModifiers()) { 2169 handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); 2170 } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) { 2171 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2172 } 2173 break; 2174 2175 case KeyEvent.KEYCODE_MOVE_HOME: 2176 if (event.hasNoModifiers()) { 2177 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); 2178 } 2179 break; 2180 2181 case KeyEvent.KEYCODE_MOVE_END: 2182 if (event.hasNoModifiers()) { 2183 handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); 2184 } 2185 break; 2186 2187 case KeyEvent.KEYCODE_TAB: 2188 // XXX Sometimes it is useful to be able to TAB through the items in 2189 // a ListView sequentially. Unfortunately this can create an 2190 // asymmetry in TAB navigation order unless the list selection 2191 // always reverts to the top or bottom when receiving TAB focus from 2192 // another widget. Leaving this behavior disabled for now but 2193 // perhaps it should be configurable (and more comprehensive). 2194 if (false) { 2195 if (event.hasNoModifiers()) { 2196 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_DOWN); 2197 } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) { 2198 handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_UP); 2199 } 2200 } 2201 break; 2202 } 2203 } 2204 2205 if (handled) { 2206 return true; 2207 } 2208 2209 if (sendToTextFilter(keyCode, count, event)) { 2210 return true; 2211 } 2212 2213 switch (action) { 2214 case KeyEvent.ACTION_DOWN: 2215 return super.onKeyDown(keyCode, event); 2216 2217 case KeyEvent.ACTION_UP: 2218 return super.onKeyUp(keyCode, event); 2219 2220 case KeyEvent.ACTION_MULTIPLE: 2221 return super.onKeyMultiple(keyCode, count, event); 2222 2223 default: // shouldn't happen 2224 return false; 2225 } 2226 } 2227 2228 /** 2229 * Scrolls up or down by the number of items currently present on screen. 2230 * 2231 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2232 * @return whether selection was moved 2233 */ 2234 boolean pageScroll(int direction) { 2235 int nextPage = -1; 2236 boolean down = false; 2237 2238 if (direction == FOCUS_UP) { 2239 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2240 } else if (direction == FOCUS_DOWN) { 2241 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2242 down = true; 2243 } 2244 2245 if (nextPage >= 0) { 2246 int position = lookForSelectablePosition(nextPage, down); 2247 if (position >= 0) { 2248 mLayoutMode = LAYOUT_SPECIFIC; 2249 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2250 2251 if (down && position > mItemCount - getChildCount()) { 2252 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2253 } 2254 2255 if (!down && position < getChildCount()) { 2256 mLayoutMode = LAYOUT_FORCE_TOP; 2257 } 2258 2259 setSelectionInt(position); 2260 invokeOnItemScrollListener(); 2261 if (!awakenScrollBars()) { 2262 invalidate(); 2263 } 2264 2265 return true; 2266 } 2267 } 2268 2269 return false; 2270 } 2271 2272 /** 2273 * Go to the last or first item if possible (not worrying about panning across or navigating 2274 * within the internal focus of the currently selected item.) 2275 * 2276 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2277 * 2278 * @return whether selection was moved 2279 */ 2280 boolean fullScroll(int direction) { 2281 boolean moved = false; 2282 if (direction == FOCUS_UP) { 2283 if (mSelectedPosition != 0) { 2284 int position = lookForSelectablePosition(0, true); 2285 if (position >= 0) { 2286 mLayoutMode = LAYOUT_FORCE_TOP; 2287 setSelectionInt(position); 2288 invokeOnItemScrollListener(); 2289 } 2290 moved = true; 2291 } 2292 } else if (direction == FOCUS_DOWN) { 2293 if (mSelectedPosition < mItemCount - 1) { 2294 int position = lookForSelectablePosition(mItemCount - 1, true); 2295 if (position >= 0) { 2296 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2297 setSelectionInt(position); 2298 invokeOnItemScrollListener(); 2299 } 2300 moved = true; 2301 } 2302 } 2303 2304 if (moved && !awakenScrollBars()) { 2305 awakenScrollBars(); 2306 invalidate(); 2307 } 2308 2309 return moved; 2310 } 2311 2312 /** 2313 * To avoid horizontal focus searches changing the selected item, we 2314 * manually focus search within the selected item (as applicable), and 2315 * prevent focus from jumping to something within another item. 2316 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2317 * @return Whether this consumes the key event. 2318 */ 2319 private boolean handleHorizontalFocusWithinListItem(int direction) { 2320 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2321 throw new IllegalArgumentException("direction must be one of" 2322 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2323 } 2324 2325 final int numChildren = getChildCount(); 2326 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2327 final View selectedView = getSelectedView(); 2328 if (selectedView != null && selectedView.hasFocus() && 2329 selectedView instanceof ViewGroup) { 2330 2331 final View currentFocus = selectedView.findFocus(); 2332 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2333 (ViewGroup) selectedView, currentFocus, direction); 2334 if (nextFocus != null) { 2335 // do the math to get interesting rect in next focus' coordinates 2336 currentFocus.getFocusedRect(mTempRect); 2337 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2338 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2339 if (nextFocus.requestFocus(direction, mTempRect)) { 2340 return true; 2341 } 2342 } 2343 // we are blocking the key from being handled (by returning true) 2344 // if the global result is going to be some other view within this 2345 // list. this is to acheive the overall goal of having 2346 // horizontal d-pad navigation remain in the current item. 2347 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2348 (ViewGroup) getRootView(), currentFocus, direction); 2349 if (globalNextFocus != null) { 2350 return isViewAncestorOf(globalNextFocus, this); 2351 } 2352 } 2353 } 2354 return false; 2355 } 2356 2357 /** 2358 * Scrolls to the next or previous item if possible. 