ListView.java revision 6198ae8468668bf7374535c2eeeab8de7f8e7e99
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 android.content.Context; 20import android.content.res.TypedArray; 21import android.graphics.Canvas; 22import android.graphics.Rect; 23import android.graphics.PixelFormat; 24import android.graphics.Paint; 25import android.graphics.drawable.Drawable; 26import android.graphics.drawable.ColorDrawable; 27import android.os.Parcel; 28import android.os.Parcelable; 29import android.util.AttributeSet; 30import android.util.SparseBooleanArray; 31import android.view.FocusFinder; 32import android.view.KeyEvent; 33import android.view.MotionEvent; 34import android.view.View; 35import android.view.ViewDebug; 36import android.view.ViewGroup; 37import android.view.ViewParent; 38import android.view.SoundEffectConstants; 39import android.view.accessibility.AccessibilityEvent; 40 41import com.google.android.collect.Lists; 42import com.android.internal.R; 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 ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 142 143 public ListView(Context context) { 144 this(context, null); 145 } 146 147 public ListView(Context context, AttributeSet attrs) { 148 this(context, attrs, com.android.internal.R.attr.listViewStyle); 149 } 150 151 public ListView(Context context, AttributeSet attrs, int defStyle) { 152 super(context, attrs, defStyle); 153 154 TypedArray a = context.obtainStyledAttributes(attrs, 155 com.android.internal.R.styleable.ListView, defStyle, 0); 156 157 CharSequence[] entries = a.getTextArray( 158 com.android.internal.R.styleable.ListView_entries); 159 if (entries != null) { 160 setAdapter(new ArrayAdapter<CharSequence>(context, 161 com.android.internal.R.layout.simple_list_item_1, entries)); 162 } 163 164 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 165 if (d != null) { 166 // If a divider is specified use its intrinsic height for divider height 167 setDivider(d); 168 } 169 170 // Use the height specified, zero being the default 171 final int dividerHeight = a.getDimensionPixelSize( 172 com.android.internal.R.styleable.ListView_dividerHeight, 0); 173 if (dividerHeight != 0) { 174 setDividerHeight(dividerHeight); 175 } 176 177 setChoiceMode(a.getInt(R.styleable.ListView_choiceMode, CHOICE_MODE_NONE)); 178 179 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 180 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 181 182 a.recycle(); 183 } 184 185 /** 186 * @return The maximum amount a list view will scroll in response to 187 * an arrow event. 188 */ 189 public int getMaxScrollAmount() { 190 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 191 } 192 193 /** 194 * Make sure views are touching the top or bottom edge, as appropriate for 195 * our gravity 196 */ 197 private void adjustViewsUpOrDown() { 198 final int childCount = getChildCount(); 199 int delta; 200 201 if (childCount > 0) { 202 View child; 203 204 if (!mStackFromBottom) { 205 // Uh-oh -- we came up short. Slide all views up to make them 206 // align with the top 207 child = getChildAt(0); 208 delta = child.getTop() - mListPadding.top; 209 if (mFirstPosition != 0) { 210 // It's OK to have some space above the first item if it is 211 // part of the vertical spacing 212 delta -= mDividerHeight; 213 } 214 if (delta < 0) { 215 // We only are looking to see if we are too low, not too high 216 delta = 0; 217 } 218 } else { 219 // we are too high, slide all views down to align with bottom 220 child = getChildAt(childCount - 1); 221 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 222 223 if (mFirstPosition + childCount < mItemCount) { 224 // It's OK to have some space below the last item if it is 225 // part of the vertical spacing 226 delta += mDividerHeight; 227 } 228 229 if (delta > 0) { 230 delta = 0; 231 } 232 } 233 234 if (delta != 0) { 235 offsetChildrenTopAndBottom(-delta); 236 } 237 } 238 } 239 240 /** 241 * Add a fixed view to appear at the top of the list. If addHeaderView is 242 * called more than once, the views will appear in the order they were 243 * added. Views added using this call can take focus if they want. 244 * <p> 245 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 246 * the supplied cursor with one that that will also account for header 247 * views. 248 * 249 * @param v The view to add. 250 * @param data Data to associate with this view 251 * @param isSelectable whether the item is selectable 252 */ 253 public void addHeaderView(View v, Object data, boolean isSelectable) { 254 255 if (mAdapter != null) { 256 throw new IllegalStateException( 257 "Cannot add header view to list -- setAdapter has already been called."); 258 } 259 260 FixedViewInfo info = new FixedViewInfo(); 261 info.view = v; 262 info.data = data; 263 info.isSelectable = isSelectable; 264 mHeaderViewInfos.add(info); 265 } 266 267 /** 268 * Add a fixed view to appear at the top of the list. If addHeaderView is 269 * called more than once, the views will appear in the order they were 270 * added. Views added using this call can take focus if they want. 271 * <p> 272 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 273 * the supplied cursor with one that that will also account for header 274 * views. 275 * 276 * @param v The view to add. 277 */ 278 public void addHeaderView(View v) { 279 addHeaderView(v, null, true); 280 } 281 282 @Override 283 public int getHeaderViewsCount() { 284 return mHeaderViewInfos.size(); 285 } 286 287 /** 288 * Removes a previously-added header view. 289 * 290 * @param v The view to remove 291 * @return true if the view was removed, false if the view was not a header 292 * view 293 */ 294 public boolean removeHeaderView(View v) { 295 if (mHeaderViewInfos.size() > 0) { 296 boolean result = false; 297 if (((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 298 mDataSetObserver.onChanged(); 299 result = true; 300 } 301 removeFixedViewInfo(v, mHeaderViewInfos); 302 return result; 303 } 304 return false; 305 } 306 307 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 308 int len = where.size(); 309 for (int i = 0; i < len; ++i) { 310 FixedViewInfo info = where.get(i); 311 if (info.view == v) { 312 where.remove(i); 313 break; 314 } 315 } 316 } 317 318 /** 319 * Add a fixed view to appear at the bottom of the list. If addFooterView is 320 * called more than once, the views will appear in the order they were 321 * added. Views added using this call can take focus if they want. 322 * <p> 323 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 324 * the supplied cursor with one that that will also account for header 325 * views. 326 * 327 * @param v The view to add. 328 * @param data Data to associate with this view 329 * @param isSelectable true if the footer view can be selected 330 */ 331 public void addFooterView(View v, Object data, boolean isSelectable) { 332 FixedViewInfo info = new FixedViewInfo(); 333 info.view = v; 334 info.data = data; 335 info.isSelectable = isSelectable; 336 mFooterViewInfos.add(info); 337 338 // in the case of re-adding a footer view, or adding one later on, 339 // we need to notify the observer 340 if (mDataSetObserver != null) { 341 mDataSetObserver.onChanged(); 342 } 343 } 344 345 /** 346 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 347 * than once, the views will appear in the order they were added. Views added using 348 * this call can take focus if they want. 349 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 350 * cursor with one that that will also account for header views. 351 * 352 * 353 * @param v The view to add. 354 */ 355 public void addFooterView(View v) { 356 addFooterView(v, null, true); 357 } 358 359 @Override 360 public int getFooterViewsCount() { 361 return mFooterViewInfos.size(); 362 } 363 364 /** 365 * Removes a previously-added footer view. 366 * 367 * @param v The view to remove 368 * @return 369 * true if the view was removed, false if the view was not a footer view 370 */ 371 public boolean removeFooterView(View v) { 372 if (mFooterViewInfos.size() > 0) { 373 boolean result = false; 374 if (((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 375 mDataSetObserver.onChanged(); 376 result = true; 377 } 378 removeFixedViewInfo(v, mFooterViewInfos); 379 return result; 380 } 381 return false; 382 } 383 384 /** 385 * Returns the adapter currently in use in this ListView. The returned adapter 386 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 387 * might be a {@link WrapperListAdapter}. 388 * 389 * @return The adapter currently used to display data in this ListView. 390 * 391 * @see #setAdapter(ListAdapter) 392 */ 393 @Override 394 public ListAdapter getAdapter() { 395 return mAdapter; 396 } 397 398 /** 399 * Sets the data behind this ListView. 400 * 401 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 402 * depending on the ListView features currently in use. For instance, adding 403 * headers and/or footers will cause the adapter to be wrapped. 404 * 405 * @param adapter The ListAdapter which is responsible for maintaining the 406 * data backing this list and for producing a view to represent an 407 * item in that data set. 408 * 409 * @see #getAdapter() 410 */ 411 @Override 412 public void setAdapter(ListAdapter adapter) { 413 if (null != mAdapter) { 414 mAdapter.unregisterDataSetObserver(mDataSetObserver); 415 } 416 417 resetList(); 418 mRecycler.clear(); 419 420 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 421 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 422 } else { 423 mAdapter = adapter; 424 } 425 426 mOldSelectedPosition = INVALID_POSITION; 427 mOldSelectedRowId = INVALID_ROW_ID; 428 if (mAdapter != null) { 429 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 430 mOldItemCount = mItemCount; 431 mItemCount = mAdapter.getCount(); 432 checkFocus(); 433 434 mDataSetObserver = new AdapterDataSetObserver(); 435 mAdapter.registerDataSetObserver(mDataSetObserver); 436 437 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 438 439 int position; 440 if (mStackFromBottom) { 441 position = lookForSelectablePosition(mItemCount - 1, false); 442 } else { 443 position = lookForSelectablePosition(0, true); 444 } 445 setSelectedPositionInt(position); 446 setNextSelectedPositionInt(position); 447 448 if (mItemCount == 0) { 449 // Nothing selected 450 checkSelectionChanged(); 451 } 452 453 } else { 454 mAreAllItemsSelectable = true; 455 checkFocus(); 456 // Nothing selected 457 checkSelectionChanged(); 458 } 459 460 if (mCheckStates != null) { 461 mCheckStates.clear(); 462 } 463 464 requestLayout(); 465 } 466 467 468 /** 469 * The list is empty. Clear everything out. 470 */ 471 @Override 472 void resetList() { 473 // The parent's resetList() will remove all views from the layout so we need to 474 // cleanup the state of our footers and headers 475 clearRecycledState(mHeaderViewInfos); 476 clearRecycledState(mFooterViewInfos); 477 478 super.resetList(); 479 480 mLayoutMode = LAYOUT_NORMAL; 481 } 482 483 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 484 if (infos != null) { 485 final int count = infos.size(); 486 487 for (int i = 0; i < count; i++) { 488 final View child = infos.get(i).view; 489 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 490 if (p != null) { 491 p.recycledHeaderFooter = false; 492 } 493 } 494 } 495 } 496 497 /** 498 * @return Whether the list needs to show the top fading edge 499 */ 500 private boolean showingTopFadingEdge() { 501 final int listTop = mScrollY + mListPadding.top; 502 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 503 } 504 505 /** 506 * @return Whether the list needs to show the bottom fading edge 507 */ 508 private boolean showingBottomFadingEdge() { 509 final int childCount = getChildCount(); 510 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 511 final int lastVisiblePosition = mFirstPosition + childCount - 1; 512 513 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 514 515 return (lastVisiblePosition < mItemCount - 1) 516 || (bottomOfBottomChild < listBottom); 517 } 518 519 520 @Override 521 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 522 523 int rectTopWithinChild = rect.top; 524 525 // offset so rect is in coordinates of the this view 526 rect.offset(child.getLeft(), child.getTop()); 527 rect.offset(-child.getScrollX(), -child.getScrollY()); 528 529 final int height = getHeight(); 530 int listUnfadedTop = getScrollY(); 531 int listUnfadedBottom = listUnfadedTop + height; 532 final int fadingEdge = getVerticalFadingEdgeLength(); 533 534 if (showingTopFadingEdge()) { 535 // leave room for top fading edge as long as rect isn't at very top 536 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 537 listUnfadedTop += fadingEdge; 538 } 539 } 540 541 int childCount = getChildCount(); 542 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 543 544 if (showingBottomFadingEdge()) { 545 // leave room for bottom fading edge as long as rect isn't at very bottom 546 if ((mSelectedPosition < mItemCount - 1) 547 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 548 listUnfadedBottom -= fadingEdge; 549 } 550 } 551 552 int scrollYDelta = 0; 553 554 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 555 // need to MOVE DOWN to get it in view: move down just enough so 556 // that the entire rectangle is in view (or at least the first 557 // screen size chunk). 