ListView.java revision f343e1ba7e796120eefa917dbf78348feea98e11
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.google.android.collect.Lists; 21 22import android.content.Context; 23import android.content.Intent; 24import android.content.res.TypedArray; 25import android.graphics.Canvas; 26import android.graphics.Paint; 27import android.graphics.PixelFormat; 28import android.graphics.Rect; 29import android.graphics.drawable.ColorDrawable; 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 * @attr ref android.R.styleable#ListView_entries 61 * @attr ref android.R.styleable#ListView_divider 62 * @attr ref android.R.styleable#ListView_dividerHeight 63 * @attr ref android.R.styleable#ListView_headerDividersEnabled 64 * @attr ref android.R.styleable#ListView_footerDividersEnabled 65 */ 66@RemoteView 67public class ListView extends AbsListView { 68 /** 69 * Used to indicate a no preference for a position type. 70 */ 71 static final int NO_POSITION = -1; 72 73 /** 74 * When arrow scrolling, ListView will never scroll more than this factor 75 * times the height of the list. 76 */ 77 private static final float MAX_SCROLL_FACTOR = 0.33f; 78 79 /** 80 * When arrow scrolling, need a certain amount of pixels to preview next 81 * items. This is usually the fading edge, but if that is small enough, 82 * we want to make sure we preview at least this many pixels. 83 */ 84 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 85 86 /** 87 * A class that represents a fixed view in a list, for example a header at the top 88 * or a footer at the bottom. 89 */ 90 public class FixedViewInfo { 91 /** The view to add to the list */ 92 public View view; 93 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 94 public Object data; 95 /** <code>true</code> if the fixed view should be selectable in the list */ 96 public boolean isSelectable; 97 } 98 99 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 100 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 101 102 Drawable mDivider; 103 int mDividerHeight; 104 105 private boolean mIsCacheColorOpaque; 106 private boolean mDividerIsOpaque; 107 private boolean mClipDivider; 108 109 private boolean mHeaderDividersEnabled; 110 private boolean mFooterDividersEnabled; 111 112 private boolean mAreAllItemsSelectable = true; 113 114 private boolean mItemsCanFocus = false; 115 116 // used for temporary calculations. 117 private final Rect mTempRect = new Rect(); 118 private Paint mDividerPaint; 119 120 // the single allocated result per list view; kinda cheesey but avoids 121 // allocating these thingies too often. 122 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 123 124 // Keeps focused children visible through resizes 125 private FocusSelector mFocusSelector; 126 127 public ListView(Context context) { 128 this(context, null); 129 } 130 131 public ListView(Context context, AttributeSet attrs) { 132 this(context, attrs, com.android.internal.R.attr.listViewStyle); 133 } 134 135 public ListView(Context context, AttributeSet attrs, int defStyle) { 136 super(context, attrs, defStyle); 137 138 TypedArray a = context.obtainStyledAttributes(attrs, 139 com.android.internal.R.styleable.ListView, defStyle, 0); 140 141 CharSequence[] entries = a.getTextArray( 142 com.android.internal.R.styleable.ListView_entries); 143 if (entries != null) { 144 setAdapter(new ArrayAdapter<CharSequence>(context, 145 com.android.internal.R.layout.simple_list_item_1, entries)); 146 } 147 148 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 149 if (d != null) { 150 // If a divider is specified use its intrinsic height for divider height 151 setDivider(d); 152 } 153 154 // Use the height specified, zero being the default 155 final int dividerHeight = a.getDimensionPixelSize( 156 com.android.internal.R.styleable.ListView_dividerHeight, 0); 157 if (dividerHeight != 0) { 158 setDividerHeight(dividerHeight); 159 } 160 161 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 162 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 163 164 a.recycle(); 165 } 166 167 /** 168 * @return The maximum amount a list view will scroll in response to 169 * an arrow event. 170 */ 171 public int getMaxScrollAmount() { 172 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 173 } 174 175 /** 176 * Make sure views are touching the top or bottom edge, as appropriate for 177 * our gravity 178 */ 179 private void adjustViewsUpOrDown() { 180 final int childCount = getChildCount(); 181 int delta; 182 183 if (childCount > 0) { 184 View child; 185 186 if (!mStackFromBottom) { 187 // Uh-oh -- we came up short. Slide all views up to make them 188 // align with the top 189 child = getChildAt(0); 190 delta = child.getTop() - mListPadding.top; 191 if (mFirstPosition != 0) { 192 // It's OK to have some space above the first item if it is 193 // part of the vertical spacing 194 delta -= mDividerHeight; 195 } 196 if (delta < 0) { 197 // We only are looking to see if we are too low, not too high 198 delta = 0; 199 } 200 } else { 201 // we are too high, slide all views down to align with bottom 202 child = getChildAt(childCount - 1); 203 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 204 205 if (mFirstPosition + childCount < mItemCount) { 206 // It's OK to have some space below the last item if it is 207 // part of the vertical spacing 208 delta += mDividerHeight; 209 } 210 211 if (delta > 0) { 212 delta = 0; 213 } 214 } 215 216 if (delta != 0) { 217 offsetChildrenTopAndBottom(-delta); 218 } 219 } 220 } 221 222 /** 223 * Add a fixed view to appear at the top of the list. If addHeaderView is 224 * called more than once, the views will appear in the order they were 225 * added. Views added using this call can take focus if they want. 226 * <p> 227 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 228 * the supplied cursor with one that will also account for header and footer 229 * views. 230 * 231 * @param v The view to add. 232 * @param data Data to associate with this view 233 * @param isSelectable whether the item is selectable 234 */ 235 public void addHeaderView(View v, Object data, boolean isSelectable) { 236 237 if (mAdapter != null) { 238 throw new IllegalStateException( 239 "Cannot add header view to list -- setAdapter has already been called."); 240 } 241 242 FixedViewInfo info = new FixedViewInfo(); 243 info.view = v; 244 info.data = data; 245 info.isSelectable = isSelectable; 246 mHeaderViewInfos.add(info); 247 } 248 249 /** 250 * Add a fixed view to appear at the top of the list. If addHeaderView is 251 * called more than once, the views will appear in the order they were 252 * added. Views added using this call can take focus if they want. 253 * <p> 254 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 255 * the supplied cursor with one that will also account for header and footer 256 * views. 257 * 258 * @param v The view to add. 259 */ 260 public void addHeaderView(View v) { 261 addHeaderView(v, null, true); 262 } 263 264 @Override 265 public int getHeaderViewsCount() { 266 return mHeaderViewInfos.size(); 267 } 268 269 /** 270 * Removes a previously-added header view. 271 * 272 * @param v The view to remove 273 * @return true if the view was removed, false if the view was not a header 274 * view 275 */ 276 public boolean removeHeaderView(View v) { 277 if (mHeaderViewInfos.size() > 0) { 278 boolean result = false; 279 if (((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 280 mDataSetObserver.onChanged(); 281 result = true; 282 } 283 removeFixedViewInfo(v, mHeaderViewInfos); 284 return result; 285 } 286 return false; 287 } 288 289 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 290 int len = where.size(); 291 for (int i = 0; i < len; ++i) { 292 FixedViewInfo info = where.get(i); 293 if (info.view == v) { 294 where.remove(i); 295 break; 296 } 297 } 298 } 299 300 /** 301 * Add a fixed view to appear at the bottom of the list. If addFooterView is 302 * called more than once, the views will appear in the order they were 303 * added. Views added using this call can take focus if they want. 304 * <p> 305 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 306 * the supplied cursor with one that will also account for header and footer 307 * views. 308 * 309 * @param v The view to add. 310 * @param data Data to associate with this view 311 * @param isSelectable true if the footer view can be selected 312 */ 313 public void addFooterView(View v, Object data, boolean isSelectable) { 314 FixedViewInfo info = new FixedViewInfo(); 315 info.view = v; 316 info.data = data; 317 info.isSelectable = isSelectable; 318 mFooterViewInfos.add(info); 319 320 // in the case of re-adding a footer view, or adding one later on, 321 // we need to notify the observer 322 if (mDataSetObserver != null) { 323 mDataSetObserver.onChanged(); 324 } 325 } 326 327 /** 328 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 329 * than once, the views will appear in the order they were added. Views added using 330 * this call can take focus if they want. 331 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 332 * cursor with one that will also account for header and footer views. 333 * 334 * 335 * @param v The view to add. 336 */ 337 public void addFooterView(View v) { 338 addFooterView(v, null, true); 339 } 340 341 @Override 342 public int getFooterViewsCount() { 343 return mFooterViewInfos.size(); 344 } 345 346 /** 347 * Removes a previously-added footer view. 348 * 349 * @param v The view to remove 350 * @return 351 * true if the view was removed, false if the view was not a footer view 352 */ 353 public boolean removeFooterView(View v) { 354 if (mFooterViewInfos.size() > 0) { 355 boolean result = false; 356 if (((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 357 mDataSetObserver.onChanged(); 358 result = true; 359 } 360 removeFixedViewInfo(v, mFooterViewInfos); 361 return result; 362 } 363 return false; 364 } 365 366 /** 367 * Returns the adapter currently in use in this ListView. The returned adapter 368 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 369 * might be a {@link WrapperListAdapter}. 370 * 371 * @return The adapter currently used to display data in this ListView. 372 * 373 * @see #setAdapter(ListAdapter) 374 */ 375 @Override 376 public ListAdapter getAdapter() { 377 return mAdapter; 378 } 379 380 /** 381 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 382 * through the specified intent. 383 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 384 */ 385 @android.view.RemotableViewMethod 386 public void setRemoteViewsAdapter(Intent intent) { 387 super.setRemoteViewsAdapter(intent); 388 } 389 390 /** 391 * Sets the data behind this ListView. 392 * 393 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 394 * depending on the ListView features currently in use. For instance, adding 395 * headers and/or footers will cause the adapter to be wrapped. 396 * 397 * @param adapter The ListAdapter which is responsible for maintaining the 398 * data backing this list and for producing a view to represent an 399 * item in that data set. 400 * 401 * @see #getAdapter() 402 */ 403 @Override 404 public void setAdapter(ListAdapter adapter) { 405 if (mAdapter != null && mDataSetObserver != null) { 406 mAdapter.unregisterDataSetObserver(mDataSetObserver); 407 } 408 409 resetList(); 410 mRecycler.clear(); 411 412 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 413 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 414 } else { 415 mAdapter = adapter; 416 } 417 418 mOldSelectedPosition = INVALID_POSITION; 419 mOldSelectedRowId = INVALID_ROW_ID; 420 421 // AbsListView#setAdapter will update choice mode states. 