2359 * 2360 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2361 * 2362 * @return whether selection was moved 2363 */ 2364 boolean arrowScroll(int direction) { 2365 try { 2366 mInLayout = true; 2367 final boolean handled = arrowScrollImpl(direction); 2368 if (handled) { 2369 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2370 } 2371 return handled; 2372 } finally { 2373 mInLayout = false; 2374 } 2375 } 2376 2377 /** 2378 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2379 * whether there are focusable items etc. 2380 * 2381 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2382 * @return Whether any scrolling, selection or focus change occured. 2383 */ 2384 private boolean arrowScrollImpl(int direction) { 2385 if (getChildCount() <= 0) { 2386 return false; 2387 } 2388 2389 View selectedView = getSelectedView(); 2390 int selectedPos = mSelectedPosition; 2391 2392 int nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 2393 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2394 2395 // if we are moving focus, we may OVERRIDE the default behavior 2396 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2397 if (focusResult != null) { 2398 nextSelectedPosition = focusResult.getSelectedPosition(); 2399 amountToScroll = focusResult.getAmountToScroll(); 2400 } 2401 2402 boolean needToRedraw = focusResult != null; 2403 if (nextSelectedPosition != INVALID_POSITION) { 2404 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2405 setSelectedPositionInt(nextSelectedPosition); 2406 setNextSelectedPositionInt(nextSelectedPosition); 2407 selectedView = getSelectedView(); 2408 selectedPos = nextSelectedPosition; 2409 if (mItemsCanFocus && focusResult == null) { 2410 // there was no new view found to take focus, make sure we 2411 // don't leave focus with the old selection 2412 final View focused = getFocusedChild(); 2413 if (focused != null) { 2414 focused.clearFocus(); 2415 } 2416 } 2417 needToRedraw = true; 2418 checkSelectionChanged(); 2419 } 2420 2421 if (amountToScroll > 0) { 2422 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2423 needToRedraw = true; 2424 } 2425 2426 // if we didn't find a new focusable, make sure any existing focused 2427 // item that was panned off screen gives up focus. 2428 if (mItemsCanFocus && (focusResult == null) 2429 && selectedView != null && selectedView.hasFocus()) { 2430 final View focused = selectedView.findFocus(); 2431 if (distanceToView(focused) > 0) { 2432 focused.clearFocus(); 2433 } 2434 } 2435 2436 // if the current selection is panned off, we need to remove the selection 2437 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2438 && !isViewAncestorOf(selectedView, this)) { 2439 selectedView = null; 2440 hideSelector(); 2441 2442 // but we don't want to set the ressurect position (that would make subsequent 2443 // unhandled key events bring back the item we just scrolled off!) 2444 mResurrectToPosition = INVALID_POSITION; 2445 } 2446 2447 if (needToRedraw) { 2448 if (selectedView != null) { 2449 positionSelector(selectedPos, selectedView); 2450 mSelectedTop = selectedView.getTop(); 2451 } 2452 if (!awakenScrollBars()) { 2453 invalidate(); 2454 } 2455 invokeOnItemScrollListener(); 2456 return true; 2457 } 2458 2459 return false; 2460 } 2461 2462 /** 2463 * When selection changes, it is possible that the previously selected or the 2464 * next selected item will change its size. If so, we need to offset some folks, 2465 * and re-layout the items as appropriate. 2466 * 2467 * @param selectedView The currently selected view (before changing selection). 2468 * should be <code>null</code> if there was no previous selection. 2469 * @param direction Either {@link android.view.View#FOCUS_UP} or 2470 * {@link android.view.View#FOCUS_DOWN}. 2471 * @param newSelectedPosition The position of the next selection. 2472 * @param newFocusAssigned whether new focus was assigned. This matters because 2473 * when something has focus, we don't want to show selection (ugh). 2474 */ 2475 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2476 boolean newFocusAssigned) { 2477 if (newSelectedPosition == INVALID_POSITION) { 2478 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2479 } 2480 2481 // whether or not we are moving down or up, we want to preserve the 2482 // top of whatever view is on top: 2483 // - moving down: the view that had selection 2484 // - moving up: the view that is getting selection 2485 View topView; 2486 View bottomView; 2487 int topViewIndex, bottomViewIndex; 2488 boolean topSelected = false; 2489 final int selectedIndex = mSelectedPosition - mFirstPosition; 2490 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2491 if (direction == View.FOCUS_UP) { 2492 topViewIndex = nextSelectedIndex; 2493 bottomViewIndex = selectedIndex; 2494 topView = getChildAt(topViewIndex); 2495 bottomView = selectedView; 2496 topSelected = true; 2497 } else { 2498 topViewIndex = selectedIndex; 2499 bottomViewIndex = nextSelectedIndex; 2500 topView = selectedView; 2501 bottomView = getChildAt(bottomViewIndex); 2502 } 2503 2504 final int numChildren = getChildCount(); 2505 2506 // start with top view: is it changing size? 2507 if (topView != null) { 2508 topView.setSelected(!newFocusAssigned && topSelected); 2509 measureAndAdjustDown(topView, topViewIndex, numChildren); 2510 } 2511 2512 // is the bottom view changing size? 2513 if (bottomView != null) { 2514 bottomView.setSelected(!newFocusAssigned && !topSelected); 2515 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2516 } 2517 } 2518 2519 /** 2520 * Re-measure a child, and if its height changes, lay it out preserving its 2521 * top, and adjust the children below it appropriately. 2522 * @param child The child 2523 * @param childIndex The view group index of the child. 