558 559 if (rect.height() > height) { 560 // just enough to get screen size chunk on 561 scrollYDelta += (rect.top - listUnfadedTop); 562 } else { 563 // get entire rect at bottom of screen 564 scrollYDelta += (rect.bottom - listUnfadedBottom); 565 } 566 567 // make sure we aren't scrolling beyond the end of our children 568 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 569 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 570 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 571 // need to MOVE UP to get it in view: move up just enough so that 572 // entire rectangle is in view (or at least the first screen 573 // size chunk of it). 574 575 if (rect.height() > height) { 576 // screen size chunk 577 scrollYDelta -= (listUnfadedBottom - rect.bottom); 578 } else { 579 // entire rect at top 580 scrollYDelta -= (listUnfadedTop - rect.top); 581 } 582 583 // make sure we aren't scrolling any further than the top our children 584 int top = getChildAt(0).getTop(); 585 int deltaToTop = top - listUnfadedTop; 586 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 587 } 588 589 final boolean scroll = scrollYDelta != 0; 590 if (scroll) { 591 scrollListItemsBy(-scrollYDelta); 592 positionSelector(child); 593 mSelectedTop = child.getTop(); 594 invalidate(); 595 } 596 return scroll; 597 } 598 599 /** 600 * {@inheritDoc} 601 */ 602 @Override 603 void fillGap(boolean down) { 604 final int count = getChildCount(); 605 if (down) { 606 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 607 getListPaddingTop(); 608 fillDown(mFirstPosition + count, startOffset); 609 correctTooHigh(getChildCount()); 610 } else { 611 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 612 getHeight() - getListPaddingBottom(); 613 fillUp(mFirstPosition - 1, startOffset); 614 correctTooLow(getChildCount()); 615 } 616 } 617 618 /** 619 * Fills the list from pos down to the end of the list view. 620 * 621 * @param pos The first position to put in the list 622 * 623 * @param nextTop The location where the top of the item associated with pos 624 * should be drawn 625 * 626 * @return The view that is currently selected, if it happens to be in the 627 * range that we draw. 628 */ 629 private View fillDown(int pos, int nextTop) { 630 View selectedView = null; 631 632 int end = (mBottom - mTop) - mListPadding.bottom; 633 634 while (nextTop < end && pos < mItemCount) { 635 // is this the selected item? 636 boolean selected = pos == mSelectedPosition; 637 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 638 639 nextTop = child.getBottom() + mDividerHeight; 640 if (selected) { 641 selectedView = child; 642 } 643 pos++; 644 } 645 646 return selectedView; 647 } 648 649 /** 650 * Fills the list from pos up to the top of the list view. 651 * 652 * @param pos The first position to put in the list 653 * 654 * @param nextBottom The location where the bottom of the item associated 655 * with pos should be drawn 656 * 657 * @return The view that is currently selected 658 */ 659 private View fillUp(int pos, int nextBottom) { 660 View selectedView = null; 661 662 int end = mListPadding.top; 663 664 while (nextBottom > end && pos >= 0) { 665 // is this the selected item? 666 boolean selected = pos == mSelectedPosition; 667 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 668 nextBottom = child.getTop() - mDividerHeight; 669 if (selected) { 670 selectedView = child; 671 } 672 pos--; 673 } 674 675 mFirstPosition = pos + 1; 676 677 return selectedView; 678 } 679 680 /** 681 * Fills the list from top to bottom, starting with mFirstPosition 682 * 683 * @param nextTop The location where the top of the first item should be 684 * drawn 685 * 686 * @return The view that is currently selected 687 */ 688 private View fillFromTop(int nextTop) { 689 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 690 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 691 if (mFirstPosition < 0) { 692 mFirstPosition = 0; 693 } 694 return fillDown(mFirstPosition, nextTop); 695 } 696 697 698 /** 699 * Put mSelectedPosition in the middle of the screen and then build up and 700 * down from there. This method forces mSelectedPosition to the center. 701 * 702 * @param childrenTop Top of the area in which children can be drawn, as 703 * measured in pixels 704 * @param childrenBottom Bottom of the area in which children can be drawn, 705 * as measured in pixels 706 * @return Currently selected view 707 */ 708 private View fillFromMiddle(int childrenTop, int childrenBottom) { 709 int height = childrenBottom - childrenTop; 710 711 int position = reconcileSelectedPosition(); 712 713 View sel = makeAndAddView(position, childrenTop, true, 714 mListPadding.left, true); 715 mFirstPosition = position; 716 717 int selHeight = sel.getMeasuredHeight(); 718 if (selHeight <= height) { 719 sel.offsetTopAndBottom((height - selHeight) / 2); 720 } 721 722 fillAboveAndBelow(sel, position); 723 724 if (!mStackFromBottom) { 725 correctTooHigh(getChildCount()); 726 } else { 727 correctTooLow(getChildCount()); 728 } 729 730 return sel; 731 } 732 733 /** 734 * Once the selected view as been placed, fill up the visible area above and 735 * below it. 736 * 737 * @param sel The selected view 738 * @param position The position corresponding to sel 739 */ 740 private void fillAboveAndBelow(View sel, int position) { 741 final int dividerHeight = mDividerHeight; 742 if (!mStackFromBottom) { 743 fillUp(position - 1, sel.getTop() - dividerHeight); 744 adjustViewsUpOrDown(); 745 fillDown(position + 1, sel.getBottom() + dividerHeight); 746 } else { 747 fillDown(position + 1, sel.getBottom() + dividerHeight); 748 adjustViewsUpOrDown(); 749 fillUp(position - 1, sel.getTop() - dividerHeight); 750 } 751 } 752 753 754 /** 755 * Fills the grid based on positioning the new selection at a specific 756 * location. The selection may be moved so that it does not intersect the 757 * faded edges. The grid is then filled upwards and downwards from there. 758 * 759 * @param selectedTop Where the selected item should be 760 * @param childrenTop Where to start drawing children 761 * @param childrenBottom Last pixel where children can be drawn 762 * @return The view that currently has selection 763 */ 764 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 765 int fadingEdgeLength = getVerticalFadingEdgeLength(); 766 final int selectedPosition = mSelectedPosition; 767 768 View sel; 769 770 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 771 selectedPosition); 772 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 773 selectedPosition); 774 775 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 776 777 778 // Some of the newly selected item extends below the bottom of the list 779 if (sel.getBottom() > bottomSelectionPixel) { 780 // Find space available above the selection into which we can scroll 781 // upwards 782 final int spaceAbove = sel.getTop() - topSelectionPixel; 783 784 // Find space required to bring the bottom of the selected item 785 // fully into view 786 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 787 final int offset = Math.min(spaceAbove, spaceBelow); 788 789 // Now offset the selected item to get it into view 790 sel.offsetTopAndBottom(-offset); 791 } else if (sel.getTop() < topSelectionPixel) { 792 // Find space required to bring the top of the selected item fully 793 // into view 794 final int spaceAbove = topSelectionPixel - sel.getTop(); 795 796 // Find space available below the selection into which we can scroll 797 // downwards 798 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 799 final int offset = Math.min(spaceAbove, spaceBelow); 800 801 // Offset the selected item to get it into view 802 sel.offsetTopAndBottom(offset); 803 } 804 805 // Fill in views above and below 806 fillAboveAndBelow(sel, selectedPosition); 807 808 if (!mStackFromBottom) { 809 correctTooHigh(getChildCount()); 810 } else { 811 correctTooLow(getChildCount()); 812 } 813 814 return sel; 815 } 816 817 /** 818 * Calculate the bottom-most pixel we can draw the selection into 819 * 820 * @param childrenBottom Bottom pixel were children can be drawn 821 * @param fadingEdgeLength Length of the fading edge in pixels, if present 822 * @param selectedPosition The position that will be selected 823 * @return The bottom-most pixel we can draw the selection into 824 */ 825 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 826 int selectedPosition) { 827 int bottomSelectionPixel = childrenBottom; 828 if (selectedPosition != mItemCount - 1) { 829 bottomSelectionPixel -= fadingEdgeLength; 830 } 831 return bottomSelectionPixel; 832 } 833 834 /** 835 * Calculate the top-most pixel we can draw the selection into 836 * 837 * @param childrenTop Top pixel were children can be drawn 838 * @param fadingEdgeLength Length of the fading edge in pixels, if present 839 * @param selectedPosition The position that will be selected 840 * @return The top-most pixel we can draw the selection into 841 */ 842 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 843 // first pixel we can draw the selection into 844 int topSelectionPixel = childrenTop; 845 if (selectedPosition > 0) { 846 topSelectionPixel += fadingEdgeLength; 847 } 848 return topSelectionPixel; 849 } 850 851 852 /** 853 * Fills the list based on positioning the new selection relative to the old 854 * selection. The new selection will be placed at, above, or below the 855 * location of the new selection depending on how the selection is moving. 856 * The selection will then be pinned to the visible part of the screen, 857 * excluding the edges that are faded. The list is then filled upwards and 858 * downwards from there. 859 * 860 * @param oldSel The old selected view. Useful for trying to put the new 861 * selection in the same place 862 * @param newSel The view that is to become selected. Useful for trying to 863 * put the new selection in the same place 864 * @param delta Which way we are moving 865 * @param childrenTop Where to start drawing children 866 * @param childrenBottom Last pixel where children can be drawn 867 * @return The view that currently has selection 868 */ 869 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 870 int childrenBottom) { 871 int fadingEdgeLength = getVerticalFadingEdgeLength(); 872 final int selectedPosition = mSelectedPosition; 873 874 View sel; 875 876 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 877 selectedPosition); 878 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 879 selectedPosition); 880 881 if (delta > 0) { 882 /* 883 * Case 1: Scrolling down. 884 */ 885 886 /* 887 * Before After 888 * | | | | 889 * +-------+ +-------+ 890 * | A | | A | 891 * | 1 | => +-------+ 892 * +-------+ | B | 893 * | B | | 2 | 894 * +-------+ +-------+ 895 * | | | | 896 * 897 * Try to keep the top of the previously selected item where it was. 898 * oldSel = A 899 * sel = B 900 */ 901 902 // Put oldSel (A) where it belongs 903 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 904 mListPadding.left, false); 905 906 final int dividerHeight = mDividerHeight; 907 908 // Now put the new selection (B) below that 909 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 910 mListPadding.left, true); 911 912 // Some of the newly selected item extends below the bottom of the list 913 if (sel.getBottom() > bottomSelectionPixel) { 914 915 // Find space available above the selection into which we can scroll upwards 916 int spaceAbove = sel.getTop() - topSelectionPixel; 917 918 // Find space required to bring the bottom of the selected item fully into view 919 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 920 921 // Don't scroll more than half the height of the list 922 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 923 int offset = Math.min(spaceAbove, spaceBelow); 924 offset = Math.min(offset, halfVerticalSpace); 925 926 // We placed oldSel, so offset that item 927 oldSel.offsetTopAndBottom(-offset); 928 // Now offset the selected item to get it into view 929 sel.offsetTopAndBottom(-offset); 930 } 931 932 // Fill in views above and below 933 if (!mStackFromBottom) { 934 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 935 adjustViewsUpOrDown(); 936 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 937 } else { 938 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 939 adjustViewsUpOrDown(); 940 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 941 } 942 } else if (delta < 0) { 943 /* 944 * Case 2: Scrolling up. 945 */ 946 947 /* 948 * Before After 949 * | | | | 950 * +-------+ +-------+ 951 * | A | | A | 952 * +-------+ => | 1 | 953 * | B | +-------+ 954 * | 2 | | B | 955 * +-------+ +-------+ 956 * | | | | 957 * 958 * Try to keep the top of the item about to become selected where it was. 959 * newSel = A 960 * olSel = B 961 */ 962 963 if (newSel != null) { 964 // Try to position the top of newSel (A) where it was before it was selected 965 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 966 true); 967 } else { 968 // If (A) was not on screen and so did not have a view, position 969 // it above the oldSel (B) 970 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 971 true); 972 } 973 974 // Some of the newly selected item extends above the top of the list 975 if (sel.getTop() < topSelectionPixel) { 976 // Find space required to bring the top of the selected item fully into view 977 int spaceAbove = topSelectionPixel - sel.getTop(); 978 979 // Find space available below the selection into which we can scroll downwards 980 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 981 982 // Don't scroll more than half the height of the list 983 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 984 int offset = Math.min(spaceAbove, spaceBelow); 985 offset = Math.min(offset, halfVerticalSpace); 986 987 // Offset the selected item to get it into view 988 sel.offsetTopAndBottom(offset); 989 } 990 991 // Fill in views above and below 992 fillAboveAndBelow(sel, selectedPosition); 993 } else { 994 995 int oldTop = oldSel.getTop(); 996 997 /* 998 * Case 3: Staying still 999 */ 1000 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1001 1002 // We're staying still... 