422 super.setAdapter(adapter); 423 424 if (mAdapter != null) { 425 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 426 mOldItemCount = mItemCount; 427 mItemCount = mAdapter.getCount(); 428 checkFocus(); 429 430 mDataSetObserver = new AdapterDataSetObserver(); 431 mAdapter.registerDataSetObserver(mDataSetObserver); 432 433 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 434 435 int position; 436 if (mStackFromBottom) { 437 position = lookForSelectablePosition(mItemCount - 1, false); 438 } else { 439 position = lookForSelectablePosition(0, true); 440 } 441 setSelectedPositionInt(position); 442 setNextSelectedPositionInt(position); 443 444 if (mItemCount == 0) { 445 // Nothing selected 446 checkSelectionChanged(); 447 } 448 } else { 449 mAreAllItemsSelectable = true; 450 checkFocus(); 451 // Nothing selected 452 checkSelectionChanged(); 453 } 454 455 requestLayout(); 456 } 457 458 459 /** 460 * The list is empty. Clear everything out. 461 */ 462 @Override 463 void resetList() { 464 // The parent's resetList() will remove all views from the layout so we need to 465 // cleanup the state of our footers and headers 466 clearRecycledState(mHeaderViewInfos); 467 clearRecycledState(mFooterViewInfos); 468 469 super.resetList(); 470 471 mLayoutMode = LAYOUT_NORMAL; 472 } 473 474 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 475 if (infos != null) { 476 final int count = infos.size(); 477 478 for (int i = 0; i < count; i++) { 479 final View child = infos.get(i).view; 480 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 481 if (p != null) { 482 p.recycledHeaderFooter = false; 483 } 484 } 485 } 486 } 487 488 /** 489 * @return Whether the list needs to show the top fading edge 490 */ 491 private boolean showingTopFadingEdge() { 492 final int listTop = mScrollY + mListPadding.top; 493 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 494 } 495 496 /** 497 * @return Whether the list needs to show the bottom fading edge 498 */ 499 private boolean showingBottomFadingEdge() { 500 final int childCount = getChildCount(); 501 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 502 final int lastVisiblePosition = mFirstPosition + childCount - 1; 503 504 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 505 506 return (lastVisiblePosition < mItemCount - 1) 507 || (bottomOfBottomChild < listBottom); 508 } 509 510 511 @Override 512 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 513 514 int rectTopWithinChild = rect.top; 515 516 // offset so rect is in coordinates of the this view 517 rect.offset(child.getLeft(), child.getTop()); 518 rect.offset(-child.getScrollX(), -child.getScrollY()); 519 520 final int height = getHeight(); 521 int listUnfadedTop = getScrollY(); 522 int listUnfadedBottom = listUnfadedTop + height; 523 final int fadingEdge = getVerticalFadingEdgeLength(); 524 525 if (showingTopFadingEdge()) { 526 // leave room for top fading edge as long as rect isn't at very top 527 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 528 listUnfadedTop += fadingEdge; 529 } 530 } 531 532 int childCount = getChildCount(); 533 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 534 535 if (showingBottomFadingEdge()) { 536 // leave room for bottom fading edge as long as rect isn't at very bottom 537 if ((mSelectedPosition < mItemCount - 1) 538 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 539 listUnfadedBottom -= fadingEdge; 540 } 541 } 542 543 int scrollYDelta = 0; 544 545 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 546 // need to MOVE DOWN to get it in view: move down just enough so 547 // that the entire rectangle is in view (or at least the first 548 // screen size chunk). 549 550 if (rect.height() > height) { 551 // just enough to get screen size chunk on 552 scrollYDelta += (rect.top - listUnfadedTop); 553 } else { 554 // get entire rect at bottom of screen 555 scrollYDelta += (rect.bottom - listUnfadedBottom); 556 } 557 558 // make sure we aren't scrolling beyond the end of our children 559 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 560 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 561 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 562 // need to MOVE UP to get it in view: move up just enough so that 563 // entire rectangle is in view (or at least the first screen 564 // size chunk of it). 565 566 if (rect.height() > height) { 567 // screen size chunk 568 scrollYDelta -= (listUnfadedBottom - rect.bottom); 569 } else { 570 // entire rect at top 571 scrollYDelta -= (listUnfadedTop - rect.top); 572 } 573 574 // make sure we aren't scrolling any further than the top our children 575 int top = getChildAt(0).getTop(); 576 int deltaToTop = top - listUnfadedTop; 577 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 578 } 579 580 final boolean scroll = scrollYDelta != 0; 581 if (scroll) { 582 scrollListItemsBy(-scrollYDelta); 583 positionSelector(child); 584 mSelectedTop = child.getTop(); 585 invalidate(); 586 } 587 return scroll; 588 } 589 590 /** 591 * {@inheritDoc} 592 */ 593 @Override 594 void fillGap(boolean down) { 595 final int count = getChildCount(); 596 if (down) { 597 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 598 getListPaddingTop(); 599 fillDown(mFirstPosition + count, startOffset); 600 correctTooHigh(getChildCount()); 601 } else { 602 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 603 getHeight() - getListPaddingBottom(); 604 fillUp(mFirstPosition - 1, startOffset); 605 correctTooLow(getChildCount()); 606 } 607 } 608 609 /** 610 * Fills the list from pos down to the end of the list view. 611 * 612 * @param pos The first position to put in the list 613 * 614 * @param nextTop The location where the top of the item associated with pos 615 * should be drawn 616 * 617 * @return The view that is currently selected, if it happens to be in the 618 * range that we draw. 619 */ 620 private View fillDown(int pos, int nextTop) { 621 View selectedView = null; 622 623 int end = (mBottom - mTop) - mListPadding.bottom; 624 625 while (nextTop < end && pos < mItemCount) { 626 // is this the selected item? 627 boolean selected = pos == mSelectedPosition; 628 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 629 630 nextTop = child.getBottom() + mDividerHeight; 631 if (selected) { 632 selectedView = child; 633 } 634 pos++; 635 } 636 637 return selectedView; 638 } 639 640 /** 641 * Fills the list from pos up to the top of the list view. 642 * 643 * @param pos The first position to put in the list 644 * 645 * @param nextBottom The location where the bottom of the item associated 646 * with pos should be drawn 647 * 648 * @return The view that is currently selected 649 */ 650 private View fillUp(int pos, int nextBottom) { 651 View selectedView = null; 652 653 int end = mListPadding.top; 654 655 while (nextBottom > end && pos >= 0) { 656 // is this the selected item? 657 boolean selected = pos == mSelectedPosition; 658 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 659 nextBottom = child.getTop() - mDividerHeight; 660 if (selected) { 661 selectedView = child; 662 } 663 pos--; 664 } 665 666 mFirstPosition = pos + 1; 667 668 return selectedView; 669 } 670 671 /** 672 * Fills the list from top to bottom, starting with mFirstPosition 673 * 674 * @param nextTop The location where the top of the first item should be 675 * drawn 676 * 677 * @return The view that is currently selected 678 */ 679 private View fillFromTop(int nextTop) { 680 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 681 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 682 if (mFirstPosition < 0) { 683 mFirstPosition = 0; 684 } 685 return fillDown(mFirstPosition, nextTop); 686 } 687 688 689 /** 690 * Put mSelectedPosition in the middle of the screen and then build up and 691 * down from there. This method forces mSelectedPosition to the center. 692 * 693 * @param childrenTop Top of the area in which children can be drawn, as 694 * measured in pixels 695 * @param childrenBottom Bottom of the area in which children can be drawn, 696 * as measured in pixels 697 * @return Currently selected view 698 */ 699 private View fillFromMiddle(int childrenTop, int childrenBottom) { 700 int height = childrenBottom - childrenTop; 701 702 int position = reconcileSelectedPosition(); 703 704 View sel = makeAndAddView(position, childrenTop, true, 705 mListPadding.left, true); 706 mFirstPosition = position; 707 708 int selHeight = sel.getMeasuredHeight(); 709 if (selHeight <= height) { 710 sel.offsetTopAndBottom((height - selHeight) / 2); 711 } 712 713 fillAboveAndBelow(sel, position); 714 715 if (!mStackFromBottom) { 716 correctTooHigh(getChildCount()); 717 } else { 718 correctTooLow(getChildCount()); 719 } 720 721 return sel; 722 } 723 724 /** 725 * Once the selected view as been placed, fill up the visible area above and 726 * below it. 727 * 728 * @param sel The selected view 729 * @param position The position corresponding to sel 730 */ 731 private void fillAboveAndBelow(View sel, int position) { 732 final int dividerHeight = mDividerHeight; 733 if (!mStackFromBottom) { 734 fillUp(position - 1, sel.getTop() - dividerHeight); 735 adjustViewsUpOrDown(); 736 fillDown(position + 1, sel.getBottom() + dividerHeight); 737 } else { 738 fillDown(position + 1, sel.getBottom() + dividerHeight); 739 adjustViewsUpOrDown(); 740 fillUp(position - 1, sel.getTop() - dividerHeight); 741 } 742 } 743 744 745 /** 746 * Fills the grid based on positioning the new selection at a specific 747 * location. The selection may be moved so that it does not intersect the 748 * faded edges. The grid is then filled upwards and downwards from there. 749 * 750 * @param selectedTop Where the selected item should be 751 * @param childrenTop Where to start drawing children 752 * @param childrenBottom Last pixel where children can be drawn 753 * @return The view that currently has selection 754 */ 755 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 756 int fadingEdgeLength = getVerticalFadingEdgeLength(); 757 final int selectedPosition = mSelectedPosition; 758 759 View sel; 760 761 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 762 selectedPosition); 763 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 764 selectedPosition); 765 766 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 767 768 769 // Some of the newly selected item extends below the bottom of the list 770 if (sel.getBottom() > bottomSelectionPixel) { 771 // Find space available above the selection into which we can scroll 772 // upwards 773 final int spaceAbove = sel.getTop() - topSelectionPixel; 774 775 // Find space required to bring the bottom of the selected item 776 // fully into view 777 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 778 final int offset = Math.min(spaceAbove, spaceBelow); 779 780 // Now offset the selected item to get it into view 781 sel.offsetTopAndBottom(-offset); 782 } else if (sel.getTop() < topSelectionPixel) { 783 // Find space required to bring the top of the selected item fully 784 // into view 785 final int spaceAbove = topSelectionPixel - sel.getTop(); 786 787 // Find space available below the selection into which we can scroll 788 // downwards 789 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 790 final int offset = Math.min(spaceAbove, spaceBelow); 791 792 // Offset the selected item to get it into view 793 sel.offsetTopAndBottom(offset); 794 } 795 796 // Fill in views above and below 797 fillAboveAndBelow(sel, selectedPosition); 798 799 if (!mStackFromBottom) { 800 correctTooHigh(getChildCount()); 801 } else { 802 correctTooLow(getChildCount()); 803 } 804 805 return sel; 806 } 807 808 /** 809 * Calculate the bottom-most pixel we can draw the selection into 810 * 811 * @param childrenBottom Bottom pixel were children can be drawn 812 * @param fadingEdgeLength Length of the fading edge in pixels, if present 813 * @param selectedPosition The position that will be selected 814 * @return The bottom-most pixel we can draw the selection into 815 */ 816 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 817 int selectedPosition) { 818 int bottomSelectionPixel = childrenBottom; 819 if (selectedPosition != mItemCount - 1) { 820 bottomSelectionPixel -= fadingEdgeLength; 821 } 822 return bottomSelectionPixel; 823 } 824 825 /** 826 * Calculate the top-most pixel we can draw the selection into 827 * 828 * @param childrenTop Top pixel were children can be drawn 829 * @param fadingEdgeLength Length of the fading edge in pixels, if present 830 * @param selectedPosition The position that will be selected 831 * @return The top-most pixel we can draw the selection into 832 */ 833 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 834 // first pixel we can draw the selection into 835 int topSelectionPixel = childrenTop; 836 if (selectedPosition > 0) { 837 topSelectionPixel += fadingEdgeLength; 838 } 839 return topSelectionPixel; 840 } 841 842 /** 843 * Smoothly scroll to the specified adapter position. The view will 844 * scroll such that the indicated position is displayed. 845 * @param position Scroll to this adapter position. 846 */ 847 @android.view.RemotableViewMethod 848 public void smoothScrollToPosition(int position) { 849 super.smoothScrollToPosition(position); 850 } 851 852 /** 853 * Smoothly scroll to the specified adapter position offset. The view will 854 * scroll such that the indicated position is displayed. 855 * @param offset The amount to offset from the adapter position to scroll to. 856 */ 857 @android.view.RemotableViewMethod 858 public void smoothScrollByOffset(int offset) { 859 super.smoothScrollByOffset(offset); 860 } 861 862 /** 863 * Fills the list based on positioning the new selection relative to the old 864 * selection. The new selection will be placed at, above, or below the 865 * location of the new selection depending on how the selection is moving. 866 * The selection will then be pinned to the visible part of the screen, 867 * excluding the edges that are faded. The list is then filled upwards and 868 * downwards from there. 