2524 * @param numChildren The number of children in the view group. 2525 */ 2526 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2527 int oldHeight = child.getHeight(); 2528 measureItem(child); 2529 if (child.getMeasuredHeight() != oldHeight) { 2530 // lay out the view, preserving its top 2531 relayoutMeasuredItem(child); 2532 2533 // adjust views below appropriately 2534 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2535 for (int i = childIndex + 1; i < numChildren; i++) { 2536 getChildAt(i).offsetTopAndBottom(heightDelta); 2537 } 2538 } 2539 } 2540 2541 /** 2542 * Measure a particular list child. 2543 * TODO: unify with setUpChild. 2544 * @param child The child. 2545 */ 2546 private void measureItem(View child) { 2547 ViewGroup.LayoutParams p = child.getLayoutParams(); 2548 if (p == null) { 2549 p = new ViewGroup.LayoutParams( 2550 ViewGroup.LayoutParams.MATCH_PARENT, 2551 ViewGroup.LayoutParams.WRAP_CONTENT); 2552 } 2553 2554 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2555 mListPadding.left + mListPadding.right, p.width); 2556 int lpHeight = p.height; 2557 int childHeightSpec; 2558 if (lpHeight > 0) { 2559 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2560 } else { 2561 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2562 } 2563 child.measure(childWidthSpec, childHeightSpec); 2564 } 2565 2566 /** 2567 * Layout a child that has been measured, preserving its top position. 2568 * TODO: unify with setUpChild. 2569 * @param child The child. 2570 */ 2571 private void relayoutMeasuredItem(View child) { 2572 final int w = child.getMeasuredWidth(); 2573 final int h = child.getMeasuredHeight(); 2574 final int childLeft = mListPadding.left; 2575 final int childRight = childLeft + w; 2576 final int childTop = child.getTop(); 2577 final int childBottom = childTop + h; 2578 child.layout(childLeft, childTop, childRight, childBottom); 2579 } 2580 2581 /** 2582 * @return The amount to preview next items when arrow srolling. 2583 */ 2584 private int getArrowScrollPreviewLength() { 2585 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2586 } 2587 2588 /** 2589 * Determine how much we need to scroll in order to get the next selected view 2590 * visible, with a fading edge showing below as applicable. The amount is 2591 * capped at {@link #getMaxScrollAmount()} . 2592 * 2593 * @param direction either {@link android.view.View#FOCUS_UP} or 2594 * {@link android.view.View#FOCUS_DOWN}. 2595 * @param nextSelectedPosition The position of the next selection, or 2596 * {@link #INVALID_POSITION} if there is no next selectable position 2597 * @return The amount to scroll. Note: this is always positive! Direction 2598 * needs to be taken into account when actually scrolling. 2599 */ 2600 private int amountToScroll(int direction, int nextSelectedPosition) { 2601 final int listBottom = getHeight() - mListPadding.bottom; 2602 final int listTop = mListPadding.top; 2603 2604 final int numChildren = getChildCount(); 2605 2606 if (direction == View.FOCUS_DOWN) { 2607 int indexToMakeVisible = numChildren - 1; 2608 if (nextSelectedPosition != INVALID_POSITION) { 2609 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2610 } 2611 2612 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2613 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2614 2615 int goalBottom = listBottom; 2616 if (positionToMakeVisible < mItemCount - 1) { 2617 goalBottom -= getArrowScrollPreviewLength(); 2618 } 2619 2620 if (viewToMakeVisible.getBottom() <= goalBottom) { 2621 // item is fully visible. 2622 return 0; 2623 } 2624 2625 if (nextSelectedPosition != INVALID_POSITION 2626 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2627 // item already has enough of it visible, changing selection is good enough 2628 return 0; 2629 } 2630 2631 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2632 2633 if ((mFirstPosition + numChildren) == mItemCount) { 2634 // last is last in list -> make sure we don't scroll past it 2635 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2636 amountToScroll = Math.min(amountToScroll, max); 2637 } 2638 2639 return Math.min(amountToScroll, getMaxScrollAmount()); 2640 } else { 2641 int indexToMakeVisible = 0; 2642 if (nextSelectedPosition != INVALID_POSITION) { 2643 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2644 } 2645 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2646 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2647 int goalTop = listTop; 2648 if (positionToMakeVisible > 0) { 2649 goalTop += getArrowScrollPreviewLength(); 2650 } 2651 if (viewToMakeVisible.getTop() >= goalTop) { 2652 // item is fully visible. 2653 return 0; 2654 } 2655 2656 if (nextSelectedPosition != INVALID_POSITION && 2657 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2658 // item already has enough of it visible, changing selection is good enough 2659 return 0; 2660 } 2661 2662 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2663 if (mFirstPosition == 0) { 2664 // first is first in list -> make sure we don't scroll past it 2665 final int max = listTop - getChildAt(0).getTop(); 2666 amountToScroll = Math.min(amountToScroll, max); 2667 } 2668 return Math.min(amountToScroll, getMaxScrollAmount()); 2669 } 2670 } 2671 2672 /** 2673 * Holds results of focus aware arrow scrolling. 2674 */ 2675 static private class ArrowScrollFocusResult { 2676 private int mSelectedPosition; 2677 private int mAmountToScroll; 2678 2679 /** 2680 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2681 */ 2682 void populate(int selectedPosition, int amountToScroll) { 2683 mSelectedPosition = selectedPosition; 2684 mAmountToScroll = amountToScroll; 2685 } 2686 2687 public int getSelectedPosition() { 2688 return mSelectedPosition; 2689 } 2690 2691 public int getAmountToScroll() { 2692 return mAmountToScroll; 2693 } 2694 } 2695 2696 /** 2697 * @param direction either {@link android.view.View#FOCUS_UP} or 2698 * {@link android.view.View#FOCUS_DOWN}. 