1003 if (oldTop < childrenTop) { 1004 // ... but the top of the old selection was off screen. 1005 // (This can happen if the data changes size out from under us) 1006 int newBottom = sel.getBottom(); 1007 if (newBottom < childrenTop + 20) { 1008 // Not enough visible -- bring it onscreen 1009 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1010 } 1011 } 1012 1013 // Fill in views above and below 1014 fillAboveAndBelow(sel, selectedPosition); 1015 } 1016 1017 return sel; 1018 } 1019 1020 @Override 1021 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1022 // Sets up mListPadding 1023 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1024 1025 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1026 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1027 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1028 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1029 1030 int childWidth = 0; 1031 int childHeight = 0; 1032 1033 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1034 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1035 heightMode == MeasureSpec.UNSPECIFIED)) { 1036 final View child = obtainView(0); 1037 1038 measureScrapChild(child, 0, widthMeasureSpec); 1039 1040 childWidth = child.getMeasuredWidth(); 1041 childHeight = child.getMeasuredHeight(); 1042 1043 if (recycleOnMeasure()) { 1044 mRecycler.addScrapView(child); 1045 } 1046 } 1047 1048 if (widthMode == MeasureSpec.UNSPECIFIED) { 1049 widthSize = mListPadding.left + mListPadding.right + childWidth + 1050 getVerticalScrollbarWidth(); 1051 } 1052 1053 if (heightMode == MeasureSpec.UNSPECIFIED) { 1054 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1055 getVerticalFadingEdgeLength() * 2; 1056 } 1057 1058 if (heightMode == MeasureSpec.AT_MOST) { 1059 // TODO: after first layout we should maybe start at the first visible position, not 0 1060 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1061 } 1062 1063 setMeasuredDimension(widthSize, heightSize); 1064 mWidthMeasureSpec = widthMeasureSpec; 1065 } 1066 1067 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1068 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1069 if (p == null) { 1070 p = new LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 1071 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1072 child.setLayoutParams(p); 1073 } 1074 p.viewType = mAdapter.getItemViewType(position); 1075 1076 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1077 mListPadding.left + mListPadding.right, p.width); 1078 int lpHeight = p.height; 1079 int childHeightSpec; 1080 if (lpHeight > 0) { 1081 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1082 } else { 1083 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1084 } 1085 child.measure(childWidthSpec, childHeightSpec); 1086 } 1087 1088 /** 1089 * @return True to recycle the views used to measure this ListView in 1090 * UNSPECIFIED/AT_MOST modes, false otherwise. 1091 * @hide 1092 */ 1093 @ViewDebug.ExportedProperty 1094 protected boolean recycleOnMeasure() { 1095 return true; 1096 } 1097 1098 /** 1099 * Measures the height of the given range of children (inclusive) and 1100 * returns the height with this ListView's padding and divider heights 1101 * included. If maxHeight is provided, the measuring will stop when the 1102 * current height reaches maxHeight. 1103 * 1104 * @param widthMeasureSpec The width measure spec to be given to a child's 1105 * {@link View#measure(int, int)}. 1106 * @param startPosition The position of the first child to be shown. 1107 * @param endPosition The (inclusive) position of the last child to be 1108 * shown. Specify {@link #NO_POSITION} if the last child should be 1109 * the last available child from the adapter. 1110 * @param maxHeight The maximum height that will be returned (if all the 1111 * children don't fit in this value, this value will be 1112 * returned). 1113 * @param disallowPartialChildPosition In general, whether the returned 1114 * height should only contain entire children. This is more 1115 * powerful--it is the first inclusive position at which partial 1116 * children will not be allowed. Example: it looks nice to have 1117 * at least 3 completely visible children, and in portrait this 1118 * will most likely fit; but in landscape there could be times 1119 * when even 2 children can not be completely shown, so a value 1120 * of 2 (remember, inclusive) would be good (assuming 1121 * startPosition is 0). 1122 * @return The height of this ListView with the given children. 1123 */ 1124 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1125 final int maxHeight, int disallowPartialChildPosition) { 1126 1127 final ListAdapter adapter = mAdapter; 1128 if (adapter == null) { 1129 return mListPadding.top + mListPadding.bottom; 1130 } 1131 1132 // Include the padding of the list 1133 int returnedHeight = mListPadding.top + mListPadding.bottom; 1134 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1135 // The previous height value that was less than maxHeight and contained 1136 // no partial children 1137 int prevHeightWithoutPartialChild = 0; 1138 int i; 1139 View child; 1140 1141 // mItemCount - 1 since endPosition parameter is inclusive 1142 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1143 final AbsListView.RecycleBin recycleBin = mRecycler; 1144 final boolean recyle = recycleOnMeasure(); 1145 1146 for (i = startPosition; i <= endPosition; ++i) { 1147 child = obtainView(i); 1148 1149 measureScrapChild(child, i, widthMeasureSpec); 1150 1151 if (i > 0) { 1152 // Count the divider for all but one child 1153 returnedHeight += dividerHeight; 1154 } 1155 1156 // Recycle the view before we possibly return from the method 1157 if (recyle) { 1158 recycleBin.addScrapView(child); 1159 } 1160 1161 returnedHeight += child.getMeasuredHeight(); 1162 1163 if (returnedHeight >= maxHeight) { 1164 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1165 // then the i'th position did not fit completely. 1166 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1167 && (i > disallowPartialChildPosition) // We've past the min pos 1168 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1169 && (returnedHeight != maxHeight) // i'th child did not fit completely 1170 ? prevHeightWithoutPartialChild 1171 : maxHeight; 1172 } 1173 1174 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1175 prevHeightWithoutPartialChild = returnedHeight; 1176 } 1177 } 1178 1179 // At this point, we went through the range of children, and they each 1180 // completely fit, so return the returnedHeight 1181 return returnedHeight; 1182 } 1183 1184 @Override 1185 int findMotionRow(int y) { 1186 int childCount = getChildCount(); 1187 if (childCount > 0) { 1188 for (int i = 0; i < childCount; i++) { 1189 View v = getChildAt(i); 1190 if (y <= v.getBottom()) { 1191 return mFirstPosition + i; 1192 } 1193 } 1194 return mFirstPosition + childCount - 1; 1195 } 1196 return INVALID_POSITION; 1197 } 1198 1199 /** 1200 * Put a specific item at a specific location on the screen and then build 1201 * up and down from there. 1202 * 1203 * @param position The reference view to use as the starting point 1204 * @param top Pixel offset from the top of this view to the top of the 1205 * reference view. 1206 * 1207 * @return The selected view, or null if the selected view is outside the 1208 * visible area. 1209 */ 1210 private View fillSpecific(int position, int top) { 1211 boolean tempIsSelected = position == mSelectedPosition; 1212 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1213 // Possibly changed again in fillUp if we add rows above this one. 1214 mFirstPosition = position; 1215 1216 View above; 1217 View below; 1218 1219 final int dividerHeight = mDividerHeight; 1220 if (!mStackFromBottom) { 1221 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1222 // This will correct for the top of the first view not touching the top of the list 1223 adjustViewsUpOrDown(); 1224 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1225 int childCount = getChildCount(); 1226 if (childCount > 0) { 1227 correctTooHigh(childCount); 1228 } 1229 } else { 1230 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1231 // This will correct for the bottom of the last view not touching the bottom of the list 1232 adjustViewsUpOrDown(); 1233 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1234 int childCount = getChildCount(); 1235 if (childCount > 0) { 1236 correctTooLow(childCount); 1237 } 1238 } 1239 1240 if (tempIsSelected) { 1241 return temp; 1242 } else if (above != null) { 1243 return above; 1244 } else { 1245 return below; 1246 } 1247 } 1248 1249 /** 1250 * Check if we have dragged the bottom of the list too high (we have pushed the 1251 * top element off the top of the screen when we did not need to). Correct by sliding 1252 * everything back down. 1253 * 1254 * @param childCount Number of children 1255 */ 1256 private void correctTooHigh(int childCount) { 1257 // First see if the last item is visible. If it is not, it is OK for the 1258 // top of the list to be pushed up. 1259 int lastPosition = mFirstPosition + childCount - 1; 1260 if (lastPosition == mItemCount - 1 && childCount > 0) { 1261 1262 // Get the last child ... 1263 final View lastChild = getChildAt(childCount - 1); 1264 1265 // ... and its bottom edge 1266 final int lastBottom = lastChild.getBottom(); 1267 1268 // This is bottom of our drawable area 1269 final int end = (mBottom - mTop) - mListPadding.bottom; 1270 1271 // This is how far the bottom edge of the last view is from the bottom of the 1272 // drawable area 1273 int bottomOffset = end - lastBottom; 1274 View firstChild = getChildAt(0); 1275 final int firstTop = firstChild.getTop(); 1276 1277 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1278 // first row or the first row is scrolled off the top of the drawable area 1279 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1280 if (mFirstPosition == 0) { 1281 // Don't pull the top too far down 1282 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1283 } 1284 // Move everything down 1285 offsetChildrenTopAndBottom(bottomOffset); 1286 if (mFirstPosition > 0) { 1287 // Fill the gap that was opened above mFirstPosition with more rows, if 1288 // possible 1289 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1290 // Close up the remaining gap 1291 adjustViewsUpOrDown(); 1292 } 1293 1294 } 1295 } 1296 } 1297 1298 /** 1299 * Check if we have dragged the bottom of the list too low (we have pushed the 1300 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1301 * everything back up. 1302 * 1303 * @param childCount Number of children 1304 */ 1305 private void correctTooLow(int childCount) { 1306 // First see if the first item is visible. If it is not, it is OK for the 1307 // bottom of the list to be pushed down. 1308 if (mFirstPosition == 0 && childCount > 0) { 1309 1310 // Get the first child ... 