869 * 870 * @param oldSel The old selected view. Useful for trying to put the new 871 * selection in the same place 872 * @param newSel The view that is to become selected. Useful for trying to 873 * put the new selection in the same place 874 * @param delta Which way we are moving 875 * @param childrenTop Where to start drawing children 876 * @param childrenBottom Last pixel where children can be drawn 877 * @return The view that currently has selection 878 */ 879 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 880 int childrenBottom) { 881 int fadingEdgeLength = getVerticalFadingEdgeLength(); 882 final int selectedPosition = mSelectedPosition; 883 884 View sel; 885 886 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 887 selectedPosition); 888 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 889 selectedPosition); 890 891 if (delta > 0) { 892 /* 893 * Case 1: Scrolling down. 894 */ 895 896 /* 897 * Before After 898 * | | | | 899 * +-------+ +-------+ 900 * | A | | A | 901 * | 1 | => +-------+ 902 * +-------+ | B | 903 * | B | | 2 | 904 * +-------+ +-------+ 905 * | | | | 906 * 907 * Try to keep the top of the previously selected item where it was. 908 * oldSel = A 909 * sel = B 910 */ 911 912 // Put oldSel (A) where it belongs 913 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 914 mListPadding.left, false); 915 916 final int dividerHeight = mDividerHeight; 917 918 // Now put the new selection (B) below that 919 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 920 mListPadding.left, true); 921 922 // Some of the newly selected item extends below the bottom of the list 923 if (sel.getBottom() > bottomSelectionPixel) { 924 925 // Find space available above the selection into which we can scroll upwards 926 int spaceAbove = sel.getTop() - topSelectionPixel; 927 928 // Find space required to bring the bottom of the selected item fully into view 929 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 930 931 // Don't scroll more than half the height of the list 932 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 933 int offset = Math.min(spaceAbove, spaceBelow); 934 offset = Math.min(offset, halfVerticalSpace); 935 936 // We placed oldSel, so offset that item 937 oldSel.offsetTopAndBottom(-offset); 938 // Now offset the selected item to get it into view 939 sel.offsetTopAndBottom(-offset); 940 } 941 942 // Fill in views above and below 943 if (!mStackFromBottom) { 944 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 945 adjustViewsUpOrDown(); 946 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 947 } else { 948 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 949 adjustViewsUpOrDown(); 950 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 951 } 952 } else if (delta < 0) { 953 /* 954 * Case 2: Scrolling up. 955 */ 956 957 /* 958 * Before After 959 * | | | | 960 * +-------+ +-------+ 961 * | A | | A | 962 * +-------+ => | 1 | 963 * | B | +-------+ 964 * | 2 | | B | 965 * +-------+ +-------+ 966 * | | | | 967 * 968 * Try to keep the top of the item about to become selected where it was. 969 * newSel = A 970 * olSel = B 971 */ 972 973 if (newSel != null) { 974 // Try to position the top of newSel (A) where it was before it was selected 975 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 976 true); 977 } else { 978 // If (A) was not on screen and so did not have a view, position 979 // it above the oldSel (B) 980 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 981 true); 982 } 983 984 // Some of the newly selected item extends above the top of the list 985 if (sel.getTop() < topSelectionPixel) { 986 // Find space required to bring the top of the selected item fully into view 987 int spaceAbove = topSelectionPixel - sel.getTop(); 988 989 // Find space available below the selection into which we can scroll downwards 990 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 991 992 // Don't scroll more than half the height of the list 993 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 994 int offset = Math.min(spaceAbove, spaceBelow); 995 offset = Math.min(offset, halfVerticalSpace); 996 997 // Offset the selected item to get it into view 998 sel.offsetTopAndBottom(offset); 999 } 1000 1001 // Fill in views above and below 1002 fillAboveAndBelow(sel, selectedPosition); 1003 } else { 1004 1005 int oldTop = oldSel.getTop(); 1006 1007 /* 1008 * Case 3: Staying still 1009 */ 1010 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1011 1012 // We're staying still... 1013 if (oldTop < childrenTop) { 1014 // ... but the top of the old selection was off screen. 1015 // (This can happen if the data changes size out from under us) 1016 int newBottom = sel.getBottom(); 1017 if (newBottom < childrenTop + 20) { 1018 // Not enough visible -- bring it onscreen 1019 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1020 } 1021 } 1022 1023 // Fill in views above and below 1024 fillAboveAndBelow(sel, selectedPosition); 1025 } 1026 1027 return sel; 1028 } 1029 1030 private class FocusSelector implements Runnable { 1031 private int mPosition; 1032 private int mPositionTop; 1033 1034 public FocusSelector setup(int position, int top) { 1035 mPosition = position; 1036 mPositionTop = top; 1037 return this; 1038 } 1039 1040 public void run() { 1041 setSelectionFromTop(mPosition, mPositionTop); 1042 } 1043 } 1044 1045 @Override 1046 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1047 if (getChildCount() > 0) { 1048 View focusedChild = getFocusedChild(); 1049 if (focusedChild != null) { 1050 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1051 final int childBottom = focusedChild.getBottom(); 1052 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1053 final int top = focusedChild.getTop() - offset; 1054 if (mFocusSelector == null) { 1055 mFocusSelector = new FocusSelector(); 1056 } 1057 post(mFocusSelector.setup(childPosition, top)); 1058 } 1059 } 1060 super.onSizeChanged(w, h, oldw, oldh); 1061 } 1062 1063 @Override 1064 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1065 // Sets up mListPadding 1066 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1067 1068 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1069 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1070 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1071 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1072 1073 int childWidth = 0; 1074 int childHeight = 0; 1075 1076 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1077 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1078 heightMode == MeasureSpec.UNSPECIFIED)) { 1079 final View child = obtainView(0, mIsScrap); 1080 1081 measureScrapChild(child, 0, widthMeasureSpec); 1082 1083 childWidth = child.getMeasuredWidth(); 1084 childHeight = child.getMeasuredHeight(); 1085 1086 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1087 ((LayoutParams) child.getLayoutParams()).viewType)) { 1088 mRecycler.addScrapView(child); 1089 } 1090 } 1091 1092 if (widthMode == MeasureSpec.UNSPECIFIED) { 1093 widthSize = mListPadding.left + mListPadding.right + childWidth + 1094 getVerticalScrollbarWidth(); 1095 } 1096 1097 if (heightMode == MeasureSpec.UNSPECIFIED) { 1098 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1099 getVerticalFadingEdgeLength() * 2; 1100 } 1101 1102 if (heightMode == MeasureSpec.AT_MOST) { 1103 // TODO: after first layout we should maybe start at the first visible position, not 0 1104 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1105 } 1106 1107 setMeasuredDimension(widthSize, heightSize); 1108 mWidthMeasureSpec = widthMeasureSpec; 1109 } 1110 1111 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1112 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1113 if (p == null) { 1114 p = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1115 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1116 child.setLayoutParams(p); 1117 } 1118 p.viewType = mAdapter.getItemViewType(position); 1119 p.forceAdd = true; 1120 1121 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1122 mListPadding.left + mListPadding.right, p.width); 1123 int lpHeight = p.height; 1124 int childHeightSpec; 1125 if (lpHeight > 0) { 1126 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1127 } else { 1128 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1129 } 1130 child.measure(childWidthSpec, childHeightSpec); 1131 } 1132 1133 /** 1134 * @return True to recycle the views used to measure this ListView in 1135 * UNSPECIFIED/AT_MOST modes, false otherwise. 1136 * @hide 1137 */ 1138 @ViewDebug.ExportedProperty(category = "list") 1139 protected boolean recycleOnMeasure() { 1140 return true; 1141 } 1142 1143 /** 1144 * Measures the height of the given range of children (inclusive) and 1145 * returns the height with this ListView's padding and divider heights 1146 * included. If maxHeight is provided, the measuring will stop when the 1147 * current height reaches maxHeight. 1148 * 1149 * @param widthMeasureSpec The width measure spec to be given to a child's 1150 * {@link View#measure(int, int)}. 1151 * @param startPosition The position of the first child to be shown. 1152 * @param endPosition The (inclusive) position of the last child to be 1153 * shown. Specify {@link #NO_POSITION} if the last child should be 1154 * the last available child from the adapter. 1155 * @param maxHeight The maximum height that will be returned (if all the 1156 * children don't fit in this value, this value will be 1157 * returned). 1158 * @param disallowPartialChildPosition In general, whether the returned 1159 * height should only contain entire children. This is more 1160 * powerful--it is the first inclusive position at which partial 1161 * children will not be allowed. Example: it looks nice to have 1162 * at least 3 completely visible children, and in portrait this 1163 * will most likely fit; but in landscape there could be times 1164 * when even 2 children can not be completely shown, so a value 1165 * of 2 (remember, inclusive) would be good (assuming 1166 * startPosition is 0). 1167 * @return The height of this ListView with the given children. 1168 */ 1169 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1170 final int maxHeight, int disallowPartialChildPosition) { 1171 1172 final ListAdapter adapter = mAdapter; 1173 if (adapter == null) { 1174 return mListPadding.top + mListPadding.bottom; 1175 } 1176 1177 // Include the padding of the list 1178 int returnedHeight = mListPadding.top + mListPadding.bottom; 1179 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1180 // The previous height value that was less than maxHeight and contained 1181 // no partial children 1182 int prevHeightWithoutPartialChild = 0; 1183 int i; 1184 View child; 1185 1186 // mItemCount - 1 since endPosition parameter is inclusive 1187 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1188 final AbsListView.RecycleBin recycleBin = mRecycler; 1189 final boolean recyle = recycleOnMeasure(); 1190 final boolean[] isScrap = mIsScrap; 1191 1192 for (i = startPosition; i <= endPosition; ++i) { 1193 child = obtainView(i, isScrap); 1194 1195 measureScrapChild(child, i, widthMeasureSpec); 1196 1197 if (i > 0) { 1198 // Count the divider for all but one child 1199 returnedHeight += dividerHeight; 1200 } 1201 1202 // Recycle the view before we possibly return from the method 1203 if (recyle && recycleBin.shouldRecycleViewType( 1204 ((LayoutParams) child.getLayoutParams()).viewType)) { 1205 recycleBin.addScrapView(child); 1206 } 1207 1208 returnedHeight += child.getMeasuredHeight(); 1209 1210 if (returnedHeight >= maxHeight) { 1211 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1212 // then the i'th position did not fit completely. 1213 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1214 && (i > disallowPartialChildPosition) // We've past the min pos 1215 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1216 && (returnedHeight != maxHeight) // i'th child did not fit completely 1217 ? prevHeightWithoutPartialChild 1218 : maxHeight; 1219 } 1220 1221 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1222 prevHeightWithoutPartialChild = returnedHeight; 1223 } 1224 } 1225 1226 // At this point, we went through the range of children, and they each 1227 // completely fit, so return the returnedHeight 1228 return returnedHeight; 1229 } 1230 1231 @Override 1232 int findMotionRow(int y) { 1233 int childCount = getChildCount(); 1234 if (childCount > 0) { 1235 if (!mStackFromBottom) { 1236 for (int i = 0; i < childCount; i++) { 1237 View v = getChildAt(i); 1238 if (y <= v.getBottom()) { 1239 return mFirstPosition + i; 1240 } 1241 } 1242 } else { 1243 for (int i = childCount - 1; i >= 0; i--) { 1244 View v = getChildAt(i); 1245 if (y >= v.getTop()) { 1246 return mFirstPosition + i; 1247 } 1248 } 1249 } 1250 } 1251 return INVALID_POSITION; 1252 } 1253 1254 /** 1255 * Put a specific item at a specific location on the screen and then build 1256 * up and down from there. 