2699 * @return The position of the next selectable position of the views that 2700 * are currently visible, taking into account the fact that there might 2701 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2702 * selectable view on screen in the given direction. 2703 */ 2704 private int lookForSelectablePositionOnScreen(int direction) { 2705 final int firstPosition = mFirstPosition; 2706 if (direction == View.FOCUS_DOWN) { 2707 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2708 mSelectedPosition + 1 : 2709 firstPosition; 2710 if (startPos >= mAdapter.getCount()) { 2711 return INVALID_POSITION; 2712 } 2713 if (startPos < firstPosition) { 2714 startPos = firstPosition; 2715 } 2716 2717 final int lastVisiblePos = getLastVisiblePosition(); 2718 final ListAdapter adapter = getAdapter(); 2719 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2720 if (adapter.isEnabled(pos) 2721 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2722 return pos; 2723 } 2724 } 2725 } else { 2726 int last = firstPosition + getChildCount() - 1; 2727 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2728 mSelectedPosition - 1 : 2729 firstPosition + getChildCount() - 1; 2730 if (startPos < 0 || startPos >= mAdapter.getCount()) { 2731 return INVALID_POSITION; 2732 } 2733 if (startPos > last) { 2734 startPos = last; 2735 } 2736 2737 final ListAdapter adapter = getAdapter(); 2738 for (int pos = startPos; pos >= firstPosition; pos--) { 2739 if (adapter.isEnabled(pos) 2740 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2741 return pos; 2742 } 2743 } 2744 } 2745 return INVALID_POSITION; 2746 } 2747 2748 /** 2749 * Do an arrow scroll based on focus searching. If a new view is 2750 * given focus, return the selection delta and amount to scroll via 2751 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2752 * 2753 * @param direction either {@link android.view.View#FOCUS_UP} or 2754 * {@link android.view.View#FOCUS_DOWN}. 2755 * @return The result if focus has changed, or <code>null</code>. 2756 */ 2757 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2758 final View selectedView = getSelectedView(); 2759 View newFocus; 2760 if (selectedView != null && selectedView.hasFocus()) { 2761 View oldFocus = selectedView.findFocus(); 2762 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2763 } else { 2764 if (direction == View.FOCUS_DOWN) { 2765 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2766 final int listTop = mListPadding.top + 2767 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2768 final int ySearchPoint = 2769 (selectedView != null && selectedView.getTop() > listTop) ? 2770 selectedView.getTop() : 2771 listTop; 2772 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2773 } else { 2774 final boolean bottomFadingEdgeShowing = 2775 (mFirstPosition + getChildCount() - 1) < mItemCount; 2776 final int listBottom = getHeight() - mListPadding.bottom - 2777 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2778 final int ySearchPoint = 2779 (selectedView != null && selectedView.getBottom() < listBottom) ? 2780 selectedView.getBottom() : 2781 listBottom; 2782 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2783 } 2784 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2785 } 2786 2787 if (newFocus != null) { 2788 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2789 2790 // if the focus change is in a different new position, make sure 2791 // we aren't jumping over another selectable position 2792 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2793 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2794 if (selectablePosition != INVALID_POSITION && 2795 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2796 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2797 return null; 2798 } 2799 } 2800 2801 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2802 2803 final int maxScrollAmount = getMaxScrollAmount(); 2804 if (focusScroll < maxScrollAmount) { 2805 // not moving too far, safe to give next view focus 2806 newFocus.requestFocus(direction); 2807 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2808 return mArrowScrollFocusResult; 2809 } else if (distanceToView(newFocus) < maxScrollAmount){ 2810 // Case to consider: 2811 // too far to get entire next focusable on screen, but by going 2812 // max scroll amount, we are getting it at least partially in view, 2813 // so give it focus and scroll the max ammount. 2814 newFocus.requestFocus(direction); 2815 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2816 return mArrowScrollFocusResult; 2817 } 2818 } 2819 return null; 2820 } 2821 2822 /** 2823 * @param newFocus The view that would have focus. 2824 * @return the position that contains newFocus 2825 */ 2826 private int positionOfNewFocus(View newFocus) { 2827 final int numChildren = getChildCount(); 2828 for (int i = 0; i < numChildren; i++) { 2829 final View child = getChildAt(i); 2830 if (isViewAncestorOf(newFocus, child)) { 2831 return mFirstPosition + i; 2832 } 2833 } 2834 throw new IllegalArgumentException("newFocus is not a child of any of the" 2835 + " children of the list!"); 2836 } 2837 2838 /** 2839 * Return true if child is an ancestor of parent, (or equal to the parent). 2840 */ 2841 private boolean isViewAncestorOf(View child, View parent) { 2842 if (child == parent) { 2843 return true; 2844 } 2845 2846 final ViewParent theParent = child.getParent(); 2847 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2848 } 2849 2850 /** 2851 * Determine how much we need to scroll in order to get newFocus in view. 2852 * @param direction either {@link android.view.View#FOCUS_UP} or 2853 * {@link android.view.View#FOCUS_DOWN}. 2854 * @param newFocus The view that would take focus. 2855 * @param positionOfNewFocus The position of the list item containing newFocus 2856 * @return The amount to scroll. Note: this is always positive! Direction 2857 * needs to be taken into account when actually scrolling. 