1311 final View firstChild = getChildAt(0); 1312 1313 // ... and its top edge 1314 final int firstTop = firstChild.getTop(); 1315 1316 // This is top of our drawable area 1317 final int start = mListPadding.top; 1318 1319 // This is bottom of our drawable area 1320 final int end = (mBottom - mTop) - mListPadding.bottom; 1321 1322 // This is how far the top edge of the first view is from the top of the 1323 // drawable area 1324 int topOffset = firstTop - start; 1325 View lastChild = getChildAt(childCount - 1); 1326 final int lastBottom = lastChild.getBottom(); 1327 int lastPosition = mFirstPosition + childCount - 1; 1328 1329 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1330 // last row or the last row is scrolled off the bottom of the drawable area 1331 if (topOffset > 0) { 1332 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1333 if (lastPosition == mItemCount - 1) { 1334 // Don't pull the bottom too far up 1335 topOffset = Math.min(topOffset, lastBottom - end); 1336 } 1337 // Move everything up 1338 offsetChildrenTopAndBottom(-topOffset); 1339 if (lastPosition < mItemCount - 1) { 1340 // Fill the gap that was opened below the last position with more rows, if 1341 // possible 1342 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1343 // Close up the remaining gap 1344 adjustViewsUpOrDown(); 1345 } 1346 } else if (lastPosition == mItemCount - 1) { 1347 adjustViewsUpOrDown(); 1348 } 1349 } 1350 } 1351 } 1352 1353 @Override 1354 protected void layoutChildren() { 1355 final boolean blockLayoutRequests = mBlockLayoutRequests; 1356 if (!blockLayoutRequests) { 1357 mBlockLayoutRequests = true; 1358 } else { 1359 return; 1360 } 1361 1362 try { 1363 super.layoutChildren(); 1364 1365 invalidate(); 1366 1367 if (mAdapter == null) { 1368 resetList(); 1369 invokeOnItemScrollListener(); 1370 return; 1371 } 1372 1373 int childrenTop = mListPadding.top; 1374 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1375 1376 int childCount = getChildCount(); 1377 int index; 1378 int delta = 0; 1379 1380 View sel; 1381 View oldSel = null; 1382 View oldFirst = null; 1383 View newSel = null; 1384 1385 View focusLayoutRestoreView = null; 1386 1387 // Remember stuff we will need down below 1388 switch (mLayoutMode) { 1389 case LAYOUT_SET_SELECTION: 1390 index = mNextSelectedPosition - mFirstPosition; 1391 if (index >= 0 && index < childCount) { 1392 newSel = getChildAt(index); 1393 } 1394 break; 1395 case LAYOUT_FORCE_TOP: 1396 case LAYOUT_FORCE_BOTTOM: 1397 case LAYOUT_SPECIFIC: 1398 case LAYOUT_SYNC: 1399 break; 1400 case LAYOUT_MOVE_SELECTION: 1401 default: 1402 // Remember the previously selected view 1403 index = mSelectedPosition - mFirstPosition; 1404 if (index >= 0 && index < childCount) { 1405 oldSel = getChildAt(index); 1406 } 1407 1408 // Remember the previous first child 1409 oldFirst = getChildAt(0); 1410 1411 if (mNextSelectedPosition >= 0) { 1412 delta = mNextSelectedPosition - mSelectedPosition; 1413 } 1414 1415 // Caution: newSel might be null 1416 newSel = getChildAt(index + delta); 1417 } 1418 1419 1420 boolean dataChanged = mDataChanged; 1421 if (dataChanged) { 1422 handleDataChanged(); 1423 } 1424 1425 // Handle the empty set by removing all views that are visible 1426 // and calling it a day 1427 if (mItemCount == 0) { 1428 resetList(); 1429 invokeOnItemScrollListener(); 1430 return; 1431 } else if (mItemCount != mAdapter.getCount()) { 1432 throw new IllegalStateException("The content of the adapter has changed but " 1433 + "ListView did not receive a notification. Make sure the content of " 1434 + "your adapter is not modified from a background thread, but only " 1435 + "from the UI thread. [in ListView(" + getId() + ", " + getClass() 1436 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1437 } 1438 1439 setSelectedPositionInt(mNextSelectedPosition); 1440 1441 // Pull all children into the RecycleBin. 1442 // These views will be reused if possible 1443 final int firstPosition = mFirstPosition; 1444 final RecycleBin recycleBin = mRecycler; 1445 1446 // reset the focus restoration 1447 View focusLayoutRestoreDirectChild = null; 1448 1449 1450 // Don't put header or footer views into the Recycler. Those are 1451 // already cached in mHeaderViews; 1452 if (dataChanged) { 1453 for (int i = 0; i < childCount; i++) { 1454 recycleBin.addScrapView(getChildAt(i)); 1455 if (ViewDebug.TRACE_RECYCLER) { 1456 ViewDebug.trace(getChildAt(i), 1457 ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i); 1458 } 1459 } 1460 } else { 1461 recycleBin.fillActiveViews(childCount, firstPosition); 1462 } 1463 1464 // take focus back to us temporarily to avoid the eventual 1465 // call to clear focus when removing the focused child below 1466 // from messing things up when ViewRoot assigns focus back 1467 // to someone else 1468 final View focusedChild = getFocusedChild(); 1469 if (focusedChild != null) { 1470 // TODO: in some cases focusedChild.getParent() == null 1471 1472 // we can remember the focused view to restore after relayout if the 1473 // data hasn't changed, or if the focused position is a header or footer 1474 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1475 focusLayoutRestoreDirectChild = focusedChild; 1476 // remember the specific view that had focus 1477 focusLayoutRestoreView = findFocus(); 1478 if (focusLayoutRestoreView != null) { 1479 // tell it we are going to mess with it 1480 focusLayoutRestoreView.onStartTemporaryDetach(); 1481 } 1482 } 1483 requestFocus(); 1484 } 1485 1486 // Clear out old views 1487 //removeAllViewsInLayout(); 1488 detachAllViewsFromParent(); 1489 1490 switch (mLayoutMode) { 1491 case LAYOUT_SET_SELECTION: 1492 if (newSel != null) { 1493 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1494 } else { 1495 sel = fillFromMiddle(childrenTop, childrenBottom); 1496 } 1497 break; 1498 case LAYOUT_SYNC: 1499 sel = fillSpecific(mSyncPosition, mSpecificTop); 1500 break; 1501 case LAYOUT_FORCE_BOTTOM: 1502 sel = fillUp(mItemCount - 1, childrenBottom); 1503 adjustViewsUpOrDown(); 1504 break; 1505 case LAYOUT_FORCE_TOP: 1506 mFirstPosition = 0; 1507 sel = fillFromTop(childrenTop); 1508 adjustViewsUpOrDown(); 1509 break; 1510 case LAYOUT_SPECIFIC: 1511 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1512 break; 1513 case LAYOUT_MOVE_SELECTION: 1514 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1515 break; 1516 default: 1517 if (childCount == 0) { 1518 if (!mStackFromBottom) { 1519 final int position = lookForSelectablePosition(0, true); 1520 setSelectedPositionInt(position); 1521 sel = fillFromTop(childrenTop); 1522 } else { 1523 final int position = lookForSelectablePosition(mItemCount - 1, false); 1524 setSelectedPositionInt(position); 1525 sel = fillUp(mItemCount - 1, childrenBottom); 1526 } 1527 } else { 1528 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1529 sel = fillSpecific(mSelectedPosition, 1530 oldSel == null ? childrenTop : oldSel.getTop()); 1531 } else if (mFirstPosition < mItemCount) { 1532 sel = fillSpecific(mFirstPosition, 1533 oldFirst == null ? childrenTop : oldFirst.getTop()); 1534 } else { 1535 sel = fillSpecific(0, childrenTop); 1536 } 1537 } 1538 break; 1539 } 1540 1541 // Flush any cached views that did not get reused above 1542 recycleBin.scrapActiveViews(); 1543 1544 if (sel != null) { 1545 // the current selected item should get focus if items 1546 // are focusable 1547 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1548 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1549 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1550 if (!focusWasTaken) { 1551 // selected item didn't take focus, fine, but still want 1552 // to make sure something else outside of the selected view 1553 // has focus 1554 final View focused = getFocusedChild(); 1555 if (focused != null) { 1556 focused.clearFocus(); 1557 } 1558 positionSelector(sel); 1559 } else { 1560 sel.setSelected(false); 1561 mSelectorRect.setEmpty(); 1562 } 1563 } else { 1564 positionSelector(sel); 1565 } 1566 mSelectedTop = sel.getTop(); 1567 } else { 1568 mSelectedTop = 0; 1569 mSelectorRect.setEmpty(); 1570 1571 // even if there is not selected position, we may need to restore 1572 // focus (i.e. something focusable in touch mode) 1573 if (hasFocus() && focusLayoutRestoreView != null) { 1574 focusLayoutRestoreView.requestFocus(); 1575 } 1576 } 1577 1578 // tell focus view we are done mucking with it, if it is still in 1579 // our view hierarchy. 1580 if (focusLayoutRestoreView != null 1581 && focusLayoutRestoreView.getWindowToken() != null) { 1582 focusLayoutRestoreView.onFinishTemporaryDetach(); 1583 } 1584 1585 mLayoutMode = LAYOUT_NORMAL; 1586 mDataChanged = false; 1587 mNeedSync = false; 1588 setNextSelectedPositionInt(mSelectedPosition); 1589 1590 updateScrollIndicators(); 1591 1592 if (mItemCount > 0) { 1593 checkSelectionChanged(); 1594 } 1595 1596 invokeOnItemScrollListener(); 1597 } finally { 1598 if (!blockLayoutRequests) { 1599 mBlockLayoutRequests = false; 1600 } 1601 } 1602 } 1603 1604 /** 1605 * @param child a direct child of this list. 1606 * @return Whether child is a header or footer view. 1607 */ 1608 private boolean isDirectChildHeaderOrFooter(View child) { 1609 1610 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1611 final int numHeaders = headers.size(); 1612 for (int i = 0; i < numHeaders; i++) { 1613 if (child == headers.get(i).view) { 1614 return true; 1615 } 1616 } 1617 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1618 final int numFooters = footers.size(); 1619 for (int i = 0; i < numFooters; i++) { 1620 if (child == footers.get(i).view) { 1621 return true; 1622 } 1623 } 1624 return false; 1625 } 1626 1627 /** 1628 * Obtain the view and add it to our list of children. The view can be made 1629 * fresh, converted from an unused view, or used as is if it was in the 1630 * recycle bin. 1631 * 1632 * @param position Logical position in the list 1633 * @param y Top or bottom edge of the view to add 1634 * @param flow If flow is true, align top edge to y. If false, align bottom 1635 * edge to y. 1636 * @param childrenLeft Left edge where children should be positioned 1637 * @param selected Is this position selected? 1638 * @return View that was added 1639 */ 1640 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1641 boolean selected) { 1642 View child; 1643 1644 1645 if (!mDataChanged) { 1646 // Try to use an exsiting view for this position 1647 child = mRecycler.getActiveView(position); 1648 if (child != null) { 1649 if (ViewDebug.TRACE_RECYCLER) { 1650 ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, 1651 position, getChildCount()); 1652 } 1653 1654 // Found it -- we're using an existing child 1655 // This just needs to be positioned 1656 setupChild(child, position, y, flow, childrenLeft, selected, true); 1657 1658 return child; 1659 } 1660 } 1661 1662 // Make a new view for this position, or convert an unused view if possible 1663 child = obtainView(position); 1664 1665 // This needs to be positioned and measured 1666 setupChild(child, position, y, flow, childrenLeft, selected, false); 1667 1668 return child; 1669 } 1670 1671 /** 1672 * Add a view as a child and make sure it is measured (if necessary) and 1673 * positioned properly. 1674 * 1675 * @param child The view to add 1676 * @param position The position of this child 1677 * @param y The y position relative to which this view will be positioned 1678 * @param flowDown If true, align top edge to y. If false, align bottom 1679 * edge to y. 1680 * @param childrenLeft Left edge where children should be positioned 1681 * @param selected Is this position selected? 1682 * @param recycled Has this view been pulled from the recycle bin? If so it 1683 * does not need to be remeasured. 1684 */ 1685 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1686 boolean selected, boolean recycled) { 1687 final boolean isSelected = selected && shouldShowSelector(); 1688 final boolean updateChildSelected = isSelected != child.isSelected(); 1689 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1690 1691 // Respect layout params that are already in the view. Otherwise make some up... 1692 // noinspection unchecked 1693 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1694 if (p == null) { 1695 p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 1696 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1697 } 1698 p.viewType = mAdapter.getItemViewType(position); 1699 1700 if (recycled || (p.recycledHeaderFooter && 1701 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1702 attachViewToParent(child, flowDown ? -1 : 0, p); 1703 } else { 1704 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1705 p.recycledHeaderFooter = true; 1706 } 1707 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1708 } 1709 1710 if (updateChildSelected) { 1711 child.setSelected(isSelected); 1712 } 1713 1714 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1715 if (child instanceof Checkable) { 1716 ((Checkable) child).setChecked(mCheckStates.get(position)); 1717 } 1718 } 1719 1720 if (needToMeasure) { 1721 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1722 mListPadding.left + mListPadding.right, p.width); 1723 int lpHeight = p.height; 1724 int childHeightSpec; 1725 if (lpHeight > 0) { 1726 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1727 } else { 1728 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1729 } 1730 child.measure(childWidthSpec, childHeightSpec); 1731 } else { 1732 cleanupLayoutState(child); 1733 } 1734 1735 final int w = child.getMeasuredWidth(); 1736 final int h = child.getMeasuredHeight(); 1737 final int childTop = flowDown ? y : y - h; 1738 1739 if (needToMeasure) { 1740 final int childRight = childrenLeft + w; 1741 final int childBottom = childTop + h; 1742 child.layout(childrenLeft, childTop, childRight, childBottom); 1743 } else { 1744 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1745 child.offsetTopAndBottom(childTop - child.getTop()); 1746 } 1747 1748 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1749 child.setDrawingCacheEnabled(true); 1750 } 1751 } 1752 1753 @Override 1754 protected boolean canAnimate() { 1755 return super.canAnimate() && mItemCount > 0; 1756 } 1757 1758 /** 1759 * Sets the currently selected item. If in touch mode, the item will not be selected 1760 * but it will still be positioned appropriately. If the specified selection position 1761 * is less than 0, then the item at position 0 will be selected. 