1257 * 1258 * @param position The reference view to use as the starting point 1259 * @param top Pixel offset from the top of this view to the top of the 1260 * reference view. 1261 * 1262 * @return The selected view, or null if the selected view is outside the 1263 * visible area. 1264 */ 1265 private View fillSpecific(int position, int top) { 1266 boolean tempIsSelected = position == mSelectedPosition; 1267 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1268 // Possibly changed again in fillUp if we add rows above this one. 1269 mFirstPosition = position; 1270 1271 View above; 1272 View below; 1273 1274 final int dividerHeight = mDividerHeight; 1275 if (!mStackFromBottom) { 1276 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1277 // This will correct for the top of the first view not touching the top of the list 1278 adjustViewsUpOrDown(); 1279 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1280 int childCount = getChildCount(); 1281 if (childCount > 0) { 1282 correctTooHigh(childCount); 1283 } 1284 } else { 1285 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1286 // This will correct for the bottom of the last view not touching the bottom of the list 1287 adjustViewsUpOrDown(); 1288 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1289 int childCount = getChildCount(); 1290 if (childCount > 0) { 1291 correctTooLow(childCount); 1292 } 1293 } 1294 1295 if (tempIsSelected) { 1296 return temp; 1297 } else if (above != null) { 1298 return above; 1299 } else { 1300 return below; 1301 } 1302 } 1303 1304 /** 1305 * Check if we have dragged the bottom of the list too high (we have pushed the 1306 * top element off the top of the screen when we did not need to). Correct by sliding 1307 * everything back down. 1308 * 1309 * @param childCount Number of children 1310 */ 1311 private void correctTooHigh(int childCount) { 1312 // First see if the last item is visible. If it is not, it is OK for the 1313 // top of the list to be pushed up. 1314 int lastPosition = mFirstPosition + childCount - 1; 1315 if (lastPosition == mItemCount - 1 && childCount > 0) { 1316 1317 // Get the last child ... 1318 final View lastChild = getChildAt(childCount - 1); 1319 1320 // ... and its bottom edge 1321 final int lastBottom = lastChild.getBottom(); 1322 1323 // This is bottom of our drawable area 1324 final int end = (mBottom - mTop) - mListPadding.bottom; 1325 1326 // This is how far the bottom edge of the last view is from the bottom of the 1327 // drawable area 1328 int bottomOffset = end - lastBottom; 1329 View firstChild = getChildAt(0); 1330 final int firstTop = firstChild.getTop(); 1331 1332 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1333 // first row or the first row is scrolled off the top of the drawable area 1334 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1335 if (mFirstPosition == 0) { 1336 // Don't pull the top too far down 1337 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1338 } 1339 // Move everything down 1340 offsetChildrenTopAndBottom(bottomOffset); 1341 if (mFirstPosition > 0) { 1342 // Fill the gap that was opened above mFirstPosition with more rows, if 1343 // possible 1344 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1345 // Close up the remaining gap 1346 adjustViewsUpOrDown(); 1347 } 1348 1349 } 1350 } 1351 } 1352 1353 /** 1354 * Check if we have dragged the bottom of the list too low (we have pushed the 1355 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1356 * everything back up. 1357 * 1358 * @param childCount Number of children 1359 */ 1360 private void correctTooLow(int childCount) { 1361 // First see if the first item is visible. If it is not, it is OK for the 1362 // bottom of the list to be pushed down. 1363 if (mFirstPosition == 0 && childCount > 0) { 1364 1365 // Get the first child ... 1366 final View firstChild = getChildAt(0); 1367 1368 // ... and its top edge 1369 final int firstTop = firstChild.getTop(); 1370 1371 // This is top of our drawable area 1372 final int start = mListPadding.top; 1373 1374 // This is bottom of our drawable area 1375 final int end = (mBottom - mTop) - mListPadding.bottom; 1376 1377 // This is how far the top edge of the first view is from the top of the 1378 // drawable area 1379 int topOffset = firstTop - start; 1380 View lastChild = getChildAt(childCount - 1); 1381 final int lastBottom = lastChild.getBottom(); 1382 int lastPosition = mFirstPosition + childCount - 1; 1383 1384 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1385 // last row or the last row is scrolled off the bottom of the drawable area 1386 if (topOffset > 0) { 1387 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1388 if (lastPosition == mItemCount - 1) { 1389 // Don't pull the bottom too far up 1390 topOffset = Math.min(topOffset, lastBottom - end); 1391 } 1392 // Move everything up 1393 offsetChildrenTopAndBottom(-topOffset); 1394 if (lastPosition < mItemCount - 1) { 1395 // Fill the gap that was opened below the last position with more rows, if 1396 // possible 1397 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1398 // Close up the remaining gap 1399 adjustViewsUpOrDown(); 1400 } 1401 } else if (lastPosition == mItemCount - 1) { 1402 adjustViewsUpOrDown(); 1403 } 1404 } 1405 } 1406 } 1407 1408 @Override 1409 protected void layoutChildren() { 1410 final boolean blockLayoutRequests = mBlockLayoutRequests; 1411 if (!blockLayoutRequests) { 1412 mBlockLayoutRequests = true; 1413 } else { 1414 return; 1415 } 1416 1417 try { 1418 super.layoutChildren(); 1419 1420 invalidate(); 1421 1422 if (mAdapter == null) { 1423 resetList(); 1424 invokeOnItemScrollListener(); 1425 return; 1426 } 1427 1428 int childrenTop = mListPadding.top; 1429 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1430 1431 int childCount = getChildCount(); 1432 int index = 0; 1433 int delta = 0; 1434 1435 View sel; 1436 View oldSel = null; 1437 View oldFirst = null; 1438 View newSel = null; 1439 1440 View focusLayoutRestoreView = null; 1441 1442 // Remember stuff we will need down below 1443 switch (mLayoutMode) { 1444 case LAYOUT_SET_SELECTION: 1445 index = mNextSelectedPosition - mFirstPosition; 1446 if (index >= 0 && index < childCount) { 1447 newSel = getChildAt(index); 1448 } 1449 break; 1450 case LAYOUT_FORCE_TOP: 1451 case LAYOUT_FORCE_BOTTOM: 1452 case LAYOUT_SPECIFIC: 1453 case LAYOUT_SYNC: 1454 break; 1455 case LAYOUT_MOVE_SELECTION: 1456 default: 1457 // Remember the previously selected view 1458 index = mSelectedPosition - mFirstPosition; 1459 if (index >= 0 && index < childCount) { 1460 oldSel = getChildAt(index); 1461 } 1462 1463 // Remember the previous first child 1464 oldFirst = getChildAt(0); 1465 1466 if (mNextSelectedPosition >= 0) { 1467 delta = mNextSelectedPosition - mSelectedPosition; 1468 } 1469 1470 // Caution: newSel might be null 1471 newSel = getChildAt(index + delta); 1472 } 1473 1474 1475 boolean dataChanged = mDataChanged; 1476 if (dataChanged) { 1477 handleDataChanged(); 1478 } 1479 1480 // Handle the empty set by removing all views that are visible 1481 // and calling it a day 1482 if (mItemCount == 0) { 1483 resetList(); 1484 invokeOnItemScrollListener(); 1485 return; 1486 } else if (mItemCount != mAdapter.getCount()) { 1487 throw new IllegalStateException("The content of the adapter has changed but " 1488 + "ListView did not receive a notification. Make sure the content of " 1489 + "your adapter is not modified from a background thread, but only " 1490 + "from the UI thread. [in ListView(" + getId() + ", " + getClass() 1491 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1492 } 1493 1494 setSelectedPositionInt(mNextSelectedPosition); 1495 1496 // Pull all children into the RecycleBin. 1497 // These views will be reused if possible 1498 final int firstPosition = mFirstPosition; 1499 final RecycleBin recycleBin = mRecycler; 1500 1501 // reset the focus restoration 1502 View focusLayoutRestoreDirectChild = null; 1503 1504 1505 // Don't put header or footer views into the Recycler. Those are 1506 // already cached in mHeaderViews; 1507 if (dataChanged) { 1508 for (int i = 0; i < childCount; i++) { 1509 recycleBin.addScrapView(getChildAt(i)); 1510 if (ViewDebug.TRACE_RECYCLER) { 1511 ViewDebug.trace(getChildAt(i), 1512 ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i); 1513 } 1514 } 1515 } else { 1516 recycleBin.fillActiveViews(childCount, firstPosition); 1517 } 1518 1519 // take focus back to us temporarily to avoid the eventual 1520 // call to clear focus when removing the focused child below 1521 // from messing things up when ViewRoot assigns focus back 1522 // to someone else 1523 final View focusedChild = getFocusedChild(); 1524 if (focusedChild != null) { 1525 // TODO: in some cases focusedChild.getParent() == null 1526 1527 // we can remember the focused view to restore after relayout if the 1528 // data hasn't changed, or if the focused position is a header or footer 1529 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1530 focusLayoutRestoreDirectChild = focusedChild; 1531 // remember the specific view that had focus 1532 focusLayoutRestoreView = findFocus(); 1533 if (focusLayoutRestoreView != null) { 1534 // tell it we are going to mess with it 1535 focusLayoutRestoreView.onStartTemporaryDetach(); 1536 } 1537 } 1538 requestFocus(); 1539 } 1540 1541 // Clear out old views 1542 detachAllViewsFromParent(); 1543 1544 switch (mLayoutMode) { 1545 case LAYOUT_SET_SELECTION: 1546 if (newSel != null) { 1547 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1548 } else { 1549 sel = fillFromMiddle(childrenTop, childrenBottom); 1550 } 1551 break; 1552 case LAYOUT_SYNC: 1553 sel = fillSpecific(mSyncPosition, mSpecificTop); 1554 break; 1555 case LAYOUT_FORCE_BOTTOM: 1556 sel = fillUp(mItemCount - 1, childrenBottom); 1557 adjustViewsUpOrDown(); 1558 break; 1559 case LAYOUT_FORCE_TOP: 1560 mFirstPosition = 0; 1561 sel = fillFromTop(childrenTop); 1562 adjustViewsUpOrDown(); 1563 break; 1564 case LAYOUT_SPECIFIC: 1565 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1566 break; 1567 case LAYOUT_MOVE_SELECTION: 1568 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1569 break; 1570 default: 1571 if (childCount == 0) { 1572 if (!mStackFromBottom) { 1573 final int position = lookForSelectablePosition(0, true); 1574 setSelectedPositionInt(position); 1575 sel = fillFromTop(childrenTop); 1576 } else { 1577 final int position = lookForSelectablePosition(mItemCount - 1, false); 1578 setSelectedPositionInt(position); 1579 sel = fillUp(mItemCount - 1, childrenBottom); 1580 } 1581 } else { 1582 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1583 sel = fillSpecific(mSelectedPosition, 1584 oldSel == null ? childrenTop : oldSel.getTop()); 1585 } else if (mFirstPosition < mItemCount) { 1586 sel = fillSpecific(mFirstPosition, 1587 oldFirst == null ? childrenTop : oldFirst.getTop()); 1588 } else { 1589 sel = fillSpecific(0, childrenTop); 1590 } 1591 } 1592 break; 1593 } 1594 1595 // Flush any cached views that did not get reused above 1596 recycleBin.scrapActiveViews(); 1597 1598 if (sel != null) { 1599 // the current selected item should get focus if items 1600 // are focusable 1601 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1602 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1603 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1604 if (!focusWasTaken) { 1605 // selected item didn't take focus, fine, but still want 1606 // to make sure something else outside of the selected view 1607 // has focus 1608 final View focused = getFocusedChild(); 1609 if (focused != null) { 1610 focused.clearFocus(); 1611 } 1612 positionSelector(sel); 1613 } else { 1614 sel.setSelected(false); 1615 mSelectorRect.setEmpty(); 1616 } 1617 } else { 1618 positionSelector(sel); 1619 } 1620 mSelectedTop = sel.getTop(); 1621 } else { 1622 if (mTouchMode > TOUCH_MODE_DOWN && mTouchMode < TOUCH_MODE_SCROLL) { 1623 View child = getChildAt(mMotionPosition - mFirstPosition); 1624 if (child != null) positionSelector(child); 1625 } else { 1626 mSelectedTop = 0; 1627 mSelectorRect.setEmpty(); 1628 } 1629 1630 // even if there is not selected position, we may need to restore 1631 // focus (i.e. something focusable in touch mode) 1632 if (hasFocus() && focusLayoutRestoreView != null) { 1633 focusLayoutRestoreView.requestFocus(); 1634 } 1635 } 1636 1637 // tell focus view we are done mucking with it, if it is still in 1638 // our view hierarchy. 1639 if (focusLayoutRestoreView != null 1640 && focusLayoutRestoreView.getWindowToken() != null) { 1641 focusLayoutRestoreView.onFinishTemporaryDetach(); 1642 } 1643 1644 mLayoutMode = LAYOUT_NORMAL; 1645 mDataChanged = false; 1646 mNeedSync = false; 1647 setNextSelectedPositionInt(mSelectedPosition); 1648 1649 updateScrollIndicators(); 1650 1651 if (mItemCount > 0) { 1652 checkSelectionChanged(); 1653 } 1654 1655 invokeOnItemScrollListener(); 1656 } finally { 1657 if (!blockLayoutRequests) { 1658 mBlockLayoutRequests = false; 1659 } 1660 } 1661 } 1662 1663 /** 1664 * @param child a direct child of this list. 1665 * @return Whether child is a header or footer view. 1666 */ 1667 private boolean isDirectChildHeaderOrFooter(View child) { 1668 1669 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1670 final int numHeaders = headers.size(); 1671 for (int i = 0; i < numHeaders; i++) { 1672 if (child == headers.get(i).view) { 1673 return true; 1674 } 1675 } 1676 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1677 final int numFooters = footers.size(); 1678 for (int i = 0; i < numFooters; i++) { 1679 if (child == footers.get(i).view) { 1680 return true; 1681 } 1682 } 1683 return false; 1684 } 1685 1686 /** 1687 * Obtain the view and add it to our list of children. The view can be made 1688 * fresh, converted from an unused view, or used as is if it was in the 1689 * recycle bin. 1690 * 1691 * @param position Logical position in the list 1692 * @param y Top or bottom edge of the view to add 1693 * @param flow If flow is true, align top edge to y. If false, align bottom 1694 * edge to y. 1695 * @param childrenLeft Left edge where children should be positioned 1696 * @param selected Is this position selected? 