ListView.java revision 0bf88594c43ced48d862d122e3e84967b3b63658
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.res.TypedArray; 24import android.graphics.Canvas; 25import android.graphics.Paint; 26import android.graphics.PixelFormat; 27import android.graphics.Rect; 28import android.graphics.drawable.ColorDrawable; 29import android.graphics.drawable.Drawable; 30import android.os.Parcel; 31import android.os.Parcelable; 32import android.util.AttributeSet; 33import android.util.SparseBooleanArray; 34import android.view.FocusFinder; 35import android.view.KeyEvent; 36import android.view.MotionEvent; 37import android.view.SoundEffectConstants; 38import android.view.View; 39import android.view.ViewDebug; 40import android.view.ViewGroup; 41import android.view.ViewParent; 42import android.view.accessibility.AccessibilityEvent; 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_choiceMode 64 * @attr ref android.R.styleable#ListView_headerDividersEnabled 65 * @attr ref android.R.styleable#ListView_footerDividersEnabled 66 */ 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 * Normal list that does not indicate choices 75 */ 76 public static final int CHOICE_MODE_NONE = 0; 77 78 /** 79 * The list allows up to one choice 80 */ 81 public static final int CHOICE_MODE_SINGLE = 1; 82 83 /** 84 * The list allows multiple choices 85 */ 86 public static final int CHOICE_MODE_MULTIPLE = 2; 87 88 /** 89 * When arrow scrolling, ListView will never scroll more than this factor 90 * times the height of the list. 91 */ 92 private static final float MAX_SCROLL_FACTOR = 0.33f; 93 94 /** 95 * When arrow scrolling, need a certain amount of pixels to preview next 96 * items. This is usually the fading edge, but if that is small enough, 97 * we want to make sure we preview at least this many pixels. 98 */ 99 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 100 101 /** 102 * A class that represents a fixed view in a list, for example a header at the top 103 * or a footer at the bottom. 104 */ 105 public class FixedViewInfo { 106 /** The view to add to the list */ 107 public View view; 108 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 109 public Object data; 110 /** <code>true</code> if the fixed view should be selectable in the list */ 111 public boolean isSelectable; 112 } 113 114 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 115 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 116 117 Drawable mDivider; 118 int mDividerHeight; 119 120 private boolean mIsCacheColorOpaque; 121 private boolean mDividerIsOpaque; 122 private boolean mClipDivider; 123 124 private boolean mHeaderDividersEnabled; 125 private boolean mFooterDividersEnabled; 126 127 private boolean mAreAllItemsSelectable = true; 128 129 private boolean mItemsCanFocus = false; 130 131 private int mChoiceMode = CHOICE_MODE_NONE; 132 133 private SparseBooleanArray mCheckStates; 134 135 // used for temporary calculations. 136 private final Rect mTempRect = new Rect(); 137 private Paint mDividerPaint; 138 139 // the single allocated result per list view; kinda cheesey but avoids 140 // allocating these thingies too often. 141 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 142 143 // Keeps focused children visible through resizes 144 private FocusSelector mFocusSelector; 145 146 public ListView(Context context) { 147 this(context, null); 148 } 149 150 public ListView(Context context, AttributeSet attrs) { 151 this(context, attrs, com.android.internal.R.attr.listViewStyle); 152 } 153 154 public ListView(Context context, AttributeSet attrs, int defStyle) { 155 super(context, attrs, defStyle); 156 157 TypedArray a = context.obtainStyledAttributes(attrs, 158 com.android.internal.R.styleable.ListView, defStyle, 0); 159 160 CharSequence[] entries = a.getTextArray( 161 com.android.internal.R.styleable.ListView_entries); 162 if (entries != null) { 163 setAdapter(new ArrayAdapter<CharSequence>(context, 164 com.android.internal.R.layout.simple_list_item_1, entries)); 165 } 166 167 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 168 if (d != null) { 169 // If a divider is specified use its intrinsic height for divider height 170 setDivider(d); 171 } 172 173 // Use the height specified, zero being the default 174 final int dividerHeight = a.getDimensionPixelSize( 175 com.android.internal.R.styleable.ListView_dividerHeight, 0); 176 if (dividerHeight != 0) { 177 setDividerHeight(dividerHeight); 178 } 179 180 setChoiceMode(a.getInt(R.styleable.ListView_choiceMode, CHOICE_MODE_NONE)); 181 182 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 183 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 184 185 a.recycle(); 186 } 187 188 /** 189 * @return The maximum amount a list view will scroll in response to 190 * an arrow event. 191 */ 192 public int getMaxScrollAmount() { 193 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 194 } 195 196 /** 197 * Make sure views are touching the top or bottom edge, as appropriate for 198 * our gravity 199 */ 200 private void adjustViewsUpOrDown() { 201 final int childCount = getChildCount(); 202 int delta; 203 204 if (childCount > 0) { 205 View child; 206 207 if (!mStackFromBottom) { 208 // Uh-oh -- we came up short. Slide all views up to make them 209 // align with the top 210 child = getChildAt(0); 211 delta = child.getTop() - mListPadding.top; 212 if (mFirstPosition != 0) { 213 // It's OK to have some space above the first item if it is 214 // part of the vertical spacing 215 delta -= mDividerHeight; 216 } 217 if (delta < 0) { 218 // We only are looking to see if we are too low, not too high 219 delta = 0; 220 } 221 } else { 222 // we are too high, slide all views down to align with bottom 223 child = getChildAt(childCount - 1); 224 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 225 226 if (mFirstPosition + childCount < mItemCount) { 227 // It's OK to have some space below the last item if it is 228 // part of the vertical spacing 229 delta += mDividerHeight; 230 } 231 232 if (delta > 0) { 233 delta = 0; 234 } 235 } 236 237 if (delta != 0) { 238 offsetChildrenTopAndBottom(-delta); 239 } 240 } 241 } 242 243 /** 244 * Add a fixed view to appear at the top of the list. If addHeaderView is 245 * called more than once, the views will appear in the order they were 246 * added. Views added using this call can take focus if they want. 247 * <p> 248 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 249 * the supplied cursor with one that will also account for header and footer 250 * views. 251 * 252 * @param v The view to add. 253 * @param data Data to associate with this view 254 * @param isSelectable whether the item is selectable 255 */ 256 public void addHeaderView(View v, Object data, boolean isSelectable) { 257 258 if (mAdapter != null) { 259 throw new IllegalStateException( 260 "Cannot add header view to list -- setAdapter has already been called."); 261 } 262 263 FixedViewInfo info = new FixedViewInfo(); 264 info.view = v; 265 info.data = data; 266 info.isSelectable = isSelectable; 267 mHeaderViewInfos.add(info); 268 } 269 270 /** 271 * Add a fixed view to appear at the top of the list. If addHeaderView is 272 * called more than once, the views will appear in the order they were 273 * added. Views added using this call can take focus if they want. 274 * <p> 275 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 276 * the supplied cursor with one that will also account for header and footer 277 * views. 278 * 279 * @param v The view to add. 280 */ 281 public void addHeaderView(View v) { 282 addHeaderView(v, null, true); 283 } 284 285 @Override 286 public int getHeaderViewsCount() { 287 return mHeaderViewInfos.size(); 288 } 289 290 /** 291 * Removes a previously-added header view. 292 * 293 * @param v The view to remove 294 * @return true if the view was removed, false if the view was not a header 295 * view 296 */ 297 public boolean removeHeaderView(View v) { 298 if (mHeaderViewInfos.size() > 0) { 299 boolean result = false; 300 if (((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 301 mDataSetObserver.onChanged(); 302 result = true; 303 } 304 removeFixedViewInfo(v, mHeaderViewInfos); 305 return result; 306 } 307 return false; 308 } 309 310 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 311 int len = where.size(); 312 for (int i = 0; i < len; ++i) { 313 FixedViewInfo info = where.get(i); 314 if (info.view == v) { 315 where.remove(i); 316 break; 317 } 318 } 319 } 320 321 /** 322 * Add a fixed view to appear at the bottom of the list. If addFooterView is 323 * called more than once, the views will appear in the order they were 324 * added. Views added using this call can take focus if they want. 325 * <p> 326 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 327 * the supplied cursor with one that will also account for header and footer 328 * views. 329 * 330 * @param v The view to add. 331 * @param data Data to associate with this view 332 * @param isSelectable true if the footer view can be selected 333 */ 334 public void addFooterView(View v, Object data, boolean isSelectable) { 335 FixedViewInfo info = new FixedViewInfo(); 336 info.view = v; 337 info.data = data; 338 info.isSelectable = isSelectable; 339 mFooterViewInfos.add(info); 340 341 // in the case of re-adding a footer view, or adding one later on, 342 // we need to notify the observer 343 if (mDataSetObserver != null) { 344 mDataSetObserver.onChanged(); 345 } 346 } 347 348 /** 349 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 350 * than once, the views will appear in the order they were added. Views added using 351 * this call can take focus if they want. 352 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 353 * cursor with one that will also account for header and footer views. 354 * 355 * 356 * @param v The view to add. 357 */ 358 public void addFooterView(View v) { 359 addFooterView(v, null, true); 360 } 361 362 @Override 363 public int getFooterViewsCount() { 364 return mFooterViewInfos.size(); 365 } 366 367 /** 368 * Removes a previously-added footer view. 369 * 370 * @param v The view to remove 371 * @return 372 * true if the view was removed, false if the view was not a footer view 373 */ 374 public boolean removeFooterView(View v) { 375 if (mFooterViewInfos.size() > 0) { 376 boolean result = false; 377 if (((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 378 mDataSetObserver.onChanged(); 379 result = true; 380 } 381 removeFixedViewInfo(v, mFooterViewInfos); 382 return result; 383 } 384 return false; 385 } 386 387 /** 388 * Returns the adapter currently in use in this ListView. The returned adapter 389 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 390 * might be a {@link WrapperListAdapter}. 391 * 392 * @return The adapter currently used to display data in this ListView. 393 * 394 * @see #setAdapter(ListAdapter) 395 */ 396 @Override 397 public ListAdapter getAdapter() { 398 return mAdapter; 399 } 400 401 /** 402 * Sets the data behind this ListView. 403 * 404 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 405 * depending on the ListView features currently in use. For instance, adding 406 * headers and/or footers will cause the adapter to be wrapped. 407 * 408 * @param adapter The ListAdapter which is responsible for maintaining the 409 * data backing this list and for producing a view to represent an 410 * item in that data set. 411 * 412 * @see #getAdapter() 413 */ 414 @Override 415 public void setAdapter(ListAdapter adapter) { 416 if (null != mAdapter) { 417 mAdapter.unregisterDataSetObserver(mDataSetObserver); 418 } 419 420 resetList(); 421 mRecycler.clear(); 422 423 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 424 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 425 } else { 426 mAdapter = adapter; 427 } 428 429 mOldSelectedPosition = INVALID_POSITION; 430 mOldSelectedRowId = INVALID_ROW_ID; 431 if (mAdapter != null) { 432 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 433 mOldItemCount = mItemCount; 434 mItemCount = mAdapter.getCount(); 435 checkFocus(); 436 437 mDataSetObserver = new AdapterDataSetObserver(); 438 mAdapter.registerDataSetObserver(mDataSetObserver); 439 440 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 441 442 int position; 443 if (mStackFromBottom) { 444 position = lookForSelectablePosition(mItemCount - 1, false); 445 } else { 446 position = lookForSelectablePosition(0, true); 447 } 448 setSelectedPositionInt(position); 449 setNextSelectedPositionInt(position); 450 451 if (mItemCount == 0) { 452 // Nothing selected 453 checkSelectionChanged(); 454 } 455 456 } else { 457 mAreAllItemsSelectable = true; 458 checkFocus(); 459 // Nothing selected 460 checkSelectionChanged(); 461 } 462 463 if (mCheckStates != null) { 464 mCheckStates.clear(); 465 } 466 467 requestLayout(); 468 } 469 470 471 /** 472 * The list is empty. Clear everything out. 473 */ 474 @Override 475 void resetList() { 476 // The parent's resetList() will remove all views from the layout so we need to 477 // cleanup the state of our footers and headers 478 clearRecycledState(mHeaderViewInfos); 479 clearRecycledState(mFooterViewInfos); 480 481 super.resetList(); 482 483 mLayoutMode = LAYOUT_NORMAL; 484 } 485 486 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 487 if (infos != null) { 488 final int count = infos.size(); 489 490 for (int i = 0; i < count; i++) { 491 final View child = infos.get(i).view; 492 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 493 if (p != null) { 494 p.recycledHeaderFooter = false; 495 } 496 } 497 } 498 } 499 500 /** 501 * @return Whether the list needs to show the top fading edge 502 */ 503 private boolean showingTopFadingEdge() { 504 final int listTop = mScrollY + mListPadding.top; 505 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 506 } 507 508 /** 509 * @return Whether the list needs to show the bottom fading edge 510 */ 511 private boolean showingBottomFadingEdge() { 512 final int childCount = getChildCount(); 513 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 514 final int lastVisiblePosition = mFirstPosition + childCount - 1; 515 516 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 517 518 return (lastVisiblePosition < mItemCount - 1) 519 || (bottomOfBottomChild < listBottom); 520 } 521 522 523 @Override 524 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 525 526 int rectTopWithinChild = rect.top; 527 528 // offset so rect is in coordinates of the this view 529 rect.offset(child.getLeft(), child.getTop()); 530 rect.offset(-child.getScrollX(), -child.getScrollY()); 531 532 final int height = getHeight(); 533 int listUnfadedTop = getScrollY(); 534 int listUnfadedBottom = listUnfadedTop + height; 535 final int fadingEdge = getVerticalFadingEdgeLength(); 536 537 if (showingTopFadingEdge()) { 538 // leave room for top fading edge as long as rect isn't at very top 539 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 540 listUnfadedTop += fadingEdge; 541 } 542 } 543 544 int childCount = getChildCount(); 545 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 546 547 if (showingBottomFadingEdge()) { 548 // leave room for bottom fading edge as long as rect isn't at very bottom 549 if ((mSelectedPosition < mItemCount - 1) 550 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 551 listUnfadedBottom -= fadingEdge; 552 } 553 } 554 555 int scrollYDelta = 0; 556 557 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 558 // need to MOVE DOWN to get it in view: move down just enough so 559 // that the entire rectangle is in view (or at least the first 560 // screen size chunk). 