ListView.java revision 079e23575024e103358c982152afb7a720ae1a8a
1/* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.widget; 18 19import com.android.internal.R; 20import com.google.android.collect.Lists; 21 22import android.content.Context; 23import android.content.Intent; 24import android.content.res.TypedArray; 25import android.graphics.Canvas; 26import android.graphics.Paint; 27import android.graphics.PixelFormat; 28import android.graphics.Rect; 29import android.graphics.drawable.Drawable; 30import android.util.AttributeSet; 31import android.util.SparseBooleanArray; 32import android.view.FocusFinder; 33import android.view.KeyEvent; 34import android.view.MotionEvent; 35import android.view.SoundEffectConstants; 36import android.view.View; 37import android.view.ViewDebug; 38import android.view.ViewGroup; 39import android.view.ViewParent; 40import android.view.accessibility.AccessibilityEvent; 41import android.widget.RemoteViews.RemoteView; 42 43import java.util.ArrayList; 44 45/* 46 * Implementation Notes: 47 * 48 * Some terminology: 49 * 50 * index - index of the items that are currently visible 51 * position - index of the items in the cursor 52 */ 53 54 55/** 56 * A view that shows items in a vertically scrolling list. The items 57 * come from the {@link ListAdapter} associated with this view. 58 * 59 * <p>See the <a href="{@docRoot}resources/tutorials/views/hello-listview.html">List View 60 * tutorial</a>.</p> 61 * 62 * @attr ref android.R.styleable#ListView_entries 63 * @attr ref android.R.styleable#ListView_divider 64 * @attr ref android.R.styleable#ListView_dividerHeight 65 * @attr ref android.R.styleable#ListView_headerDividersEnabled 66 * @attr ref android.R.styleable#ListView_footerDividersEnabled 67 */ 68@RemoteView 69public class ListView extends AbsListView { 70 /** 71 * Used to indicate a no preference for a position type. 72 */ 73 static final int NO_POSITION = -1; 74 75 /** 76 * When arrow scrolling, ListView will never scroll more than this factor 77 * times the height of the list. 78 */ 79 private static final float MAX_SCROLL_FACTOR = 0.33f; 80 81 /** 82 * When arrow scrolling, need a certain amount of pixels to preview next 83 * items. This is usually the fading edge, but if that is small enough, 84 * we want to make sure we preview at least this many pixels. 85 */ 86 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 87 88 /** 89 * A class that represents a fixed view in a list, for example a header at the top 90 * or a footer at the bottom. 91 */ 92 public class FixedViewInfo { 93 /** The view to add to the list */ 94 public View view; 95 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 96 public Object data; 97 /** <code>true</code> if the fixed view should be selectable in the list */ 98 public boolean isSelectable; 99 } 100 101 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 102 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 103 104 Drawable mDivider; 105 int mDividerHeight; 106 107 private boolean mIsCacheColorOpaque; 108 private boolean mDividerIsOpaque; 109 110 private boolean mHeaderDividersEnabled; 111 private boolean mFooterDividersEnabled; 112 113 private boolean mAreAllItemsSelectable = true; 114 115 private boolean mItemsCanFocus = false; 116 117 // used for temporary calculations. 118 private final Rect mTempRect = new Rect(); 119 private Paint mDividerPaint; 120 121 // the single allocated result per list view; kinda cheesey but avoids 122 // allocating these thingies too often. 123 private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 124 125 // Keeps focused children visible through resizes 126 private FocusSelector mFocusSelector; 127 128 public ListView(Context context) { 129 this(context, null); 130 } 131 132 public ListView(Context context, AttributeSet attrs) { 133 this(context, attrs, com.android.internal.R.attr.listViewStyle); 134 } 135 136 public ListView(Context context, AttributeSet attrs, int defStyle) { 137 super(context, attrs, defStyle); 138 139 TypedArray a = context.obtainStyledAttributes(attrs, 140 com.android.internal.R.styleable.ListView, defStyle, 0); 141 142 CharSequence[] entries = a.getTextArray( 143 com.android.internal.R.styleable.ListView_entries); 144 if (entries != null) { 145 setAdapter(new ArrayAdapter<CharSequence>(context, 146 com.android.internal.R.layout.simple_list_item_1, entries)); 147 } 148 149 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 150 if (d != null) { 151 // If a divider is specified use its intrinsic height for divider height 152 setDivider(d); 153 } 154 155 // Use the height specified, zero being the default 156 final int dividerHeight = a.getDimensionPixelSize( 157 com.android.internal.R.styleable.ListView_dividerHeight, 0); 158 if (dividerHeight != 0) { 159 setDividerHeight(dividerHeight); 160 } 161 162 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 163 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 164 165 a.recycle(); 166 } 167 168 /** 169 * @return The maximum amount a list view will scroll in response to 170 * an arrow event. 171 */ 172 public int getMaxScrollAmount() { 173 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 174 } 175 176 /** 177 * Make sure views are touching the top or bottom edge, as appropriate for 178 * our gravity 179 */ 180 private void adjustViewsUpOrDown() { 181 final int childCount = getChildCount(); 182 int delta; 183 184 if (childCount > 0) { 185 View child; 186 187 if (!mStackFromBottom) { 188 // Uh-oh -- we came up short. Slide all views up to make them 189 // align with the top 190 child = getChildAt(0); 191 delta = child.getTop() - mListPadding.top; 192 if (mFirstPosition != 0) { 193 // It's OK to have some space above the first item if it is 194 // part of the vertical spacing 195 delta -= mDividerHeight; 196 } 197 if (delta < 0) { 198 // We only are looking to see if we are too low, not too high 199 delta = 0; 200 } 201 } else { 202 // we are too high, slide all views down to align with bottom 203 child = getChildAt(childCount - 1); 204 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 205 206 if (mFirstPosition + childCount < mItemCount) { 207 // It's OK to have some space below the last item if it is 208 // part of the vertical spacing 209 delta += mDividerHeight; 210 } 211 212 if (delta > 0) { 213 delta = 0; 214 } 215 } 216 217 if (delta != 0) { 218 offsetChildrenTopAndBottom(-delta); 219 } 220 } 221 } 222 223 /** 224 * Add a fixed view to appear at the top of the list. If addHeaderView is 225 * called more than once, the views will appear in the order they were 226 * added. Views added using this call can take focus if they want. 227 * <p> 228 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 229 * the supplied cursor with one that will also account for header and footer 230 * views. 231 * 232 * @param v The view to add. 233 * @param data Data to associate with this view 234 * @param isSelectable whether the item is selectable 235 */ 236 public void addHeaderView(View v, Object data, boolean isSelectable) { 237 238 if (mAdapter != null) { 239 throw new IllegalStateException( 240 "Cannot add header view to list -- setAdapter has already been called."); 241 } 242 243 FixedViewInfo info = new FixedViewInfo(); 244 info.view = v; 245 info.data = data; 246 info.isSelectable = isSelectable; 247 mHeaderViewInfos.add(info); 248 } 249 250 /** 251 * Add a fixed view to appear at the top of the list. If addHeaderView is 252 * called more than once, the views will appear in the order they were 253 * added. Views added using this call can take focus if they want. 254 * <p> 255 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 256 * the supplied cursor with one that will also account for header and footer 257 * views. 258 * 259 * @param v The view to add. 260 */ 261 public void addHeaderView(View v) { 262 addHeaderView(v, null, true); 263 } 264 265 @Override 266 public int getHeaderViewsCount() { 267 return mHeaderViewInfos.size(); 268 } 269 270 /** 271 * Removes a previously-added header view. 272 * 273 * @param v The view to remove 274 * @return true if the view was removed, false if the view was not a header 275 * view 276 */ 277 public boolean removeHeaderView(View v) { 278 if (mHeaderViewInfos.size() > 0) { 279 boolean result = false; 280 if (((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 281 mDataSetObserver.onChanged(); 282 result = true; 283 } 284 removeFixedViewInfo(v, mHeaderViewInfos); 285 return result; 286 } 287 return false; 288 } 289 290 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 291 int len = where.size(); 292 for (int i = 0; i < len; ++i) { 293 FixedViewInfo info = where.get(i); 294 if (info.view == v) { 295 where.remove(i); 296 break; 297 } 298 } 299 } 300 301 /** 302 * Add a fixed view to appear at the bottom of the list. If addFooterView is 303 * called more than once, the views will appear in the order they were 304 * added. Views added using this call can take focus if they want. 305 * <p> 306 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 307 * the supplied cursor with one that will also account for header and footer 308 * views. 