1697 * @return View that was added 1698 */ 1699 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1700 boolean selected) { 1701 View child; 1702 1703 1704 if (!mDataChanged) { 1705 // Try to use an exsiting view for this position 1706 child = mRecycler.getActiveView(position); 1707 if (child != null) { 1708 if (ViewDebug.TRACE_RECYCLER) { 1709 ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, 1710 position, getChildCount()); 1711 } 1712 1713 // Found it -- we're using an existing child 1714 // This just needs to be positioned 1715 setupChild(child, position, y, flow, childrenLeft, selected, true); 1716 1717 return child; 1718 } 1719 } 1720 1721 // Make a new view for this position, or convert an unused view if possible 1722 child = obtainView(position, mIsScrap); 1723 1724 // This needs to be positioned and measured 1725 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1726 1727 return child; 1728 } 1729 1730 /** 1731 * Add a view as a child and make sure it is measured (if necessary) and 1732 * positioned properly. 1733 * 1734 * @param child The view to add 1735 * @param position The position of this child 1736 * @param y The y position relative to which this view will be positioned 1737 * @param flowDown If true, align top edge to y. If false, align bottom 1738 * edge to y. 1739 * @param childrenLeft Left edge where children should be positioned 1740 * @param selected Is this position selected? 1741 * @param recycled Has this view been pulled from the recycle bin? If so it 1742 * does not need to be remeasured. 1743 */ 1744 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1745 boolean selected, boolean recycled) { 1746 final boolean isSelected = selected && shouldShowSelector(); 1747 final boolean updateChildSelected = isSelected != child.isSelected(); 1748 final int mode = mTouchMode; 1749 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1750 mMotionPosition == position; 1751 final boolean updateChildPressed = isPressed != child.isPressed(); 1752 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1753 1754 // Respect layout params that are already in the view. Otherwise make some up... 1755 // noinspection unchecked 1756 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1757 if (p == null) { 1758 p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1759 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1760 } 1761 p.viewType = mAdapter.getItemViewType(position); 1762 1763 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1764 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1765 attachViewToParent(child, flowDown ? -1 : 0, p); 1766 } else { 1767 p.forceAdd = false; 1768 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1769 p.recycledHeaderFooter = true; 1770 } 1771 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1772 } 1773 1774 if (updateChildSelected) { 1775 child.setSelected(isSelected); 1776 } 1777 1778 if (updateChildPressed) { 1779 child.setPressed(isPressed); 1780 } 1781 1782 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1783 if (child instanceof Checkable) { 1784 ((Checkable) child).setChecked(mCheckStates.get(position)); 1785 } 1786 } 1787 1788 if (needToMeasure) { 1789 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1790 mListPadding.left + mListPadding.right, p.width); 1791 int lpHeight = p.height; 1792 int childHeightSpec; 1793 if (lpHeight > 0) { 1794 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1795 } else { 1796 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1797 } 1798 child.measure(childWidthSpec, childHeightSpec); 1799 } else { 1800 cleanupLayoutState(child); 1801 } 1802 1803 final int w = child.getMeasuredWidth(); 1804 final int h = child.getMeasuredHeight(); 1805 final int childTop = flowDown ? y : y - h; 1806 1807 if (needToMeasure) { 1808 final int childRight = childrenLeft + w; 1809 final int childBottom = childTop + h; 1810 child.layout(childrenLeft, childTop, childRight, childBottom); 1811 } else { 1812 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1813 child.offsetTopAndBottom(childTop - child.getTop()); 1814 } 1815 1816 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1817 child.setDrawingCacheEnabled(true); 1818 } 1819 } 1820 1821 @Override 1822 protected boolean canAnimate() { 1823 return super.canAnimate() && mItemCount > 0; 1824 } 1825 1826 /** 1827 * Sets the currently selected item. If in touch mode, the item will not be selected 1828 * but it will still be positioned appropriately. If the specified selection position 1829 * is less than 0, then the item at position 0 will be selected. 1830 * 1831 * @param position Index (starting at 0) of the data item to be selected. 1832 */ 1833 @Override 1834 public void setSelection(int position) { 1835 setSelectionFromTop(position, 0); 1836 } 1837 1838 /** 1839 * Sets the selected item and positions the selection y pixels from the top edge 1840 * of the ListView. (If in touch mode, the item will not be selected but it will 1841 * still be positioned appropriately.) 1842 * 1843 * @param position Index (starting at 0) of the data item to be selected. 1844 * @param y The distance from the top edge of the ListView (plus padding) that the 1845 * item will be positioned. 1846 */ 1847 public void setSelectionFromTop(int position, int y) { 1848 if (mAdapter == null) { 1849 return; 1850 } 1851 1852 if (!isInTouchMode()) { 1853 position = lookForSelectablePosition(position, true); 1854 if (position >= 0) { 1855 setNextSelectedPositionInt(position); 1856 } 1857 } else { 1858 mResurrectToPosition = position; 1859 } 1860 1861 if (position >= 0) { 1862 mLayoutMode = LAYOUT_SPECIFIC; 1863 mSpecificTop = mListPadding.top + y; 1864 1865 if (mNeedSync) { 1866 mSyncPosition = position; 1867 mSyncRowId = mAdapter.getItemId(position); 1868 } 1869 1870 requestLayout(); 1871 } 1872 } 1873 1874 /** 1875 * Makes the item at the supplied position selected. 1876 * 1877 * @param position the position of the item to select 1878 */ 1879 @Override 1880 void setSelectionInt(int position) { 1881 setNextSelectedPositionInt(position); 1882 boolean awakeScrollbars = false; 1883 1884 final int selectedPosition = mSelectedPosition; 1885 1886 if (selectedPosition >= 0) { 1887 if (position == selectedPosition - 1) { 1888 awakeScrollbars = true; 1889 } else if (position == selectedPosition + 1) { 1890 awakeScrollbars = true; 1891 } 1892 } 1893 1894 layoutChildren(); 1895 1896 if (awakeScrollbars) { 1897 awakenScrollBars(); 1898 } 1899 } 1900 1901 /** 1902 * Find a position that can be selected (i.e., is not a separator). 1903 * 1904 * @param position The starting position to look at. 1905 * @param lookDown Whether to look down for other positions. 1906 * @return The next selectable position starting at position and then searching either up or 1907 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1908 */ 1909 @Override 1910 int lookForSelectablePosition(int position, boolean lookDown) { 1911 final ListAdapter adapter = mAdapter; 1912 if (adapter == null || isInTouchMode()) { 1913 return INVALID_POSITION; 1914 } 1915 1916 final int count = adapter.getCount(); 1917 if (!mAreAllItemsSelectable) { 1918 if (lookDown) { 1919 position = Math.max(0, position); 1920 while (position < count && !adapter.isEnabled(position)) { 1921 position++; 1922 } 1923 } else { 1924 position = Math.min(position, count - 1); 1925 while (position >= 0 && !adapter.isEnabled(position)) { 1926 position--; 1927 } 1928 } 1929 1930 if (position < 0 || position >= count) { 1931 return INVALID_POSITION; 1932 } 1933 return position; 1934 } else { 1935 if (position < 0 || position >= count) { 1936 return INVALID_POSITION; 1937 } 1938 return position; 1939 } 1940 } 1941 1942 @Override 1943 public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { 1944 boolean populated = super.dispatchPopulateAccessibilityEvent(event); 1945 1946 // If the item count is less than 15 then subtract disabled items from the count and 1947 // position. Otherwise ignore disabled items. 1948 if (!populated) { 1949 int itemCount = 0; 1950 int currentItemIndex = getSelectedItemPosition(); 1951 1952 ListAdapter adapter = getAdapter(); 1953 if (adapter != null) { 1954 final int count = adapter.getCount(); 1955 if (count < 15) { 1956 for (int i = 0; i < count; i++) { 1957 if (adapter.isEnabled(i)) { 1958 itemCount++; 1959 } else if (i <= currentItemIndex) { 1960 currentItemIndex--; 1961 } 1962 } 1963 } else { 1964 itemCount = count; 1965 } 1966 } 1967 1968 event.setItemCount(itemCount); 1969 event.setCurrentItemIndex(currentItemIndex); 1970 } 1971 1972 return populated; 1973 } 1974 1975 /** 1976 * setSelectionAfterHeaderView set the selection to be the first list item 1977 * after the header views. 1978 */ 1979 public void setSelectionAfterHeaderView() { 1980 final int count = mHeaderViewInfos.size(); 1981 if (count > 0) { 1982 mNextSelectedPosition = 0; 1983 return; 1984 } 1985 1986 if (mAdapter != null) { 1987 setSelection(count); 1988 } else { 1989 mNextSelectedPosition = count; 1990 mLayoutMode = LAYOUT_SET_SELECTION; 1991 } 1992 1993 } 1994 1995 @Override 1996 public boolean dispatchKeyEvent(KeyEvent event) { 1997 // Dispatch in the normal way 1998 boolean handled = super.dispatchKeyEvent(event); 1999 if (!handled) { 2000 // If we didn't handle it... 2001 View focused = getFocusedChild(); 2002 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2003 // ... and our focused child didn't handle it 2004 // ... give it to ourselves so we can scroll if necessary 2005 handled = onKeyDown(event.getKeyCode(), event); 2006 } 2007 } 2008 return handled; 2009 } 2010 2011 @Override 2012 public boolean onKeyDown(int keyCode, KeyEvent event) { 2013 return commonKey(keyCode, 1, event); 2014 } 2015 2016 @Override 2017 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2018 return commonKey(keyCode, repeatCount, event); 2019 } 2020 2021 @Override 2022 public boolean onKeyUp(int keyCode, KeyEvent event) { 2023 return commonKey(keyCode, 1, event); 2024 } 2025 2026 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2027 if (mAdapter == null) { 2028 return false; 2029 } 2030 2031 if (mDataChanged) { 2032 layoutChildren(); 2033 } 2034 2035 boolean handled = false; 2036 int action = event.getAction(); 2037 2038 if (action != KeyEvent.ACTION_UP) { 2039 if (mSelectedPosition < 0) { 2040 switch (keyCode) { 2041 case KeyEvent.KEYCODE_DPAD_UP: 2042 case KeyEvent.KEYCODE_DPAD_DOWN: 2043 case KeyEvent.KEYCODE_DPAD_CENTER: 2044 case KeyEvent.KEYCODE_ENTER: 2045 case KeyEvent.KEYCODE_SPACE: 2046 if (resurrectSelection()) { 2047 return true; 2048 } 2049 } 2050 } 2051 switch (keyCode) { 2052 case KeyEvent.KEYCODE_DPAD_UP: 2053 if (!event.isAltPressed()) { 2054 while (count > 0) { 2055 handled = arrowScroll(FOCUS_UP); 2056 count--; 2057 } 2058 } else { 2059 handled = fullScroll(FOCUS_UP); 2060 } 2061 break; 2062 2063 case KeyEvent.KEYCODE_DPAD_DOWN: 2064 if (!event.isAltPressed()) { 2065 while (count > 0) { 2066 handled = arrowScroll(FOCUS_DOWN); 2067 count--; 2068 } 2069 } else { 2070 handled = fullScroll(FOCUS_DOWN); 2071 } 2072 break; 2073 2074 case KeyEvent.KEYCODE_DPAD_LEFT: 2075 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2076 break; 2077 case KeyEvent.KEYCODE_DPAD_RIGHT: 2078 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2079 break; 2080 2081 case KeyEvent.KEYCODE_DPAD_CENTER: 2082 case KeyEvent.KEYCODE_ENTER: 2083 if (mItemCount > 0 && event.getRepeatCount() == 0) { 2084 keyPressed(); 2085 } 2086 handled = true; 2087 break; 2088 2089 case KeyEvent.KEYCODE_SPACE: 2090 if (mPopup == null || !mPopup.isShowing()) { 2091 if (!event.isShiftPressed()) { 2092 pageScroll(FOCUS_DOWN); 2093 } else { 2094 pageScroll(FOCUS_UP); 2095 } 2096 handled = true; 2097 } 2098 break; 2099 } 2100 } 2101 2102 if (!handled) { 2103 handled = sendToTextFilter(keyCode, count, event); 2104 } 2105 2106 if (handled) { 2107 return true; 2108 } else { 2109 switch (action) { 2110 case KeyEvent.ACTION_DOWN: 2111 return super.onKeyDown(keyCode, event); 2112 2113 case KeyEvent.ACTION_UP: 2114 return super.onKeyUp(keyCode, event); 2115 2116 case KeyEvent.ACTION_MULTIPLE: 2117 return super.onKeyMultiple(keyCode, count, event); 2118 2119 default: // shouldn't happen 2120 return false; 2121 } 2122 } 2123 } 2124 2125 /** 2126 * Scrolls up or down by the number of items currently present on screen. 