561 562 if (rect.height() > height) { 563 // just enough to get screen size chunk on 564 scrollYDelta += (rect.top - listUnfadedTop); 565 } else { 566 // get entire rect at bottom of screen 567 scrollYDelta += (rect.bottom - listUnfadedBottom); 568 } 569 570 // make sure we aren't scrolling beyond the end of our children 571 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 572 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 573 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 574 // need to MOVE UP to get it in view: move up just enough so that 575 // entire rectangle is in view (or at least the first screen 576 // size chunk of it). 577 578 if (rect.height() > height) { 579 // screen size chunk 580 scrollYDelta -= (listUnfadedBottom - rect.bottom); 581 } else { 582 // entire rect at top 583 scrollYDelta -= (listUnfadedTop - rect.top); 584 } 585 586 // make sure we aren't scrolling any further than the top our children 587 int top = getChildAt(0).getTop(); 588 int deltaToTop = top - listUnfadedTop; 589 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 590 } 591 592 final boolean scroll = scrollYDelta != 0; 593 if (scroll) { 594 scrollListItemsBy(-scrollYDelta); 595 positionSelector(child); 596 mSelectedTop = child.getTop(); 597 invalidate(); 598 } 599 return scroll; 600 } 601 602 /** 603 * {@inheritDoc} 604 */ 605 @Override 606 void fillGap(boolean down) { 607 final int count = getChildCount(); 608 if (down) { 609 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 610 getListPaddingTop(); 611 fillDown(mFirstPosition + count, startOffset); 612 correctTooHigh(getChildCount()); 613 } else { 614 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 615 getHeight() - getListPaddingBottom(); 616 fillUp(mFirstPosition - 1, startOffset); 617 correctTooLow(getChildCount()); 618 } 619 } 620 621 /** 622 * Fills the list from pos down to the end of the list view. 623 * 624 * @param pos The first position to put in the list 625 * 626 * @param nextTop The location where the top of the item associated with pos 627 * should be drawn 628 * 629 * @return The view that is currently selected, if it happens to be in the 630 * range that we draw. 631 */ 632 private View fillDown(int pos, int nextTop) { 633 View selectedView = null; 634 635 int end = (mBottom - mTop) - mListPadding.bottom; 636 637 while (nextTop < end && pos < mItemCount) { 638 // is this the selected item? 639 boolean selected = pos == mSelectedPosition; 640 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 641 642 nextTop = child.getBottom() + mDividerHeight; 643 if (selected) { 644 selectedView = child; 645 } 646 pos++; 647 } 648 649 return selectedView; 650 } 651 652 /** 653 * Fills the list from pos up to the top of the list view. 654 * 655 * @param pos The first position to put in the list 656 * 657 * @param nextBottom The location where the bottom of the item associated 658 * with pos should be drawn 659 * 660 * @return The view that is currently selected 661 */ 662 private View fillUp(int pos, int nextBottom) { 663 View selectedView = null; 664 665 int end = mListPadding.top; 666 667 while (nextBottom > end && pos >= 0) { 668 // is this the selected item? 669 boolean selected = pos == mSelectedPosition; 670 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 671 nextBottom = child.getTop() - mDividerHeight; 672 if (selected) { 673 selectedView = child; 674 } 675 pos--; 676 } 677 678 mFirstPosition = pos + 1; 679 680 return selectedView; 681 } 682 683 /** 684 * Fills the list from top to bottom, starting with mFirstPosition 685 * 686 * @param nextTop The location where the top of the first item should be 687 * drawn 688 * 689 * @return The view that is currently selected 690 */ 691 private View fillFromTop(int nextTop) { 692 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 693 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 694 if (mFirstPosition < 0) { 695 mFirstPosition = 0; 696 } 697 return fillDown(mFirstPosition, nextTop); 698 } 699 700 701 /** 702 * Put mSelectedPosition in the middle of the screen and then build up and 703 * down from there. This method forces mSelectedPosition to the center. 704 * 705 * @param childrenTop Top of the area in which children can be drawn, as 706 * measured in pixels 707 * @param childrenBottom Bottom of the area in which children can be drawn, 708 * as measured in pixels 709 * @return Currently selected view 710 */ 711 private View fillFromMiddle(int childrenTop, int childrenBottom) { 712 int height = childrenBottom - childrenTop; 713 714 int position = reconcileSelectedPosition(); 715 716 View sel = makeAndAddView(position, childrenTop, true, 717 mListPadding.left, true); 718 mFirstPosition = position; 719 720 int selHeight = sel.getMeasuredHeight(); 721 if (selHeight <= height) { 722 sel.offsetTopAndBottom((height - selHeight) / 2); 723 } 724 725 fillAboveAndBelow(sel, position); 726 727 if (!mStackFromBottom) { 728 correctTooHigh(getChildCount()); 729 } else { 730 correctTooLow(getChildCount()); 731 } 732 733 return sel; 734 } 735 736 /** 737 * Once the selected view as been placed, fill up the visible area above and 738 * below it. 739 * 740 * @param sel The selected view 741 * @param position The position corresponding to sel 742 */ 743 private void fillAboveAndBelow(View sel, int position) { 744 final int dividerHeight = mDividerHeight; 745 if (!mStackFromBottom) { 746 fillUp(position - 1, sel.getTop() - dividerHeight); 747 adjustViewsUpOrDown(); 748 fillDown(position + 1, sel.getBottom() + dividerHeight); 749 } else { 750 fillDown(position + 1, sel.getBottom() + dividerHeight); 751 adjustViewsUpOrDown(); 752 fillUp(position - 1, sel.getTop() - dividerHeight); 753 } 754 } 755 756 757 /** 758 * Fills the grid based on positioning the new selection at a specific 759 * location. The selection may be moved so that it does not intersect the 760 * faded edges. The grid is then filled upwards and downwards from there. 761 * 762 * @param selectedTop Where the selected item should be 763 * @param childrenTop Where to start drawing children 764 * @param childrenBottom Last pixel where children can be drawn 765 * @return The view that currently has selection 766 */ 767 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 768 int fadingEdgeLength = getVerticalFadingEdgeLength(); 769 final int selectedPosition = mSelectedPosition; 770 771 View sel; 772 773 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 774 selectedPosition); 775 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 776 selectedPosition); 777 778 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 779 780 781 // Some of the newly selected item extends below the bottom of the list 782 if (sel.getBottom() > bottomSelectionPixel) { 783 // Find space available above the selection into which we can scroll 784 // upwards 785 final int spaceAbove = sel.getTop() - topSelectionPixel; 786 787 // Find space required to bring the bottom of the selected item 788 // fully into view 789 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 790 final int offset = Math.min(spaceAbove, spaceBelow); 791 792 // Now offset the selected item to get it into view 793 sel.offsetTopAndBottom(-offset); 794 } else if (sel.getTop() < topSelectionPixel) { 795 // Find space required to bring the top of the selected item fully 796 // into view 797 final int spaceAbove = topSelectionPixel - sel.getTop(); 798 799 // Find space available below the selection into which we can scroll 800 // downwards 801 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 802 final int offset = Math.min(spaceAbove, spaceBelow); 803 804 // Offset the selected item to get it into view 805 sel.offsetTopAndBottom(offset); 806 } 807 808 // Fill in views above and below 809 fillAboveAndBelow(sel, selectedPosition); 810 811 if (!mStackFromBottom) { 812 correctTooHigh(getChildCount()); 813 } else { 814 correctTooLow(getChildCount()); 815 } 816 817 return sel; 818 } 819 820 /** 821 * Calculate the bottom-most pixel we can draw the selection into 822 * 823 * @param childrenBottom Bottom pixel were children can be drawn 824 * @param fadingEdgeLength Length of the fading edge in pixels, if present 825 * @param selectedPosition The position that will be selected 826 * @return The bottom-most pixel we can draw the selection into 827 */ 828 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 829 int selectedPosition) { 830 int bottomSelectionPixel = childrenBottom; 831 if (selectedPosition != mItemCount - 1) { 832 bottomSelectionPixel -= fadingEdgeLength; 833 } 834 return bottomSelectionPixel; 835 } 836 837 /** 838 * Calculate the top-most pixel we can draw the selection into 839 * 840 * @param childrenTop Top pixel were children can be drawn 841 * @param fadingEdgeLength Length of the fading edge in pixels, if present 842 * @param selectedPosition The position that will be selected 843 * @return The top-most pixel we can draw the selection into 844 */ 845 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 846 // first pixel we can draw the selection into 847 int topSelectionPixel = childrenTop; 848 if (selectedPosition > 0) { 849 topSelectionPixel += fadingEdgeLength; 850 } 851 return topSelectionPixel; 852 } 853 854 855 /** 856 * Fills the list based on positioning the new selection relative to the old 857 * selection. The new selection will be placed at, above, or below the 858 * location of the new selection depending on how the selection is moving. 859 * The selection will then be pinned to the visible part of the screen, 860 * excluding the edges that are faded. The list is then filled upwards and 861 * downwards from there. 862 * 863 * @param oldSel The old selected view. Useful for trying to put the new 864 * selection in the same place 865 * @param newSel The view that is to become selected. Useful for trying to 866 * put the new selection in the same place 867 * @param delta Which way we are moving 868 * @param childrenTop Where to start drawing children 869 * @param childrenBottom Last pixel where children can be drawn 870 * @return The view that currently has selection 871 */ 872 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 873 int childrenBottom) { 874 int fadingEdgeLength = getVerticalFadingEdgeLength(); 875 final int selectedPosition = mSelectedPosition; 876 877 View sel; 878 879 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 880 selectedPosition); 881 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 882 selectedPosition); 883 884 if (delta > 0) { 885 /* 886 * Case 1: Scrolling down. 887 */ 888 889 /* 890 * Before After 891 * | | | | 892 * +-------+ +-------+ 893 * | A | | A | 894 * | 1 | => +-------+ 895 * +-------+ | B | 896 * | B | | 2 | 897 * +-------+ +-------+ 898 * | | | | 899 * 900 * Try to keep the top of the previously selected item where it was. 901 * oldSel = A 902 * sel = B 903 */ 904 905 // Put oldSel (A) where it belongs 906 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 907 mListPadding.left, false); 908 909 final int dividerHeight = mDividerHeight; 910 911 // Now put the new selection (B) below that 912 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 913 mListPadding.left, true); 914 915 // Some of the newly selected item extends below the bottom of the list 916 if (sel.getBottom() > bottomSelectionPixel) { 917 918 // Find space available above the selection into which we can scroll upwards 919 int spaceAbove = sel.getTop() - topSelectionPixel; 920 921 // Find space required to bring the bottom of the selected item fully into view 922 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 923 924 // Don't scroll more than half the height of the list 925 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 926 int offset = Math.min(spaceAbove, spaceBelow); 927 offset = Math.min(offset, halfVerticalSpace); 928 929 // We placed oldSel, so offset that item 930 oldSel.offsetTopAndBottom(-offset); 931 // Now offset the selected item to get it into view 932 sel.offsetTopAndBottom(-offset); 933 } 934 935 // Fill in views above and below 936 if (!mStackFromBottom) { 937 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 938 adjustViewsUpOrDown(); 939 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 940 } else { 941 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 942 adjustViewsUpOrDown(); 943 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 944 } 945 } else if (delta < 0) { 946 /* 947 * Case 2: Scrolling up. 948 */ 949 950 /* 951 * Before After 952 * | | | | 953 * +-------+ +-------+ 954 * | A | | A | 955 * +-------+ => | 1 | 956 * | B | +-------+ 957 * | 2 | | B | 958 * +-------+ +-------+ 959 * | | | | 960 * 961 * Try to keep the top of the item about to become selected where it was. 962 * newSel = A 963 * olSel = B 964 */ 965 966 if (newSel != null) { 967 // Try to position the top of newSel (A) where it was before it was selected 968 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 969 true); 970 } else { 971 // If (A) was not on screen and so did not have a view, position 972 // it above the oldSel (B) 973 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 974 true); 975 } 976 977 // Some of the newly selected item extends above the top of the list 978 if (sel.getTop() < topSelectionPixel) { 979 // Find space required to bring the top of the selected item fully into view 980 int spaceAbove = topSelectionPixel - sel.getTop(); 981 982 // Find space available below the selection into which we can scroll downwards 983 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 984 985 // Don't scroll more than half the height of the list 986 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 987 int offset = Math.min(spaceAbove, spaceBelow); 988 offset = Math.min(offset, halfVerticalSpace); 989 990 // Offset the selected item to get it into view 991 sel.offsetTopAndBottom(offset); 992 } 993 994 // Fill in views above and below 995 fillAboveAndBelow(sel, selectedPosition); 996 } else { 997 998 int oldTop = oldSel.getTop(); 999 1000 /* 1001 * Case 3: Staying still 1002 */ 1003 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1004 1005 // We're staying still... 1006 if (oldTop < childrenTop) { 1007 // ... but the top of the old selection was off screen. 1008 // (This can happen if the data changes size out from under us) 1009 int newBottom = sel.getBottom(); 1010 if (newBottom < childrenTop + 20) { 1011 // Not enough visible -- bring it onscreen 1012 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1013 } 1014 } 1015 1016 // Fill in views above and below 1017 fillAboveAndBelow(sel, selectedPosition); 1018 } 1019 1020 return sel; 1021 } 1022 1023 private class FocusSelector implements Runnable { 1024 private int mPosition; 1025 private int mPositionTop; 1026 1027 public FocusSelector setup(int position, int top) { 1028 mPosition = position; 1029 mPositionTop = top; 1030 return this; 1031 } 1032 1033 public void run() { 1034 setSelectionFromTop(mPosition, mPositionTop); 1035 } 1036 } 1037 1038 @Override 1039 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1040 if (getChildCount() > 0) { 1041 View focusedChild = getFocusedChild(); 1042 if (focusedChild != null) { 1043 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1044 final int childBottom = focusedChild.getBottom(); 1045 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1046 final int top = focusedChild.getTop() - offset; 1047 if (mFocusSelector == null) { 1048 mFocusSelector = new FocusSelector(); 1049 } 1050 post(mFocusSelector.setup(childPosition, top)); 1051 } 1052 } 1053 super.onSizeChanged(w, h, oldw, oldh); 1054 } 1055 1056 @Override 1057 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1058 // Sets up mListPadding 1059 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1060 1061 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1062 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1063 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1064 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1065 1066 int childWidth = 0; 1067 int childHeight = 0; 1068 1069 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1070 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1071 heightMode == MeasureSpec.UNSPECIFIED)) { 1072 final View child = obtainView(0, mIsScrap); 1073 1074 measureScrapChild(child, 0, widthMeasureSpec); 1075 1076 childWidth = child.getMeasuredWidth(); 1077 childHeight = child.getMeasuredHeight(); 1078 1079 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1080 ((LayoutParams) child.getLayoutParams()).viewType)) { 1081 mRecycler.addScrapView(child); 1082 } 1083 } 1084 1085 if (widthMode == MeasureSpec.UNSPECIFIED) { 1086 widthSize = mListPadding.left + mListPadding.right + childWidth + 1087 getVerticalScrollbarWidth(); 1088 } 1089 1090 if (heightMode == MeasureSpec.UNSPECIFIED) { 1091 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1092 getVerticalFadingEdgeLength() * 2; 1093 } 1094 1095 if (heightMode == MeasureSpec.AT_MOST) { 1096 // TODO: after first layout we should maybe start at the first visible position, not 0 1097 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1098 } 1099 1100 setMeasuredDimension(widthSize, heightSize); 1101 mWidthMeasureSpec = widthMeasureSpec; 1102 } 1103 1104 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1105 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1106 if (p == null) { 1107 p = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1108 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1109 child.setLayoutParams(p); 1110 } 1111 p.viewType = mAdapter.getItemViewType(position); 1112 p.forceAdd = true; 1113 1114 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1115 mListPadding.left + mListPadding.right, p.width); 1116 int lpHeight = p.height; 1117 int childHeightSpec; 1118 if (lpHeight > 0) { 1119 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1120 } else { 1121 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1122 } 1123 child.measure(childWidthSpec, childHeightSpec); 1124 } 1125 1126 /** 1127 * @return True to recycle the views used to measure this ListView in 1128 * UNSPECIFIED/AT_MOST modes, false otherwise. 1129 * @hide 1130 */ 1131 @ViewDebug.ExportedProperty 1132 protected boolean recycleOnMeasure() { 1133 return true; 1134 } 1135 1136 /** 1137 * Measures the height of the given range of children (inclusive) and 1138 * returns the height with this ListView's padding and divider heights 1139 * included. If maxHeight is provided, the measuring will stop when the 1140 * current height reaches maxHeight. 1141 * 1142 * @param widthMeasureSpec The width measure spec to be given to a child's 1143 * {@link View#measure(int, int)}. 1144 * @param startPosition The position of the first child to be shown. 1145 * @param endPosition The (inclusive) position of the last child to be 1146 * shown. Specify {@link #NO_POSITION} if the last child should be 1147 * the last available child from the adapter. 1148 * @param maxHeight The maximum height that will be returned (if all the 1149 * children don't fit in this value, this value will be 1150 * returned). 1151 * @param disallowPartialChildPosition In general, whether the returned 1152 * height should only contain entire children. This is more 1153 * powerful--it is the first inclusive position at which partial 1154 * children will not be allowed. Example: it looks nice to have 1155 * at least 3 completely visible children, and in portrait this 1156 * will most likely fit; but in landscape there could be times 1157 * when even 2 children can not be completely shown, so a value 1158 * of 2 (remember, inclusive) would be good (assuming 1159 * startPosition is 0). 1160 * @return The height of this ListView with the given children. 1161 */ 1162 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1163 final int maxHeight, int disallowPartialChildPosition) { 1164 1165 final ListAdapter adapter = mAdapter; 1166 if (adapter == null) { 1167 return mListPadding.top + mListPadding.bottom; 1168 } 1169 1170 // Include the padding of the list 1171 int returnedHeight = mListPadding.top + mListPadding.bottom; 1172 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1173 // The previous height value that was less than maxHeight and contained 1174 // no partial children 1175 int prevHeightWithoutPartialChild = 0; 1176 int i; 1177 View child; 1178 1179 // mItemCount - 1 since endPosition parameter is inclusive 1180 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1181 final AbsListView.RecycleBin recycleBin = mRecycler; 1182 final boolean recyle = recycleOnMeasure(); 1183 final boolean[] isScrap = mIsScrap; 1184 1185 for (i = startPosition; i <= endPosition; ++i) { 1186 child = obtainView(i, isScrap); 1187 1188 measureScrapChild(child, i, widthMeasureSpec); 1189 1190 if (i > 0) { 1191 // Count the divider for all but one child 1192 returnedHeight += dividerHeight; 1193 } 1194 1195 // Recycle the view before we possibly return from the method 1196 if (recyle && recycleBin.shouldRecycleViewType( 1197 ((LayoutParams) child.getLayoutParams()).viewType)) { 1198 recycleBin.addScrapView(child); 1199 } 1200 1201 returnedHeight += child.getMeasuredHeight(); 1202 1203 if (returnedHeight >= maxHeight) { 1204 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1205 // then the i'th position did not fit completely. 1206 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1207 && (i > disallowPartialChildPosition) // We've past the min pos 1208 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1209 && (returnedHeight != maxHeight) // i'th child did not fit completely 1210 ? prevHeightWithoutPartialChild 1211 : maxHeight; 1212 } 1213 1214 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1215 prevHeightWithoutPartialChild = returnedHeight; 1216 } 1217 } 1218 1219 // At this point, we went through the range of children, and they each 1220 // completely fit, so return the returnedHeight 1221 return returnedHeight; 1222 } 1223 1224 @Override 1225 int findMotionRow(int y) { 1226 int childCount = getChildCount(); 1227 if (childCount > 0) { 1228 for (int i = 0; i < childCount; i++) { 1229 View v = getChildAt(i); 1230 if (y <= v.getBottom()) { 1231 return mFirstPosition + i; 1232 } 1233 } 1234 } 1235 return INVALID_POSITION; 1236 } 1237 1238 /** 1239 * Put a specific item at a specific location on the screen and then build 1240 * up and down from there. 1241 * 1242 * @param position The reference view to use as the starting point 1243 * @param top Pixel offset from the top of this view to the top of the 1244 * reference view. 1245 * 1246 * @return The selected view, or null if the selected view is outside the 1247 * visible area. 1248 */ 1249 private View fillSpecific(int position, int top) { 1250 boolean tempIsSelected = position == mSelectedPosition; 1251 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1252 // Possibly changed again in fillUp if we add rows above this one. 1253 mFirstPosition = position; 1254 1255 View above; 1256 View below; 1257 1258 final int dividerHeight = mDividerHeight; 1259 if (!mStackFromBottom) { 1260 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1261 // This will correct for the top of the first view not touching the top of the list 1262 adjustViewsUpOrDown(); 1263 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1264 int childCount = getChildCount(); 1265 if (childCount > 0) { 1266 correctTooHigh(childCount); 1267 } 1268 } else { 1269 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1270 // This will correct for the bottom of the last view not touching the bottom of the list 1271 adjustViewsUpOrDown(); 1272 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1273 int childCount = getChildCount(); 1274 if (childCount > 0) { 1275 correctTooLow(childCount); 1276 } 1277 } 1278 1279 if (tempIsSelected) { 1280 return temp; 1281 } else if (above != null) { 1282 return above; 1283 } else { 1284 return below; 1285 } 1286 } 1287 1288 /** 1289 * Check if we have dragged the bottom of the list too high (we have pushed the 1290 * top element off the top of the screen when we did not need to). Correct by sliding 1291 * everything back down. 1292 * 1293 * @param childCount Number of children 1294 */ 1295 private void correctTooHigh(int childCount) { 1296 // First see if the last item is visible. If it is not, it is OK for the 1297 // top of the list to be pushed up. 1298 int lastPosition = mFirstPosition + childCount - 1; 1299 if (lastPosition == mItemCount - 1 && childCount > 0) { 1300 1301 // Get the last child ... 1302 final View lastChild = getChildAt(childCount - 1); 1303 1304 // ... and its bottom edge 1305 final int lastBottom = lastChild.getBottom(); 1306 1307 // This is bottom of our drawable area 1308 final int end = (mBottom - mTop) - mListPadding.bottom; 1309 1310 // This is how far the bottom edge of the last view is from the bottom of the 1311 // drawable area 1312 int bottomOffset = end - lastBottom; 1313 View firstChild = getChildAt(0); 1314 final int firstTop = firstChild.getTop(); 1315 1316 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1317 // first row or the first row is scrolled off the top of the drawable area 1318 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1319 if (mFirstPosition == 0) { 1320 // Don't pull the top too far down 1321 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1322 } 1323 // Move everything down 1324 offsetChildrenTopAndBottom(bottomOffset); 1325 if (mFirstPosition > 0) { 1326 // Fill the gap that was opened above mFirstPosition with more rows, if 1327 // possible 1328 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1329 // Close up the remaining gap 1330 adjustViewsUpOrDown(); 1331 } 1332 1333 } 1334 } 1335 } 1336 1337 /** 1338 * Check if we have dragged the bottom of the list too low (we have pushed the 1339 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1340 * everything back up. 1341 * 1342 * @param childCount Number of children 1343 */ 1344 private void correctTooLow(int childCount) { 1345 // First see if the first item is visible. If it is not, it is OK for the 1346 // bottom of the list to be pushed down. 1347 if (mFirstPosition == 0 && childCount > 0) { 1348 1349 // Get the first child ... 