309 * 310 * @param v The view to add. 311 * @param data Data to associate with this view 312 * @param isSelectable true if the footer view can be selected 313 */ 314 public void addFooterView(View v, Object data, boolean isSelectable) { 315 FixedViewInfo info = new FixedViewInfo(); 316 info.view = v; 317 info.data = data; 318 info.isSelectable = isSelectable; 319 mFooterViewInfos.add(info); 320 321 // in the case of re-adding a footer view, or adding one later on, 322 // we need to notify the observer 323 if (mDataSetObserver != null) { 324 mDataSetObserver.onChanged(); 325 } 326 } 327 328 /** 329 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 330 * than once, the views will appear in the order they were added. Views added using 331 * this call can take focus if they want. 332 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 333 * cursor with one that will also account for header and footer views. 334 * 335 * 336 * @param v The view to add. 337 */ 338 public void addFooterView(View v) { 339 addFooterView(v, null, true); 340 } 341 342 @Override 343 public int getFooterViewsCount() { 344 return mFooterViewInfos.size(); 345 } 346 347 /** 348 * Removes a previously-added footer view. 349 * 350 * @param v The view to remove 351 * @return 352 * true if the view was removed, false if the view was not a footer view 353 */ 354 public boolean removeFooterView(View v) { 355 if (mFooterViewInfos.size() > 0) { 356 boolean result = false; 357 if (((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 358 mDataSetObserver.onChanged(); 359 result = true; 360 } 361 removeFixedViewInfo(v, mFooterViewInfos); 362 return result; 363 } 364 return false; 365 } 366 367 /** 368 * Returns the adapter currently in use in this ListView. The returned adapter 369 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 370 * might be a {@link WrapperListAdapter}. 371 * 372 * @return The adapter currently used to display data in this ListView. 373 * 374 * @see #setAdapter(ListAdapter) 375 */ 376 @Override 377 public ListAdapter getAdapter() { 378 return mAdapter; 379 } 380 381 /** 382 * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService 383 * through the specified intent. 384 * @param intent the intent used to identify the RemoteViewsService for the adapter to connect to. 385 */ 386 @android.view.RemotableViewMethod 387 public void setRemoteViewsAdapter(Intent intent) { 388 super.setRemoteViewsAdapter(intent); 389 } 390 391 /** 392 * Sets the data behind this ListView. 393 * 394 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 395 * depending on the ListView features currently in use. For instance, adding 396 * headers and/or footers will cause the adapter to be wrapped. 397 * 398 * @param adapter The ListAdapter which is responsible for maintaining the 399 * data backing this list and for producing a view to represent an 400 * item in that data set. 401 * 402 * @see #getAdapter() 403 */ 404 @Override 405 public void setAdapter(ListAdapter adapter) { 406 if (mAdapter != null && mDataSetObserver != null) { 407 mAdapter.unregisterDataSetObserver(mDataSetObserver); 408 } 409 410 resetList(); 411 mRecycler.clear(); 412 413 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 414 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 415 } else { 416 mAdapter = adapter; 417 } 418 419 mOldSelectedPosition = INVALID_POSITION; 420 mOldSelectedRowId = INVALID_ROW_ID; 421 422 // AbsListView#setAdapter will update choice mode states. 423 super.setAdapter(adapter); 424 425 if (mAdapter != null) { 426 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 427 mOldItemCount = mItemCount; 428 mItemCount = mAdapter.getCount(); 429 checkFocus(); 430 431 mDataSetObserver = new AdapterDataSetObserver(); 432 mAdapter.registerDataSetObserver(mDataSetObserver); 433 434 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 435 436 int position; 437 if (mStackFromBottom) { 438 position = lookForSelectablePosition(mItemCount - 1, false); 439 } else { 440 position = lookForSelectablePosition(0, true); 441 } 442 setSelectedPositionInt(position); 443 setNextSelectedPositionInt(position); 444 445 if (mItemCount == 0) { 446 // Nothing selected 447 checkSelectionChanged(); 448 } 449 } else { 450 mAreAllItemsSelectable = true; 451 checkFocus(); 452 // Nothing selected 453 checkSelectionChanged(); 454 } 455 456 requestLayout(); 457 } 458 459 460 /** 461 * The list is empty. Clear everything out. 462 */ 463 @Override 464 void resetList() { 465 // The parent's resetList() will remove all views from the layout so we need to 466 // cleanup the state of our footers and headers 467 clearRecycledState(mHeaderViewInfos); 468 clearRecycledState(mFooterViewInfos); 469 470 super.resetList(); 471 472 mLayoutMode = LAYOUT_NORMAL; 473 } 474 475 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 476 if (infos != null) { 477 final int count = infos.size(); 478 479 for (int i = 0; i < count; i++) { 480 final View child = infos.get(i).view; 481 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 482 if (p != null) { 483 p.recycledHeaderFooter = false; 484 } 485 } 486 } 487 } 488 489 /** 490 * @return Whether the list needs to show the top fading edge 491 */ 492 private boolean showingTopFadingEdge() { 493 final int listTop = mScrollY + mListPadding.top; 494 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 495 } 496 497 /** 498 * @return Whether the list needs to show the bottom fading edge 499 */ 500 private boolean showingBottomFadingEdge() { 501 final int childCount = getChildCount(); 502 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 503 final int lastVisiblePosition = mFirstPosition + childCount - 1; 504 505 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 506 507 return (lastVisiblePosition < mItemCount - 1) 508 || (bottomOfBottomChild < listBottom); 509 } 510 511 512 @Override 513 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 514 515 int rectTopWithinChild = rect.top; 516 517 // offset so rect is in coordinates of the this view 518 rect.offset(child.getLeft(), child.getTop()); 519 rect.offset(-child.getScrollX(), -child.getScrollY()); 520 521 final int height = getHeight(); 522 int listUnfadedTop = getScrollY(); 523 int listUnfadedBottom = listUnfadedTop + height; 524 final int fadingEdge = getVerticalFadingEdgeLength(); 525 526 if (showingTopFadingEdge()) { 527 // leave room for top fading edge as long as rect isn't at very top 528 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 529 listUnfadedTop += fadingEdge; 530 } 531 } 532 533 int childCount = getChildCount(); 534 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 535 536 if (showingBottomFadingEdge()) { 537 // leave room for bottom fading edge as long as rect isn't at very bottom 538 if ((mSelectedPosition < mItemCount - 1) 539 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 540 listUnfadedBottom -= fadingEdge; 541 } 542 } 543 544 int scrollYDelta = 0; 545 546 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 547 // need to MOVE DOWN to get it in view: move down just enough so 548 // that the entire rectangle is in view (or at least the first 549 // screen size chunk). 550 551 if (rect.height() > height) { 552 // just enough to get screen size chunk on 553 scrollYDelta += (rect.top - listUnfadedTop); 554 } else { 555 // get entire rect at bottom of screen 556 scrollYDelta += (rect.bottom - listUnfadedBottom); 557 } 558 559 // make sure we aren't scrolling beyond the end of our children 560 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 561 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 562 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 563 // need to MOVE UP to get it in view: move up just enough so that 564 // entire rectangle is in view (or at least the first screen 565 // size chunk of it). 