2127 * 2128 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2129 * @return whether selection was moved 2130 */ 2131 boolean pageScroll(int direction) { 2132 int nextPage = -1; 2133 boolean down = false; 2134 2135 if (direction == FOCUS_UP) { 2136 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2137 } else if (direction == FOCUS_DOWN) { 2138 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2139 down = true; 2140 } 2141 2142 if (nextPage >= 0) { 2143 int position = lookForSelectablePosition(nextPage, down); 2144 if (position >= 0) { 2145 mLayoutMode = LAYOUT_SPECIFIC; 2146 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2147 2148 if (down && position > mItemCount - getChildCount()) { 2149 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2150 } 2151 2152 if (!down && position < getChildCount()) { 2153 mLayoutMode = LAYOUT_FORCE_TOP; 2154 } 2155 2156 setSelectionInt(position); 2157 invokeOnItemScrollListener(); 2158 if (!awakenScrollBars()) { 2159 invalidate(); 2160 } 2161 2162 return true; 2163 } 2164 } 2165 2166 return false; 2167 } 2168 2169 /** 2170 * Go to the last or first item if possible (not worrying about panning across or navigating 2171 * within the internal focus of the currently selected item.) 2172 * 2173 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2174 * 2175 * @return whether selection was moved 2176 */ 2177 boolean fullScroll(int direction) { 2178 boolean moved = false; 2179 if (direction == FOCUS_UP) { 2180 if (mSelectedPosition != 0) { 2181 int position = lookForSelectablePosition(0, true); 2182 if (position >= 0) { 2183 mLayoutMode = LAYOUT_FORCE_TOP; 2184 setSelectionInt(position); 2185 invokeOnItemScrollListener(); 2186 } 2187 moved = true; 2188 } 2189 } else if (direction == FOCUS_DOWN) { 2190 if (mSelectedPosition < mItemCount - 1) { 2191 int position = lookForSelectablePosition(mItemCount - 1, true); 2192 if (position >= 0) { 2193 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2194 setSelectionInt(position); 2195 invokeOnItemScrollListener(); 2196 } 2197 moved = true; 2198 } 2199 } 2200 2201 if (moved && !awakenScrollBars()) { 2202 awakenScrollBars(); 2203 invalidate(); 2204 } 2205 2206 return moved; 2207 } 2208 2209 /** 2210 * To avoid horizontal focus searches changing the selected item, we 2211 * manually focus search within the selected item (as applicable), and 2212 * prevent focus from jumping to something within another item. 2213 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2214 * @return Whether this consumes the key event. 2215 */ 2216 private boolean handleHorizontalFocusWithinListItem(int direction) { 2217 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2218 throw new IllegalArgumentException("direction must be one of" 2219 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2220 } 2221 2222 final int numChildren = getChildCount(); 2223 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2224 final View selectedView = getSelectedView(); 2225 if (selectedView != null && selectedView.hasFocus() && 2226 selectedView instanceof ViewGroup) { 2227 2228 final View currentFocus = selectedView.findFocus(); 2229 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2230 (ViewGroup) selectedView, currentFocus, direction); 2231 if (nextFocus != null) { 2232 // do the math to get interesting rect in next focus' coordinates 2233 currentFocus.getFocusedRect(mTempRect); 2234 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2235 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2236 if (nextFocus.requestFocus(direction, mTempRect)) { 2237 return true; 2238 } 2239 } 2240 // we are blocking the key from being handled (by returning true) 2241 // if the global result is going to be some other view within this 2242 // list. this is to acheive the overall goal of having 2243 // horizontal d-pad navigation remain in the current item. 2244 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2245 (ViewGroup) getRootView(), currentFocus, direction); 2246 if (globalNextFocus != null) { 2247 return isViewAncestorOf(globalNextFocus, this); 2248 } 2249 } 2250 } 2251 return false; 2252 } 2253 2254 /** 2255 * Scrolls to the next or previous item if possible. 2256 * 2257 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2258 * 2259 * @return whether selection was moved 2260 */ 2261 boolean arrowScroll(int direction) { 2262 try { 2263 mInLayout = true; 2264 final boolean handled = arrowScrollImpl(direction); 2265 if (handled) { 2266 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2267 } 2268 return handled; 2269 } finally { 2270 mInLayout = false; 2271 } 2272 } 2273 2274 /** 2275 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2276 * whether there are focusable items etc. 2277 * 2278 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2279 * @return Whether any scrolling, selection or focus change occured. 2280 */ 2281 private boolean arrowScrollImpl(int direction) { 2282 if (getChildCount() <= 0) { 2283 return false; 2284 } 2285 2286 View selectedView = getSelectedView(); 2287 2288 int nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 2289 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2290 2291 // if we are moving focus, we may OVERRIDE the default behavior 2292 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2293 if (focusResult != null) { 2294 nextSelectedPosition = focusResult.getSelectedPosition(); 2295 amountToScroll = focusResult.getAmountToScroll(); 2296 } 2297 2298 boolean needToRedraw = focusResult != null; 2299 if (nextSelectedPosition != INVALID_POSITION) { 2300 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2301 setSelectedPositionInt(nextSelectedPosition); 2302 setNextSelectedPositionInt(nextSelectedPosition); 2303 selectedView = getSelectedView(); 2304 if (mItemsCanFocus && focusResult == null) { 2305 // there was no new view found to take focus, make sure we 2306 // don't leave focus with the old selection 2307 final View focused = getFocusedChild(); 2308 if (focused != null) { 2309 focused.clearFocus(); 2310 } 2311 } 2312 needToRedraw = true; 2313 checkSelectionChanged(); 2314 } 2315 2316 if (amountToScroll > 0) { 2317 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2318 needToRedraw = true; 2319 } 2320 2321 // if we didn't find a new focusable, make sure any existing focused 2322 // item that was panned off screen gives up focus. 2323 if (mItemsCanFocus && (focusResult == null) 2324 && selectedView != null && selectedView.hasFocus()) { 2325 final View focused = selectedView.findFocus(); 2326 if (distanceToView(focused) > 0) { 2327 focused.clearFocus(); 2328 } 2329 } 2330 2331 // if the current selection is panned off, we need to remove the selection 2332 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2333 && !isViewAncestorOf(selectedView, this)) { 2334 selectedView = null; 2335 hideSelector(); 2336 2337 // but we don't want to set the ressurect position (that would make subsequent 2338 // unhandled key events bring back the item we just scrolled off!) 2339 mResurrectToPosition = INVALID_POSITION; 2340 } 2341 2342 if (needToRedraw) { 2343 if (selectedView != null) { 2344 positionSelector(selectedView); 2345 mSelectedTop = selectedView.getTop(); 2346 } 2347 if (!awakenScrollBars()) { 2348 invalidate(); 2349 } 2350 invokeOnItemScrollListener(); 2351 return true; 2352 } 2353 2354 return false; 2355 } 2356 2357 /** 2358 * When selection changes, it is possible that the previously selected or the 2359 * next selected item will change its size. If so, we need to offset some folks, 2360 * and re-layout the items as appropriate. 2361 * 2362 * @param selectedView The currently selected view (before changing selection). 2363 * should be <code>null</code> if there was no previous selection. 2364 * @param direction Either {@link android.view.View#FOCUS_UP} or 2365 * {@link android.view.View#FOCUS_DOWN}. 2366 * @param newSelectedPosition The position of the next selection. 2367 * @param newFocusAssigned whether new focus was assigned. This matters because 2368 * when something has focus, we don't want to show selection (ugh). 2369 */ 2370 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2371 boolean newFocusAssigned) { 2372 if (newSelectedPosition == INVALID_POSITION) { 2373 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2374 } 2375 2376 // whether or not we are moving down or up, we want to preserve the 2377 // top of whatever view is on top: 2378 // - moving down: the view that had selection 2379 // - moving up: the view that is getting selection 2380 View topView; 2381 View bottomView; 2382 int topViewIndex, bottomViewIndex; 2383 boolean topSelected = false; 2384 final int selectedIndex = mSelectedPosition - mFirstPosition; 2385 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2386 if (direction == View.FOCUS_UP) { 2387 topViewIndex = nextSelectedIndex; 2388 bottomViewIndex = selectedIndex; 2389 topView = getChildAt(topViewIndex); 2390 bottomView = selectedView; 2391 topSelected = true; 2392 } else { 2393 topViewIndex = selectedIndex; 2394 bottomViewIndex = nextSelectedIndex; 2395 topView = selectedView; 2396 bottomView = getChildAt(bottomViewIndex); 2397 } 2398 2399 final int numChildren = getChildCount(); 2400 2401 // start with top view: is it changing size? 2402 if (topView != null) { 2403 topView.setSelected(!newFocusAssigned && topSelected); 2404 measureAndAdjustDown(topView, topViewIndex, numChildren); 2405 } 2406 2407 // is the bottom view changing size? 2408 if (bottomView != null) { 2409 bottomView.setSelected(!newFocusAssigned && !topSelected); 2410 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2411 } 2412 } 2413 2414 /** 2415 * Re-measure a child, and if its height changes, lay it out preserving its 2416 * top, and adjust the children below it appropriately. 2417 * @param child The child 2418 * @param childIndex The view group index of the child. 2419 * @param numChildren The number of children in the view group. 2420 */ 2421 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2422 int oldHeight = child.getHeight(); 2423 measureItem(child); 2424 if (child.getMeasuredHeight() != oldHeight) { 2425 // lay out the view, preserving its top 2426 relayoutMeasuredItem(child); 2427 2428 // adjust views below appropriately 2429 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2430 for (int i = childIndex + 1; i < numChildren; i++) { 2431 getChildAt(i).offsetTopAndBottom(heightDelta); 2432 } 2433 } 2434 } 2435 2436 /** 2437 * Measure a particular list child. 2438 * TODO: unify with setUpChild. 2439 * @param child The child. 2440 */ 2441 private void measureItem(View child) { 2442 ViewGroup.LayoutParams p = child.getLayoutParams(); 2443 if (p == null) { 2444 p = new ViewGroup.LayoutParams( 2445 ViewGroup.LayoutParams.MATCH_PARENT, 2446 ViewGroup.LayoutParams.WRAP_CONTENT); 2447 } 2448 2449 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2450 mListPadding.left + mListPadding.right, p.width); 2451 int lpHeight = p.height; 2452 int childHeightSpec; 2453 if (lpHeight > 0) { 2454 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2455 } else { 2456 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2457 } 2458 child.measure(childWidthSpec, childHeightSpec); 2459 } 2460 2461 /** 2462 * Layout a child that has been measured, preserving its top position. 2463 * TODO: unify with setUpChild. 2464 * @param child The child. 2465 */ 2466 private void relayoutMeasuredItem(View child) { 2467 final int w = child.getMeasuredWidth(); 2468 final int h = child.getMeasuredHeight(); 2469 final int childLeft = mListPadding.left; 2470 final int childRight = childLeft + w; 2471 final int childTop = child.getTop(); 2472 final int childBottom = childTop + h; 2473 child.layout(childLeft, childTop, childRight, childBottom); 2474 } 2475 2476 /** 2477 * @return The amount to preview next items when arrow srolling. 2478 */ 2479 private int getArrowScrollPreviewLength() { 2480 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2481 } 2482 2483 /** 2484 * Determine how much we need to scroll in order to get the next selected view 2485 * visible, with a fading edge showing below as applicable. The amount is 2486 * capped at {@link #getMaxScrollAmount()} . 2487 * 2488 * @param direction either {@link android.view.View#FOCUS_UP} or 2489 * {@link android.view.View#FOCUS_DOWN}. 2490 * @param nextSelectedPosition The position of the next selection, or 2491 * {@link #INVALID_POSITION} if there is no next selectable position 2492 * @return The amount to scroll. Note: this is always positive! Direction 2493 * needs to be taken into account when actually scrolling. 2494 */ 2495 private int amountToScroll(int direction, int nextSelectedPosition) { 2496 final int listBottom = getHeight() - mListPadding.bottom; 2497 final int listTop = mListPadding.top; 2498 2499 final int numChildren = getChildCount(); 2500 2501 if (direction == View.FOCUS_DOWN) { 2502 int indexToMakeVisible = numChildren - 1; 2503 if (nextSelectedPosition != INVALID_POSITION) { 2504 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2505 } 2506 2507 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2508 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2509 2510 int goalBottom = listBottom; 2511 if (positionToMakeVisible < mItemCount - 1) { 2512 goalBottom -= getArrowScrollPreviewLength(); 2513 } 2514 2515 if (viewToMakeVisible.getBottom() <= goalBottom) { 2516 // item is fully visible. 