2858 */ 2859 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2860 int amountToScroll = 0; 2861 newFocus.getDrawingRect(mTempRect); 2862 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2863 if (direction == View.FOCUS_UP) { 2864 if (mTempRect.top < mListPadding.top) { 2865 amountToScroll = mListPadding.top - mTempRect.top; 2866 if (positionOfNewFocus > 0) { 2867 amountToScroll += getArrowScrollPreviewLength(); 2868 } 2869 } 2870 } else { 2871 final int listBottom = getHeight() - mListPadding.bottom; 2872 if (mTempRect.bottom > listBottom) { 2873 amountToScroll = mTempRect.bottom - listBottom; 2874 if (positionOfNewFocus < mItemCount - 1) { 2875 amountToScroll += getArrowScrollPreviewLength(); 2876 } 2877 } 2878 } 2879 return amountToScroll; 2880 } 2881 2882 /** 2883 * Determine the distance to the nearest edge of a view in a particular 2884 * direction. 2885 * 2886 * @param descendant A descendant of this list. 2887 * @return The distance, or 0 if the nearest edge is already on screen. 2888 */ 2889 private int distanceToView(View descendant) { 2890 int distance = 0; 2891 descendant.getDrawingRect(mTempRect); 2892 offsetDescendantRectToMyCoords(descendant, mTempRect); 2893 final int listBottom = mBottom - mTop - mListPadding.bottom; 2894 if (mTempRect.bottom < mListPadding.top) { 2895 distance = mListPadding.top - mTempRect.bottom; 2896 } else if (mTempRect.top > listBottom) { 2897 distance = mTempRect.top - listBottom; 2898 } 2899 return distance; 2900 } 2901 2902 2903 /** 2904 * Scroll the children by amount, adding a view at the end and removing 2905 * views that fall off as necessary. 2906 * 2907 * @param amount The amount (positive or negative) to scroll. 2908 */ 2909 private void scrollListItemsBy(int amount) { 2910 offsetChildrenTopAndBottom(amount); 2911 2912 final int listBottom = getHeight() - mListPadding.bottom; 2913 final int listTop = mListPadding.top; 2914 final AbsListView.RecycleBin recycleBin = mRecycler; 2915 2916 if (amount < 0) { 2917 // shifted items up 2918 2919 // may need to pan views into the bottom space 2920 int numChildren = getChildCount(); 2921 View last = getChildAt(numChildren - 1); 2922 while (last.getBottom() < listBottom) { 2923 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2924 if (lastVisiblePosition < mItemCount - 1) { 2925 last = addViewBelow(last, lastVisiblePosition); 2926 numChildren++; 2927 } else { 2928 break; 2929 } 2930 } 2931 2932 // may have brought in the last child of the list that is skinnier 2933 // than the fading edge, thereby leaving space at the end. need 2934 // to shift back 2935 if (last.getBottom() < listBottom) { 2936 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2937 } 2938 2939 // top views may be panned off screen 2940 View first = getChildAt(0); 2941 while (first.getBottom() < listTop) { 2942 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2943 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2944 detachViewFromParent(first); 2945 recycleBin.addScrapView(first, mFirstPosition); 2946 } else { 2947 removeViewInLayout(first); 2948 } 2949 first = getChildAt(0); 2950 mFirstPosition++; 2951 } 2952 } else { 2953 // shifted items down 2954 View first = getChildAt(0); 2955 2956 // may need to pan views into top 2957 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2958 first = addViewAbove(first, mFirstPosition); 2959 mFirstPosition--; 2960 } 2961 2962 // may have brought the very first child of the list in too far and 2963 // need to shift it back 2964 if (first.getTop() > listTop) { 2965 offsetChildrenTopAndBottom(listTop - first.getTop()); 2966 } 2967 2968 int lastIndex = getChildCount() - 1; 2969 View last = getChildAt(lastIndex); 2970 2971 // bottom view may be panned off screen 2972 while (last.getTop() > listBottom) { 2973 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 2974 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2975 detachViewFromParent(last); 2976 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 2977 } else { 2978 removeViewInLayout(last); 2979 } 2980 last = getChildAt(--lastIndex); 2981 } 2982 } 2983 } 2984 2985 private View addViewAbove(View theView, int position) { 2986 int abovePosition = position - 1; 2987 View view = obtainView(abovePosition, mIsScrap); 2988 int edgeOfNewChild = theView.getTop() - mDividerHeight; 2989 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 2990 false, mIsScrap[0]); 2991 return view; 2992 } 2993 2994 private View addViewBelow(View theView, int position) { 2995 int belowPosition = position + 1; 2996 View view = obtainView(belowPosition, mIsScrap); 2997 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 2998 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 2999 false, mIsScrap[0]); 3000 return view; 3001 } 3002 3003 /** 3004 * Indicates that the views created by the ListAdapter can contain focusable 3005 * items. 3006 * 3007 * @param itemsCanFocus true if items can get focus, false otherwise 3008 */ 3009 public void setItemsCanFocus(boolean itemsCanFocus) { 3010 mItemsCanFocus = itemsCanFocus; 3011 if (!itemsCanFocus) { 3012 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 3013 } 3014 } 3015 3016 /** 3017 * @return Whether the views created by the ListAdapter can contain focusable 3018 * items. 