1350 final View firstChild = getChildAt(0); 1351 1352 // ... and its top edge 1353 final int firstTop = firstChild.getTop(); 1354 1355 // This is top of our drawable area 1356 final int start = mListPadding.top; 1357 1358 // This is bottom of our drawable area 1359 final int end = (mBottom - mTop) - mListPadding.bottom; 1360 1361 // This is how far the top edge of the first view is from the top of the 1362 // drawable area 1363 int topOffset = firstTop - start; 1364 View lastChild = getChildAt(childCount - 1); 1365 final int lastBottom = lastChild.getBottom(); 1366 int lastPosition = mFirstPosition + childCount - 1; 1367 1368 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1369 // last row or the last row is scrolled off the bottom of the drawable area 1370 if (topOffset > 0) { 1371 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1372 if (lastPosition == mItemCount - 1) { 1373 // Don't pull the bottom too far up 1374 topOffset = Math.min(topOffset, lastBottom - end); 1375 } 1376 // Move everything up 1377 offsetChildrenTopAndBottom(-topOffset); 1378 if (lastPosition < mItemCount - 1) { 1379 // Fill the gap that was opened below the last position with more rows, if 1380 // possible 1381 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1382 // Close up the remaining gap 1383 adjustViewsUpOrDown(); 1384 } 1385 } else if (lastPosition == mItemCount - 1) { 1386 adjustViewsUpOrDown(); 1387 } 1388 } 1389 } 1390 } 1391 1392 @Override 1393 protected void layoutChildren() { 1394 final boolean blockLayoutRequests = mBlockLayoutRequests; 1395 if (!blockLayoutRequests) { 1396 mBlockLayoutRequests = true; 1397 } else { 1398 return; 1399 } 1400 1401 try { 1402 super.layoutChildren(); 1403 1404 invalidate(); 1405 1406 if (mAdapter == null) { 1407 resetList(); 1408 invokeOnItemScrollListener(); 1409 return; 1410 } 1411 1412 int childrenTop = mListPadding.top; 1413 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1414 1415 int childCount = getChildCount(); 1416 int index = 0; 1417 int delta = 0; 1418 1419 View sel; 1420 View oldSel = null; 1421 View oldFirst = null; 1422 View newSel = null; 1423 1424 View focusLayoutRestoreView = null; 1425 1426 // Remember stuff we will need down below 1427 switch (mLayoutMode) { 1428 case LAYOUT_SET_SELECTION: 1429 index = mNextSelectedPosition - mFirstPosition; 1430 if (index >= 0 && index < childCount) { 1431 newSel = getChildAt(index); 1432 } 1433 break; 1434 case LAYOUT_FORCE_TOP: 1435 case LAYOUT_FORCE_BOTTOM: 1436 case LAYOUT_SPECIFIC: 1437 case LAYOUT_SYNC: 1438 break; 1439 case LAYOUT_MOVE_SELECTION: 1440 default: 1441 // Remember the previously selected view 1442 index = mSelectedPosition - mFirstPosition; 1443 if (index >= 0 && index < childCount) { 1444 oldSel = getChildAt(index); 1445 } 1446 1447 // Remember the previous first child 1448 oldFirst = getChildAt(0); 1449 1450 if (mNextSelectedPosition >= 0) { 1451 delta = mNextSelectedPosition - mSelectedPosition; 1452 } 1453 1454 // Caution: newSel might be null 1455 newSel = getChildAt(index + delta); 1456 } 1457 1458 1459 boolean dataChanged = mDataChanged; 1460 if (dataChanged) { 1461 handleDataChanged(); 1462 } 1463 1464 // Handle the empty set by removing all views that are visible 1465 // and calling it a day 1466 if (mItemCount == 0) { 1467 resetList(); 1468 invokeOnItemScrollListener(); 1469 return; 1470 } else if (mItemCount != mAdapter.getCount()) { 1471 throw new IllegalStateException("The content of the adapter has changed but " 1472 + "ListView did not receive a notification. Make sure the content of " 1473 + "your adapter is not modified from a background thread, but only " 1474 + "from the UI thread. [in ListView(" + getId() + ", " + getClass() 1475 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1476 } 1477 1478 setSelectedPositionInt(mNextSelectedPosition); 1479 1480 // Pull all children into the RecycleBin. 1481 // These views will be reused if possible 1482 final int firstPosition = mFirstPosition; 1483 final RecycleBin recycleBin = mRecycler; 1484 1485 // reset the focus restoration 1486 View focusLayoutRestoreDirectChild = null; 1487 1488 1489 // Don't put header or footer views into the Recycler. Those are 1490 // already cached in mHeaderViews; 1491 if (dataChanged) { 1492 for (int i = 0; i < childCount; i++) { 1493 recycleBin.addScrapView(getChildAt(i)); 1494 if (ViewDebug.TRACE_RECYCLER) { 1495 ViewDebug.trace(getChildAt(i), 1496 ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i); 1497 } 1498 } 1499 } else { 1500 recycleBin.fillActiveViews(childCount, firstPosition); 1501 } 1502 1503 // take focus back to us temporarily to avoid the eventual 1504 // call to clear focus when removing the focused child below 1505 // from messing things up when ViewRoot assigns focus back 1506 // to someone else 1507 final View focusedChild = getFocusedChild(); 1508 if (focusedChild != null) { 1509 // TODO: in some cases focusedChild.getParent() == null 1510 1511 // we can remember the focused view to restore after relayout if the 1512 // data hasn't changed, or if the focused position is a header or footer 1513 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1514 focusLayoutRestoreDirectChild = focusedChild; 1515 // remember the specific view that had focus 1516 focusLayoutRestoreView = findFocus(); 1517 if (focusLayoutRestoreView != null) { 1518 // tell it we are going to mess with it 1519 focusLayoutRestoreView.onStartTemporaryDetach(); 1520 } 1521 } 1522 requestFocus(); 1523 } 1524 1525 // Clear out old views 1526 detachAllViewsFromParent(); 1527 1528 switch (mLayoutMode) { 1529 case LAYOUT_SET_SELECTION: 1530 if (newSel != null) { 1531 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1532 } else { 1533 sel = fillFromMiddle(childrenTop, childrenBottom); 1534 } 1535 break; 1536 case LAYOUT_SYNC: 1537 sel = fillSpecific(mSyncPosition, mSpecificTop); 1538 break; 1539 case LAYOUT_FORCE_BOTTOM: 1540 sel = fillUp(mItemCount - 1, childrenBottom); 1541 adjustViewsUpOrDown(); 1542 break; 1543 case LAYOUT_FORCE_TOP: 1544 mFirstPosition = 0; 1545 sel = fillFromTop(childrenTop); 1546 adjustViewsUpOrDown(); 1547 break; 1548 case LAYOUT_SPECIFIC: 1549 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1550 break; 1551 case LAYOUT_MOVE_SELECTION: 1552 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1553 break; 1554 default: 1555 if (childCount == 0) { 1556 if (!mStackFromBottom) { 1557 final int position = lookForSelectablePosition(0, true); 1558 setSelectedPositionInt(position); 1559 sel = fillFromTop(childrenTop); 1560 } else { 1561 final int position = lookForSelectablePosition(mItemCount - 1, false); 1562 setSelectedPositionInt(position); 1563 sel = fillUp(mItemCount - 1, childrenBottom); 1564 } 1565 } else { 1566 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1567 sel = fillSpecific(mSelectedPosition, 1568 oldSel == null ? childrenTop : oldSel.getTop()); 1569 } else if (mFirstPosition < mItemCount) { 1570 sel = fillSpecific(mFirstPosition, 1571 oldFirst == null ? childrenTop : oldFirst.getTop()); 1572 } else { 1573 sel = fillSpecific(0, childrenTop); 1574 } 1575 } 1576 break; 1577 } 1578 1579 // Flush any cached views that did not get reused above 1580 recycleBin.scrapActiveViews(); 1581 1582 if (sel != null) { 1583 // the current selected item should get focus if items 1584 // are focusable 1585 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1586 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1587 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1588 if (!focusWasTaken) { 1589 // selected item didn't take focus, fine, but still want 1590 // to make sure something else outside of the selected view 1591 // has focus 1592 final View focused = getFocusedChild(); 1593 if (focused != null) { 1594 focused.clearFocus(); 1595 } 1596 positionSelector(sel); 1597 } else { 1598 sel.setSelected(false); 1599 mSelectorRect.setEmpty(); 1600 } 1601 } else { 1602 positionSelector(sel); 1603 } 1604 mSelectedTop = sel.getTop(); 1605 } else { 1606 if (mTouchMode > TOUCH_MODE_DOWN && mTouchMode < TOUCH_MODE_SCROLL) { 1607 View child = getChildAt(mMotionPosition - mFirstPosition); 1608 if (child != null) positionSelector(child); 1609 } else { 1610 mSelectedTop = 0; 1611 mSelectorRect.setEmpty(); 1612 } 1613 1614 // even if there is not selected position, we may need to restore 1615 // focus (i.e. something focusable in touch mode) 1616 if (hasFocus() && focusLayoutRestoreView != null) { 1617 focusLayoutRestoreView.requestFocus(); 1618 } 1619 } 1620 1621 // tell focus view we are done mucking with it, if it is still in 1622 // our view hierarchy. 1623 if (focusLayoutRestoreView != null 1624 && focusLayoutRestoreView.getWindowToken() != null) { 1625 focusLayoutRestoreView.onFinishTemporaryDetach(); 1626 } 1627 1628 mLayoutMode = LAYOUT_NORMAL; 1629 mDataChanged = false; 1630 mNeedSync = false; 1631 setNextSelectedPositionInt(mSelectedPosition); 1632 1633 updateScrollIndicators(); 1634 1635 if (mItemCount > 0) { 1636 checkSelectionChanged(); 1637 } 1638 1639 invokeOnItemScrollListener(); 1640 } finally { 1641 if (!blockLayoutRequests) { 1642 mBlockLayoutRequests = false; 1643 } 1644 } 1645 } 1646 1647 /** 1648 * @param child a direct child of this list. 1649 * @return Whether child is a header or footer view. 1650 */ 1651 private boolean isDirectChildHeaderOrFooter(View child) { 1652 1653 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1654 final int numHeaders = headers.size(); 1655 for (int i = 0; i < numHeaders; i++) { 1656 if (child == headers.get(i).view) { 1657 return true; 1658 } 1659 } 1660 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1661 final int numFooters = footers.size(); 1662 for (int i = 0; i < numFooters; i++) { 1663 if (child == footers.get(i).view) { 1664 return true; 1665 } 1666 } 1667 return false; 1668 } 1669 1670 /** 1671 * Obtain the view and add it to our list of children. The view can be made 1672 * fresh, converted from an unused view, or used as is if it was in the 1673 * recycle bin. 1674 * 1675 * @param position Logical position in the list 1676 * @param y Top or bottom edge of the view to add 1677 * @param flow If flow is true, align top edge to y. If false, align bottom 1678 * edge to y. 1679 * @param childrenLeft Left edge where children should be positioned 1680 * @param selected Is this position selected? 1681 * @return View that was added 1682 */ 1683 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1684 boolean selected) { 1685 View child; 1686 1687 1688 if (!mDataChanged) { 1689 // Try to use an exsiting view for this position 1690 child = mRecycler.getActiveView(position); 1691 if (child != null) { 1692 if (ViewDebug.TRACE_RECYCLER) { 1693 ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, 1694 position, getChildCount()); 1695 } 1696 1697 // Found it -- we're using an existing child 1698 // This just needs to be positioned 1699 setupChild(child, position, y, flow, childrenLeft, selected, true); 1700 1701 return child; 1702 } 1703 } 1704 1705 // Make a new view for this position, or convert an unused view if possible 1706 child = obtainView(position, mIsScrap); 1707 1708 // This needs to be positioned and measured 1709 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1710 1711 return child; 1712 } 1713 1714 /** 1715 * Add a view as a child and make sure it is measured (if necessary) and 1716 * positioned properly. 1717 * 1718 * @param child The view to add 1719 * @param position The position of this child 1720 * @param y The y position relative to which this view will be positioned 1721 * @param flowDown If true, align top edge to y. If false, align bottom 1722 * edge to y. 1723 * @param childrenLeft Left edge where children should be positioned 1724 * @param selected Is this position selected? 1725 * @param recycled Has this view been pulled from the recycle bin? If so it 1726 * does not need to be remeasured. 