2517 return 0; 2518 } 2519 2520 if (nextSelectedPosition != INVALID_POSITION 2521 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2522 // item already has enough of it visible, changing selection is good enough 2523 return 0; 2524 } 2525 2526 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2527 2528 if ((mFirstPosition + numChildren) == mItemCount) { 2529 // last is last in list -> make sure we don't scroll past it 2530 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2531 amountToScroll = Math.min(amountToScroll, max); 2532 } 2533 2534 return Math.min(amountToScroll, getMaxScrollAmount()); 2535 } else { 2536 int indexToMakeVisible = 0; 2537 if (nextSelectedPosition != INVALID_POSITION) { 2538 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2539 } 2540 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2541 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2542 int goalTop = listTop; 2543 if (positionToMakeVisible > 0) { 2544 goalTop += getArrowScrollPreviewLength(); 2545 } 2546 if (viewToMakeVisible.getTop() >= goalTop) { 2547 // item is fully visible. 2548 return 0; 2549 } 2550 2551 if (nextSelectedPosition != INVALID_POSITION && 2552 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2553 // item already has enough of it visible, changing selection is good enough 2554 return 0; 2555 } 2556 2557 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2558 if (mFirstPosition == 0) { 2559 // first is first in list -> make sure we don't scroll past it 2560 final int max = listTop - getChildAt(0).getTop(); 2561 amountToScroll = Math.min(amountToScroll, max); 2562 } 2563 return Math.min(amountToScroll, getMaxScrollAmount()); 2564 } 2565 } 2566 2567 /** 2568 * Holds results of focus aware arrow scrolling. 2569 */ 2570 static private class ArrowScrollFocusResult { 2571 private int mSelectedPosition; 2572 private int mAmountToScroll; 2573 2574 /** 2575 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2576 */ 2577 void populate(int selectedPosition, int amountToScroll) { 2578 mSelectedPosition = selectedPosition; 2579 mAmountToScroll = amountToScroll; 2580 } 2581 2582 public int getSelectedPosition() { 2583 return mSelectedPosition; 2584 } 2585 2586 public int getAmountToScroll() { 2587 return mAmountToScroll; 2588 } 2589 } 2590 2591 /** 2592 * @param direction either {@link android.view.View#FOCUS_UP} or 2593 * {@link android.view.View#FOCUS_DOWN}. 2594 * @return The position of the next selectable position of the views that 2595 * are currently visible, taking into account the fact that there might 2596 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2597 * selectable view on screen in the given direction. 2598 */ 2599 private int lookForSelectablePositionOnScreen(int direction) { 2600 final int firstPosition = mFirstPosition; 2601 if (direction == View.FOCUS_DOWN) { 2602 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2603 mSelectedPosition + 1 : 2604 firstPosition; 2605 if (startPos >= mAdapter.getCount()) { 2606 return INVALID_POSITION; 2607 } 2608 if (startPos < firstPosition) { 2609 startPos = firstPosition; 2610 } 2611 2612 final int lastVisiblePos = getLastVisiblePosition(); 2613 final ListAdapter adapter = getAdapter(); 2614 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2615 if (adapter.isEnabled(pos) 2616 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2617 return pos; 2618 } 2619 } 2620 } else { 2621 int last = firstPosition + getChildCount() - 1; 2622 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2623 mSelectedPosition - 1 : 2624 firstPosition + getChildCount() - 1; 2625 if (startPos < 0) { 2626 return INVALID_POSITION; 2627 } 2628 if (startPos > last) { 2629 startPos = last; 2630 } 2631 2632 final ListAdapter adapter = getAdapter(); 2633 for (int pos = startPos; pos >= firstPosition; pos--) { 2634 if (adapter.isEnabled(pos) 2635 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2636 return pos; 2637 } 2638 } 2639 } 2640 return INVALID_POSITION; 2641 } 2642 2643 /** 2644 * Do an arrow scroll based on focus searching. If a new view is 2645 * given focus, return the selection delta and amount to scroll via 2646 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2647 * 2648 * @param direction either {@link android.view.View#FOCUS_UP} or 2649 * {@link android.view.View#FOCUS_DOWN}. 2650 * @return The result if focus has changed, or <code>null</code>. 2651 */ 2652 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2653 final View selectedView = getSelectedView(); 2654 View newFocus; 2655 if (selectedView != null && selectedView.hasFocus()) { 2656 View oldFocus = selectedView.findFocus(); 2657 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2658 } else { 2659 if (direction == View.FOCUS_DOWN) { 2660 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2661 final int listTop = mListPadding.top + 2662 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2663 final int ySearchPoint = 2664 (selectedView != null && selectedView.getTop() > listTop) ? 2665 selectedView.getTop() : 2666 listTop; 2667 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2668 } else { 2669 final boolean bottomFadingEdgeShowing = 2670 (mFirstPosition + getChildCount() - 1) < mItemCount; 2671 final int listBottom = getHeight() - mListPadding.bottom - 2672 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2673 final int ySearchPoint = 2674 (selectedView != null && selectedView.getBottom() < listBottom) ? 2675 selectedView.getBottom() : 2676 listBottom; 2677 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2678 } 2679 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2680 } 2681 2682 if (newFocus != null) { 2683 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2684 2685 // if the focus change is in a different new position, make sure 2686 // we aren't jumping over another selectable position 2687 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2688 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2689 if (selectablePosition != INVALID_POSITION && 2690 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2691 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2692 return null; 2693 } 2694 } 2695 2696 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2697 2698 final int maxScrollAmount = getMaxScrollAmount(); 2699 if (focusScroll < maxScrollAmount) { 2700 // not moving too far, safe to give next view focus 2701 newFocus.requestFocus(direction); 2702 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2703 return mArrowScrollFocusResult; 2704 } else if (distanceToView(newFocus) < maxScrollAmount){ 2705 // Case to consider: 2706 // too far to get entire next focusable on screen, but by going 2707 // max scroll amount, we are getting it at least partially in view, 2708 // so give it focus and scroll the max ammount. 2709 newFocus.requestFocus(direction); 2710 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2711 return mArrowScrollFocusResult; 2712 } 2713 } 2714 return null; 2715 } 2716 2717 /** 2718 * @param newFocus The view that would have focus. 2719 * @return the position that contains newFocus 2720 */ 2721 private int positionOfNewFocus(View newFocus) { 2722 final int numChildren = getChildCount(); 2723 for (int i = 0; i < numChildren; i++) { 2724 final View child = getChildAt(i); 2725 if (isViewAncestorOf(newFocus, child)) { 2726 return mFirstPosition + i; 2727 } 2728 } 2729 throw new IllegalArgumentException("newFocus is not a child of any of the" 2730 + " children of the list!"); 2731 } 2732 2733 /** 2734 * Return true if child is an ancestor of parent, (or equal to the parent). 2735 */ 2736 private boolean isViewAncestorOf(View child, View parent) { 2737 if (child == parent) { 2738 return true; 2739 } 2740 2741 final ViewParent theParent = child.getParent(); 2742 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2743 } 2744 2745 /** 2746 * Determine how much we need to scroll in order to get newFocus in view. 2747 * @param direction either {@link android.view.View#FOCUS_UP} or 2748 * {@link android.view.View#FOCUS_DOWN}. 2749 * @param newFocus The view that would take focus. 2750 * @param positionOfNewFocus The position of the list item containing newFocus 2751 * @return The amount to scroll. Note: this is always positive! Direction 2752 * needs to be taken into account when actually scrolling. 2753 */ 2754 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2755 int amountToScroll = 0; 2756 newFocus.getDrawingRect(mTempRect); 2757 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2758 if (direction == View.FOCUS_UP) { 2759 if (mTempRect.top < mListPadding.top) { 2760 amountToScroll = mListPadding.top - mTempRect.top; 2761 if (positionOfNewFocus > 0) { 2762 amountToScroll += getArrowScrollPreviewLength(); 2763 } 2764 } 2765 } else { 2766 final int listBottom = getHeight() - mListPadding.bottom; 2767 if (mTempRect.bottom > listBottom) { 2768 amountToScroll = mTempRect.bottom - listBottom; 2769 if (positionOfNewFocus < mItemCount - 1) { 2770 amountToScroll += getArrowScrollPreviewLength(); 2771 } 2772 } 2773 } 2774 return amountToScroll; 2775 } 2776 2777 /** 2778 * Determine the distance to the nearest edge of a view in a particular 2779 * direction. 2780 * 2781 * @param descendant A descendant of this list. 2782 * @return The distance, or 0 if the nearest edge is already on screen. 2783 */ 2784 private int distanceToView(View descendant) { 2785 int distance = 0; 2786 descendant.getDrawingRect(mTempRect); 2787 offsetDescendantRectToMyCoords(descendant, mTempRect); 2788 final int listBottom = mBottom - mTop - mListPadding.bottom; 2789 if (mTempRect.bottom < mListPadding.top) { 2790 distance = mListPadding.top - mTempRect.bottom; 2791 } else if (mTempRect.top > listBottom) { 2792 distance = mTempRect.top - listBottom; 2793 } 2794 return distance; 2795 } 2796 2797 2798 /** 2799 * Scroll the children by amount, adding a view at the end and removing 2800 * views that fall off as necessary. 2801 * 2802 * @param amount The amount (positive or negative) to scroll. 2803 */ 2804 private void scrollListItemsBy(int amount) { 2805 offsetChildrenTopAndBottom(amount); 2806 2807 final int listBottom = getHeight() - mListPadding.bottom; 2808 final int listTop = mListPadding.top; 2809 final AbsListView.RecycleBin recycleBin = mRecycler; 2810 2811 if (amount < 0) { 2812 // shifted items up 2813 2814 // may need to pan views into the bottom space 2815 int numChildren = getChildCount(); 2816 View last = getChildAt(numChildren - 1); 2817 while (last.getBottom() < listBottom) { 2818 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2819 if (lastVisiblePosition < mItemCount - 1) { 2820 last = addViewBelow(last, lastVisiblePosition); 2821 numChildren++; 2822 } else { 2823 break; 2824 } 2825 } 2826 2827 // may have brought in the last child of the list that is skinnier 2828 // than the fading edge, thereby leaving space at the end. need 2829 // to shift back 2830 if (last.getBottom() < listBottom) { 2831 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2832 } 2833 2834 // top views may be panned off screen 2835 View first = getChildAt(0); 2836 while (first.getBottom() < listTop) { 2837 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2838 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2839 detachViewFromParent(first); 2840 recycleBin.addScrapView(first); 2841 } else { 2842 removeViewInLayout(first); 2843 } 2844 first = getChildAt(0); 2845 mFirstPosition++; 2846 } 2847 } else { 2848 // shifted items down 2849 View first = getChildAt(0); 2850 2851 // may need to pan views into top 2852 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2853 first = addViewAbove(first, mFirstPosition); 2854 mFirstPosition--; 2855 } 2856 2857 // may have brought the very first child of the list in too far and 2858 // need to shift it back 2859 if (first.getTop() > listTop) { 2860 offsetChildrenTopAndBottom(listTop - first.getTop()); 2861 } 2862 2863 int lastIndex = getChildCount() - 1; 2864 View last = getChildAt(lastIndex); 2865 2866 // bottom view may be panned off screen 2867 while (last.getTop() > listBottom) { 2868 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 2869 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2870 detachViewFromParent(last); 2871 recycleBin.addScrapView(last); 2872 } else { 2873 removeViewInLayout(last); 2874 } 2875 last = getChildAt(--lastIndex); 2876 } 2877 } 2878 } 2879 2880 private View addViewAbove(View theView, int position) { 2881 int abovePosition = position - 1; 2882 View view = obtainView(abovePosition, mIsScrap); 2883 int edgeOfNewChild = theView.getTop() - mDividerHeight; 2884 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 2885 false, mIsScrap[0]); 2886 return view; 2887 } 2888 2889 private View addViewBelow(View theView, int position) { 2890 int belowPosition = position + 1; 2891 View view = obtainView(belowPosition, mIsScrap); 2892 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 2893 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 2894 false, mIsScrap[0]); 2895 return view; 2896 } 2897 2898 /** 2899 * Indicates that the views created by the ListAdapter can contain focusable 2900 * items. 2901 * 2902 * @param itemsCanFocus true if items can get focus, false otherwise 2903 */ 2904 public void setItemsCanFocus(boolean itemsCanFocus) { 2905 mItemsCanFocus = itemsCanFocus; 2906 if (!itemsCanFocus) { 2907 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 2908 } 2909 } 2910 2911 /** 2912 * @return Whether the views created by the ListAdapter can contain focusable 2913 * items. 