3019 */ 3020 public boolean getItemsCanFocus() { 3021 return mItemsCanFocus; 3022 } 3023 3024 @Override 3025 public boolean isOpaque() { 3026 boolean retValue = (mCachingActive && mIsCacheColorOpaque && mDividerIsOpaque && 3027 hasOpaqueScrollbars()) || super.isOpaque(); 3028 if (retValue) { 3029 // only return true if the list items cover the entire area of the view 3030 final int listTop = mListPadding != null ? mListPadding.top : mPaddingTop; 3031 View first = getChildAt(0); 3032 if (first == null || first.getTop() > listTop) { 3033 return false; 3034 } 3035 final int listBottom = getHeight() - 3036 (mListPadding != null ? mListPadding.bottom : mPaddingBottom); 3037 View last = getChildAt(getChildCount() - 1); 3038 if (last == null || last.getBottom() < listBottom) { 3039 return false; 3040 } 3041 } 3042 return retValue; 3043 } 3044 3045 @Override 3046 public void setCacheColorHint(int color) { 3047 final boolean opaque = (color >>> 24) == 0xFF; 3048 mIsCacheColorOpaque = opaque; 3049 if (opaque) { 3050 if (mDividerPaint == null) { 3051 mDividerPaint = new Paint(); 3052 } 3053 mDividerPaint.setColor(color); 3054 } 3055 super.setCacheColorHint(color); 3056 } 3057 3058 void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) { 3059 final int height = drawable.getMinimumHeight(); 3060 3061 canvas.save(); 3062 canvas.clipRect(bounds); 3063 3064 final int span = bounds.bottom - bounds.top; 3065 if (span < height) { 3066 bounds.top = bounds.bottom - height; 3067 } 3068 3069 drawable.setBounds(bounds); 3070 drawable.draw(canvas); 3071 3072 canvas.restore(); 3073 } 3074 3075 void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) { 3076 final int height = drawable.getMinimumHeight(); 3077 3078 canvas.save(); 3079 canvas.clipRect(bounds); 3080 3081 final int span = bounds.bottom - bounds.top; 3082 if (span < height) { 3083 bounds.bottom = bounds.top + height; 3084 } 3085 3086 drawable.setBounds(bounds); 3087 drawable.draw(canvas); 3088 3089 canvas.restore(); 3090 } 3091 3092 @Override 3093 protected void dispatchDraw(Canvas canvas) { 3094 if (mCachingStarted) { 3095 mCachingActive = true; 3096 } 3097 3098 // Draw the dividers 3099 final int dividerHeight = mDividerHeight; 3100 final Drawable overscrollHeader = mOverScrollHeader; 3101 final Drawable overscrollFooter = mOverScrollFooter; 3102 final boolean drawOverscrollHeader = overscrollHeader != null; 3103 final boolean drawOverscrollFooter = overscrollFooter != null; 3104 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 3105 3106 if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) { 3107 // Only modify the top and bottom in the loop, we set the left and right here 3108 final Rect bounds = mTempRect; 3109 bounds.left = mPaddingLeft; 3110 bounds.right = mRight - mLeft - mPaddingRight; 3111 3112 final int count = getChildCount(); 3113 final int headerCount = mHeaderViewInfos.size(); 3114 final int itemCount = mItemCount; 3115 final int footerLimit = itemCount - mFooterViewInfos.size() - 1; 3116 final boolean headerDividers = mHeaderDividersEnabled; 3117 final boolean footerDividers = mFooterDividersEnabled; 3118 final int first = mFirstPosition; 3119 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 3120 final ListAdapter adapter = mAdapter; 3121 // If the list is opaque *and* the background is not, we want to 3122 // fill a rect where the dividers would be for non-selectable items 3123 // If the list is opaque and the background is also opaque, we don't 3124 // need to draw anything since the background will do it for us 3125 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 3126 3127 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 3128 mDividerPaint = new Paint(); 3129 mDividerPaint.setColor(getCacheColorHint()); 3130 } 3131 final Paint paint = mDividerPaint; 3132 3133 int effectivePaddingTop = 0; 3134 int effectivePaddingBottom = 0; 3135 if ((mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK) { 3136 effectivePaddingTop = mListPadding.top; 3137 effectivePaddingBottom = mListPadding.bottom; 3138 } 3139 3140 final int listBottom = mBottom - mTop - effectivePaddingBottom + mScrollY; 3141 if (!mStackFromBottom) { 3142 int bottom = 0; 3143 3144 // Draw top divider or header for overscroll 3145 final int scrollY = mScrollY; 3146 if (count > 0 && scrollY < 0) { 3147 if (drawOverscrollHeader) { 3148 bounds.bottom = 0; 3149 bounds.top = scrollY; 3150 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3151 } else if (drawDividers) { 3152 bounds.bottom = 0; 3153 bounds.top = -dividerHeight; 3154 drawDivider(canvas, bounds, -1); 3155 } 3156 } 3157 3158 for (int i = 0; i < count; i++) { 3159 if ((headerDividers || first + i >= headerCount) && 3160 (footerDividers || first + i < footerLimit)) { 3161 View child = getChildAt(i); 3162 bottom = child.getBottom(); 3163 // Don't draw dividers next to items that are not enabled 3164 3165 if (drawDividers && 3166 (bottom < listBottom && !(drawOverscrollFooter && i == count - 1))) { 3167 if ((areAllItemsSelectable || 3168 (adapter.isEnabled(first + i) && (i == count - 1 || 3169 adapter.isEnabled(first + i + 1))))) { 3170 bounds.top = bottom; 3171 bounds.bottom = bottom + dividerHeight; 3172 drawDivider(canvas, bounds, i); 3173 } else if (fillForMissingDividers) { 3174 bounds.top = bottom; 3175 bounds.bottom = bottom + dividerHeight; 3176 canvas.drawRect(bounds, paint); 3177 } 3178 } 3179 } 3180 } 3181 3182 final int overFooterBottom = mBottom + mScrollY; 3183 if (drawOverscrollFooter && first + count == itemCount && 3184 overFooterBottom > bottom) { 3185 bounds.top = bottom; 3186 bounds.bottom = overFooterBottom; 3187 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3188 } 3189 } else { 3190 int top; 3191 3192 final int scrollY = mScrollY; 3193 3194 if (count > 0 && drawOverscrollHeader) { 3195 bounds.top = scrollY; 3196 bounds.bottom = getChildAt(0).getTop(); 3197 drawOverscrollHeader(canvas, overscrollHeader, bounds); 3198 } 3199 3200 final int start = drawOverscrollHeader ? 1 : 0; 3201 for (int i = start; i < count; i++) { 3202 if ((headerDividers || first + i >= headerCount) && 3203 (footerDividers || first + i < footerLimit)) { 3204 View child = getChildAt(i); 3205 top = child.getTop(); 3206 // Don't draw dividers next to items that are not enabled 3207 if (top > effectivePaddingTop) { 3208 if ((areAllItemsSelectable || 3209 (adapter.isEnabled(first + i) && (i == count - 1 || 3210 adapter.isEnabled(first + i + 1))))) { 3211 bounds.top = top - dividerHeight; 3212 bounds.bottom = top; 3213 // Give the method the child ABOVE the divider, so we 3214 // subtract one from our child 3215 // position. Give -1 when there is no child above the 3216 // divider. 