566 567 if (rect.height() > height) { 568 // screen size chunk 569 scrollYDelta -= (listUnfadedBottom - rect.bottom); 570 } else { 571 // entire rect at top 572 scrollYDelta -= (listUnfadedTop - rect.top); 573 } 574 575 // make sure we aren't scrolling any further than the top our children 576 int top = getChildAt(0).getTop(); 577 int deltaToTop = top - listUnfadedTop; 578 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 579 } 580 581 final boolean scroll = scrollYDelta != 0; 582 if (scroll) { 583 scrollListItemsBy(-scrollYDelta); 584 positionSelector(INVALID_POSITION, child); 585 mSelectedTop = child.getTop(); 586 invalidate(); 587 } 588 return scroll; 589 } 590 591 /** 592 * {@inheritDoc} 593 */ 594 @Override 595 void fillGap(boolean down) { 596 final int count = getChildCount(); 597 if (down) { 598 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 599 getListPaddingTop(); 600 fillDown(mFirstPosition + count, startOffset); 601 correctTooHigh(getChildCount()); 602 } else { 603 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 604 getHeight() - getListPaddingBottom(); 605 fillUp(mFirstPosition - 1, startOffset); 606 correctTooLow(getChildCount()); 607 } 608 } 609 610 /** 611 * Fills the list from pos down to the end of the list view. 612 * 613 * @param pos The first position to put in the list 614 * 615 * @param nextTop The location where the top of the item associated with pos 616 * should be drawn 617 * 618 * @return The view that is currently selected, if it happens to be in the 619 * range that we draw. 620 */ 621 private View fillDown(int pos, int nextTop) { 622 View selectedView = null; 623 624 int end = (mBottom - mTop) - mListPadding.bottom; 625 626 while (nextTop < end && pos < mItemCount) { 627 // is this the selected item? 628 boolean selected = pos == mSelectedPosition; 629 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 630 631 nextTop = child.getBottom() + mDividerHeight; 632 if (selected) { 633 selectedView = child; 634 } 635 pos++; 636 } 637 638 return selectedView; 639 } 640 641 /** 642 * Fills the list from pos up to the top of the list view. 643 * 644 * @param pos The first position to put in the list 645 * 646 * @param nextBottom The location where the bottom of the item associated 647 * with pos should be drawn 648 * 649 * @return The view that is currently selected 650 */ 651 private View fillUp(int pos, int nextBottom) { 652 View selectedView = null; 653 654 int end = mListPadding.top; 655 656 while (nextBottom > end && pos >= 0) { 657 // is this the selected item? 658 boolean selected = pos == mSelectedPosition; 659 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 660 nextBottom = child.getTop() - mDividerHeight; 661 if (selected) { 662 selectedView = child; 663 } 664 pos--; 665 } 666 667 mFirstPosition = pos + 1; 668 669 return selectedView; 670 } 671 672 /** 673 * Fills the list from top to bottom, starting with mFirstPosition 674 * 675 * @param nextTop The location where the top of the first item should be 676 * drawn 677 * 678 * @return The view that is currently selected 679 */ 680 private View fillFromTop(int nextTop) { 681 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 682 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 683 if (mFirstPosition < 0) { 684 mFirstPosition = 0; 685 } 686 return fillDown(mFirstPosition, nextTop); 687 } 688 689 690 /** 691 * Put mSelectedPosition in the middle of the screen and then build up and 692 * down from there. This method forces mSelectedPosition to the center. 693 * 694 * @param childrenTop Top of the area in which children can be drawn, as 695 * measured in pixels 696 * @param childrenBottom Bottom of the area in which children can be drawn, 697 * as measured in pixels 698 * @return Currently selected view 699 */ 700 private View fillFromMiddle(int childrenTop, int childrenBottom) { 701 int height = childrenBottom - childrenTop; 702 703 int position = reconcileSelectedPosition(); 704 705 View sel = makeAndAddView(position, childrenTop, true, 706 mListPadding.left, true); 707 mFirstPosition = position; 708 709 int selHeight = sel.getMeasuredHeight(); 710 if (selHeight <= height) { 711 sel.offsetTopAndBottom((height - selHeight) / 2); 712 } 713 714 fillAboveAndBelow(sel, position); 715 716 if (!mStackFromBottom) { 717 correctTooHigh(getChildCount()); 718 } else { 719 correctTooLow(getChildCount()); 720 } 721 722 return sel; 723 } 724 725 /** 726 * Once the selected view as been placed, fill up the visible area above and 727 * below it. 728 * 729 * @param sel The selected view 730 * @param position The position corresponding to sel 731 */ 732 private void fillAboveAndBelow(View sel, int position) { 733 final int dividerHeight = mDividerHeight; 734 if (!mStackFromBottom) { 735 fillUp(position - 1, sel.getTop() - dividerHeight); 736 adjustViewsUpOrDown(); 737 fillDown(position + 1, sel.getBottom() + dividerHeight); 738 } else { 739 fillDown(position + 1, sel.getBottom() + dividerHeight); 740 adjustViewsUpOrDown(); 741 fillUp(position - 1, sel.getTop() - dividerHeight); 742 } 743 } 744 745 746 /** 747 * Fills the grid based on positioning the new selection at a specific 748 * location. The selection may be moved so that it does not intersect the 749 * faded edges. The grid is then filled upwards and downwards from there. 750 * 751 * @param selectedTop Where the selected item should be 752 * @param childrenTop Where to start drawing children 753 * @param childrenBottom Last pixel where children can be drawn 754 * @return The view that currently has selection 755 */ 756 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 757 int fadingEdgeLength = getVerticalFadingEdgeLength(); 758 final int selectedPosition = mSelectedPosition; 759 760 View sel; 761 762 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 763 selectedPosition); 764 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 765 selectedPosition); 766 767 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 768 769 770 // Some of the newly selected item extends below the bottom of the list 771 if (sel.getBottom() > bottomSelectionPixel) { 772 // Find space available above the selection into which we can scroll 773 // upwards 774 final int spaceAbove = sel.getTop() - topSelectionPixel; 775 776 // Find space required to bring the bottom of the selected item 777 // fully into view 778 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 779 final int offset = Math.min(spaceAbove, spaceBelow); 780 781 // Now offset the selected item to get it into view 782 sel.offsetTopAndBottom(-offset); 783 } else if (sel.getTop() < topSelectionPixel) { 784 // Find space required to bring the top of the selected item fully 785 // into view 786 final int spaceAbove = topSelectionPixel - sel.getTop(); 787 788 // Find space available below the selection into which we can scroll 789 // downwards 790 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 791 final int offset = Math.min(spaceAbove, spaceBelow); 792 793 // Offset the selected item to get it into view 794 sel.offsetTopAndBottom(offset); 795 } 796 797 // Fill in views above and below 798 fillAboveAndBelow(sel, selectedPosition); 799 800 if (!mStackFromBottom) { 801 correctTooHigh(getChildCount()); 802 } else { 803 correctTooLow(getChildCount()); 804 } 805 806 return sel; 807 } 808 809 /** 810 * Calculate the bottom-most pixel we can draw the selection into 811 * 812 * @param childrenBottom Bottom pixel were children can be drawn 813 * @param fadingEdgeLength Length of the fading edge in pixels, if present 814 * @param selectedPosition The position that will be selected 815 * @return The bottom-most pixel we can draw the selection into 816 */ 817 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 818 int selectedPosition) { 819 int bottomSelectionPixel = childrenBottom; 820 if (selectedPosition != mItemCount - 1) { 821 bottomSelectionPixel -= fadingEdgeLength; 822 } 823 return bottomSelectionPixel; 824 } 825 826 /** 827 * Calculate the top-most pixel we can draw the selection into 828 * 829 * @param childrenTop Top pixel were children can be drawn 830 * @param fadingEdgeLength Length of the fading edge in pixels, if present 831 * @param selectedPosition The position that will be selected 832 * @return The top-most pixel we can draw the selection into 833 */ 834 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 835 // first pixel we can draw the selection into 836 int topSelectionPixel = childrenTop; 837 if (selectedPosition > 0) { 838 topSelectionPixel += fadingEdgeLength; 839 } 840 return topSelectionPixel; 841 } 842 843 /** 844 * Smoothly scroll to the specified adapter position. The view will 845 * scroll such that the indicated position is displayed. 846 * @param position Scroll to this adapter position. 847 */ 848 @android.view.RemotableViewMethod 849 public void smoothScrollToPosition(int position) { 850 super.smoothScrollToPosition(position); 851 } 852 853 /** 854 * Smoothly scroll to the specified adapter position offset. The view will 855 * scroll such that the indicated position is displayed. 856 * @param offset The amount to offset from the adapter position to scroll to. 857 */ 858 @android.view.RemotableViewMethod 859 public void smoothScrollByOffset(int offset) { 860 super.smoothScrollByOffset(offset); 861 } 862 863 /** 864 * Fills the list based on positioning the new selection relative to the old 865 * selection. The new selection will be placed at, above, or below the 866 * location of the new selection depending on how the selection is moving. 