2914 */ 2915 public boolean getItemsCanFocus() { 2916 return mItemsCanFocus; 2917 } 2918 2919 /** 2920 * @hide Pending API council approval. 2921 */ 2922 @Override 2923 public boolean isOpaque() { 2924 return (mCachingStarted && mIsCacheColorOpaque && mDividerIsOpaque && 2925 hasOpaqueScrollbars()) || super.isOpaque(); 2926 } 2927 2928 @Override 2929 public void setCacheColorHint(int color) { 2930 final boolean opaque = (color >>> 24) == 0xFF; 2931 mIsCacheColorOpaque = opaque; 2932 if (opaque) { 2933 if (mDividerPaint == null) { 2934 mDividerPaint = new Paint(); 2935 } 2936 mDividerPaint.setColor(color); 2937 } 2938 super.setCacheColorHint(color); 2939 } 2940 2941 @Override 2942 protected void dispatchDraw(Canvas canvas) { 2943 // Draw the dividers 2944 final int dividerHeight = mDividerHeight; 2945 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 2946 2947 if (drawDividers) { 2948 // Only modify the top and bottom in the loop, we set the left and right here 2949 final Rect bounds = mTempRect; 2950 bounds.left = mPaddingLeft; 2951 bounds.right = mRight - mLeft - mPaddingRight; 2952 2953 final int count = getChildCount(); 2954 final int headerCount = mHeaderViewInfos.size(); 2955 final int itemCount = mItemCount; 2956 final int footerLimit = itemCount - mFooterViewInfos.size() - 1; 2957 final boolean headerDividers = mHeaderDividersEnabled; 2958 final boolean footerDividers = mFooterDividersEnabled; 2959 final int first = mFirstPosition; 2960 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 2961 final ListAdapter adapter = mAdapter; 2962 // If the list is opaque *and* the background is not, we want to 2963 // fill a rect where the dividers would be for non-selectable items 2964 // If the list is opaque and the background is also opaque, we don't 2965 // need to draw anything since the background will do it for us 2966 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 2967 2968 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 2969 mDividerPaint = new Paint(); 2970 mDividerPaint.setColor(getCacheColorHint()); 2971 } 2972 final Paint paint = mDividerPaint; 2973 2974 final int listBottom = mBottom - mTop - mListPadding.bottom + mScrollY; 2975 if (!mStackFromBottom) { 2976 int bottom; 2977 2978 final int scrollY = mScrollY; 2979 for (int i = 0; i < count; i++) { 2980 if ((headerDividers || first + i >= headerCount) && 2981 (footerDividers || first + i < footerLimit)) { 2982 View child = getChildAt(i); 2983 bottom = child.getBottom(); 2984 // Don't draw dividers next to items that are not enabled 2985 if ((areAllItemsSelectable || 2986 (adapter.isEnabled(first + i) && (i == count - 1 || 2987 adapter.isEnabled(first + i + 1))))) { 2988 bounds.top = bottom; 2989 bounds.bottom = bottom + dividerHeight; 2990 drawDivider(canvas, bounds, i); 2991 } else if (fillForMissingDividers) { 2992 bounds.top = bottom; 2993 bounds.bottom = bottom + dividerHeight; 2994 canvas.drawRect(bounds, paint); 2995 } 2996 } 2997 } 2998 } else { 2999 int top; 3000 int listTop = mListPadding.top; 3001 3002 final int scrollY = mScrollY; 3003 3004 for (int i = 0; i < count; i++) { 3005 if ((headerDividers || first + i >= headerCount) && 3006 (footerDividers || first + i < footerLimit)) { 3007 View child = getChildAt(i); 3008 top = child.getTop(); 3009 // Don't draw dividers next to items that are not enabled 3010 if (top > listTop) { 3011 if ((areAllItemsSelectable || 3012 (adapter.isEnabled(first + i) && (i == count - 1 || 3013 adapter.isEnabled(first + i + 1))))) { 3014 bounds.top = top - dividerHeight; 3015 bounds.bottom = top; 3016 // Give the method the child ABOVE the divider, so we 3017 // subtract one from our child 3018 // position. Give -1 when there is no child above the 3019 // divider. 3020 drawDivider(canvas, bounds, i - 1); 3021 } else if (fillForMissingDividers) { 3022 bounds.top = top - dividerHeight; 3023 bounds.bottom = top; 3024 canvas.drawRect(bounds, paint); 3025 } 3026 } 3027 } 3028 } 3029 3030 if (count > 0 && scrollY > 0) { 3031 bounds.top = listBottom; 3032 bounds.bottom = listBottom + dividerHeight; 3033 drawDivider(canvas, bounds, -1); 3034 } 3035 } 3036 } 3037 3038 // Draw the indicators (these should be drawn above the dividers) and children 3039 super.dispatchDraw(canvas); 3040 } 3041 3042 /** 3043 * Draws a divider for the given child in the given bounds. 3044 * 3045 * @param canvas The canvas to draw to. 3046 * @param bounds The bounds of the divider. 3047 * @param childIndex The index of child (of the View) above the divider. 3048 * This will be -1 if there is no child above the divider to be 3049 * drawn. 3050 */ 3051 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3052 // This widget draws the same divider for all children 3053 final Drawable divider = mDivider; 3054 final boolean clipDivider = mClipDivider; 3055 3056 if (!clipDivider) { 3057 divider.setBounds(bounds); 3058 } else { 3059 canvas.save(); 3060 canvas.clipRect(bounds); 3061 } 3062 3063 divider.draw(canvas); 3064 3065 if (clipDivider) { 3066 canvas.restore(); 3067 } 3068 } 3069 3070 /** 3071 * Returns the drawable that will be drawn between each item in the list. 3072 * 3073 * @return the current drawable drawn between list elements 3074 */ 3075 public Drawable getDivider() { 3076 return mDivider; 3077 } 3078 3079 /** 3080 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3081 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3082 * 3083 * @param divider The drawable to use. 3084 */ 3085 public void setDivider(Drawable divider) { 3086 if (divider != null) { 3087 mDividerHeight = divider.getIntrinsicHeight(); 3088 mClipDivider = divider instanceof ColorDrawable; 3089 } else { 3090 mDividerHeight = 0; 3091 mClipDivider = false; 3092 } 3093 mDivider = divider; 3094 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3095 requestLayoutIfNecessary(); 3096 } 3097 3098 /** 3099 * @return Returns the height of the divider that will be drawn between each item in the list. 3100 */ 3101 public int getDividerHeight() { 3102 return mDividerHeight; 3103 } 3104 3105 /** 3106 * Sets the height of the divider that will be drawn between each item in the list. Calling 3107 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3108 * 3109 * @param height The new height of the divider in pixels. 3110 */ 3111 public void setDividerHeight(int height) { 3112 mDividerHeight = height; 3113 requestLayoutIfNecessary(); 3114 } 3115 3116 /** 3117 * Enables or disables the drawing of the divider for header views. 3118 * 3119 * @param headerDividersEnabled True to draw the headers, false otherwise. 3120 * 3121 * @see #setFooterDividersEnabled(boolean) 3122 * @see #addHeaderView(android.view.View) 3123 */ 3124 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3125 mHeaderDividersEnabled = headerDividersEnabled; 3126 invalidate(); 3127 } 3128 3129 /** 3130 * Enables or disables the drawing of the divider for footer views. 3131 * 3132 * @param footerDividersEnabled True to draw the footers, false otherwise. 3133 * 3134 * @see #setHeaderDividersEnabled(boolean) 3135 * @see #addFooterView(android.view.View) 3136 */ 3137 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3138 mFooterDividersEnabled = footerDividersEnabled; 3139 invalidate(); 3140 } 3141 3142 @Override 3143 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3144 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3145 3146 int closetChildIndex = -1; 3147 if (gainFocus && previouslyFocusedRect != null) { 3148 previouslyFocusedRect.offset(mScrollX, mScrollY); 3149 3150 final ListAdapter adapter = mAdapter; 3151 // Don't cache the result of getChildCount or mFirstPosition here, 3152 // it could change in layoutChildren. 3153 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3154 mLayoutMode = LAYOUT_NORMAL; 3155 layoutChildren(); 3156 } 3157 3158 // figure out which item should be selected based on previously 3159 // focused rect 3160 Rect otherRect = mTempRect; 3161 int minDistance = Integer.MAX_VALUE; 3162 final int childCount = getChildCount(); 3163 final int firstPosition = mFirstPosition; 3164 3165 for (int i = 0; i < childCount; i++) { 3166 // only consider selectable views 3167 if (!adapter.isEnabled(firstPosition + i)) { 3168 continue; 3169 } 3170 3171 View other = getChildAt(i); 3172 other.getDrawingRect(otherRect); 3173 offsetDescendantRectToMyCoords(other, otherRect); 3174 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3175 3176 if (distance < minDistance) { 3177 minDistance = distance; 3178 closetChildIndex = i; 3179 } 3180 } 3181 } 3182 3183 if (closetChildIndex >= 0) { 3184 setSelection(closetChildIndex + mFirstPosition); 3185 } else { 3186 requestLayout(); 3187 } 3188 } 3189 3190 3191 /* 3192 * (non-Javadoc) 3193 * 3194 * Children specified in XML are assumed to be header views. After we have 3195 * parsed them move them out of the children list and into mHeaderViews. 3196 */ 3197 @Override 3198 protected void onFinishInflate() { 3199 super.onFinishInflate(); 3200 3201 int count = getChildCount(); 3202 if (count > 0) { 3203 for (int i = 0; i < count; ++i) { 3204 addHeaderView(getChildAt(i)); 3205 } 3206 removeAllViews(); 3207 } 3208 } 3209 3210 /* (non-Javadoc) 3211 * @see android.view.View#findViewById(int) 3212 * First look in our children, then in any header and footer views that may be scrolled off. 3213 */ 3214 @Override 3215 protected View findViewTraversal(int id) { 3216 View v; 3217 v = super.findViewTraversal(id); 3218 if (v == null) { 3219 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3220 if (v != null) { 3221 return v; 3222 } 3223 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3224 if (v != null) { 3225 return v; 3226 } 3227 } 3228 return v; 3229 } 3230 3231 /* (non-Javadoc) 3232 * 3233 * Look in the passed in list of headers or footers for the view. 3234 */ 3235 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3236 if (where != null) { 3237 int len = where.size(); 3238 View v; 3239 3240 for (int i = 0; i < len; i++) { 3241 v = where.get(i).view; 3242 3243 if (!v.isRootNamespace()) { 3244 v = v.findViewById(id); 3245 3246 if (v != null) { 3247 return v; 3248 } 3249 } 3250 } 3251 } 3252 return null; 3253 } 3254 3255 /* (non-Javadoc) 3256 * @see android.view.View#findViewWithTag(String) 3257 * First look in our children, then in any header and footer views that may be scrolled off. 3258 */ 3259 @Override 3260 protected View findViewWithTagTraversal(Object tag) { 3261 View v; 3262 v = super.findViewWithTagTraversal(tag); 3263 if (v == null) { 3264 v = findViewTagInHeadersOrFooters(mHeaderViewInfos, tag); 3265 if (v != null) { 3266 return v; 3267 } 3268 3269 v = findViewTagInHeadersOrFooters(mFooterViewInfos, tag); 3270 if (v != null) { 3271 return v; 3272 } 3273 } 3274 return v; 3275 } 3276 3277 /* (non-Javadoc) 3278 * 3279 * Look in the passed in list of headers or footers for the view with the tag. 3280 */ 3281 View findViewTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3282 if (where != null) { 3283 int len = where.size(); 3284 View v; 3285 3286 for (int i = 0; i < len; i++) { 3287 v = where.get(i).view; 3288 3289 if (!v.isRootNamespace()) { 3290 v = v.findViewWithTag(tag); 3291 3292 if (v != null) { 3293 return v; 3294 } 3295 } 3296 } 3297 } 3298 return null; 3299 } 3300 3301 @Override 3302 public boolean onTouchEvent(MotionEvent ev) { 3303 if (mItemsCanFocus && ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { 3304 // Don't handle edge touches immediately -- they may actually belong to one of our 3305 // descendants. 3306 return false; 3307 } 3308 return super.onTouchEvent(ev); 3309 } 3310 3311 /** 3312 * Returns the set of checked items ids. The result is only valid if the 3313 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3314 * 3315 * @return A new array which contains the id of each checked item in the 3316 * list. 3317 * 3318 * @deprecated Use {@link #getCheckedItemIds()} instead. 3319 */ 3320 @Deprecated 3321 public long[] getCheckItemIds() { 3322 // Use new behavior that correctly handles stable ID mapping. 3323 if (mAdapter != null && mAdapter.hasStableIds()) { 3324 return getCheckedItemIds(); 3325 } 3326 3327 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3328 // Fall back to it to support legacy apps. 3329 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3330 final SparseBooleanArray states = mCheckStates; 3331 final int count = states.size(); 3332 final long[] ids = new long[count]; 3333 final ListAdapter adapter = mAdapter; 3334 3335 int checkedCount = 0; 3336 for (int i = 0; i < count; i++) { 3337 if (states.valueAt(i)) { 3338 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3339 } 3340 } 3341 3342 // Trim array if needed. mCheckStates may contain false values 3343 // resulting in checkedCount being smaller than count. 3344 if (checkedCount == count) { 3345 return ids; 3346 } else { 3347 final long[] result = new long[checkedCount]; 3348 System.arraycopy(ids, 0, result, 0, checkedCount); 3349 3350 return result; 3351 } 3352 } 3353 return new long[0]; 3354 } 3355} 3356