1762 * 1763 * @param position Index (starting at 0) of the data item to be selected. 1764 */ 1765 @Override 1766 public void setSelection(int position) { 1767 setSelectionFromTop(position, 0); 1768 } 1769 1770 /** 1771 * Sets the selected item and positions the selection y pixels from the top edge 1772 * of the ListView. (If in touch mode, the item will not be selected but it will 1773 * still be positioned appropriately.) 1774 * 1775 * @param position Index (starting at 0) of the data item to be selected. 1776 * @param y The distance from the top edge of the ListView (plus padding) that the 1777 * item will be positioned. 1778 */ 1779 public void setSelectionFromTop(int position, int y) { 1780 if (mAdapter == null) { 1781 return; 1782 } 1783 1784 if (!isInTouchMode()) { 1785 position = lookForSelectablePosition(position, true); 1786 if (position >= 0) { 1787 setNextSelectedPositionInt(position); 1788 } 1789 } else { 1790 mResurrectToPosition = position; 1791 } 1792 1793 if (position >= 0) { 1794 mLayoutMode = LAYOUT_SPECIFIC; 1795 mSpecificTop = mListPadding.top + y; 1796 1797 if (mNeedSync) { 1798 mSyncPosition = position; 1799 mSyncRowId = mAdapter.getItemId(position); 1800 } 1801 1802 requestLayout(); 1803 } 1804 } 1805 1806 /** 1807 * Makes the item at the supplied position selected. 1808 * 1809 * @param position the position of the item to select 1810 */ 1811 @Override 1812 void setSelectionInt(int position) { 1813 setNextSelectedPositionInt(position); 1814 layoutChildren(); 1815 } 1816 1817 /** 1818 * Find a position that can be selected (i.e., is not a separator). 1819 * 1820 * @param position The starting position to look at. 1821 * @param lookDown Whether to look down for other positions. 1822 * @return The next selectable position starting at position and then searching either up or 1823 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1824 */ 1825 @Override 1826 int lookForSelectablePosition(int position, boolean lookDown) { 1827 final ListAdapter adapter = mAdapter; 1828 if (adapter == null || isInTouchMode()) { 1829 return INVALID_POSITION; 1830 } 1831 1832 final int count = adapter.getCount(); 1833 if (!mAreAllItemsSelectable) { 1834 if (lookDown) { 1835 position = Math.max(0, position); 1836 while (position < count && !adapter.isEnabled(position)) { 1837 position++; 1838 } 1839 } else { 1840 position = Math.min(position, count - 1); 1841 while (position >= 0 && !adapter.isEnabled(position)) { 1842 position--; 1843 } 1844 } 1845 1846 if (position < 0 || position >= count) { 1847 return INVALID_POSITION; 1848 } 1849 return position; 1850 } else { 1851 if (position < 0 || position >= count) { 1852 return INVALID_POSITION; 1853 } 1854 return position; 1855 } 1856 } 1857 1858 @Override 1859 public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { 1860 boolean populated = super.dispatchPopulateAccessibilityEvent(event); 1861 1862 // If the item count is less than 15 then subtract disabled items from the count and 1863 // position. Otherwise ignore disabled items. 1864 if (!populated) { 1865 int itemCount = 0; 1866 int currentItemIndex = getSelectedItemPosition(); 1867 1868 ListAdapter adapter = getAdapter(); 1869 if (adapter != null) { 1870 final int count = adapter.getCount(); 1871 if (count < 15) { 1872 for (int i = 0; i < count; i++) { 1873 if (adapter.isEnabled(i)) { 1874 itemCount++; 1875 } else if (i <= currentItemIndex) { 1876 currentItemIndex--; 1877 } 1878 } 1879 } else { 1880 itemCount = count; 1881 } 1882 } 1883 1884 event.setItemCount(itemCount); 1885 event.setCurrentItemIndex(currentItemIndex); 1886 } 1887 1888 return populated; 1889 } 1890 1891 /** 1892 * setSelectionAfterHeaderView set the selection to be the first list item 1893 * after the header views. 1894 */ 1895 public void setSelectionAfterHeaderView() { 1896 final int count = mHeaderViewInfos.size(); 1897 if (count > 0) { 1898 mNextSelectedPosition = 0; 1899 return; 1900 } 1901 1902 if (mAdapter != null) { 1903 setSelection(count); 1904 } else { 1905 mNextSelectedPosition = count; 1906 mLayoutMode = LAYOUT_SET_SELECTION; 1907 } 1908 1909 } 1910 1911 @Override 1912 public boolean dispatchKeyEvent(KeyEvent event) { 1913 // Dispatch in the normal way 1914 boolean handled = super.dispatchKeyEvent(event); 1915 if (!handled) { 1916 // If we didn't handle it... 1917 View focused = getFocusedChild(); 1918 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 1919 // ... and our focused child didn't handle it 1920 // ... give it to ourselves so we can scroll if necessary 1921 handled = onKeyDown(event.getKeyCode(), event); 1922 } 1923 } 1924 return handled; 1925 } 1926 1927 @Override 1928 public boolean onKeyDown(int keyCode, KeyEvent event) { 1929 return commonKey(keyCode, 1, event); 1930 } 1931 1932 @Override 1933 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 1934 return commonKey(keyCode, repeatCount, event); 1935 } 1936 1937 @Override 1938 public boolean onKeyUp(int keyCode, KeyEvent event) { 1939 return commonKey(keyCode, 1, event); 1940 } 1941 1942 private boolean commonKey(int keyCode, int count, KeyEvent event) { 1943 if (mAdapter == null) { 1944 return false; 1945 } 1946 1947 if (mDataChanged) { 1948 layoutChildren(); 1949 } 1950 1951 boolean handled = false; 1952 int action = event.getAction(); 1953 1954 if (action != KeyEvent.ACTION_UP) { 1955 if (mSelectedPosition < 0) { 1956 switch (keyCode) { 1957 case KeyEvent.KEYCODE_DPAD_UP: 1958 case KeyEvent.KEYCODE_DPAD_DOWN: 1959 case KeyEvent.KEYCODE_DPAD_CENTER: 1960 case KeyEvent.KEYCODE_ENTER: 1961 case KeyEvent.KEYCODE_SPACE: 1962 if (resurrectSelection()) { 1963 return true; 1964 } 1965 } 1966 } 1967 switch (keyCode) { 1968 case KeyEvent.KEYCODE_DPAD_UP: 1969 if (!event.isAltPressed()) { 1970 while (count > 0) { 1971 handled = arrowScroll(FOCUS_UP); 1972 count--; 1973 } 1974 } else { 1975 handled = fullScroll(FOCUS_UP); 1976 } 1977 break; 1978 1979 case KeyEvent.KEYCODE_DPAD_DOWN: 1980 if (!event.isAltPressed()) { 1981 while (count > 0) { 1982 handled = arrowScroll(FOCUS_DOWN); 1983 count--; 1984 } 1985 } else { 1986 handled = fullScroll(FOCUS_DOWN); 1987 } 1988 break; 1989 1990 case KeyEvent.KEYCODE_DPAD_LEFT: 1991 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 1992 break; 1993 case KeyEvent.KEYCODE_DPAD_RIGHT: 1994 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 1995 break; 1996 1997 case KeyEvent.KEYCODE_DPAD_CENTER: 1998 case KeyEvent.KEYCODE_ENTER: 1999 if (mItemCount > 0 && event.getRepeatCount() == 0) { 2000 keyPressed(); 2001 } 2002 handled = true; 2003 break; 2004 2005 case KeyEvent.KEYCODE_SPACE: 2006 if (mPopup == null || !mPopup.isShowing()) { 2007 if (!event.isShiftPressed()) { 2008 pageScroll(FOCUS_DOWN); 2009 } else { 2010 pageScroll(FOCUS_UP); 2011 } 2012 handled = true; 2013 } 2014 break; 2015 } 2016 } 2017 2018 if (!handled) { 2019 handled = sendToTextFilter(keyCode, count, event); 2020 } 2021 2022 if (handled) { 2023 return true; 2024 } else { 2025 switch (action) { 2026 case KeyEvent.ACTION_DOWN: 2027 return super.onKeyDown(keyCode, event); 2028 2029 case KeyEvent.ACTION_UP: 2030 return super.onKeyUp(keyCode, event); 2031 2032 case KeyEvent.ACTION_MULTIPLE: 2033 return super.onKeyMultiple(keyCode, count, event); 2034 2035 default: // shouldn't happen 2036 return false; 2037 } 2038 } 2039 } 2040 2041 /** 2042 * Scrolls up or down by the number of items currently present on screen. 2043 * 2044 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2045 * @return whether selection was moved 2046 */ 2047 boolean pageScroll(int direction) { 2048 int nextPage = -1; 2049 boolean down = false; 2050 2051 if (direction == FOCUS_UP) { 2052 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2053 } else if (direction == FOCUS_DOWN) { 2054 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2055 down = true; 2056 } 2057 2058 if (nextPage >= 0) { 2059 int position = lookForSelectablePosition(nextPage, down); 2060 if (position >= 0) { 2061 mLayoutMode = LAYOUT_SPECIFIC; 2062 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2063 2064 if (down && position > mItemCount - getChildCount()) { 2065 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2066 } 2067 2068 if (!down && position < getChildCount()) { 2069 mLayoutMode = LAYOUT_FORCE_TOP; 2070 } 2071 2072 setSelectionInt(position); 2073 invokeOnItemScrollListener(); 2074 invalidate(); 2075 2076 return true; 2077 } 2078 } 2079 2080 return false; 2081 } 2082 2083 /** 2084 * Go to the last or first item if possible (not worrying about panning across or navigating 2085 * within the internal focus of the currently selected item.) 2086 * 2087 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2088 * 2089 * @return whether selection was moved 2090 */ 2091 boolean fullScroll(int direction) { 2092 boolean moved = false; 2093 if (direction == FOCUS_UP) { 2094 if (mSelectedPosition != 0) { 2095 int position = lookForSelectablePosition(0, true); 2096 if (position >= 0) { 2097 mLayoutMode = LAYOUT_FORCE_TOP; 2098 setSelectionInt(position); 2099 invokeOnItemScrollListener(); 2100 } 2101 moved = true; 2102 } 2103 } else if (direction == FOCUS_DOWN) { 2104 if (mSelectedPosition < mItemCount - 1) { 2105 int position = lookForSelectablePosition(mItemCount - 1, true); 2106 if (position >= 0) { 2107 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2108 setSelectionInt(position); 2109 invokeOnItemScrollListener(); 2110 } 2111 moved = true; 2112 } 2113 } 2114 2115 if (moved) { 2116 invalidate(); 2117 } 2118 2119 return moved; 2120 } 2121 2122 /** 2123 * To avoid horizontal focus searches changing the selected item, we 2124 * manually focus search within the selected item (as applicable), and 2125 * prevent focus from jumping to something within another item. 2126 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2127 * @return Whether this consumes the key event. 2128 */ 2129 private boolean handleHorizontalFocusWithinListItem(int direction) { 2130 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2131 throw new IllegalArgumentException("direction must be one of" 2132 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2133 } 2134 2135 final int numChildren = getChildCount(); 2136 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2137 final View selectedView = getSelectedView(); 2138 if (selectedView != null && selectedView.hasFocus() && 2139 selectedView instanceof ViewGroup) { 2140 2141 final View currentFocus = selectedView.findFocus(); 2142 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2143 (ViewGroup) selectedView, currentFocus, direction); 2144 if (nextFocus != null) { 2145 // do the math to get interesting rect in next focus' coordinates 2146 currentFocus.getFocusedRect(mTempRect); 2147 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2148 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2149 if (nextFocus.requestFocus(direction, mTempRect)) { 2150 return true; 2151 } 2152 } 2153 // we are blocking the key from being handled (by returning true) 2154 // if the global result is going to be some other view within this 2155 // list. this is to acheive the overall goal of having 2156 // horizontal d-pad navigation remain in the current item. 2157 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2158 (ViewGroup) getRootView(), currentFocus, direction); 2159 if (globalNextFocus != null) { 2160 return isViewAncestorOf(globalNextFocus, this); 2161 } 2162 } 2163 } 2164 return false; 2165 } 2166 2167 /** 2168 * Scrolls to the next or previous item if possible. 2169 * 2170 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2171 * 2172 * @return whether selection was moved 2173 */ 2174 boolean arrowScroll(int direction) { 2175 try { 2176 mInLayout = true; 2177 final boolean handled = arrowScrollImpl(direction); 2178 if (handled) { 2179 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2180 } 2181 return handled; 2182 } finally { 2183 mInLayout = false; 2184 } 2185 } 2186 2187 /** 2188 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2189 * whether there are focusable items etc. 2190 * 2191 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2192 * @return Whether any scrolling, selection or focus change occured. 