867 * The selection will then be pinned to the visible part of the screen, 868 * excluding the edges that are faded. The list is then filled upwards and 869 * downwards from there. 870 * 871 * @param oldSel The old selected view. Useful for trying to put the new 872 * selection in the same place 873 * @param newSel The view that is to become selected. Useful for trying to 874 * put the new selection in the same place 875 * @param delta Which way we are moving 876 * @param childrenTop Where to start drawing children 877 * @param childrenBottom Last pixel where children can be drawn 878 * @return The view that currently has selection 879 */ 880 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 881 int childrenBottom) { 882 int fadingEdgeLength = getVerticalFadingEdgeLength(); 883 final int selectedPosition = mSelectedPosition; 884 885 View sel; 886 887 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 888 selectedPosition); 889 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 890 selectedPosition); 891 892 if (delta > 0) { 893 /* 894 * Case 1: Scrolling down. 895 */ 896 897 /* 898 * Before After 899 * | | | | 900 * +-------+ +-------+ 901 * | A | | A | 902 * | 1 | => +-------+ 903 * +-------+ | B | 904 * | B | | 2 | 905 * +-------+ +-------+ 906 * | | | | 907 * 908 * Try to keep the top of the previously selected item where it was. 909 * oldSel = A 910 * sel = B 911 */ 912 913 // Put oldSel (A) where it belongs 914 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 915 mListPadding.left, false); 916 917 final int dividerHeight = mDividerHeight; 918 919 // Now put the new selection (B) below that 920 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 921 mListPadding.left, true); 922 923 // Some of the newly selected item extends below the bottom of the list 924 if (sel.getBottom() > bottomSelectionPixel) { 925 926 // Find space available above the selection into which we can scroll upwards 927 int spaceAbove = sel.getTop() - topSelectionPixel; 928 929 // Find space required to bring the bottom of the selected item fully into view 930 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 931 932 // Don't scroll more than half the height of the list 933 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 934 int offset = Math.min(spaceAbove, spaceBelow); 935 offset = Math.min(offset, halfVerticalSpace); 936 937 // We placed oldSel, so offset that item 938 oldSel.offsetTopAndBottom(-offset); 939 // Now offset the selected item to get it into view 940 sel.offsetTopAndBottom(-offset); 941 } 942 943 // Fill in views above and below 944 if (!mStackFromBottom) { 945 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 946 adjustViewsUpOrDown(); 947 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 948 } else { 949 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 950 adjustViewsUpOrDown(); 951 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 952 } 953 } else if (delta < 0) { 954 /* 955 * Case 2: Scrolling up. 956 */ 957 958 /* 959 * Before After 960 * | | | | 961 * +-------+ +-------+ 962 * | A | | A | 963 * +-------+ => | 1 | 964 * | B | +-------+ 965 * | 2 | | B | 966 * +-------+ +-------+ 967 * | | | | 968 * 969 * Try to keep the top of the item about to become selected where it was. 970 * newSel = A 971 * olSel = B 972 */ 973 974 if (newSel != null) { 975 // Try to position the top of newSel (A) where it was before it was selected 976 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 977 true); 978 } else { 979 // If (A) was not on screen and so did not have a view, position 980 // it above the oldSel (B) 981 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 982 true); 983 } 984 985 // Some of the newly selected item extends above the top of the list 986 if (sel.getTop() < topSelectionPixel) { 987 // Find space required to bring the top of the selected item fully into view 988 int spaceAbove = topSelectionPixel - sel.getTop(); 989 990 // Find space available below the selection into which we can scroll downwards 991 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 992 993 // Don't scroll more than half the height of the list 994 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 995 int offset = Math.min(spaceAbove, spaceBelow); 996 offset = Math.min(offset, halfVerticalSpace); 997 998 // Offset the selected item to get it into view 999 sel.offsetTopAndBottom(offset); 1000 } 1001 1002 // Fill in views above and below 1003 fillAboveAndBelow(sel, selectedPosition); 1004 } else { 1005 1006 int oldTop = oldSel.getTop(); 1007 1008 /* 1009 * Case 3: Staying still 1010 */ 1011 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 1012 1013 // We're staying still... 1014 if (oldTop < childrenTop) { 1015 // ... but the top of the old selection was off screen. 1016 // (This can happen if the data changes size out from under us) 1017 int newBottom = sel.getBottom(); 1018 if (newBottom < childrenTop + 20) { 1019 // Not enough visible -- bring it onscreen 1020 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1021 } 1022 } 1023 1024 // Fill in views above and below 1025 fillAboveAndBelow(sel, selectedPosition); 1026 } 1027 1028 return sel; 1029 } 1030 1031 private class FocusSelector implements Runnable { 1032 private int mPosition; 1033 private int mPositionTop; 1034 1035 public FocusSelector setup(int position, int top) { 1036 mPosition = position; 1037 mPositionTop = top; 1038 return this; 1039 } 1040 1041 public void run() { 1042 setSelectionFromTop(mPosition, mPositionTop); 1043 } 1044 } 1045 1046 @Override 1047 protected void onSizeChanged(int w, int h, int oldw, int oldh) { 1048 if (getChildCount() > 0) { 1049 View focusedChild = getFocusedChild(); 1050 if (focusedChild != null) { 1051 final int childPosition = mFirstPosition + indexOfChild(focusedChild); 1052 final int childBottom = focusedChild.getBottom(); 1053 final int offset = Math.max(0, childBottom - (h - mPaddingTop)); 1054 final int top = focusedChild.getTop() - offset; 1055 if (mFocusSelector == null) { 1056 mFocusSelector = new FocusSelector(); 1057 } 1058 post(mFocusSelector.setup(childPosition, top)); 1059 } 1060 } 1061 super.onSizeChanged(w, h, oldw, oldh); 1062 } 1063 1064 @Override 1065 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1066 // Sets up mListPadding 1067 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1068 1069 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1070 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1071 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1072 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1073 1074 int childWidth = 0; 1075 int childHeight = 0; 1076 1077 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1078 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1079 heightMode == MeasureSpec.UNSPECIFIED)) { 1080 final View child = obtainView(0, mIsScrap); 1081 1082 measureScrapChild(child, 0, widthMeasureSpec); 1083 1084 childWidth = child.getMeasuredWidth(); 1085 childHeight = child.getMeasuredHeight(); 1086 1087 if (recycleOnMeasure() && mRecycler.shouldRecycleViewType( 1088 ((LayoutParams) child.getLayoutParams()).viewType)) { 1089 mRecycler.addScrapView(child, -1); 1090 } 1091 } 1092 1093 if (widthMode == MeasureSpec.UNSPECIFIED) { 1094 widthSize = mListPadding.left + mListPadding.right + childWidth + 1095 getVerticalScrollbarWidth(); 1096 } 1097 1098 if (heightMode == MeasureSpec.UNSPECIFIED) { 1099 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1100 getVerticalFadingEdgeLength() * 2; 1101 } 1102 1103 if (heightMode == MeasureSpec.AT_MOST) { 1104 // TODO: after first layout we should maybe start at the first visible position, not 0 1105 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1106 } 1107 1108 setMeasuredDimension(widthSize, heightSize); 1109 mWidthMeasureSpec = widthMeasureSpec; 1110 } 1111 1112 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1113 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1114 if (p == null) { 1115 p = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1116 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1117 child.setLayoutParams(p); 1118 } 1119 p.viewType = mAdapter.getItemViewType(position); 1120 p.forceAdd = true; 1121 1122 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1123 mListPadding.left + mListPadding.right, p.width); 1124 int lpHeight = p.height; 1125 int childHeightSpec; 1126 if (lpHeight > 0) { 1127 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1128 } else { 1129 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1130 } 1131 child.measure(childWidthSpec, childHeightSpec); 1132 } 1133 1134 /** 1135 * @return True to recycle the views used to measure this ListView in 1136 * UNSPECIFIED/AT_MOST modes, false otherwise. 