3217 drawDivider(canvas, bounds, i - 1); 3218 } else if (fillForMissingDividers) { 3219 bounds.top = top - dividerHeight; 3220 bounds.bottom = top; 3221 canvas.drawRect(bounds, paint); 3222 } 3223 } 3224 } 3225 } 3226 3227 if (count > 0 && scrollY > 0) { 3228 if (drawOverscrollFooter) { 3229 final int absListBottom = mBottom; 3230 bounds.top = absListBottom; 3231 bounds.bottom = absListBottom + scrollY; 3232 drawOverscrollFooter(canvas, overscrollFooter, bounds); 3233 } else if (drawDividers) { 3234 bounds.top = listBottom; 3235 bounds.bottom = listBottom + dividerHeight; 3236 drawDivider(canvas, bounds, -1); 3237 } 3238 } 3239 } 3240 } 3241 3242 // Draw the indicators (these should be drawn above the dividers) and children 3243 super.dispatchDraw(canvas); 3244 } 3245 3246 @Override 3247 protected boolean drawChild(Canvas canvas, View child, long drawingTime) { 3248 boolean more = super.drawChild(canvas, child, drawingTime); 3249 if (mCachingActive && child.mCachingFailed) { 3250 mCachingActive = false; 3251 } 3252 return more; 3253 } 3254 3255 /** 3256 * Draws a divider for the given child in the given bounds. 3257 * 3258 * @param canvas The canvas to draw to. 3259 * @param bounds The bounds of the divider. 3260 * @param childIndex The index of child (of the View) above the divider. 3261 * This will be -1 if there is no child above the divider to be 3262 * drawn. 3263 */ 3264 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3265 // This widget draws the same divider for all children 3266 final Drawable divider = mDivider; 3267 3268 divider.setBounds(bounds); 3269 divider.draw(canvas); 3270 } 3271 3272 /** 3273 * Returns the drawable that will be drawn between each item in the list. 3274 * 3275 * @return the current drawable drawn between list elements 3276 */ 3277 public Drawable getDivider() { 3278 return mDivider; 3279 } 3280 3281 /** 3282 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3283 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3284 * 3285 * @param divider The drawable to use. 3286 */ 3287 public void setDivider(Drawable divider) { 3288 if (divider != null) { 3289 mDividerHeight = divider.getIntrinsicHeight(); 3290 } else { 3291 mDividerHeight = 0; 3292 } 3293 mDivider = divider; 3294 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3295 requestLayout(); 3296 invalidate(); 3297 } 3298 3299 /** 3300 * @return Returns the height of the divider that will be drawn between each item in the list. 3301 */ 3302 public int getDividerHeight() { 3303 return mDividerHeight; 3304 } 3305 3306 /** 3307 * Sets the height of the divider that will be drawn between each item in the list. Calling 3308 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3309 * 3310 * @param height The new height of the divider in pixels. 3311 */ 3312 public void setDividerHeight(int height) { 3313 mDividerHeight = height; 3314 requestLayout(); 3315 invalidate(); 3316 } 3317 3318 /** 3319 * Enables or disables the drawing of the divider for header views. 3320 * 3321 * @param headerDividersEnabled True to draw the headers, false otherwise. 3322 * 3323 * @see #setFooterDividersEnabled(boolean) 3324 * @see #addHeaderView(android.view.View) 3325 */ 3326 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3327 mHeaderDividersEnabled = headerDividersEnabled; 3328 invalidate(); 3329 } 3330 3331 /** 3332 * Enables or disables the drawing of the divider for footer views. 3333 * 3334 * @param footerDividersEnabled True to draw the footers, false otherwise. 3335 * 3336 * @see #setHeaderDividersEnabled(boolean) 3337 * @see #addFooterView(android.view.View) 3338 */ 3339 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3340 mFooterDividersEnabled = footerDividersEnabled; 3341 invalidate(); 3342 } 3343 3344 /** 3345 * Sets the drawable that will be drawn above all other list content. 3346 * This area can become visible when the user overscrolls the list. 3347 * 3348 * @param header The drawable to use 3349 */ 3350 public void setOverscrollHeader(Drawable header) { 3351 mOverScrollHeader = header; 3352 if (mScrollY < 0) { 3353 invalidate(); 3354 } 3355 } 3356 3357 /** 3358 * @return The drawable that will be drawn above all other list content 3359 */ 3360 public Drawable getOverscrollHeader() { 3361 return mOverScrollHeader; 3362 } 3363 3364 /** 3365 * Sets the drawable that will be drawn below all other list content. 3366 * This area can become visible when the user overscrolls the list, 3367 * or when the list's content does not fully fill the container area. 3368 * 3369 * @param footer The drawable to use 3370 */ 3371 public void setOverscrollFooter(Drawable footer) { 3372 mOverScrollFooter = footer; 3373 invalidate(); 3374 } 3375 3376 /** 3377 * @return The drawable that will be drawn below all other list content 3378 */ 3379 public Drawable getOverscrollFooter() { 3380 return mOverScrollFooter; 3381 } 3382 3383 @Override 3384 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3385 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3386 3387 int closetChildIndex = -1; 3388 if (gainFocus && previouslyFocusedRect != null) { 3389 previouslyFocusedRect.offset(mScrollX, mScrollY); 3390 3391 final ListAdapter adapter = mAdapter; 3392 // Don't cache the result of getChildCount or mFirstPosition here, 3393 // it could change in layoutChildren. 