2193 */ 2194 private boolean arrowScrollImpl(int direction) { 2195 if (getChildCount() <= 0) { 2196 return false; 2197 } 2198 2199 View selectedView = getSelectedView(); 2200 2201 int nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 2202 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2203 2204 // if we are moving focus, we may OVERRIDE the default behavior 2205 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2206 if (focusResult != null) { 2207 nextSelectedPosition = focusResult.getSelectedPosition(); 2208 amountToScroll = focusResult.getAmountToScroll(); 2209 } 2210 2211 boolean needToRedraw = focusResult != null; 2212 if (nextSelectedPosition != INVALID_POSITION) { 2213 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2214 setSelectedPositionInt(nextSelectedPosition); 2215 setNextSelectedPositionInt(nextSelectedPosition); 2216 selectedView = getSelectedView(); 2217 if (mItemsCanFocus && focusResult == null) { 2218 // there was no new view found to take focus, make sure we 2219 // don't leave focus with the old selection 2220 final View focused = getFocusedChild(); 2221 if (focused != null) { 2222 focused.clearFocus(); 2223 } 2224 } 2225 needToRedraw = true; 2226 checkSelectionChanged(); 2227 } 2228 2229 if (amountToScroll > 0) { 2230 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2231 needToRedraw = true; 2232 } 2233 2234 // if we didn't find a new focusable, make sure any existing focused 2235 // item that was panned off screen gives up focus. 2236 if (mItemsCanFocus && (focusResult == null) 2237 && selectedView != null && selectedView.hasFocus()) { 2238 final View focused = selectedView.findFocus(); 2239 if (distanceToView(focused) > 0) { 2240 focused.clearFocus(); 2241 } 2242 } 2243 2244 // if the current selection is panned off, we need to remove the selection 2245 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2246 && !isViewAncestorOf(selectedView, this)) { 2247 selectedView = null; 2248 hideSelector(); 2249 2250 // but we don't want to set the ressurect position (that would make subsequent 2251 // unhandled key events bring back the item we just scrolled off!) 2252 mResurrectToPosition = INVALID_POSITION; 2253 } 2254 2255 if (needToRedraw) { 2256 if (selectedView != null) { 2257 positionSelector(selectedView); 2258 mSelectedTop = selectedView.getTop(); 2259 } 2260 invalidate(); 2261 invokeOnItemScrollListener(); 2262 return true; 2263 } 2264 2265 return false; 2266 } 2267 2268 /** 2269 * When selection changes, it is possible that the previously selected or the 2270 * next selected item will change its size. If so, we need to offset some folks, 2271 * and re-layout the items as appropriate. 2272 * 2273 * @param selectedView The currently selected view (before changing selection). 2274 * should be <code>null</code> if there was no previous selection. 2275 * @param direction Either {@link android.view.View#FOCUS_UP} or 2276 * {@link android.view.View#FOCUS_DOWN}. 2277 * @param newSelectedPosition The position of the next selection. 2278 * @param newFocusAssigned whether new focus was assigned. This matters because 2279 * when something has focus, we don't want to show selection (ugh). 2280 */ 2281 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2282 boolean newFocusAssigned) { 2283 if (newSelectedPosition == INVALID_POSITION) { 2284 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2285 } 2286 2287 // whether or not we are moving down or up, we want to preserve the 2288 // top of whatever view is on top: 2289 // - moving down: the view that had selection 2290 // - moving up: the view that is getting selection 2291 View topView; 2292 View bottomView; 2293 int topViewIndex, bottomViewIndex; 2294 boolean topSelected = false; 2295 final int selectedIndex = mSelectedPosition - mFirstPosition; 2296 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2297 if (direction == View.FOCUS_UP) { 2298 topViewIndex = nextSelectedIndex; 2299 bottomViewIndex = selectedIndex; 2300 topView = getChildAt(topViewIndex); 2301 bottomView = selectedView; 2302 topSelected = true; 2303 } else { 2304 topViewIndex = selectedIndex; 2305 bottomViewIndex = nextSelectedIndex; 2306 topView = selectedView; 2307 bottomView = getChildAt(bottomViewIndex); 2308 } 2309 2310 final int numChildren = getChildCount(); 2311 2312 // start with top view: is it changing size? 2313 if (topView != null) { 2314 topView.setSelected(!newFocusAssigned && topSelected); 2315 measureAndAdjustDown(topView, topViewIndex, numChildren); 2316 } 2317 2318 // is the bottom view changing size? 2319 if (bottomView != null) { 2320 bottomView.setSelected(!newFocusAssigned && !topSelected); 2321 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2322 } 2323 } 2324 2325 /** 2326 * Re-measure a child, and if its height changes, lay it out preserving its 2327 * top, and adjust the children below it appropriately. 2328 * @param child The child 2329 * @param childIndex The view group index of the child. 2330 * @param numChildren The number of children in the view group. 2331 */ 2332 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2333 int oldHeight = child.getHeight(); 2334 measureItem(child); 2335 if (child.getMeasuredHeight() != oldHeight) { 2336 // lay out the view, preserving its top 2337 relayoutMeasuredItem(child); 2338 2339 // adjust views below appropriately 2340 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2341 for (int i = childIndex + 1; i < numChildren; i++) { 2342 getChildAt(i).offsetTopAndBottom(heightDelta); 2343 } 2344 } 2345 } 2346 2347 /** 2348 * Measure a particular list child. 2349 * TODO: unify with setUpChild. 2350 * @param child The child. 2351 */ 2352 private void measureItem(View child) { 2353 ViewGroup.LayoutParams p = child.getLayoutParams(); 2354 if (p == null) { 2355 p = new ViewGroup.LayoutParams( 2356 ViewGroup.LayoutParams.FILL_PARENT, 2357 ViewGroup.LayoutParams.WRAP_CONTENT); 2358 } 2359 2360 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2361 mListPadding.left + mListPadding.right, p.width); 2362 int lpHeight = p.height; 2363 int childHeightSpec; 2364 if (lpHeight > 0) { 2365 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2366 } else { 2367 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2368 } 2369 child.measure(childWidthSpec, childHeightSpec); 2370 } 2371 2372 /** 2373 * Layout a child that has been measured, preserving its top position. 2374 * TODO: unify with setUpChild. 2375 * @param child The child. 2376 */ 2377 private void relayoutMeasuredItem(View child) { 2378 final int w = child.getMeasuredWidth(); 2379 final int h = child.getMeasuredHeight(); 2380 final int childLeft = mListPadding.left; 2381 final int childRight = childLeft + w; 2382 final int childTop = child.getTop(); 2383 final int childBottom = childTop + h; 2384 child.layout(childLeft, childTop, childRight, childBottom); 2385 } 2386 2387 /** 2388 * @return The amount to preview next items when arrow srolling. 2389 */ 2390 private int getArrowScrollPreviewLength() { 2391 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2392 } 2393 2394 /** 2395 * Determine how much we need to scroll in order to get the next selected view 2396 * visible, with a fading edge showing below as applicable. The amount is 2397 * capped at {@link #getMaxScrollAmount()} . 2398 * 2399 * @param direction either {@link android.view.View#FOCUS_UP} or 2400 * {@link android.view.View#FOCUS_DOWN}. 2401 * @param nextSelectedPosition The position of the next selection, or 2402 * {@link #INVALID_POSITION} if there is no next selectable position 2403 * @return The amount to scroll. Note: this is always positive! Direction 2404 * needs to be taken into account when actually scrolling. 2405 */ 2406 private int amountToScroll(int direction, int nextSelectedPosition) { 2407 final int listBottom = getHeight() - mListPadding.bottom; 2408 final int listTop = mListPadding.top; 2409 2410 final int numChildren = getChildCount(); 2411 2412 if (direction == View.FOCUS_DOWN) { 2413 int indexToMakeVisible = numChildren - 1; 2414 if (nextSelectedPosition != INVALID_POSITION) { 2415 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2416 } 2417 2418 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2419 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2420 2421 int goalBottom = listBottom; 2422 if (positionToMakeVisible < mItemCount - 1) { 2423 goalBottom -= getArrowScrollPreviewLength(); 2424 } 2425 2426 if (viewToMakeVisible.getBottom() <= goalBottom) { 2427 // item is fully visible. 2428 return 0; 2429 } 2430 2431 if (nextSelectedPosition != INVALID_POSITION 2432 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2433 // item already has enough of it visible, changing selection is good enough 2434 return 0; 2435 } 2436 2437 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2438 2439 if ((mFirstPosition + numChildren) == mItemCount) { 2440 // last is last in list -> make sure we don't scroll past it 2441 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2442 amountToScroll = Math.min(amountToScroll, max); 2443 } 2444 2445 return Math.min(amountToScroll, getMaxScrollAmount()); 2446 } else { 2447 int indexToMakeVisible = 0; 2448 if (nextSelectedPosition != INVALID_POSITION) { 2449 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2450 } 2451 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2452 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2453 int goalTop = listTop; 2454 if (positionToMakeVisible > 0) { 2455 goalTop += getArrowScrollPreviewLength(); 2456 } 2457 if (viewToMakeVisible.getTop() >= goalTop) { 2458 // item is fully visible. 2459 return 0; 2460 } 2461 2462 if (nextSelectedPosition != INVALID_POSITION && 2463 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2464 // item already has enough of it visible, changing selection is good enough 2465 return 0; 2466 } 2467 2468 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2469 if (mFirstPosition == 0) { 2470 // first is first in list -> make sure we don't scroll past it 2471 final int max = listTop - getChildAt(0).getTop(); 2472 amountToScroll = Math.min(amountToScroll, max); 2473 } 2474 return Math.min(amountToScroll, getMaxScrollAmount()); 2475 } 2476 } 2477 2478 /** 2479 * Holds results of focus aware arrow scrolling. 2480 */ 2481 static private class ArrowScrollFocusResult { 2482 private int mSelectedPosition; 2483 private int mAmountToScroll; 2484 2485 /** 2486 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2487 */ 2488 void populate(int selectedPosition, int amountToScroll) { 2489 mSelectedPosition = selectedPosition; 2490 mAmountToScroll = amountToScroll; 2491 } 2492 2493 public int getSelectedPosition() { 2494 return mSelectedPosition; 2495 } 2496 2497 public int getAmountToScroll() { 2498 return mAmountToScroll; 2499 } 2500 } 2501 2502 /** 2503 * @param direction either {@link android.view.View#FOCUS_UP} or 2504 * {@link android.view.View#FOCUS_DOWN}. 2505 * @return The position of the next selectable position of the views that 2506 * are currently visible, taking into account the fact that there might 2507 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2508 * selectable view on screen in the given direction. 2509 */ 2510 private int lookForSelectablePositionOnScreen(int direction) { 2511 final int firstPosition = mFirstPosition; 2512 if (direction == View.FOCUS_DOWN) { 2513 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2514 mSelectedPosition + 1 : 2515 firstPosition; 2516 if (startPos >= mAdapter.getCount()) { 2517 return INVALID_POSITION; 2518 } 2519 if (startPos < firstPosition) { 2520 startPos = firstPosition; 2521 } 2522 2523 final int lastVisiblePos = getLastVisiblePosition(); 2524 final ListAdapter adapter = getAdapter(); 2525 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2526 if (adapter.isEnabled(pos) 2527 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2528 return pos; 2529 } 2530 } 2531 } else { 2532 int last = firstPosition + getChildCount() - 1; 2533 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2534 mSelectedPosition - 1 : 2535 firstPosition + getChildCount() - 1; 2536 if (startPos < 0) { 2537 return INVALID_POSITION; 2538 } 2539 if (startPos > last) { 2540 startPos = last; 2541 } 2542 2543 final ListAdapter adapter = getAdapter(); 2544 for (int pos = startPos; pos >= firstPosition; pos--) { 2545 if (adapter.isEnabled(pos) 2546 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2547 return pos; 2548 } 2549 } 2550 } 2551 return INVALID_POSITION; 2552 } 2553 2554 /** 2555 * Do an arrow scroll based on focus searching. If a new view is 2556 * given focus, return the selection delta and amount to scroll via 2557 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2558 * 2559 * @param direction either {@link android.view.View#FOCUS_UP} or 2560 * {@link android.view.View#FOCUS_DOWN}. 2561 * @return The result if focus has changed, or <code>null</code>. 2562 */ 2563 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2564 final View selectedView = getSelectedView(); 2565 View newFocus; 2566 if (selectedView != null && selectedView.hasFocus()) { 2567 View oldFocus = selectedView.findFocus(); 2568 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2569 } else { 2570 if (direction == View.FOCUS_DOWN) { 2571 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2572 final int listTop = mListPadding.top + 2573 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2574 final int ySearchPoint = 2575 (selectedView != null && selectedView.getTop() > listTop) ? 2576 selectedView.getTop() : 2577 listTop; 2578 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2579 } else { 2580 final boolean bottomFadingEdgeShowing = 2581 (mFirstPosition + getChildCount() - 1) < mItemCount; 2582 final int listBottom = getHeight() - mListPadding.bottom - 2583 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2584 final int ySearchPoint = 2585 (selectedView != null && selectedView.getBottom() < listBottom) ? 