1137 * @hide 1138 */ 1139 @ViewDebug.ExportedProperty(category = "list") 1140 protected boolean recycleOnMeasure() { 1141 return true; 1142 } 1143 1144 /** 1145 * Measures the height of the given range of children (inclusive) and 1146 * returns the height with this ListView's padding and divider heights 1147 * included. If maxHeight is provided, the measuring will stop when the 1148 * current height reaches maxHeight. 1149 * 1150 * @param widthMeasureSpec The width measure spec to be given to a child's 1151 * {@link View#measure(int, int)}. 1152 * @param startPosition The position of the first child to be shown. 1153 * @param endPosition The (inclusive) position of the last child to be 1154 * shown. Specify {@link #NO_POSITION} if the last child should be 1155 * the last available child from the adapter. 1156 * @param maxHeight The maximum height that will be returned (if all the 1157 * children don't fit in this value, this value will be 1158 * returned). 1159 * @param disallowPartialChildPosition In general, whether the returned 1160 * height should only contain entire children. This is more 1161 * powerful--it is the first inclusive position at which partial 1162 * children will not be allowed. Example: it looks nice to have 1163 * at least 3 completely visible children, and in portrait this 1164 * will most likely fit; but in landscape there could be times 1165 * when even 2 children can not be completely shown, so a value 1166 * of 2 (remember, inclusive) would be good (assuming 1167 * startPosition is 0). 1168 * @return The height of this ListView with the given children. 1169 */ 1170 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1171 final int maxHeight, int disallowPartialChildPosition) { 1172 1173 final ListAdapter adapter = mAdapter; 1174 if (adapter == null) { 1175 return mListPadding.top + mListPadding.bottom; 1176 } 1177 1178 // Include the padding of the list 1179 int returnedHeight = mListPadding.top + mListPadding.bottom; 1180 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1181 // The previous height value that was less than maxHeight and contained 1182 // no partial children 1183 int prevHeightWithoutPartialChild = 0; 1184 int i; 1185 View child; 1186 1187 // mItemCount - 1 since endPosition parameter is inclusive 1188 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1189 final AbsListView.RecycleBin recycleBin = mRecycler; 1190 final boolean recyle = recycleOnMeasure(); 1191 final boolean[] isScrap = mIsScrap; 1192 1193 for (i = startPosition; i <= endPosition; ++i) { 1194 child = obtainView(i, isScrap); 1195 1196 measureScrapChild(child, i, widthMeasureSpec); 1197 1198 if (i > 0) { 1199 // Count the divider for all but one child 1200 returnedHeight += dividerHeight; 1201 } 1202 1203 // Recycle the view before we possibly return from the method 1204 if (recyle && recycleBin.shouldRecycleViewType( 1205 ((LayoutParams) child.getLayoutParams()).viewType)) { 1206 recycleBin.addScrapView(child, -1); 1207 } 1208 1209 returnedHeight += child.getMeasuredHeight(); 1210 1211 if (returnedHeight >= maxHeight) { 1212 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1213 // then the i'th position did not fit completely. 1214 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1215 && (i > disallowPartialChildPosition) // We've past the min pos 1216 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1217 && (returnedHeight != maxHeight) // i'th child did not fit completely 1218 ? prevHeightWithoutPartialChild 1219 : maxHeight; 1220 } 1221 1222 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1223 prevHeightWithoutPartialChild = returnedHeight; 1224 } 1225 } 1226 1227 // At this point, we went through the range of children, and they each 1228 // completely fit, so return the returnedHeight 1229 return returnedHeight; 1230 } 1231 1232 @Override 1233 int findMotionRow(int y) { 1234 int childCount = getChildCount(); 1235 if (childCount > 0) { 1236 if (!mStackFromBottom) { 1237 for (int i = 0; i < childCount; i++) { 1238 View v = getChildAt(i); 1239 if (y <= v.getBottom()) { 1240 return mFirstPosition + i; 1241 } 1242 } 1243 } else { 1244 for (int i = childCount - 1; i >= 0; i--) { 1245 View v = getChildAt(i); 1246 if (y >= v.getTop()) { 1247 return mFirstPosition + i; 1248 } 1249 } 1250 } 1251 } 1252 return INVALID_POSITION; 1253 } 1254 1255 /** 1256 * Put a specific item at a specific location on the screen and then build 1257 * up and down from there. 1258 * 1259 * @param position The reference view to use as the starting point 1260 * @param top Pixel offset from the top of this view to the top of the 1261 * reference view. 1262 * 1263 * @return The selected view, or null if the selected view is outside the 1264 * visible area. 1265 */ 1266 private View fillSpecific(int position, int top) { 1267 boolean tempIsSelected = position == mSelectedPosition; 1268 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1269 // Possibly changed again in fillUp if we add rows above this one. 1270 mFirstPosition = position; 1271 1272 View above; 1273 View below; 1274 1275 final int dividerHeight = mDividerHeight; 1276 if (!mStackFromBottom) { 1277 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1278 // This will correct for the top of the first view not touching the top of the list 1279 adjustViewsUpOrDown(); 1280 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1281 int childCount = getChildCount(); 1282 if (childCount > 0) { 1283 correctTooHigh(childCount); 1284 } 1285 } else { 1286 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1287 // This will correct for the bottom of the last view not touching the bottom of the list 1288 adjustViewsUpOrDown(); 1289 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1290 int childCount = getChildCount(); 1291 if (childCount > 0) { 1292 correctTooLow(childCount); 1293 } 1294 } 1295 1296 if (tempIsSelected) { 1297 return temp; 1298 } else if (above != null) { 1299 return above; 1300 } else { 1301 return below; 1302 } 1303 } 1304 1305 /** 1306 * Check if we have dragged the bottom of the list too high (we have pushed the 1307 * top element off the top of the screen when we did not need to). Correct by sliding 1308 * everything back down. 1309 * 1310 * @param childCount Number of children 1311 */ 1312 private void correctTooHigh(int childCount) { 1313 // First see if the last item is visible. If it is not, it is OK for the 1314 // top of the list to be pushed up. 1315 int lastPosition = mFirstPosition + childCount - 1; 1316 if (lastPosition == mItemCount - 1 && childCount > 0) { 1317 1318 // Get the last child ... 1319 final View lastChild = getChildAt(childCount - 1); 1320 1321 // ... and its bottom edge 1322 final int lastBottom = lastChild.getBottom(); 1323 1324 // This is bottom of our drawable area 1325 final int end = (mBottom - mTop) - mListPadding.bottom; 1326 1327 // This is how far the bottom edge of the last view is from the bottom of the 1328 // drawable area 1329 int bottomOffset = end - lastBottom; 1330 View firstChild = getChildAt(0); 1331 final int firstTop = firstChild.getTop(); 1332 1333 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1334 // first row or the first row is scrolled off the top of the drawable area 1335 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1336 if (mFirstPosition == 0) { 1337 // Don't pull the top too far down 1338 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1339 } 1340 // Move everything down 1341 offsetChildrenTopAndBottom(bottomOffset); 1342 if (mFirstPosition > 0) { 1343 // Fill the gap that was opened above mFirstPosition with more rows, if 1344 // possible 1345 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1346 // Close up the remaining gap 1347 adjustViewsUpOrDown(); 1348 } 1349 1350 } 1351 } 1352 } 1353 1354 /** 1355 * Check if we have dragged the bottom of the list too low (we have pushed the 1356 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1357 * everything back up. 1358 * 1359 * @param childCount Number of children 1360 */ 1361 private void correctTooLow(int childCount) { 1362 // First see if the first item is visible. If it is not, it is OK for the 1363 // bottom of the list to be pushed down. 1364 if (mFirstPosition == 0 && childCount > 0) { 1365 1366 // Get the first child ... 