1727 */ 1728 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1729 boolean selected, boolean recycled) { 1730 final boolean isSelected = selected && shouldShowSelector(); 1731 final boolean updateChildSelected = isSelected != child.isSelected(); 1732 final int mode = mTouchMode; 1733 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1734 mMotionPosition == position; 1735 final boolean updateChildPressed = isPressed != child.isPressed(); 1736 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1737 1738 // Respect layout params that are already in the view. Otherwise make some up... 1739 // noinspection unchecked 1740 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1741 if (p == null) { 1742 p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1743 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1744 } 1745 p.viewType = mAdapter.getItemViewType(position); 1746 1747 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1748 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1749 attachViewToParent(child, flowDown ? -1 : 0, p); 1750 } else { 1751 p.forceAdd = false; 1752 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1753 p.recycledHeaderFooter = true; 1754 } 1755 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1756 } 1757 1758 if (updateChildSelected) { 1759 child.setSelected(isSelected); 1760 } 1761 1762 if (updateChildPressed) { 1763 child.setPressed(isPressed); 1764 } 1765 1766 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1767 if (child instanceof Checkable) { 1768 ((Checkable) child).setChecked(mCheckStates.get(position)); 1769 } 1770 } 1771 1772 if (needToMeasure) { 1773 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1774 mListPadding.left + mListPadding.right, p.width); 1775 int lpHeight = p.height; 1776 int childHeightSpec; 1777 if (lpHeight > 0) { 1778 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1779 } else { 1780 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1781 } 1782 child.measure(childWidthSpec, childHeightSpec); 1783 } else { 1784 cleanupLayoutState(child); 1785 } 1786 1787 final int w = child.getMeasuredWidth(); 1788 final int h = child.getMeasuredHeight(); 1789 final int childTop = flowDown ? y : y - h; 1790 1791 if (needToMeasure) { 1792 final int childRight = childrenLeft + w; 1793 final int childBottom = childTop + h; 1794 child.layout(childrenLeft, childTop, childRight, childBottom); 1795 } else { 1796 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1797 child.offsetTopAndBottom(childTop - child.getTop()); 1798 } 1799 1800 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1801 child.setDrawingCacheEnabled(true); 1802 } 1803 } 1804 1805 @Override 1806 protected boolean canAnimate() { 1807 return super.canAnimate() && mItemCount > 0; 1808 } 1809 1810 /** 1811 * Sets the currently selected item. If in touch mode, the item will not be selected 1812 * but it will still be positioned appropriately. If the specified selection position 1813 * is less than 0, then the item at position 0 will be selected. 1814 * 1815 * @param position Index (starting at 0) of the data item to be selected. 1816 */ 1817 @Override 1818 public void setSelection(int position) { 1819 setSelectionFromTop(position, 0); 1820 } 1821 1822 /** 1823 * Sets the selected item and positions the selection y pixels from the top edge 1824 * of the ListView. (If in touch mode, the item will not be selected but it will 1825 * still be positioned appropriately.) 1826 * 1827 * @param position Index (starting at 0) of the data item to be selected. 1828 * @param y The distance from the top edge of the ListView (plus padding) that the 1829 * item will be positioned. 1830 */ 1831 public void setSelectionFromTop(int position, int y) { 1832 if (mAdapter == null) { 1833 return; 1834 } 1835 1836 if (!isInTouchMode()) { 1837 position = lookForSelectablePosition(position, true); 1838 if (position >= 0) { 1839 setNextSelectedPositionInt(position); 1840 } 1841 } else { 1842 mResurrectToPosition = position; 1843 } 1844 1845 if (position >= 0) { 1846 mLayoutMode = LAYOUT_SPECIFIC; 1847 mSpecificTop = mListPadding.top + y; 1848 1849 if (mNeedSync) { 1850 mSyncPosition = position; 1851 mSyncRowId = mAdapter.getItemId(position); 1852 } 1853 1854 requestLayout(); 1855 } 1856 } 1857 1858 /** 1859 * Makes the item at the supplied position selected. 1860 * 1861 * @param position the position of the item to select 1862 */ 1863 @Override 1864 void setSelectionInt(int position) { 1865 setNextSelectedPositionInt(position); 1866 boolean awakeScrollbars = false; 1867 1868 final int selectedPosition = mSelectedPosition; 1869 1870 if (selectedPosition >= 0) { 1871 if (position == selectedPosition - 1) { 1872 awakeScrollbars = true; 1873 } else if (position == selectedPosition + 1) { 1874 awakeScrollbars = true; 1875 } 1876 } 1877 1878 layoutChildren(); 1879 1880 if (awakeScrollbars) { 1881 awakenScrollBars(); 1882 } 1883 } 1884 1885 /** 1886 * Find a position that can be selected (i.e., is not a separator). 1887 * 1888 * @param position The starting position to look at. 1889 * @param lookDown Whether to look down for other positions. 1890 * @return The next selectable position starting at position and then searching either up or 1891 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1892 */ 1893 @Override 1894 int lookForSelectablePosition(int position, boolean lookDown) { 1895 final ListAdapter adapter = mAdapter; 1896 if (adapter == null || isInTouchMode()) { 1897 return INVALID_POSITION; 1898 } 1899 1900 final int count = adapter.getCount(); 1901 if (!mAreAllItemsSelectable) { 1902 if (lookDown) { 1903 position = Math.max(0, position); 1904 while (position < count && !adapter.isEnabled(position)) { 1905 position++; 1906 } 1907 } else { 1908 position = Math.min(position, count - 1); 1909 while (position >= 0 && !adapter.isEnabled(position)) { 1910 position--; 1911 } 1912 } 1913 1914 if (position < 0 || position >= count) { 1915 return INVALID_POSITION; 1916 } 1917 return position; 1918 } else { 1919 if (position < 0 || position >= count) { 1920 return INVALID_POSITION; 1921 } 1922 return position; 1923 } 1924 } 1925 1926 @Override 1927 public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { 1928 boolean populated = super.dispatchPopulateAccessibilityEvent(event); 1929 1930 // If the item count is less than 15 then subtract disabled items from the count and 1931 // position. Otherwise ignore disabled items. 1932 if (!populated) { 1933 int itemCount = 0; 1934 int currentItemIndex = getSelectedItemPosition(); 1935 1936 ListAdapter adapter = getAdapter(); 1937 if (adapter != null) { 1938 final int count = adapter.getCount(); 1939 if (count < 15) { 1940 for (int i = 0; i < count; i++) { 1941 if (adapter.isEnabled(i)) { 1942 itemCount++; 1943 } else if (i <= currentItemIndex) { 1944 currentItemIndex--; 1945 } 1946 } 1947 } else { 1948 itemCount = count; 1949 } 1950 } 1951 1952 event.setItemCount(itemCount); 1953 event.setCurrentItemIndex(currentItemIndex); 1954 } 1955 1956 return populated; 1957 } 1958 1959 /** 1960 * setSelectionAfterHeaderView set the selection to be the first list item 1961 * after the header views. 1962 */ 1963 public void setSelectionAfterHeaderView() { 1964 final int count = mHeaderViewInfos.size(); 1965 if (count > 0) { 1966 mNextSelectedPosition = 0; 1967 return; 1968 } 1969 1970 if (mAdapter != null) { 1971 setSelection(count); 1972 } else { 1973 mNextSelectedPosition = count; 1974 mLayoutMode = LAYOUT_SET_SELECTION; 1975 } 1976 1977 } 1978 1979 @Override 1980 public boolean dispatchKeyEvent(KeyEvent event) { 1981 // Dispatch in the normal way 1982 boolean handled = super.dispatchKeyEvent(event); 1983 if (!handled) { 1984 // If we didn't handle it... 1985 View focused = getFocusedChild(); 1986 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 1987 // ... and our focused child didn't handle it 1988 // ... give it to ourselves so we can scroll if necessary 1989 handled = onKeyDown(event.getKeyCode(), event); 1990 } 1991 } 1992 return handled; 1993 } 1994 1995 @Override 1996 public boolean onKeyDown(int keyCode, KeyEvent event) { 1997 return commonKey(keyCode, 1, event); 1998 } 1999 2000 @Override 2001 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2002 return commonKey(keyCode, repeatCount, event); 2003 } 2004 2005 @Override 2006 public boolean onKeyUp(int keyCode, KeyEvent event) { 2007 return commonKey(keyCode, 1, event); 2008 } 2009 2010 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2011 if (mAdapter == null) { 2012 return false; 2013 } 2014 2015 if (mDataChanged) { 2016 layoutChildren(); 2017 } 2018 2019 boolean handled = false; 2020 int action = event.getAction(); 2021 2022 if (action != KeyEvent.ACTION_UP) { 2023 if (mSelectedPosition < 0) { 2024 switch (keyCode) { 2025 case KeyEvent.KEYCODE_DPAD_UP: 2026 case KeyEvent.KEYCODE_DPAD_DOWN: 2027 case KeyEvent.KEYCODE_DPAD_CENTER: 2028 case KeyEvent.KEYCODE_ENTER: 2029 case KeyEvent.KEYCODE_SPACE: 2030 if (resurrectSelection()) { 2031 return true; 2032 } 2033 } 2034 } 2035 switch (keyCode) { 2036 case KeyEvent.KEYCODE_DPAD_UP: 2037 if (!event.isAltPressed()) { 2038 while (count > 0) { 2039 handled = arrowScroll(FOCUS_UP); 2040 count--; 2041 } 2042 } else { 2043 handled = fullScroll(FOCUS_UP); 2044 } 2045 break; 2046 2047 case KeyEvent.KEYCODE_DPAD_DOWN: 2048 if (!event.isAltPressed()) { 2049 while (count > 0) { 2050 handled = arrowScroll(FOCUS_DOWN); 2051 count--; 2052 } 2053 } else { 2054 handled = fullScroll(FOCUS_DOWN); 2055 } 2056 break; 2057 2058 case KeyEvent.KEYCODE_DPAD_LEFT: 2059 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2060 break; 2061 case KeyEvent.KEYCODE_DPAD_RIGHT: 2062 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2063 break; 2064 2065 case KeyEvent.KEYCODE_DPAD_CENTER: 2066 case KeyEvent.KEYCODE_ENTER: 2067 if (mItemCount > 0 && event.getRepeatCount() == 0) { 2068 keyPressed(); 2069 } 2070 handled = true; 2071 break; 2072 2073 case KeyEvent.KEYCODE_SPACE: 2074 if (mPopup == null || !mPopup.isShowing()) { 2075 if (!event.isShiftPressed()) { 2076 pageScroll(FOCUS_DOWN); 2077 } else { 2078 pageScroll(FOCUS_UP); 2079 } 2080 handled = true; 2081 } 2082 break; 2083 } 2084 } 2085 2086 if (!handled) { 2087 handled = sendToTextFilter(keyCode, count, event); 2088 } 2089 2090 if (handled) { 2091 return true; 2092 } else { 2093 switch (action) { 2094 case KeyEvent.ACTION_DOWN: 2095 return super.onKeyDown(keyCode, event); 2096 2097 case KeyEvent.ACTION_UP: 2098 return super.onKeyUp(keyCode, event); 2099 2100 case KeyEvent.ACTION_MULTIPLE: 2101 return super.onKeyMultiple(keyCode, count, event); 2102 2103 default: // shouldn't happen 2104 return false; 2105 } 2106 } 2107 } 2108 2109 /** 2110 * Scrolls up or down by the number of items currently present on screen. 2111 * 2112 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2113 * @return whether selection was moved 2114 */ 2115 boolean pageScroll(int direction) { 2116 int nextPage = -1; 2117 boolean down = false; 2118 2119 if (direction == FOCUS_UP) { 2120 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2121 } else if (direction == FOCUS_DOWN) { 2122 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2123 down = true; 2124 } 2125 2126 if (nextPage >= 0) { 2127 int position = lookForSelectablePosition(nextPage, down); 2128 if (position >= 0) { 2129 mLayoutMode = LAYOUT_SPECIFIC; 2130 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2131 2132 if (down && position > mItemCount - getChildCount()) { 2133 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2134 } 2135 2136 if (!down && position < getChildCount()) { 2137 mLayoutMode = LAYOUT_FORCE_TOP; 2138 } 2139 2140 setSelectionInt(position); 2141 invokeOnItemScrollListener(); 2142 if (!awakenScrollBars()) { 2143 invalidate(); 2144 } 2145 2146 return true; 2147 } 2148 } 2149 2150 return false; 2151 } 2152 2153 /** 2154 * Go to the last or first item if possible (not worrying about panning across or navigating 2155 * within the internal focus of the currently selected item.) 2156 * 2157 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2158 * 2159 * @return whether selection was moved 2160 */ 2161 boolean fullScroll(int direction) { 2162 boolean moved = false; 2163 if (direction == FOCUS_UP) { 2164 if (mSelectedPosition != 0) { 2165 int position = lookForSelectablePosition(0, true); 2166 if (position >= 0) { 2167 mLayoutMode = LAYOUT_FORCE_TOP; 2168 setSelectionInt(position); 2169 invokeOnItemScrollListener(); 2170 } 2171 moved = true; 2172 } 2173 } else if (direction == FOCUS_DOWN) { 2174 if (mSelectedPosition < mItemCount - 1) { 2175 int position = lookForSelectablePosition(mItemCount - 1, true); 2176 if (position >= 0) { 2177 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2178 setSelectionInt(position); 2179 invokeOnItemScrollListener(); 2180 } 2181 moved = true; 2182 } 2183 } 2184 2185 if (moved && !awakenScrollBars()) { 2186 awakenScrollBars(); 2187 invalidate(); 2188 } 2189 2190 return moved; 2191 } 2192 2193 /** 2194 * To avoid horizontal focus searches changing the selected item, we 2195 * manually focus search within the selected item (as applicable), and 2196 * prevent focus from jumping to something within another item. 2197 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2198 * @return Whether this consumes the key event. 2199 */ 2200 private boolean handleHorizontalFocusWithinListItem(int direction) { 2201 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2202 throw new IllegalArgumentException("direction must be one of" 2203 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2204 } 2205 2206 final int numChildren = getChildCount(); 2207 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2208 final View selectedView = getSelectedView(); 2209 if (selectedView != null && selectedView.hasFocus() && 2210 selectedView instanceof ViewGroup) { 2211 2212 final View currentFocus = selectedView.findFocus(); 2213 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2214 (ViewGroup) selectedView, currentFocus, direction); 2215 if (nextFocus != null) { 2216 // do the math to get interesting rect in next focus' coordinates 2217 currentFocus.getFocusedRect(mTempRect); 2218 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2219 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2220 if (nextFocus.requestFocus(direction, mTempRect)) { 2221 return true; 2222 } 2223 } 2224 // we are blocking the key from being handled (by returning true) 2225 // if the global result is going to be some other view within this 2226 // list. this is to acheive the overall goal of having 2227 // horizontal d-pad navigation remain in the current item. 2228 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2229 (ViewGroup) getRootView(), currentFocus, direction); 2230 if (globalNextFocus != null) { 2231 return isViewAncestorOf(globalNextFocus, this); 2232 } 2233 } 2234 } 2235 return false; 2236 } 2237 2238 /** 2239 * Scrolls to the next or previous item if possible. 