2586 selectedView.getBottom() : 2587 listBottom; 2588 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2589 } 2590 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2591 } 2592 2593 if (newFocus != null) { 2594 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2595 2596 // if the focus change is in a different new position, make sure 2597 // we aren't jumping over another selectable position 2598 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2599 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2600 if (selectablePosition != INVALID_POSITION && 2601 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2602 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2603 return null; 2604 } 2605 } 2606 2607 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2608 2609 final int maxScrollAmount = getMaxScrollAmount(); 2610 if (focusScroll < maxScrollAmount) { 2611 // not moving too far, safe to give next view focus 2612 newFocus.requestFocus(direction); 2613 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2614 return mArrowScrollFocusResult; 2615 } else if (distanceToView(newFocus) < maxScrollAmount){ 2616 // Case to consider: 2617 // too far to get entire next focusable on screen, but by going 2618 // max scroll amount, we are getting it at least partially in view, 2619 // so give it focus and scroll the max ammount. 2620 newFocus.requestFocus(direction); 2621 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2622 return mArrowScrollFocusResult; 2623 } 2624 } 2625 return null; 2626 } 2627 2628 /** 2629 * @param newFocus The view that would have focus. 2630 * @return the position that contains newFocus 2631 */ 2632 private int positionOfNewFocus(View newFocus) { 2633 final int numChildren = getChildCount(); 2634 for (int i = 0; i < numChildren; i++) { 2635 final View child = getChildAt(i); 2636 if (isViewAncestorOf(newFocus, child)) { 2637 return mFirstPosition + i; 2638 } 2639 } 2640 throw new IllegalArgumentException("newFocus is not a child of any of the" 2641 + " children of the list!"); 2642 } 2643 2644 /** 2645 * Return true if child is an ancestor of parent, (or equal to the parent). 2646 */ 2647 private boolean isViewAncestorOf(View child, View parent) { 2648 if (child == parent) { 2649 return true; 2650 } 2651 2652 final ViewParent theParent = child.getParent(); 2653 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2654 } 2655 2656 /** 2657 * Determine how much we need to scroll in order to get newFocus in view. 2658 * @param direction either {@link android.view.View#FOCUS_UP} or 2659 * {@link android.view.View#FOCUS_DOWN}. 2660 * @param newFocus The view that would take focus. 2661 * @param positionOfNewFocus The position of the list item containing newFocus 2662 * @return The amount to scroll. Note: this is always positive! Direction 2663 * needs to be taken into account when actually scrolling. 2664 */ 2665 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2666 int amountToScroll = 0; 2667 newFocus.getDrawingRect(mTempRect); 2668 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2669 if (direction == View.FOCUS_UP) { 2670 if (mTempRect.top < mListPadding.top) { 2671 amountToScroll = mListPadding.top - mTempRect.top; 2672 if (positionOfNewFocus > 0) { 2673 amountToScroll += getArrowScrollPreviewLength(); 2674 } 2675 } 2676 } else { 2677 final int listBottom = getHeight() - mListPadding.bottom; 2678 if (mTempRect.bottom > listBottom) { 2679 amountToScroll = mTempRect.bottom - listBottom; 2680 if (positionOfNewFocus < mItemCount - 1) { 2681 amountToScroll += getArrowScrollPreviewLength(); 2682 } 2683 } 2684 } 2685 return amountToScroll; 2686 } 2687 2688 /** 2689 * Determine the distance to the nearest edge of a view in a particular 2690 * direciton. 2691 * @param descendant A descendant of this list. 2692 * @return The distance, or 0 if the nearest edge is already on screen. 2693 */ 2694 private int distanceToView(View descendant) { 2695 int distance = 0; 2696 descendant.getDrawingRect(mTempRect); 2697 offsetDescendantRectToMyCoords(descendant, mTempRect); 2698 final int listBottom = mBottom - mTop - mListPadding.bottom; 2699 if (mTempRect.bottom < mListPadding.top) { 2700 distance = mListPadding.top - mTempRect.bottom; 2701 } else if (mTempRect.top > listBottom) { 2702 distance = mTempRect.top - listBottom; 2703 } 2704 return distance; 2705 } 2706 2707 2708 /** 2709 * Scroll the children by amount, adding a view at the end and removing 2710 * views that fall off as necessary. 2711 * 2712 * @param amount The amount (positive or negative) to scroll. 2713 */ 2714 private void scrollListItemsBy(int amount) { 2715 offsetChildrenTopAndBottom(amount); 2716 2717 final int listBottom = getHeight() - mListPadding.bottom; 2718 final int listTop = mListPadding.top; 2719 final AbsListView.RecycleBin recycleBin = mRecycler; 2720 2721 if (amount < 0) { 2722 // shifted items up 2723 2724 // may need to pan views into the bottom space 2725 int numChildren = getChildCount(); 2726 View last = getChildAt(numChildren - 1); 2727 while (last.getBottom() < listBottom) { 2728 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2729 if (lastVisiblePosition < mItemCount - 1) { 2730 last = addViewBelow(last, lastVisiblePosition); 2731 numChildren++; 2732 } else { 2733 break; 2734 } 2735 } 2736 2737 // may have brought in the last child of the list that is skinnier 2738 // than the fading edge, thereby leaving space at the end. need 2739 // to shift back 2740 if (last.getBottom() < listBottom) { 2741 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2742 } 2743 2744 // top views may be panned off screen 2745 View first = getChildAt(0); 2746 while (first.getBottom() < listTop) { 2747 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2748 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2749 removeViewInLayout(first); 2750 recycleBin.addScrapView(first); 2751 } else { 2752 detachViewFromParent(first); 2753 } 2754 first = getChildAt(0); 2755 mFirstPosition++; 2756 } 2757 } else { 2758 // shifted items down 2759 View first = getChildAt(0); 2760 2761 // may need to pan views into top 2762 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2763 first = addViewAbove(first, mFirstPosition); 2764 mFirstPosition--; 2765 } 2766 2767 // may have brought the very first child of the list in too far and 2768 // need to shift it back 2769 if (first.getTop() > listTop) { 2770 offsetChildrenTopAndBottom(listTop - first.getTop()); 2771 } 2772 2773 int lastIndex = getChildCount() - 1; 2774 View last = getChildAt(lastIndex); 2775 2776 // bottom view may be panned off screen 2777 while (last.getTop() > listBottom) { 2778 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 2779 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2780 removeViewInLayout(last); 2781 recycleBin.addScrapView(last); 2782 } else { 2783 detachViewFromParent(last); 2784 } 2785 last = getChildAt(--lastIndex); 2786 } 2787 } 2788 } 2789 2790 private View addViewAbove(View theView, int position) { 2791 int abovePosition = position - 1; 2792 View view = obtainView(abovePosition); 2793 int edgeOfNewChild = theView.getTop() - mDividerHeight; 2794 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, false, false); 2795 return view; 2796 } 2797 2798 private View addViewBelow(View theView, int position) { 2799 int belowPosition = position + 1; 2800 View view = obtainView(belowPosition); 2801 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 2802 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, false, false); 2803 return view; 2804 } 2805 2806 /** 2807 * Indicates that the views created by the ListAdapter can contain focusable 2808 * items. 2809 * 2810 * @param itemsCanFocus true if items can get focus, false otherwise 2811 */ 2812 public void setItemsCanFocus(boolean itemsCanFocus) { 2813 mItemsCanFocus = itemsCanFocus; 2814 if (!itemsCanFocus) { 2815 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 2816 } 2817 } 2818 2819 /** 2820 * @return Whether the views created by the ListAdapter can contain focusable 2821 * items. 2822 */ 2823 public boolean getItemsCanFocus() { 2824 return mItemsCanFocus; 2825 } 2826 2827 /** 2828 * @hide Pending API council approval. 2829 */ 2830 @Override 2831 public boolean isOpaque() { 2832 return (mCachingStarted && mIsCacheColorOpaque && mDividerIsOpaque && 2833 hasOpaqueScrollbars()) || super.isOpaque(); 2834 } 2835 2836 @Override 2837 public void setCacheColorHint(int color) { 2838 final boolean opaque = (color >>> 24) == 0xFF; 2839 mIsCacheColorOpaque = opaque; 2840 if (opaque) { 2841 if (mDividerPaint == null) { 2842 mDividerPaint = new Paint(); 2843 } 2844 mDividerPaint.setColor(color); 2845 } 2846 super.setCacheColorHint(color); 2847 } 2848 2849 @Override 2850 protected void dispatchDraw(Canvas canvas) { 2851 // Draw the dividers 2852 final int dividerHeight = mDividerHeight; 2853 2854 if (dividerHeight > 0 && mDivider != null) { 2855 // Only modify the top and bottom in the loop, we set the left and right here 2856 final Rect bounds = mTempRect; 2857 bounds.left = mPaddingLeft; 2858 bounds.right = mRight - mLeft - mPaddingRight; 2859 2860 final int count = getChildCount(); 2861 final int headerCount = mHeaderViewInfos.size(); 2862 final int footerLimit = mItemCount - mFooterViewInfos.size() - 1; 2863 final boolean headerDividers = mHeaderDividersEnabled; 2864 final boolean footerDividers = mFooterDividersEnabled; 2865 final int first = mFirstPosition; 2866 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 2867 final ListAdapter adapter = mAdapter; 2868 // If the list is opaque *and* the background is not, we want to 2869 // fill a rect where the dividers would be for non-selectable items 2870 // If the list is opaque and the background is also opaque, we don't 2871 // need to draw anything since the background will do it for us 2872 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 2873 2874 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 2875 mDividerPaint = new Paint(); 2876 mDividerPaint.setColor(getCacheColorHint()); 2877 } 2878 final Paint paint = mDividerPaint; 2879 2880 if (!mStackFromBottom) { 2881 int bottom; 2882 int listBottom = mBottom - mTop - mListPadding.bottom; 2883 2884 for (int i = 0; i < count; i++) { 2885 if ((headerDividers || first + i >= headerCount) && 2886 (footerDividers || first + i < footerLimit)) { 2887 View child = getChildAt(i); 2888 bottom = child.getBottom(); 2889 // Don't draw dividers next to items that are not enabled 2890 if (bottom < listBottom) { 2891 if ((areAllItemsSelectable || 2892 (adapter.isEnabled(first + i) && (i == count - 1 || 2893 adapter.isEnabled(first + i + 1))))) { 2894 bounds.top = bottom; 2895 bounds.bottom = bottom + dividerHeight; 2896 drawDivider(canvas, bounds, i); 2897 } else if (fillForMissingDividers) { 2898 bounds.top = bottom; 2899 bounds.bottom = bottom + dividerHeight; 2900 canvas.drawRect(bounds, paint); 2901 } 2902 } 2903 } 2904 } 2905 } else { 2906 int top; 2907 int listTop = mListPadding.top; 2908 2909 for (int i = 0; i < count; i++) { 2910 if ((headerDividers || first + i >= headerCount) && 2911 (footerDividers || first + i < footerLimit)) { 2912 View child = getChildAt(i); 2913 top = child.getTop(); 2914 // Don't draw dividers next to items that are not enabled 2915 if (top > listTop) { 2916 if ((areAllItemsSelectable || 2917 (adapter.isEnabled(first + i) && (i == count - 1 || 2918 adapter.isEnabled(first + i + 1))))) { 2919 bounds.top = top - dividerHeight; 2920 bounds.bottom = top; 2921 // Give the method the child ABOVE the divider, so we 2922 // subtract one from our child 2923 // position. Give -1 when there is no child above the 2924 // divider. 2925 drawDivider(canvas, bounds, i - 1); 2926 } else if (fillForMissingDividers) { 2927 bounds.top = top - dividerHeight; 2928 bounds.bottom = top; 2929 canvas.drawRect(bounds, paint); 2930 } 2931 } 2932 } 2933 } 2934 } 2935 } 2936 2937 // Draw the indicators (these should be drawn above the dividers) and children 2938 super.dispatchDraw(canvas); 2939 } 2940 2941 /** 2942 * Draws a divider for the given child in the given bounds. 2943 * 2944 * @param canvas The canvas to draw to. 2945 * @param bounds The bounds of the divider. 2946 * @param childIndex The index of child (of the View) above the divider. 2947 * This will be -1 if there is no child above the divider to be 2948 * drawn. 