3394 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3395 mLayoutMode = LAYOUT_NORMAL; 3396 layoutChildren(); 3397 } 3398 3399 // figure out which item should be selected based on previously 3400 // focused rect 3401 Rect otherRect = mTempRect; 3402 int minDistance = Integer.MAX_VALUE; 3403 final int childCount = getChildCount(); 3404 final int firstPosition = mFirstPosition; 3405 3406 for (int i = 0; i < childCount; i++) { 3407 // only consider selectable views 3408 if (!adapter.isEnabled(firstPosition + i)) { 3409 continue; 3410 } 3411 3412 View other = getChildAt(i); 3413 other.getDrawingRect(otherRect); 3414 offsetDescendantRectToMyCoords(other, otherRect); 3415 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3416 3417 if (distance < minDistance) { 3418 minDistance = distance; 3419 closetChildIndex = i; 3420 } 3421 } 3422 } 3423 3424 if (closetChildIndex >= 0) { 3425 setSelection(closetChildIndex + mFirstPosition); 3426 } else { 3427 requestLayout(); 3428 } 3429 } 3430 3431 3432 /* 3433 * (non-Javadoc) 3434 * 3435 * Children specified in XML are assumed to be header views. After we have 3436 * parsed them move them out of the children list and into mHeaderViews. 3437 */ 3438 @Override 3439 protected void onFinishInflate() { 3440 super.onFinishInflate(); 3441 3442 int count = getChildCount(); 3443 if (count > 0) { 3444 for (int i = 0; i < count; ++i) { 3445 addHeaderView(getChildAt(i)); 3446 } 3447 removeAllViews(); 3448 } 3449 } 3450 3451 /* (non-Javadoc) 3452 * @see android.view.View#findViewById(int) 3453 * First look in our children, then in any header and footer views that may be scrolled off. 3454 */ 3455 @Override 3456 protected View findViewTraversal(int id) { 3457 View v; 3458 v = super.findViewTraversal(id); 3459 if (v == null) { 3460 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3461 if (v != null) { 3462 return v; 3463 } 3464 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3465 if (v != null) { 3466 return v; 3467 } 3468 } 3469 return v; 3470 } 3471 3472 /* (non-Javadoc) 3473 * 3474 * Look in the passed in list of headers or footers for the view. 3475 */ 3476 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3477 if (where != null) { 3478 int len = where.size(); 3479 View v; 3480 3481 for (int i = 0; i < len; i++) { 3482 v = where.get(i).view; 3483 3484 if (!v.isRootNamespace()) { 3485 v = v.findViewById(id); 3486 3487 if (v != null) { 3488 return v; 3489 } 3490 } 3491 } 3492 } 3493 return null; 3494 } 3495 3496 /* (non-Javadoc) 3497 * @see android.view.View#findViewWithTag(Object) 3498 * First look in our children, then in any header and footer views that may be scrolled off. 3499 */ 3500 @Override 3501 protected View findViewWithTagTraversal(Object tag) { 3502 View v; 3503 v = super.findViewWithTagTraversal(tag); 3504 if (v == null) { 3505 v = findViewWithTagInHeadersOrFooters(mHeaderViewInfos, tag); 3506 if (v != null) { 3507 return v; 3508 } 3509 3510 v = findViewWithTagInHeadersOrFooters(mFooterViewInfos, tag); 3511 if (v != null) { 3512 return v; 3513 } 3514 } 3515 return v; 3516 } 3517 3518 /* (non-Javadoc) 3519 * 3520 * Look in the passed in list of headers or footers for the view with the tag. 3521 */ 3522 View findViewWithTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3523 if (where != null) { 3524 int len = where.size(); 3525 View v; 3526 3527 for (int i = 0; i < len; i++) { 3528 v = where.get(i).view; 3529 3530 if (!v.isRootNamespace()) { 3531 v = v.findViewWithTag(tag); 3532 3533 if (v != null) { 3534 return v; 3535 } 3536 } 3537 } 3538 } 3539 return null; 3540 } 3541 3542 /** 3543 * @hide 3544 * @see android.view.View#findViewByPredicate(Predicate) 3545 * First look in our children, then in any header and footer views that may be scrolled off. 3546 */ 3547 @Override 3548 protected View findViewByPredicateTraversal(Predicate<View> predicate) { 3549 View v; 3550 v = super.findViewByPredicateTraversal(predicate); 3551 if (v == null) { 3552 v = findViewByPredicateInHeadersOrFooters(mHeaderViewInfos, predicate); 3553 if (v != null) { 3554 return v; 3555 } 3556 3557 v = findViewByPredicateInHeadersOrFooters(mFooterViewInfos, predicate); 3558 if (v != null) { 3559 return v; 3560 } 3561 } 3562 return v; 3563 } 3564 3565 /* (non-Javadoc) 3566 * 3567 * Look in the passed in list of headers or footers for the first view that matches 3568 * the predicate. 3569 */ 3570 View findViewByPredicateInHeadersOrFooters(ArrayList<FixedViewInfo> where, 3571 Predicate<View> predicate) { 3572 if (where != null) { 3573 int len = where.size(); 3574 View v; 3575 3576 for (int i = 0; i < len; i++) { 3577 v = where.get(i).view; 3578 3579 if (!v.isRootNamespace()) { 3580 v = v.findViewByPredicate(predicate); 3581 3582 if (v != null) { 3583 return v; 3584 } 3585 } 3586 } 3587 } 3588 return null; 3589 } 3590 3591 /** 3592 * Returns the set of checked items ids. The result is only valid if the 3593 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3594 * 3595 * @return A new array which contains the id of each checked item in the 3596 * list. 3597 * 3598 * @deprecated Use {@link #getCheckedItemIds()} instead. 3599 */ 3600 @Deprecated 3601 public long[] getCheckItemIds() { 3602 // Use new behavior that correctly handles stable ID mapping. 3603 if (mAdapter != null && mAdapter.hasStableIds()) { 3604 return getCheckedItemIds(); 3605 } 3606 3607 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3608 // Fall back to it to support legacy apps. 3609 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3610 final SparseBooleanArray states = mCheckStates; 3611 final int count = states.size(); 3612 final long[] ids = new long[count]; 3613 final ListAdapter adapter = mAdapter; 3614 3615 int checkedCount = 0; 3616 for (int i = 0; i < count; i++) { 3617 if (states.valueAt(i)) { 3618 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3619 } 3620 } 3621 3622 // Trim array if needed. mCheckStates may contain false values 3623 // resulting in checkedCount being smaller than count. 3624 if (checkedCount == count) { 3625 return ids; 3626 } else { 3627 final long[] result = new long[checkedCount]; 3628 System.arraycopy(ids, 0, result, 0, checkedCount); 3629 3630 return result; 3631 } 3632 } 3633 return new long[0]; 3634 } 3635} 3636