2240 * 2241 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2242 * 2243 * @return whether selection was moved 2244 */ 2245 boolean arrowScroll(int direction) { 2246 try { 2247 mInLayout = true; 2248 final boolean handled = arrowScrollImpl(direction); 2249 if (handled) { 2250 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2251 } 2252 return handled; 2253 } finally { 2254 mInLayout = false; 2255 } 2256 } 2257 2258 /** 2259 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2260 * whether there are focusable items etc. 2261 * 2262 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2263 * @return Whether any scrolling, selection or focus change occured. 2264 */ 2265 private boolean arrowScrollImpl(int direction) { 2266 if (getChildCount() <= 0) { 2267 return false; 2268 } 2269 2270 View selectedView = getSelectedView(); 2271 2272 int nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 2273 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2274 2275 // if we are moving focus, we may OVERRIDE the default behavior 2276 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2277 if (focusResult != null) { 2278 nextSelectedPosition = focusResult.getSelectedPosition(); 2279 amountToScroll = focusResult.getAmountToScroll(); 2280 } 2281 2282 boolean needToRedraw = focusResult != null; 2283 if (nextSelectedPosition != INVALID_POSITION) { 2284 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2285 setSelectedPositionInt(nextSelectedPosition); 2286 setNextSelectedPositionInt(nextSelectedPosition); 2287 selectedView = getSelectedView(); 2288 if (mItemsCanFocus && focusResult == null) { 2289 // there was no new view found to take focus, make sure we 2290 // don't leave focus with the old selection 2291 final View focused = getFocusedChild(); 2292 if (focused != null) { 2293 focused.clearFocus(); 2294 } 2295 } 2296 needToRedraw = true; 2297 checkSelectionChanged(); 2298 } 2299 2300 if (amountToScroll > 0) { 2301 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2302 needToRedraw = true; 2303 } 2304 2305 // if we didn't find a new focusable, make sure any existing focused 2306 // item that was panned off screen gives up focus. 2307 if (mItemsCanFocus && (focusResult == null) 2308 && selectedView != null && selectedView.hasFocus()) { 2309 final View focused = selectedView.findFocus(); 2310 if (distanceToView(focused) > 0) { 2311 focused.clearFocus(); 2312 } 2313 } 2314 2315 // if the current selection is panned off, we need to remove the selection 2316 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2317 && !isViewAncestorOf(selectedView, this)) { 2318 selectedView = null; 2319 hideSelector(); 2320 2321 // but we don't want to set the ressurect position (that would make subsequent 2322 // unhandled key events bring back the item we just scrolled off!) 2323 mResurrectToPosition = INVALID_POSITION; 2324 } 2325 2326 if (needToRedraw) { 2327 if (selectedView != null) { 2328 positionSelector(selectedView); 2329 mSelectedTop = selectedView.getTop(); 2330 } 2331 if (!awakenScrollBars()) { 2332 invalidate(); 2333 } 2334 invokeOnItemScrollListener(); 2335 return true; 2336 } 2337 2338 return false; 2339 } 2340 2341 /** 2342 * When selection changes, it is possible that the previously selected or the 2343 * next selected item will change its size. If so, we need to offset some folks, 2344 * and re-layout the items as appropriate. 2345 * 2346 * @param selectedView The currently selected view (before changing selection). 2347 * should be <code>null</code> if there was no previous selection. 2348 * @param direction Either {@link android.view.View#FOCUS_UP} or 2349 * {@link android.view.View#FOCUS_DOWN}. 2350 * @param newSelectedPosition The position of the next selection. 2351 * @param newFocusAssigned whether new focus was assigned. This matters because 2352 * when something has focus, we don't want to show selection (ugh). 2353 */ 2354 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2355 boolean newFocusAssigned) { 2356 if (newSelectedPosition == INVALID_POSITION) { 2357 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2358 } 2359 2360 // whether or not we are moving down or up, we want to preserve the 2361 // top of whatever view is on top: 2362 // - moving down: the view that had selection 2363 // - moving up: the view that is getting selection 2364 View topView; 2365 View bottomView; 2366 int topViewIndex, bottomViewIndex; 2367 boolean topSelected = false; 2368 final int selectedIndex = mSelectedPosition - mFirstPosition; 2369 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2370 if (direction == View.FOCUS_UP) { 2371 topViewIndex = nextSelectedIndex; 2372 bottomViewIndex = selectedIndex; 2373 topView = getChildAt(topViewIndex); 2374 bottomView = selectedView; 2375 topSelected = true; 2376 } else { 2377 topViewIndex = selectedIndex; 2378 bottomViewIndex = nextSelectedIndex; 2379 topView = selectedView; 2380 bottomView = getChildAt(bottomViewIndex); 2381 } 2382 2383 final int numChildren = getChildCount(); 2384 2385 // start with top view: is it changing size? 2386 if (topView != null) { 2387 topView.setSelected(!newFocusAssigned && topSelected); 2388 measureAndAdjustDown(topView, topViewIndex, numChildren); 2389 } 2390 2391 // is the bottom view changing size? 2392 if (bottomView != null) { 2393 bottomView.setSelected(!newFocusAssigned && !topSelected); 2394 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2395 } 2396 } 2397 2398 /** 2399 * Re-measure a child, and if its height changes, lay it out preserving its 2400 * top, and adjust the children below it appropriately. 2401 * @param child The child 2402 * @param childIndex The view group index of the child. 2403 * @param numChildren The number of children in the view group. 2404 */ 2405 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2406 int oldHeight = child.getHeight(); 2407 measureItem(child); 2408 if (child.getMeasuredHeight() != oldHeight) { 2409 // lay out the view, preserving its top 2410 relayoutMeasuredItem(child); 2411 2412 // adjust views below appropriately 2413 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2414 for (int i = childIndex + 1; i < numChildren; i++) { 2415 getChildAt(i).offsetTopAndBottom(heightDelta); 2416 } 2417 } 2418 } 2419 2420 /** 2421 * Measure a particular list child. 2422 * TODO: unify with setUpChild. 2423 * @param child The child. 2424 */ 2425 private void measureItem(View child) { 2426 ViewGroup.LayoutParams p = child.getLayoutParams(); 2427 if (p == null) { 2428 p = new ViewGroup.LayoutParams( 2429 ViewGroup.LayoutParams.MATCH_PARENT, 2430 ViewGroup.LayoutParams.WRAP_CONTENT); 2431 } 2432 2433 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2434 mListPadding.left + mListPadding.right, p.width); 2435 int lpHeight = p.height; 2436 int childHeightSpec; 2437 if (lpHeight > 0) { 2438 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2439 } else { 2440 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2441 } 2442 child.measure(childWidthSpec, childHeightSpec); 2443 } 2444 2445 /** 2446 * Layout a child that has been measured, preserving its top position. 2447 * TODO: unify with setUpChild. 2448 * @param child The child. 2449 */ 2450 private void relayoutMeasuredItem(View child) { 2451 final int w = child.getMeasuredWidth(); 2452 final int h = child.getMeasuredHeight(); 2453 final int childLeft = mListPadding.left; 2454 final int childRight = childLeft + w; 2455 final int childTop = child.getTop(); 2456 final int childBottom = childTop + h; 2457 child.layout(childLeft, childTop, childRight, childBottom); 2458 } 2459 2460 /** 2461 * @return The amount to preview next items when arrow srolling. 2462 */ 2463 private int getArrowScrollPreviewLength() { 2464 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2465 } 2466 2467 /** 2468 * Determine how much we need to scroll in order to get the next selected view 2469 * visible, with a fading edge showing below as applicable. The amount is 2470 * capped at {@link #getMaxScrollAmount()} . 2471 * 2472 * @param direction either {@link android.view.View#FOCUS_UP} or 2473 * {@link android.view.View#FOCUS_DOWN}. 2474 * @param nextSelectedPosition The position of the next selection, or 2475 * {@link #INVALID_POSITION} if there is no next selectable position 2476 * @return The amount to scroll. Note: this is always positive! Direction 2477 * needs to be taken into account when actually scrolling. 2478 */ 2479 private int amountToScroll(int direction, int nextSelectedPosition) { 2480 final int listBottom = getHeight() - mListPadding.bottom; 2481 final int listTop = mListPadding.top; 2482 2483 final int numChildren = getChildCount(); 2484 2485 if (direction == View.FOCUS_DOWN) { 2486 int indexToMakeVisible = numChildren - 1; 2487 if (nextSelectedPosition != INVALID_POSITION) { 2488 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2489 } 2490 2491 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2492 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2493 2494 int goalBottom = listBottom; 2495 if (positionToMakeVisible < mItemCount - 1) { 2496 goalBottom -= getArrowScrollPreviewLength(); 2497 } 2498 2499 if (viewToMakeVisible.getBottom() <= goalBottom) { 2500 // item is fully visible. 2501 return 0; 2502 } 2503 2504 if (nextSelectedPosition != INVALID_POSITION 2505 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2506 // item already has enough of it visible, changing selection is good enough 2507 return 0; 2508 } 2509 2510 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2511 2512 if ((mFirstPosition + numChildren) == mItemCount) { 2513 // last is last in list -> make sure we don't scroll past it 2514 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2515 amountToScroll = Math.min(amountToScroll, max); 2516 } 2517 2518 return Math.min(amountToScroll, getMaxScrollAmount()); 2519 } else { 2520 int indexToMakeVisible = 0; 2521 if (nextSelectedPosition != INVALID_POSITION) { 2522 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2523 } 2524 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2525 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2526 int goalTop = listTop; 2527 if (positionToMakeVisible > 0) { 2528 goalTop += getArrowScrollPreviewLength(); 2529 } 2530 if (viewToMakeVisible.getTop() >= goalTop) { 2531 // item is fully visible. 2532 return 0; 2533 } 2534 2535 if (nextSelectedPosition != INVALID_POSITION && 2536 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2537 // item already has enough of it visible, changing selection is good enough 2538 return 0; 2539 } 2540 2541 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2542 if (mFirstPosition == 0) { 2543 // first is first in list -> make sure we don't scroll past it 2544 final int max = listTop - getChildAt(0).getTop(); 2545 amountToScroll = Math.min(amountToScroll, max); 2546 } 2547 return Math.min(amountToScroll, getMaxScrollAmount()); 2548 } 2549 } 2550 2551 /** 2552 * Holds results of focus aware arrow scrolling. 2553 */ 2554 static private class ArrowScrollFocusResult { 2555 private int mSelectedPosition; 2556 private int mAmountToScroll; 2557 2558 /** 2559 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2560 */ 2561 void populate(int selectedPosition, int amountToScroll) { 2562 mSelectedPosition = selectedPosition; 2563 mAmountToScroll = amountToScroll; 2564 } 2565 2566 public int getSelectedPosition() { 2567 return mSelectedPosition; 2568 } 2569 2570 public int getAmountToScroll() { 2571 return mAmountToScroll; 2572 } 2573 } 2574 2575 /** 2576 * @param direction either {@link android.view.View#FOCUS_UP} or 2577 * {@link android.view.View#FOCUS_DOWN}. 2578 * @return The position of the next selectable position of the views that 2579 * are currently visible, taking into account the fact that there might 2580 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2581 * selectable view on screen in the given direction. 2582 */ 2583 private int lookForSelectablePositionOnScreen(int direction) { 2584 final int firstPosition = mFirstPosition; 2585 if (direction == View.FOCUS_DOWN) { 2586 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2587 mSelectedPosition + 1 : 2588 firstPosition; 2589 if (startPos >= mAdapter.getCount()) { 2590 return INVALID_POSITION; 2591 } 2592 if (startPos < firstPosition) { 2593 startPos = firstPosition; 2594 } 2595 2596 final int lastVisiblePos = getLastVisiblePosition(); 2597 final ListAdapter adapter = getAdapter(); 2598 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2599 if (adapter.isEnabled(pos) 2600 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2601 return pos; 2602 } 2603 } 2604 } else { 2605 int last = firstPosition + getChildCount() - 1; 2606 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2607 mSelectedPosition - 1 : 2608 firstPosition + getChildCount() - 1; 2609 if (startPos < 0) { 2610 return INVALID_POSITION; 2611 } 2612 if (startPos > last) { 2613 startPos = last; 2614 } 2615 2616 final ListAdapter adapter = getAdapter(); 2617 for (int pos = startPos; pos >= firstPosition; pos--) { 2618 if (adapter.isEnabled(pos) 2619 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2620 return pos; 2621 } 2622 } 2623 } 2624 return INVALID_POSITION; 2625 } 2626 2627 /** 2628 * Do an arrow scroll based on focus searching. If a new view is 2629 * given focus, return the selection delta and amount to scroll via 2630 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2631 * 2632 * @param direction either {@link android.view.View#FOCUS_UP} or 2633 * {@link android.view.View#FOCUS_DOWN}. 2634 * @return The result if focus has changed, or <code>null</code>. 2635 */ 2636 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2637 final View selectedView = getSelectedView(); 2638 View newFocus; 2639 if (selectedView != null && selectedView.hasFocus()) { 2640 View oldFocus = selectedView.findFocus(); 2641 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2642 } else { 2643 if (direction == View.FOCUS_DOWN) { 2644 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2645 final int listTop = mListPadding.top + 2646 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2647 final int ySearchPoint = 2648 (selectedView != null && selectedView.getTop() > listTop) ? 