2949 */ 2950 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 2951 // This widget draws the same divider for all children 2952 final Drawable divider = mDivider; 2953 final boolean clipDivider = mClipDivider; 2954 2955 if (!clipDivider) { 2956 divider.setBounds(bounds); 2957 } else { 2958 canvas.save(); 2959 canvas.clipRect(bounds); 2960 } 2961 2962 divider.draw(canvas); 2963 2964 if (clipDivider) { 2965 canvas.restore(); 2966 } 2967 } 2968 2969 /** 2970 * Returns the drawable that will be drawn between each item in the list. 2971 * 2972 * @return the current drawable drawn between list elements 2973 */ 2974 public Drawable getDivider() { 2975 return mDivider; 2976 } 2977 2978 /** 2979 * Sets the drawable that will be drawn between each item in the list. If the drawable does 2980 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 2981 * 2982 * @param divider The drawable to use. 2983 */ 2984 public void setDivider(Drawable divider) { 2985 if (divider != null) { 2986 mDividerHeight = divider.getIntrinsicHeight(); 2987 mClipDivider = divider instanceof ColorDrawable; 2988 } else { 2989 mDividerHeight = 0; 2990 mClipDivider = false; 2991 } 2992 mDivider = divider; 2993 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 2994 requestLayoutIfNecessary(); 2995 } 2996 2997 /** 2998 * @return Returns the height of the divider that will be drawn between each item in the list. 2999 */ 3000 public int getDividerHeight() { 3001 return mDividerHeight; 3002 } 3003 3004 /** 3005 * Sets the height of the divider that will be drawn between each item in the list. Calling 3006 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3007 * 3008 * @param height The new height of the divider in pixels. 3009 */ 3010 public void setDividerHeight(int height) { 3011 mDividerHeight = height; 3012 requestLayoutIfNecessary(); 3013 } 3014 3015 /** 3016 * Enables or disables the drawing of the divider for header views. 3017 * 3018 * @param headerDividersEnabled True to draw the headers, false otherwise. 3019 * 3020 * @see #setFooterDividersEnabled(boolean) 3021 * @see #addHeaderView(android.view.View) 3022 */ 3023 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3024 mHeaderDividersEnabled = headerDividersEnabled; 3025 invalidate(); 3026 } 3027 3028 /** 3029 * Enables or disables the drawing of the divider for footer views. 3030 * 3031 * @param footerDividersEnabled True to draw the footers, false otherwise. 3032 * 3033 * @see #setHeaderDividersEnabled(boolean) 3034 * @see #addFooterView(android.view.View) 3035 */ 3036 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3037 mFooterDividersEnabled = footerDividersEnabled; 3038 invalidate(); 3039 } 3040 3041 @Override 3042 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3043 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3044 3045 int closetChildIndex = -1; 3046 if (gainFocus && previouslyFocusedRect != null) { 3047 previouslyFocusedRect.offset(mScrollX, mScrollY); 3048 3049 // figure out which item should be selected based on previously 3050 // focused rect 3051 Rect otherRect = mTempRect; 3052 int minDistance = Integer.MAX_VALUE; 3053 final int childCount = getChildCount(); 3054 final int firstPosition = mFirstPosition; 3055 final ListAdapter adapter = mAdapter; 3056 3057 for (int i = 0; i < childCount; i++) { 3058 // only consider selectable views 3059 if (!adapter.isEnabled(firstPosition + i)) { 3060 continue; 3061 } 3062 3063 View other = getChildAt(i); 3064 other.getDrawingRect(otherRect); 3065 offsetDescendantRectToMyCoords(other, otherRect); 3066 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3067 3068 if (distance < minDistance) { 3069 minDistance = distance; 3070 closetChildIndex = i; 3071 } 3072 } 3073 } 3074 3075 if (closetChildIndex >= 0) { 3076 setSelection(closetChildIndex + mFirstPosition); 3077 } else { 3078 requestLayout(); 3079 } 3080 } 3081 3082 3083 /* 3084 * (non-Javadoc) 3085 * 3086 * Children specified in XML are assumed to be header views. After we have 3087 * parsed them move them out of the children list and into mHeaderViews. 3088 */ 3089 @Override 3090 protected void onFinishInflate() { 3091 super.onFinishInflate(); 3092 3093 int count = getChildCount(); 3094 if (count > 0) { 3095 for (int i = 0; i < count; ++i) { 3096 addHeaderView(getChildAt(i)); 3097 } 3098 removeAllViews(); 3099 } 3100 } 3101 3102 /* (non-Javadoc) 3103 * @see android.view.View#findViewById(int) 3104 * First look in our children, then in any header and footer views that may be scrolled off. 3105 */ 3106 @Override 3107 protected View findViewTraversal(int id) { 3108 View v; 3109 v = super.findViewTraversal(id); 3110 if (v == null) { 3111 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3112 if (v != null) { 3113 return v; 3114 } 3115 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3116 if (v != null) { 3117 return v; 3118 } 3119 } 3120 return v; 3121 } 3122 3123 /* (non-Javadoc) 3124 * 3125 * Look in the passed in list of headers or footers for the view. 3126 */ 3127 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3128 if (where != null) { 3129 int len = where.size(); 3130 View v; 3131 3132 for (int i = 0; i < len; i++) { 3133 v = where.get(i).view; 3134 3135 if (!v.isRootNamespace()) { 3136 v = v.findViewById(id); 3137 3138 if (v != null) { 3139 return v; 3140 } 3141 } 3142 } 3143 } 3144 return null; 3145 } 3146 3147 /* (non-Javadoc) 3148 * @see android.view.View#findViewWithTag(String) 3149 * First look in our children, then in any header and footer views that may be scrolled off. 3150 */ 3151 @Override 3152 protected View findViewWithTagTraversal(Object tag) { 3153 View v; 3154 v = super.findViewWithTagTraversal(tag); 3155 if (v == null) { 3156 v = findViewTagInHeadersOrFooters(mHeaderViewInfos, tag); 3157 if (v != null) { 3158 return v; 3159 } 3160 3161 v = findViewTagInHeadersOrFooters(mFooterViewInfos, tag); 3162 if (v != null) { 3163 return v; 3164 } 3165 } 3166 return v; 3167 } 3168 3169 /* (non-Javadoc) 3170 * 3171 * Look in the passed in list of headers or footers for the view with the tag. 3172 */ 3173 View findViewTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3174 if (where != null) { 3175 int len = where.size(); 3176 View v; 3177 3178 for (int i = 0; i < len; i++) { 3179 v = where.get(i).view; 3180 3181 if (!v.isRootNamespace()) { 3182 v = v.findViewWithTag(tag); 3183 3184 if (v != null) { 3185 return v; 3186 } 3187 } 3188 } 3189 } 3190 return null; 3191 } 3192 3193 @Override 3194 public boolean onTouchEvent(MotionEvent ev) { 3195 if (mItemsCanFocus && ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { 3196 // Don't handle edge touches immediately -- they may actually belong to one of our 3197 // descendants. 3198 return false; 3199 } 3200 return super.onTouchEvent(ev); 3201 } 3202 3203 /** 3204 * @see #setChoiceMode(int) 3205 * 3206 * @return The current choice mode 3207 */ 3208 public int getChoiceMode() { 3209 return mChoiceMode; 3210 } 3211 3212 /** 3213 * Defines the choice behavior for the List. By default, Lists do not have any choice behavior 3214 * ({@link #CHOICE_MODE_NONE}). By setting the choiceMode to {@link #CHOICE_MODE_SINGLE}, the 3215 * List allows up to one item to be in a chosen state. By setting the choiceMode to 3216 * {@link #CHOICE_MODE_MULTIPLE}, the list allows any number of items to be chosen. 3217 * 3218 * @param choiceMode One of {@link #CHOICE_MODE_NONE}, {@link #CHOICE_MODE_SINGLE}, or 3219 * {@link #CHOICE_MODE_MULTIPLE} 3220 */ 3221 public void setChoiceMode(int choiceMode) { 3222 mChoiceMode = choiceMode; 3223 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates == null) { 3224 mCheckStates = new SparseBooleanArray(); 3225 } 3226 } 3227 3228 @Override 3229 public boolean performItemClick(View view, int position, long id) { 3230 boolean handled = false; 3231 3232 if (mChoiceMode != CHOICE_MODE_NONE) { 3233 handled = true; 3234 3235 if (mChoiceMode == CHOICE_MODE_MULTIPLE) { 3236 boolean oldValue = mCheckStates.get(position, false); 3237 mCheckStates.put(position, !oldValue); 3238 } else { 3239 boolean oldValue = mCheckStates.get(position, false); 3240 if (!oldValue) { 3241 mCheckStates.clear(); 3242 mCheckStates.put(position, true); 3243 } 3244 } 3245 3246 mDataChanged = true; 3247 rememberSyncState(); 3248 requestLayout(); 3249 } 3250 3251 handled |= super.performItemClick(view, position, id); 3252 3253 return handled; 3254 } 3255 3256 /** 3257 * Sets the checked state of the specified position. The is only valid if 3258 * the choice mode has been set to {@link #CHOICE_MODE_SINGLE} or 3259 * {@link #CHOICE_MODE_MULTIPLE}. 3260 * 3261 * @param position The item whose checked state is to be checked 3262 * @param value The new checked sate for the item 3263 */ 3264 public void setItemChecked(int position, boolean value) { 3265 if (mChoiceMode == CHOICE_MODE_NONE) { 3266 return; 3267 } 3268 3269 if (mChoiceMode == CHOICE_MODE_MULTIPLE) { 3270 mCheckStates.put(position, value); 3271 } else { 3272 // Clear all values if we're checking something, or unchecking the currently 3273 // selected item 3274 if (value || isItemChecked(position)) { 3275 mCheckStates.clear(); 3276 } 3277 // this may end up selecting the value we just cleared but this way 3278 // we ensure length of mCheckStates is 1, a fact getCheckedItemPosition relies on 3279 if (value) { 3280 mCheckStates.put(position, true); 3281 } 3282 } 3283 3284 // Do not generate a data change while we are in the layout phase 3285 if (!mInLayout && !mBlockLayoutRequests) { 3286 mDataChanged = true; 3287 rememberSyncState(); 3288 requestLayout(); 3289 } 3290 } 3291 3292 /** 3293 * Returns the checked state of the specified position. The result is only 3294 * valid if the choice mode has been set to {@link #CHOICE_MODE_SINGLE} 3295 * or {@link #CHOICE_MODE_MULTIPLE}. 3296 * 3297 * @param position The item whose checked state to return 3298 * @return The item's checked state or <code>false</code> if choice mode 3299 * is invalid 3300 * 3301 * @see #setChoiceMode(int) 3302 */ 3303 public boolean isItemChecked(int position) { 3304 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 3305 return mCheckStates.get(position); 3306 } 3307 3308 return false; 3309 } 3310 3311 /** 3312 * Returns the currently checked item. The result is only valid if the choice 3313 * mode has been set to {@link #CHOICE_MODE_SINGLE}. 3314 * 3315 * @return The position of the currently checked item or 3316 * {@link #INVALID_POSITION} if nothing is selected 3317 * 3318 * @see #setChoiceMode(int) 3319 */ 3320 public int getCheckedItemPosition() { 3321 if (mChoiceMode == CHOICE_MODE_SINGLE && mCheckStates != null && mCheckStates.size() == 1) { 3322 return mCheckStates.keyAt(0); 3323 } 3324 3325 return INVALID_POSITION; 3326 } 3327 3328 /** 3329 * Returns the set of checked items in the list. The result is only valid if 3330 * the choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3331 * 3332 * @return A SparseBooleanArray which will return true for each call to 3333 * get(int position) where position is a position in the list, 3334 * or <code>null</code> if the choice mode is set to 3335 * {@link #CHOICE_MODE_NONE}. 3336 */ 3337 public SparseBooleanArray getCheckedItemPositions() { 3338 if (mChoiceMode != CHOICE_MODE_NONE) { 3339 return mCheckStates; 3340 } 3341 return null; 3342 } 3343 3344 /** 3345 * Returns the set of checked items ids. The result is only valid if 3346 * the choice mode has not been set to {@link #CHOICE_MODE_SINGLE}. 3347 * 3348 * @return A new array which contains the id of each checked item in the list. 3349 */ 3350 public long[] getCheckItemIds() { 3351 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3352 final SparseBooleanArray states = mCheckStates; 3353 final int count = states.size(); 3354 final long[] ids = new long[count]; 3355 final ListAdapter adapter = mAdapter; 3356 3357 for (int i = 0; i < count; i++) { 3358 ids[i]= adapter.getItemId(states.keyAt(i)); 3359 } 3360 3361 return ids; 3362 } 3363 3364 return new long[0]; 3365 } 3366 3367 /** 3368 * Clear any choices previously set 3369 */ 3370 public void clearChoices() { 3371 if (mCheckStates != null) { 3372 mCheckStates.clear(); 3373 } 3374 } 3375 3376 static class SavedState extends BaseSavedState { 3377 SparseBooleanArray checkState; 3378 3379 /** 3380 * Constructor called from {@link ListView#onSaveInstanceState()} 3381 */ 3382 SavedState(Parcelable superState, SparseBooleanArray checkState) { 3383 super(superState); 3384 this.checkState = checkState; 3385 } 3386 3387 /** 3388 * Constructor called from {@link #CREATOR} 3389 */ 3390 private SavedState(Parcel in) { 3391 super(in); 3392 checkState = in.readSparseBooleanArray(); 3393 } 3394 3395 @Override 3396 public void writeToParcel(Parcel out, int flags) { 3397 super.writeToParcel(out, flags); 3398 out.writeSparseBooleanArray(checkState); 3399 } 3400 3401 @Override 3402 public String toString() { 3403 return "ListView.SavedState{" 3404 + Integer.toHexString(System.identityHashCode(this)) 3405 + " checkState=" + checkState + "}"; 3406 } 3407 3408 public static final Parcelable.Creator<SavedState> CREATOR 3409 = new Parcelable.Creator<SavedState>() { 3410 public SavedState createFromParcel(Parcel in) { 3411 return new SavedState(in); 3412 } 3413 3414 public SavedState[] newArray(int size) { 3415 return new SavedState[size]; 3416 } 3417 }; 3418 } 3419 3420 @Override 3421 public Parcelable onSaveInstanceState() { 3422 Parcelable superState = super.onSaveInstanceState(); 3423 return new SavedState(superState, mCheckStates); 3424 } 3425 3426 @Override 3427 public void onRestoreInstanceState(Parcelable state) { 3428 SavedState ss = (SavedState) state; 3429 3430 super.onRestoreInstanceState(ss.getSuperState()); 3431 3432 if (ss.checkState != null) { 3433 mCheckStates = ss.checkState; 3434 } 3435 3436 } 3437} 3438