1367 final View firstChild = getChildAt(0); 1368 1369 // ... and its top edge 1370 final int firstTop = firstChild.getTop(); 1371 1372 // This is top of our drawable area 1373 final int start = mListPadding.top; 1374 1375 // This is bottom of our drawable area 1376 final int end = (mBottom - mTop) - mListPadding.bottom; 1377 1378 // This is how far the top edge of the first view is from the top of the 1379 // drawable area 1380 int topOffset = firstTop - start; 1381 View lastChild = getChildAt(childCount - 1); 1382 final int lastBottom = lastChild.getBottom(); 1383 int lastPosition = mFirstPosition + childCount - 1; 1384 1385 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1386 // last row or the last row is scrolled off the bottom of the drawable area 1387 if (topOffset > 0) { 1388 if (lastPosition < mItemCount - 1 || lastBottom > end) { 1389 if (lastPosition == mItemCount - 1) { 1390 // Don't pull the bottom too far up 1391 topOffset = Math.min(topOffset, lastBottom - end); 1392 } 1393 // Move everything up 1394 offsetChildrenTopAndBottom(-topOffset); 1395 if (lastPosition < mItemCount - 1) { 1396 // Fill the gap that was opened below the last position with more rows, if 1397 // possible 1398 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1399 // Close up the remaining gap 1400 adjustViewsUpOrDown(); 1401 } 1402 } else if (lastPosition == mItemCount - 1) { 1403 adjustViewsUpOrDown(); 1404 } 1405 } 1406 } 1407 } 1408 1409 @Override 1410 protected void layoutChildren() { 1411 final boolean blockLayoutRequests = mBlockLayoutRequests; 1412 if (!blockLayoutRequests) { 1413 mBlockLayoutRequests = true; 1414 } else { 1415 return; 1416 } 1417 1418 try { 1419 super.layoutChildren(); 1420 1421 invalidate(); 1422 1423 if (mAdapter == null) { 1424 resetList(); 1425 invokeOnItemScrollListener(); 1426 return; 1427 } 1428 1429 int childrenTop = mListPadding.top; 1430 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1431 1432 int childCount = getChildCount(); 1433 int index = 0; 1434 int delta = 0; 1435 1436 View sel; 1437 View oldSel = null; 1438 View oldFirst = null; 1439 View newSel = null; 1440 1441 View focusLayoutRestoreView = null; 1442 1443 // Remember stuff we will need down below 1444 switch (mLayoutMode) { 1445 case LAYOUT_SET_SELECTION: 1446 index = mNextSelectedPosition - mFirstPosition; 1447 if (index >= 0 && index < childCount) { 1448 newSel = getChildAt(index); 1449 } 1450 break; 1451 case LAYOUT_FORCE_TOP: 1452 case LAYOUT_FORCE_BOTTOM: 1453 case LAYOUT_SPECIFIC: 1454 case LAYOUT_SYNC: 1455 break; 1456 case LAYOUT_MOVE_SELECTION: 1457 default: 1458 // Remember the previously selected view 1459 index = mSelectedPosition - mFirstPosition; 1460 if (index >= 0 && index < childCount) { 1461 oldSel = getChildAt(index); 1462 } 1463 1464 // Remember the previous first child 1465 oldFirst = getChildAt(0); 1466 1467 if (mNextSelectedPosition >= 0) { 1468 delta = mNextSelectedPosition - mSelectedPosition; 1469 } 1470 1471 // Caution: newSel might be null 1472 newSel = getChildAt(index + delta); 1473 } 1474 1475 1476 boolean dataChanged = mDataChanged; 1477 if (dataChanged) { 1478 handleDataChanged(); 1479 } 1480 1481 // Handle the empty set by removing all views that are visible 1482 // and calling it a day 1483 if (mItemCount == 0) { 1484 resetList(); 1485 invokeOnItemScrollListener(); 1486 return; 1487 } else if (mItemCount != mAdapter.getCount()) { 1488 throw new IllegalStateException("The content of the adapter has changed but " 1489 + "ListView did not receive a notification. Make sure the content of " 1490 + "your adapter is not modified from a background thread, but only " 1491 + "from the UI thread. [in ListView(" + getId() + ", " + getClass() 1492 + ") with Adapter(" + mAdapter.getClass() + ")]"); 1493 } 1494 1495 setSelectedPositionInt(mNextSelectedPosition); 1496 1497 // Pull all children into the RecycleBin. 1498 // These views will be reused if possible 1499 final int firstPosition = mFirstPosition; 1500 final RecycleBin recycleBin = mRecycler; 1501 1502 // reset the focus restoration 1503 View focusLayoutRestoreDirectChild = null; 1504 1505 1506 // Don't put header or footer views into the Recycler. Those are 1507 // already cached in mHeaderViews; 1508 if (dataChanged) { 1509 for (int i = 0; i < childCount; i++) { 1510 recycleBin.addScrapView(getChildAt(i), firstPosition+i); 1511 if (ViewDebug.TRACE_RECYCLER) { 1512 ViewDebug.trace(getChildAt(i), 1513 ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i); 1514 } 1515 } 1516 } else { 1517 recycleBin.fillActiveViews(childCount, firstPosition); 1518 } 1519 1520 // take focus back to us temporarily to avoid the eventual 1521 // call to clear focus when removing the focused child below 1522 // from messing things up when ViewRoot assigns focus back 1523 // to someone else 1524 final View focusedChild = getFocusedChild(); 1525 if (focusedChild != null) { 1526 // TODO: in some cases focusedChild.getParent() == null 1527 1528 // we can remember the focused view to restore after relayout if the 1529 // data hasn't changed, or if the focused position is a header or footer 1530 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1531 focusLayoutRestoreDirectChild = focusedChild; 1532 // remember the specific view that had focus 1533 focusLayoutRestoreView = findFocus(); 1534 if (focusLayoutRestoreView != null) { 1535 // tell it we are going to mess with it 1536 focusLayoutRestoreView.onStartTemporaryDetach(); 1537 } 1538 } 1539 requestFocus(); 1540 } 1541 1542 // Clear out old views 1543 detachAllViewsFromParent(); 1544 1545 switch (mLayoutMode) { 1546 case LAYOUT_SET_SELECTION: 1547 if (newSel != null) { 1548 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1549 } else { 1550 sel = fillFromMiddle(childrenTop, childrenBottom); 1551 } 1552 break; 1553 case LAYOUT_SYNC: 1554 sel = fillSpecific(mSyncPosition, mSpecificTop); 1555 break; 1556 case LAYOUT_FORCE_BOTTOM: 1557 sel = fillUp(mItemCount - 1, childrenBottom); 1558 adjustViewsUpOrDown(); 1559 break; 1560 case LAYOUT_FORCE_TOP: 1561 mFirstPosition = 0; 1562 sel = fillFromTop(childrenTop); 1563 adjustViewsUpOrDown(); 1564 break; 1565 case LAYOUT_SPECIFIC: 1566 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1567 break; 1568 case LAYOUT_MOVE_SELECTION: 1569 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1570 break; 1571 default: 1572 if (childCount == 0) { 1573 if (!mStackFromBottom) { 1574 final int position = lookForSelectablePosition(0, true); 1575 setSelectedPositionInt(position); 1576 sel = fillFromTop(childrenTop); 1577 } else { 1578 final int position = lookForSelectablePosition(mItemCount - 1, false); 1579 setSelectedPositionInt(position); 1580 sel = fillUp(mItemCount - 1, childrenBottom); 1581 } 1582 } else { 1583 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1584 sel = fillSpecific(mSelectedPosition, 1585 oldSel == null ? childrenTop : oldSel.getTop()); 1586 } else if (mFirstPosition < mItemCount) { 1587 sel = fillSpecific(mFirstPosition, 1588 oldFirst == null ? childrenTop : oldFirst.getTop()); 1589 } else { 1590 sel = fillSpecific(0, childrenTop); 1591 } 1592 } 1593 break; 1594 } 1595 1596 // Flush any cached views that did not get reused above 1597 recycleBin.scrapActiveViews(); 1598 1599 if (sel != null) { 1600 // the current selected item should get focus if items 1601 // are focusable 1602 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1603 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1604 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1605 if (!focusWasTaken) { 1606 // selected item didn't take focus, fine, but still want 1607 // to make sure something else outside of the selected view 1608 // has focus 1609 final View focused = getFocusedChild(); 1610 if (focused != null) { 1611 focused.clearFocus(); 1612 } 1613 positionSelector(INVALID_POSITION, sel); 1614 } else { 1615 sel.setSelected(false); 1616 mSelectorRect.setEmpty(); 1617 } 1618 } else { 1619 positionSelector(INVALID_POSITION, sel); 1620 } 1621 mSelectedTop = sel.getTop(); 1622 } else { 1623 if (mTouchMode > TOUCH_MODE_DOWN && mTouchMode < TOUCH_MODE_SCROLL) { 1624 View child = getChildAt(mMotionPosition - mFirstPosition); 1625 if (child != null) positionSelector(mMotionPosition, child); 1626 } else { 1627 mSelectedTop = 0; 1628 mSelectorRect.setEmpty(); 1629 } 1630 1631 // even if there is not selected position, we may need to restore 1632 // focus (i.e. something focusable in touch mode) 1633 if (hasFocus() && focusLayoutRestoreView != null) { 1634 focusLayoutRestoreView.requestFocus(); 1635 } 1636 } 1637 1638 // tell focus view we are done mucking with it, if it is still in 1639 // our view hierarchy. 