2649 selectedView.getTop() : 2650 listTop; 2651 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2652 } else { 2653 final boolean bottomFadingEdgeShowing = 2654 (mFirstPosition + getChildCount() - 1) < mItemCount; 2655 final int listBottom = getHeight() - mListPadding.bottom - 2656 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2657 final int ySearchPoint = 2658 (selectedView != null && selectedView.getBottom() < listBottom) ? 2659 selectedView.getBottom() : 2660 listBottom; 2661 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2662 } 2663 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2664 } 2665 2666 if (newFocus != null) { 2667 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2668 2669 // if the focus change is in a different new position, make sure 2670 // we aren't jumping over another selectable position 2671 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2672 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2673 if (selectablePosition != INVALID_POSITION && 2674 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2675 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2676 return null; 2677 } 2678 } 2679 2680 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2681 2682 final int maxScrollAmount = getMaxScrollAmount(); 2683 if (focusScroll < maxScrollAmount) { 2684 // not moving too far, safe to give next view focus 2685 newFocus.requestFocus(direction); 2686 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2687 return mArrowScrollFocusResult; 2688 } else if (distanceToView(newFocus) < maxScrollAmount){ 2689 // Case to consider: 2690 // too far to get entire next focusable on screen, but by going 2691 // max scroll amount, we are getting it at least partially in view, 2692 // so give it focus and scroll the max ammount. 2693 newFocus.requestFocus(direction); 2694 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2695 return mArrowScrollFocusResult; 2696 } 2697 } 2698 return null; 2699 } 2700 2701 /** 2702 * @param newFocus The view that would have focus. 2703 * @return the position that contains newFocus 2704 */ 2705 private int positionOfNewFocus(View newFocus) { 2706 final int numChildren = getChildCount(); 2707 for (int i = 0; i < numChildren; i++) { 2708 final View child = getChildAt(i); 2709 if (isViewAncestorOf(newFocus, child)) { 2710 return mFirstPosition + i; 2711 } 2712 } 2713 throw new IllegalArgumentException("newFocus is not a child of any of the" 2714 + " children of the list!"); 2715 } 2716 2717 /** 2718 * Return true if child is an ancestor of parent, (or equal to the parent). 2719 */ 2720 private boolean isViewAncestorOf(View child, View parent) { 2721 if (child == parent) { 2722 return true; 2723 } 2724 2725 final ViewParent theParent = child.getParent(); 2726 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2727 } 2728 2729 /** 2730 * Determine how much we need to scroll in order to get newFocus in view. 2731 * @param direction either {@link android.view.View#FOCUS_UP} or 2732 * {@link android.view.View#FOCUS_DOWN}. 2733 * @param newFocus The view that would take focus. 2734 * @param positionOfNewFocus The position of the list item containing newFocus 2735 * @return The amount to scroll. Note: this is always positive! Direction 2736 * needs to be taken into account when actually scrolling. 2737 */ 2738 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2739 int amountToScroll = 0; 2740 newFocus.getDrawingRect(mTempRect); 2741 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2742 if (direction == View.FOCUS_UP) { 2743 if (mTempRect.top < mListPadding.top) { 2744 amountToScroll = mListPadding.top - mTempRect.top; 2745 if (positionOfNewFocus > 0) { 2746 amountToScroll += getArrowScrollPreviewLength(); 2747 } 2748 } 2749 } else { 2750 final int listBottom = getHeight() - mListPadding.bottom; 2751 if (mTempRect.bottom > listBottom) { 2752 amountToScroll = mTempRect.bottom - listBottom; 2753 if (positionOfNewFocus < mItemCount - 1) { 2754 amountToScroll += getArrowScrollPreviewLength(); 2755 } 2756 } 2757 } 2758 return amountToScroll; 2759 } 2760 2761 /** 2762 * Determine the distance to the nearest edge of a view in a particular 2763 * direction. 2764 * 2765 * @param descendant A descendant of this list. 2766 * @return The distance, or 0 if the nearest edge is already on screen. 2767 */ 2768 private int distanceToView(View descendant) { 2769 int distance = 0; 2770 descendant.getDrawingRect(mTempRect); 2771 offsetDescendantRectToMyCoords(descendant, mTempRect); 2772 final int listBottom = mBottom - mTop - mListPadding.bottom; 2773 if (mTempRect.bottom < mListPadding.top) { 2774 distance = mListPadding.top - mTempRect.bottom; 2775 } else if (mTempRect.top > listBottom) { 2776 distance = mTempRect.top - listBottom; 2777 } 2778 return distance; 2779 } 2780 2781 2782 /** 2783 * Scroll the children by amount, adding a view at the end and removing 2784 * views that fall off as necessary. 2785 * 2786 * @param amount The amount (positive or negative) to scroll. 2787 */ 2788 private void scrollListItemsBy(int amount) { 2789 offsetChildrenTopAndBottom(amount); 2790 2791 final int listBottom = getHeight() - mListPadding.bottom; 2792 final int listTop = mListPadding.top; 2793 final AbsListView.RecycleBin recycleBin = mRecycler; 2794 2795 if (amount < 0) { 2796 // shifted items up 2797 2798 // may need to pan views into the bottom space 2799 int numChildren = getChildCount(); 2800 View last = getChildAt(numChildren - 1); 2801 while (last.getBottom() < listBottom) { 2802 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2803 if (lastVisiblePosition < mItemCount - 1) { 2804 last = addViewBelow(last, lastVisiblePosition); 2805 numChildren++; 2806 } else { 2807 break; 2808 } 2809 } 2810 2811 // may have brought in the last child of the list that is skinnier 2812 // than the fading edge, thereby leaving space at the end. need 2813 // to shift back 2814 if (last.getBottom() < listBottom) { 2815 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2816 } 2817 2818 // top views may be panned off screen 2819 View first = getChildAt(0); 2820 while (first.getBottom() < listTop) { 2821 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2822 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2823 detachViewFromParent(first); 2824 recycleBin.addScrapView(first); 2825 } else { 2826 removeViewInLayout(first); 2827 } 2828 first = getChildAt(0); 2829 mFirstPosition++; 2830 } 2831 } else { 2832 // shifted items down 2833 View first = getChildAt(0); 2834 2835 // may need to pan views into top 2836 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2837 first = addViewAbove(first, mFirstPosition); 2838 mFirstPosition--; 2839 } 2840 2841 // may have brought the very first child of the list in too far and 2842 // need to shift it back 2843 if (first.getTop() > listTop) { 2844 offsetChildrenTopAndBottom(listTop - first.getTop()); 2845 } 2846 2847 int lastIndex = getChildCount() - 1; 2848 View last = getChildAt(lastIndex); 2849 2850 // bottom view may be panned off screen 2851 while (last.getTop() > listBottom) { 2852 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 2853 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2854 detachViewFromParent(last); 2855 recycleBin.addScrapView(last); 2856 } else { 2857 removeViewInLayout(last); 2858 } 2859 last = getChildAt(--lastIndex); 2860 } 2861 } 2862 } 2863 2864 private View addViewAbove(View theView, int position) { 2865 int abovePosition = position - 1; 2866 View view = obtainView(abovePosition, mIsScrap); 2867 int edgeOfNewChild = theView.getTop() - mDividerHeight; 2868 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 2869 false, mIsScrap[0]); 2870 return view; 2871 } 2872 2873 private View addViewBelow(View theView, int position) { 2874 int belowPosition = position + 1; 2875 View view = obtainView(belowPosition, mIsScrap); 2876 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 2877 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 2878 false, mIsScrap[0]); 2879 return view; 2880 } 2881 2882 /** 2883 * Indicates that the views created by the ListAdapter can contain focusable 2884 * items. 2885 * 2886 * @param itemsCanFocus true if items can get focus, false otherwise 2887 */ 2888 public void setItemsCanFocus(boolean itemsCanFocus) { 2889 mItemsCanFocus = itemsCanFocus; 2890 if (!itemsCanFocus) { 2891 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 2892 } 2893 } 2894 2895 /** 2896 * @return Whether the views created by the ListAdapter can contain focusable 2897 * items. 2898 */ 2899 public boolean getItemsCanFocus() { 2900 return mItemsCanFocus; 2901 } 2902 2903 /** 2904 * @hide Pending API council approval. 2905 */ 2906 @Override 2907 public boolean isOpaque() { 2908 return (mCachingStarted && mIsCacheColorOpaque && mDividerIsOpaque && 2909 hasOpaqueScrollbars()) || super.isOpaque(); 2910 } 2911 2912 @Override 2913 public void setCacheColorHint(int color) { 2914 final boolean opaque = (color >>> 24) == 0xFF; 2915 mIsCacheColorOpaque = opaque; 2916 if (opaque) { 2917 if (mDividerPaint == null) { 2918 mDividerPaint = new Paint(); 2919 } 2920 mDividerPaint.setColor(color); 2921 } 2922 super.setCacheColorHint(color); 2923 } 2924 2925 @Override 2926 protected void dispatchDraw(Canvas canvas) { 2927 // Draw the dividers 2928 final int dividerHeight = mDividerHeight; 2929 2930 if (dividerHeight > 0 && mDivider != null) { 2931 // Only modify the top and bottom in the loop, we set the left and right here 2932 final Rect bounds = mTempRect; 2933 bounds.left = mPaddingLeft; 2934 bounds.right = mRight - mLeft - mPaddingRight; 2935 2936 final int count = getChildCount(); 2937 final int headerCount = mHeaderViewInfos.size(); 2938 final int footerLimit = mItemCount - mFooterViewInfos.size() - 1; 2939 final boolean headerDividers = mHeaderDividersEnabled; 2940 final boolean footerDividers = mFooterDividersEnabled; 2941 final int first = mFirstPosition; 2942 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 2943 final ListAdapter adapter = mAdapter; 2944 // If the list is opaque *and* the background is not, we want to 2945 // fill a rect where the dividers would be for non-selectable items 2946 // If the list is opaque and the background is also opaque, we don't 2947 // need to draw anything since the background will do it for us 2948 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 2949 2950 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 2951 mDividerPaint = new Paint(); 2952 mDividerPaint.setColor(getCacheColorHint()); 2953 } 2954 final Paint paint = mDividerPaint; 2955 2956 if (!mStackFromBottom) { 2957 int bottom; 2958 int listBottom = mBottom - mTop - mListPadding.bottom + mScrollY; 2959 2960 // Draw top divider for overscroll 2961 if (count > 0 && mScrollY < 0) { 2962 bounds.bottom = 0; 2963 bounds.top = -dividerHeight; 2964 drawDivider(canvas, bounds, -1); 2965 } 2966 2967 for (int i = 0; i < count; i++) { 2968 if ((headerDividers || first + i >= headerCount) && 2969 (footerDividers || first + i < footerLimit)) { 2970 View child = getChildAt(i); 2971 bottom = child.getBottom(); 2972 // Don't draw dividers next to items that are not enabled 2973 if (bottom < listBottom) { 2974 if ((areAllItemsSelectable || 2975 (adapter.isEnabled(first + i) && (i == count - 1 || 2976 adapter.isEnabled(first + i + 1))))) { 2977 bounds.top = bottom; 2978 bounds.bottom = bottom + dividerHeight; 2979 drawDivider(canvas, bounds, i); 2980 } else if (fillForMissingDividers) { 2981 bounds.top = bottom; 2982 bounds.bottom = bottom + dividerHeight; 2983 canvas.drawRect(bounds, paint); 2984 } 2985 } 2986 } 2987 } 2988 } else { 2989 int top; 2990 int listTop = mListPadding.top; 2991 2992 for (int i = 0; i < count; i++) { 2993 if ((headerDividers || first + i >= headerCount) && 2994 (footerDividers || first + i < footerLimit)) { 2995 View child = getChildAt(i); 2996 top = child.getTop(); 2997 // Don't draw dividers next to items that are not enabled 2998 if (top > listTop) { 2999 if ((areAllItemsSelectable || 3000 (adapter.isEnabled(first + i) && (i == count - 1 || 3001 adapter.isEnabled(first + i + 1))))) { 3002 bounds.top = top - dividerHeight; 3003 bounds.bottom = top; 3004 // Give the method the child ABOVE the divider, so we 3005 // subtract one from our child 3006 // position. Give -1 when there is no child above the 3007 // divider. 3008 drawDivider(canvas, bounds, i - 1); 3009 } else if (fillForMissingDividers) { 3010 bounds.top = top - dividerHeight; 3011 bounds.bottom = top; 3012 canvas.drawRect(bounds, paint); 3013 } 3014 } 3015 } 3016 } 3017 } 3018 } 3019 3020 // Draw the indicators (these should be drawn above the dividers) and children 3021 super.dispatchDraw(canvas); 3022 } 3023 3024 /** 3025 * Draws a divider for the given child in the given bounds. 3026 * 3027 * @param canvas The canvas to draw to. 3028 * @param bounds The bounds of the divider. 3029 * @param childIndex The index of child (of the View) above the divider. 3030 * This will be -1 if there is no child above the divider to be 3031 * drawn. 3032 */ 3033 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3034 // This widget draws the same divider for all children 3035 final Drawable divider = mDivider; 3036 final boolean clipDivider = mClipDivider; 3037 3038 if (!clipDivider) { 3039 divider.setBounds(bounds); 3040 } else { 3041 canvas.save(); 3042 canvas.clipRect(bounds); 3043 } 3044 3045 divider.draw(canvas); 3046 3047 if (clipDivider) { 3048 canvas.restore(); 3049 } 3050 } 3051 3052 /** 3053 * Returns the drawable that will be drawn between each item in the list. 3054 * 3055 * @return the current drawable drawn between list elements 3056 */ 3057 public Drawable getDivider() { 3058 return mDivider; 3059 } 3060 3061 /** 3062 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3063 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3064 * 3065 * @param divider The drawable to use. 3066 */ 3067 public void setDivider(Drawable divider) { 3068 if (divider != null) { 3069 mDividerHeight = divider.getIntrinsicHeight(); 3070 mClipDivider = divider instanceof ColorDrawable; 3071 } else { 3072 mDividerHeight = 0; 3073 mClipDivider = false; 3074 } 3075 mDivider = divider; 3076 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3077 requestLayoutIfNecessary(); 3078 } 3079 3080 /** 3081 * @return Returns the height of the divider that will be drawn between each item in the list. 3082 */ 3083 public int getDividerHeight() { 3084 return mDividerHeight; 3085 } 3086 3087 /** 3088 * Sets the height of the divider that will be drawn between each item in the list. Calling 3089 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3090 * 3091 * @param height The new height of the divider in pixels. 3092 */ 3093 public void setDividerHeight(int height) { 3094 mDividerHeight = height; 3095 requestLayoutIfNecessary(); 3096 } 3097 3098 /** 3099 * Enables or disables the drawing of the divider for header views. 3100 * 3101 * @param headerDividersEnabled True to draw the headers, false otherwise. 3102 * 3103 * @see #setFooterDividersEnabled(boolean) 3104 * @see #addHeaderView(android.view.View) 3105 */ 3106 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3107 mHeaderDividersEnabled = headerDividersEnabled; 3108 invalidate(); 3109 } 3110 3111 /** 3112 * Enables or disables the drawing of the divider for footer views. 3113 * 3114 * @param footerDividersEnabled True to draw the footers, false otherwise. 3115 * 3116 * @see #setHeaderDividersEnabled(boolean) 3117 * @see #addFooterView(android.view.View) 3118 */ 3119 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3120 mFooterDividersEnabled = footerDividersEnabled; 3121 invalidate(); 3122 } 3123 3124 @Override 3125 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3126 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3127 3128 int closetChildIndex = -1; 3129 if (gainFocus && previouslyFocusedRect != null) { 3130 previouslyFocusedRect.offset(mScrollX, mScrollY); 3131 3132 final ListAdapter adapter = mAdapter; 3133 // Don't cache the result of getChildCount or mFirstPosition here, 3134 // it could change in layoutChildren. 3135 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3136 mLayoutMode = LAYOUT_NORMAL; 3137 layoutChildren(); 3138 } 3139 3140 // figure out which item should be selected based on previously 3141 // focused rect 3142 Rect otherRect = mTempRect; 3143 int minDistance = Integer.MAX_VALUE; 3144 final int childCount = getChildCount(); 3145 final int firstPosition = mFirstPosition; 3146 3147 for (int i = 0; i < childCount; i++) { 3148 // only consider selectable views 3149 if (!adapter.isEnabled(firstPosition + i)) { 3150 continue; 3151 } 3152 3153 View other = getChildAt(i); 3154 other.getDrawingRect(otherRect); 3155 offsetDescendantRectToMyCoords(other, otherRect); 3156 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3157 3158 if (distance < minDistance) { 3159 minDistance = distance; 3160 closetChildIndex = i; 3161 } 3162 } 3163 } 3164 3165 if (closetChildIndex >= 0) { 3166 setSelection(closetChildIndex + mFirstPosition); 3167 } else { 3168 requestLayout(); 3169 } 3170 } 3171 3172 3173 /* 3174 * (non-Javadoc) 3175 * 3176 * Children specified in XML are assumed to be header views. After we have 3177 * parsed them move them out of the children list and into mHeaderViews. 3178 */ 3179 @Override 3180 protected void onFinishInflate() { 3181 super.onFinishInflate(); 3182 3183 int count = getChildCount(); 3184 if (count > 0) { 3185 for (int i = 0; i < count; ++i) { 3186 addHeaderView(getChildAt(i)); 3187 } 3188 removeAllViews(); 3189 } 3190 } 3191 3192 /* (non-Javadoc) 3193 * @see android.view.View#findViewById(int) 3194 * First look in our children, then in any header and footer views that may be scrolled off. 3195 */ 3196 @Override 3197 protected View findViewTraversal(int id) { 3198 View v; 3199 v = super.findViewTraversal(id); 3200 if (v == null) { 3201 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3202 if (v != null) { 3203 return v; 3204 } 3205 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3206 if (v != null) { 3207 return v; 3208 } 3209 } 3210 return v; 3211 } 3212 3213 /* (non-Javadoc) 3214 * 3215 * Look in the passed in list of headers or footers for the view. 3216 */ 3217 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3218 if (where != null) { 3219 int len = where.size(); 3220 View v; 3221 3222 for (int i = 0; i < len; i++) { 3223 v = where.get(i).view; 3224 3225 if (!v.isRootNamespace()) { 3226 v = v.findViewById(id); 3227 3228 if (v != null) { 3229 return v; 3230 } 3231 } 3232 } 3233 } 3234 return null; 3235 } 3236 3237 /* (non-Javadoc) 3238 * @see android.view.View#findViewWithTag(String) 3239 * First look in our children, then in any header and footer views that may be scrolled off. 3240 */ 3241 @Override 3242 protected View findViewWithTagTraversal(Object tag) { 3243 View v; 3244 v = super.findViewWithTagTraversal(tag); 3245 if (v == null) { 3246 v = findViewTagInHeadersOrFooters(mHeaderViewInfos, tag); 3247 if (v != null) { 3248 return v; 3249 } 3250 3251 v = findViewTagInHeadersOrFooters(mFooterViewInfos, tag); 3252 if (v != null) { 3253 return v; 3254 } 3255 } 3256 return v; 3257 } 3258 3259 /* (non-Javadoc) 3260 * 3261 * Look in the passed in list of headers or footers for the view with the tag. 3262 */ 3263 View findViewTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3264 if (where != null) { 3265 int len = where.size(); 3266 View v; 3267 3268 for (int i = 0; i < len; i++) { 3269 v = where.get(i).view; 3270 3271 if (!v.isRootNamespace()) { 3272 v = v.findViewWithTag(tag); 3273 3274 if (v != null) { 3275 return v; 3276 } 3277 } 3278 } 3279 } 3280 return null; 3281 } 3282 3283 @Override 3284 public boolean onTouchEvent(MotionEvent ev) { 3285 if (mItemsCanFocus && ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { 3286 // Don't handle edge touches immediately -- they may actually belong to one of our 3287 // descendants. 3288 return false; 3289 } 3290 return super.onTouchEvent(ev); 3291 } 3292 3293 /** 3294 * @see #setChoiceMode(int) 3295 * 3296 * @return The current choice mode 3297 */ 3298 public int getChoiceMode() { 3299 return mChoiceMode; 3300 } 3301 3302 /** 3303 * Defines the choice behavior for the List. By default, Lists do not have any choice behavior 3304 * ({@link #CHOICE_MODE_NONE}). By setting the choiceMode to {@link #CHOICE_MODE_SINGLE}, the 3305 * List allows up to one item to be in a chosen state. By setting the choiceMode to 3306 * {@link #CHOICE_MODE_MULTIPLE}, the list allows any number of items to be chosen. 3307 * 3308 * @param choiceMode One of {@link #CHOICE_MODE_NONE}, {@link #CHOICE_MODE_SINGLE}, or 3309 * {@link #CHOICE_MODE_MULTIPLE} 3310 */ 3311 public void setChoiceMode(int choiceMode) { 3312 mChoiceMode = choiceMode; 3313 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates == null) { 3314 mCheckStates = new SparseBooleanArray(); 3315 } 3316 } 3317 3318 @Override 3319 public boolean performItemClick(View view, int position, long id) { 3320 boolean handled = false; 3321 3322 if (mChoiceMode != CHOICE_MODE_NONE) { 3323 handled = true; 3324 3325 if (mChoiceMode == CHOICE_MODE_MULTIPLE) { 3326 boolean oldValue = mCheckStates.get(position, false); 3327 mCheckStates.put(position, !oldValue); 3328 } else { 3329 boolean oldValue = mCheckStates.get(position, false); 3330 if (!oldValue) { 3331 mCheckStates.clear(); 3332 mCheckStates.put(position, true); 3333 } 3334 } 3335 3336 mDataChanged = true; 3337 rememberSyncState(); 3338 requestLayout(); 3339 } 3340 3341 handled |= super.performItemClick(view, position, id); 3342 3343 return handled; 3344 } 3345 3346 /** 3347 * Sets the checked state of the specified position. The is only valid if 3348 * the choice mode has been set to {@link #CHOICE_MODE_SINGLE} or 3349 * {@link #CHOICE_MODE_MULTIPLE}. 3350 * 3351 * @param position The item whose checked state is to be checked 3352 * @param value The new checked state for the item 3353 */ 3354 public void setItemChecked(int position, boolean value) { 3355 if (mChoiceMode == CHOICE_MODE_NONE) { 3356 return; 3357 } 3358 3359 if (mChoiceMode == CHOICE_MODE_MULTIPLE) { 3360 mCheckStates.put(position, value); 3361 } else { 3362 // Clear all values if we're checking something, or unchecking the currently 3363 // selected item 3364 if (value || isItemChecked(position)) { 3365 mCheckStates.clear(); 3366 } 3367 // this may end up selecting the value we just cleared but this way 3368 // we ensure length of mCheckStates is 1, a fact getCheckedItemPosition relies on 3369 if (value) { 3370 mCheckStates.put(position, true); 3371 } 3372 } 3373 3374 // Do not generate a data change while we are in the layout phase 3375 if (!mInLayout && !mBlockLayoutRequests) { 3376 mDataChanged = true; 3377 rememberSyncState(); 3378 requestLayout(); 3379 } 3380 } 3381 3382 /** 3383 * Returns the checked state of the specified position. The result is only 3384 * valid if the choice mode has been set to {@link #CHOICE_MODE_SINGLE} 3385 * or {@link #CHOICE_MODE_MULTIPLE}. 3386 * 3387 * @param position The item whose checked state to return 3388 * @return The item's checked state or <code>false</code> if choice mode 3389 * is invalid 3390 * 3391 * @see #setChoiceMode(int) 3392 */ 3393 public boolean isItemChecked(int position) { 3394 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 3395 return mCheckStates.get(position); 3396 } 3397 3398 return false; 3399 } 3400 3401 /** 3402 * Returns the currently checked item. The result is only valid if the choice 3403 * mode has been set to {@link #CHOICE_MODE_SINGLE}. 3404 * 3405 * @return The position of the currently checked item or 3406 * {@link #INVALID_POSITION} if nothing is selected 3407 * 3408 * @see #setChoiceMode(int) 3409 */ 3410 public int getCheckedItemPosition() { 3411 if (mChoiceMode == CHOICE_MODE_SINGLE && mCheckStates != null && mCheckStates.size() == 1) { 3412 return mCheckStates.keyAt(0); 3413 } 3414 3415 return INVALID_POSITION; 3416 } 3417 3418 /** 3419 * Returns the set of checked items in the list. The result is only valid if 3420 * the choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3421 * 3422 * @return A SparseBooleanArray which will return true for each call to 3423 * get(int position) where position is a position in the list, 3424 * or <code>null</code> if the choice mode is set to 3425 * {@link #CHOICE_MODE_NONE}. 3426 */ 3427 public SparseBooleanArray getCheckedItemPositions() { 3428 if (mChoiceMode != CHOICE_MODE_NONE) { 3429 return mCheckStates; 3430 } 3431 return null; 3432 } 3433 3434 /** 3435 * Returns the set of checked items ids. The result is only valid if the 3436 * choice mode has not been set to {@link #CHOICE_MODE_SINGLE}. 3437 * 3438 * @return A new array which contains the id of each checked item in the 3439 * list. 3440 */ 3441 public long[] getCheckItemIds() { 3442 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3443 final SparseBooleanArray states = mCheckStates; 3444 final int count = states.size(); 3445 final long[] ids = new long[count]; 3446 final ListAdapter adapter = mAdapter; 3447 3448 int checkedCount = 0; 3449 for (int i = 0; i < count; i++) { 3450 if (states.valueAt(i)) { 3451 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3452 } 3453 } 3454 3455 // Trim array if needed. mCheckStates may contain false values 3456 // resulting in checkedCount being smaller than count. 3457 if (checkedCount == count) { 3458 return ids; 3459 } else { 3460 final long[] result = new long[checkedCount]; 3461 System.arraycopy(ids, 0, result, 0, checkedCount); 3462 3463 return result; 3464 } 3465 } 3466 3467 return new long[0]; 3468 } 3469 3470 /** 3471 * Clear any choices previously set 3472 */ 3473 public void clearChoices() { 3474 if (mCheckStates != null) { 3475 mCheckStates.clear(); 3476 } 3477 } 3478 3479 static class SavedState extends BaseSavedState { 3480 SparseBooleanArray checkState; 3481 3482 /** 3483 * Constructor called from {@link ListView#onSaveInstanceState()} 3484 */ 3485 SavedState(Parcelable superState, SparseBooleanArray checkState) { 3486 super(superState); 3487 this.checkState = checkState; 3488 } 3489 3490 /** 3491 * Constructor called from {@link #CREATOR} 3492 */ 3493 private SavedState(Parcel in) { 3494 super(in); 3495 checkState = in.readSparseBooleanArray(); 3496 } 3497 3498 @Override 3499 public void writeToParcel(Parcel out, int flags) { 3500 super.writeToParcel(out, flags); 3501 out.writeSparseBooleanArray(checkState); 3502 } 3503 3504 @Override 3505 public String toString() { 3506 return "ListView.SavedState{" 3507 + Integer.toHexString(System.identityHashCode(this)) 3508 + " checkState=" + checkState + "}"; 3509 } 3510 3511 public static final Parcelable.Creator<SavedState> CREATOR 3512 = new Parcelable.Creator<SavedState>() { 3513 public SavedState createFromParcel(Parcel in) { 3514 return new SavedState(in); 3515 } 3516 3517 public SavedState[] newArray(int size) { 3518 return new SavedState[size]; 3519 } 3520 }; 3521 } 3522 3523 @Override 3524 public Parcelable onSaveInstanceState() { 3525 Parcelable superState = super.onSaveInstanceState(); 3526 return new SavedState(superState, mCheckStates); 3527 } 3528 3529 @Override 3530 public void onRestoreInstanceState(Parcelable state) { 3531 SavedState ss = (SavedState) state; 3532 3533 super.onRestoreInstanceState(ss.getSuperState()); 3534 3535 if (ss.checkState != null) { 3536 mCheckStates = ss.checkState; 3537 } 3538 3539 } 3540} 3541