1640 if (focusLayoutRestoreView != null 1641 && focusLayoutRestoreView.getWindowToken() != null) { 1642 focusLayoutRestoreView.onFinishTemporaryDetach(); 1643 } 1644 1645 mLayoutMode = LAYOUT_NORMAL; 1646 mDataChanged = false; 1647 mNeedSync = false; 1648 setNextSelectedPositionInt(mSelectedPosition); 1649 1650 updateScrollIndicators(); 1651 1652 if (mItemCount > 0) { 1653 checkSelectionChanged(); 1654 } 1655 1656 invokeOnItemScrollListener(); 1657 } finally { 1658 if (!blockLayoutRequests) { 1659 mBlockLayoutRequests = false; 1660 } 1661 } 1662 } 1663 1664 /** 1665 * @param child a direct child of this list. 1666 * @return Whether child is a header or footer view. 1667 */ 1668 private boolean isDirectChildHeaderOrFooter(View child) { 1669 1670 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1671 final int numHeaders = headers.size(); 1672 for (int i = 0; i < numHeaders; i++) { 1673 if (child == headers.get(i).view) { 1674 return true; 1675 } 1676 } 1677 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1678 final int numFooters = footers.size(); 1679 for (int i = 0; i < numFooters; i++) { 1680 if (child == footers.get(i).view) { 1681 return true; 1682 } 1683 } 1684 return false; 1685 } 1686 1687 /** 1688 * Obtain the view and add it to our list of children. The view can be made 1689 * fresh, converted from an unused view, or used as is if it was in the 1690 * recycle bin. 1691 * 1692 * @param position Logical position in the list 1693 * @param y Top or bottom edge of the view to add 1694 * @param flow If flow is true, align top edge to y. If false, align bottom 1695 * edge to y. 1696 * @param childrenLeft Left edge where children should be positioned 1697 * @param selected Is this position selected? 1698 * @return View that was added 1699 */ 1700 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1701 boolean selected) { 1702 View child; 1703 1704 1705 if (!mDataChanged) { 1706 // Try to use an existing view for this position 1707 child = mRecycler.getActiveView(position); 1708 if (child != null) { 1709 if (ViewDebug.TRACE_RECYCLER) { 1710 ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, 1711 position, getChildCount()); 1712 } 1713 1714 // Found it -- we're using an existing child 1715 // This just needs to be positioned 1716 setupChild(child, position, y, flow, childrenLeft, selected, true); 1717 1718 return child; 1719 } 1720 } 1721 1722 // Make a new view for this position, or convert an unused view if possible 1723 child = obtainView(position, mIsScrap); 1724 1725 // This needs to be positioned and measured 1726 setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); 1727 1728 return child; 1729 } 1730 1731 /** 1732 * Add a view as a child and make sure it is measured (if necessary) and 1733 * positioned properly. 1734 * 1735 * @param child The view to add 1736 * @param position The position of this child 1737 * @param y The y position relative to which this view will be positioned 1738 * @param flowDown If true, align top edge to y. If false, align bottom 1739 * edge to y. 1740 * @param childrenLeft Left edge where children should be positioned 1741 * @param selected Is this position selected? 1742 * @param recycled Has this view been pulled from the recycle bin? If so it 1743 * does not need to be remeasured. 1744 */ 1745 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1746 boolean selected, boolean recycled) { 1747 final boolean isSelected = selected && shouldShowSelector(); 1748 final boolean updateChildSelected = isSelected != child.isSelected(); 1749 final int mode = mTouchMode; 1750 final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && 1751 mMotionPosition == position; 1752 final boolean updateChildPressed = isPressed != child.isPressed(); 1753 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1754 1755 // Respect layout params that are already in the view. Otherwise make some up... 1756 // noinspection unchecked 1757 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1758 if (p == null) { 1759 p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 1760 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1761 } 1762 p.viewType = mAdapter.getItemViewType(position); 1763 1764 if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && 1765 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1766 attachViewToParent(child, flowDown ? -1 : 0, p); 1767 } else { 1768 p.forceAdd = false; 1769 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1770 p.recycledHeaderFooter = true; 1771 } 1772 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1773 } 1774 1775 if (updateChildSelected) { 1776 child.setSelected(isSelected); 1777 } 1778 1779 if (updateChildPressed) { 1780 child.setPressed(isPressed); 1781 } 1782 1783 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1784 if (child instanceof Checkable) { 1785 ((Checkable) child).setChecked(mCheckStates.get(position)); 1786 } else if (getContext().getApplicationInfo().targetSdkVersion 1787 >= android.os.Build.VERSION_CODES.HONEYCOMB) { 1788 child.setActivated(mCheckStates.get(position)); 1789 } 1790 } 1791 1792 if (needToMeasure) { 1793 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1794 mListPadding.left + mListPadding.right, p.width); 1795 int lpHeight = p.height; 1796 int childHeightSpec; 1797 if (lpHeight > 0) { 1798 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1799 } else { 1800 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1801 } 1802 child.measure(childWidthSpec, childHeightSpec); 1803 } else { 1804 cleanupLayoutState(child); 1805 } 1806 1807 final int w = child.getMeasuredWidth(); 1808 final int h = child.getMeasuredHeight(); 1809 final int childTop = flowDown ? y : y - h; 1810 1811 if (needToMeasure) { 1812 final int childRight = childrenLeft + w; 1813 final int childBottom = childTop + h; 1814 child.layout(childrenLeft, childTop, childRight, childBottom); 1815 } else { 1816 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1817 child.offsetTopAndBottom(childTop - child.getTop()); 1818 } 1819 1820 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1821 child.setDrawingCacheEnabled(true); 1822 } 1823 1824 if (recycled && (((AbsListView.LayoutParams)child.getLayoutParams()).scrappedFromPosition) 1825 != position) { 1826 child.jumpDrawablesToCurrentState(); 1827 } 1828 } 1829 1830 @Override 1831 protected boolean canAnimate() { 1832 return super.canAnimate() && mItemCount > 0; 1833 } 1834 1835 /** 1836 * Sets the currently selected item. If in touch mode, the item will not be selected 1837 * but it will still be positioned appropriately. If the specified selection position 1838 * is less than 0, then the item at position 0 will be selected. 1839 * 1840 * @param position Index (starting at 0) of the data item to be selected. 1841 */ 1842 @Override 1843 public void setSelection(int position) { 1844 setSelectionFromTop(position, 0); 1845 } 1846 1847 /** 1848 * Sets the selected item and positions the selection y pixels from the top edge 1849 * of the ListView. (If in touch mode, the item will not be selected but it will 1850 * still be positioned appropriately.) 1851 * 1852 * @param position Index (starting at 0) of the data item to be selected. 1853 * @param y The distance from the top edge of the ListView (plus padding) that the 1854 * item will be positioned. 1855 */ 1856 public void setSelectionFromTop(int position, int y) { 1857 if (mAdapter == null) { 1858 return; 1859 } 1860 1861 if (!isInTouchMode()) { 1862 position = lookForSelectablePosition(position, true); 1863 if (position >= 0) { 1864 setNextSelectedPositionInt(position); 1865 } 1866 } else { 1867 mResurrectToPosition = position; 1868 } 1869 1870 if (position >= 0) { 1871 mLayoutMode = LAYOUT_SPECIFIC; 1872 mSpecificTop = mListPadding.top + y; 1873 1874 if (mNeedSync) { 1875 mSyncPosition = position; 1876 mSyncRowId = mAdapter.getItemId(position); 1877 } 1878 1879 requestLayout(); 1880 } 1881 } 1882 1883 /** 1884 * Makes the item at the supplied position selected. 1885 * 1886 * @param position the position of the item to select 1887 */ 1888 @Override 1889 void setSelectionInt(int position) { 1890 setNextSelectedPositionInt(position); 1891 boolean awakeScrollbars = false; 1892 1893 final int selectedPosition = mSelectedPosition; 1894 1895 if (selectedPosition >= 0) { 1896 if (position == selectedPosition - 1) { 1897 awakeScrollbars = true; 1898 } else if (position == selectedPosition + 1) { 1899 awakeScrollbars = true; 1900 } 1901 } 1902 1903 layoutChildren(); 1904 1905 if (awakeScrollbars) { 1906 awakenScrollBars(); 1907 } 1908 } 1909 1910 /** 1911 * Find a position that can be selected (i.e., is not a separator). 1912 * 1913 * @param position The starting position to look at. 1914 * @param lookDown Whether to look down for other positions. 1915 * @return The next selectable position starting at position and then searching either up or 1916 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1917 */ 1918 @Override 1919 int lookForSelectablePosition(int position, boolean lookDown) { 1920 final ListAdapter adapter = mAdapter; 1921 if (adapter == null || isInTouchMode()) { 1922 return INVALID_POSITION; 1923 } 1924 1925 final int count = adapter.getCount(); 1926 if (!mAreAllItemsSelectable) { 1927 if (lookDown) { 1928 position = Math.max(0, position); 1929 while (position < count && !adapter.isEnabled(position)) { 1930 position++; 1931 } 1932 } else { 1933 position = Math.min(position, count - 1); 1934 while (position >= 0 && !adapter.isEnabled(position)) { 1935 position--; 1936 } 1937 } 1938 1939 if (position < 0 || position >= count) { 1940 return INVALID_POSITION; 1941 } 1942 return position; 1943 } else { 1944 if (position < 0 || position >= count) { 1945 return INVALID_POSITION; 1946 } 1947 return position; 1948 } 1949 } 1950 1951 @Override 1952 public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { 1953 boolean populated = super.dispatchPopulateAccessibilityEvent(event); 1954 1955 // If the item count is less than 15 then subtract disabled items from the count and 1956 // position. Otherwise ignore disabled items. 1957 if (!populated) { 1958 int itemCount = 0; 1959 int currentItemIndex = getSelectedItemPosition(); 1960 1961 ListAdapter adapter = getAdapter(); 1962 if (adapter != null) { 1963 final int count = adapter.getCount(); 1964 if (count < 15) { 1965 for (int i = 0; i < count; i++) { 1966 if (adapter.isEnabled(i)) { 1967 itemCount++; 1968 } else if (i <= currentItemIndex) { 1969 currentItemIndex--; 1970 } 1971 } 1972 } else { 1973 itemCount = count; 1974 } 1975 } 1976 1977 event.setItemCount(itemCount); 1978 event.setCurrentItemIndex(currentItemIndex); 1979 } 1980 1981 return populated; 1982 } 1983 1984 /** 1985 * setSelectionAfterHeaderView set the selection to be the first list item 1986 * after the header views. 1987 */ 1988 public void setSelectionAfterHeaderView() { 1989 final int count = mHeaderViewInfos.size(); 1990 if (count > 0) { 1991 mNextSelectedPosition = 0; 1992 return; 1993 } 1994 1995 if (mAdapter != null) { 1996 setSelection(count); 1997 } else { 1998 mNextSelectedPosition = count; 1999 mLayoutMode = LAYOUT_SET_SELECTION; 2000 } 2001 2002 } 2003 2004 @Override 2005 public boolean dispatchKeyEvent(KeyEvent event) { 2006 // Dispatch in the normal way 2007 boolean handled = super.dispatchKeyEvent(event); 2008 if (!handled) { 2009 // If we didn't handle it... 2010 View focused = getFocusedChild(); 2011 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 2012 // ... and our focused child didn't handle it 2013 // ... give it to ourselves so we can scroll if necessary 2014 handled = onKeyDown(event.getKeyCode(), event); 2015 } 2016 } 2017 return handled; 2018 } 2019 2020 @Override 2021 public boolean onKeyDown(int keyCode, KeyEvent event) { 2022 return commonKey(keyCode, 1, event); 2023 } 2024 2025 @Override 2026 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 2027 return commonKey(keyCode, repeatCount, event); 2028 } 2029 2030 @Override 2031 public boolean onKeyUp(int keyCode, KeyEvent event) { 2032 return commonKey(keyCode, 1, event); 2033 } 2034 2035 private boolean commonKey(int keyCode, int count, KeyEvent event) { 2036 if (mAdapter == null) { 2037 return false; 2038 } 2039 2040 if (mDataChanged) { 2041 layoutChildren(); 2042 } 2043 2044 boolean handled = false; 2045 int action = event.getAction(); 2046 2047 if (action != KeyEvent.ACTION_UP) { 2048 if (mSelectedPosition < 0) { 2049 switch (keyCode) { 2050 case KeyEvent.KEYCODE_DPAD_UP: 2051 case KeyEvent.KEYCODE_DPAD_DOWN: 2052 case KeyEvent.KEYCODE_DPAD_CENTER: 2053 case KeyEvent.KEYCODE_ENTER: 2054 case KeyEvent.KEYCODE_SPACE: 2055 if (resurrectSelection()) { 2056 return true; 2057 } 2058 } 2059 } 2060 switch (keyCode) { 2061 case KeyEvent.KEYCODE_DPAD_UP: 2062 if (!event.isAltPressed()) { 2063 while (count > 0) { 2064 handled = arrowScroll(FOCUS_UP); 2065 count--; 2066 } 2067 } else { 2068 handled = fullScroll(FOCUS_UP); 2069 } 2070 break; 2071 2072 case KeyEvent.KEYCODE_DPAD_DOWN: 2073 if (!event.isAltPressed()) { 2074 while (count > 0) { 2075 handled = arrowScroll(FOCUS_DOWN); 2076 count--; 2077 } 2078 } else { 2079 handled = fullScroll(FOCUS_DOWN); 2080 } 2081 break; 2082 2083 case KeyEvent.KEYCODE_DPAD_LEFT: 2084 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 2085 break; 2086 case KeyEvent.KEYCODE_DPAD_RIGHT: 2087 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 2088 break; 2089 2090 case KeyEvent.KEYCODE_DPAD_CENTER: 2091 case KeyEvent.KEYCODE_ENTER: 2092 if (mItemCount > 0 && event.getRepeatCount() == 0) { 2093 keyPressed(); 2094 } 2095 handled = true; 2096 break; 2097 2098 case KeyEvent.KEYCODE_SPACE: 2099 if (mPopup == null || !mPopup.isShowing()) { 2100 if (!event.isShiftPressed()) { 2101 pageScroll(FOCUS_DOWN); 2102 } else { 2103 pageScroll(FOCUS_UP); 2104 } 2105 handled = true; 2106 } 2107 break; 2108 } 2109 } 2110 2111 if (!handled) { 2112 handled = sendToTextFilter(keyCode, count, event); 2113 } 2114 2115 if (handled) { 2116 return true; 2117 } else { 2118 switch (action) { 2119 case KeyEvent.ACTION_DOWN: 2120 return super.onKeyDown(keyCode, event); 2121 2122 case KeyEvent.ACTION_UP: 2123 return super.onKeyUp(keyCode, event); 2124 2125 case KeyEvent.ACTION_MULTIPLE: 2126 return super.onKeyMultiple(keyCode, count, event); 2127 2128 default: // shouldn't happen 2129 return false; 2130 } 2131 } 2132 } 2133 2134 /** 2135 * Scrolls up or down by the number of items currently present on screen. 2136 * 2137 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2138 * @return whether selection was moved 2139 */ 2140 boolean pageScroll(int direction) { 2141 int nextPage = -1; 2142 boolean down = false; 2143 2144 if (direction == FOCUS_UP) { 2145 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2146 } else if (direction == FOCUS_DOWN) { 2147 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2148 down = true; 2149 } 2150 2151 if (nextPage >= 0) { 2152 int position = lookForSelectablePosition(nextPage, down); 2153 if (position >= 0) { 2154 mLayoutMode = LAYOUT_SPECIFIC; 2155 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2156 2157 if (down && position > mItemCount - getChildCount()) { 2158 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2159 } 2160 2161 if (!down && position < getChildCount()) { 2162 mLayoutMode = LAYOUT_FORCE_TOP; 2163 } 2164 2165 setSelectionInt(position); 2166 invokeOnItemScrollListener(); 2167 if (!awakenScrollBars()) { 2168 invalidate(); 2169 } 2170 2171 return true; 2172 } 2173 } 2174 2175 return false; 2176 } 2177 2178 /** 2179 * Go to the last or first item if possible (not worrying about panning across or navigating 2180 * within the internal focus of the currently selected item.) 2181 * 2182 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2183 * 2184 * @return whether selection was moved 2185 */ 2186 boolean fullScroll(int direction) { 2187 boolean moved = false; 2188 if (direction == FOCUS_UP) { 2189 if (mSelectedPosition != 0) { 2190 int position = lookForSelectablePosition(0, true); 2191 if (position >= 0) { 2192 mLayoutMode = LAYOUT_FORCE_TOP; 2193 setSelectionInt(position); 2194 invokeOnItemScrollListener(); 2195 } 2196 moved = true; 2197 } 2198 } else if (direction == FOCUS_DOWN) { 2199 if (mSelectedPosition < mItemCount - 1) { 2200 int position = lookForSelectablePosition(mItemCount - 1, true); 2201 if (position >= 0) { 2202 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2203 setSelectionInt(position); 2204 invokeOnItemScrollListener(); 2205 } 2206 moved = true; 2207 } 2208 } 2209 2210 if (moved && !awakenScrollBars()) { 2211 awakenScrollBars(); 2212 invalidate(); 2213 } 2214 2215 return moved; 2216 } 2217 2218 /** 2219 * To avoid horizontal focus searches changing the selected item, we 2220 * manually focus search within the selected item (as applicable), and 2221 * prevent focus from jumping to something within another item. 2222 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2223 * @return Whether this consumes the key event. 2224 */ 2225 private boolean handleHorizontalFocusWithinListItem(int direction) { 2226 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2227 throw new IllegalArgumentException("direction must be one of" 2228 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2229 } 2230 2231 final int numChildren = getChildCount(); 2232 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2233 final View selectedView = getSelectedView(); 2234 if (selectedView != null && selectedView.hasFocus() && 2235 selectedView instanceof ViewGroup) { 2236 2237 final View currentFocus = selectedView.findFocus(); 2238 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2239 (ViewGroup) selectedView, currentFocus, direction); 2240 if (nextFocus != null) { 2241 // do the math to get interesting rect in next focus' coordinates 2242 currentFocus.getFocusedRect(mTempRect); 2243 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2244 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2245 if (nextFocus.requestFocus(direction, mTempRect)) { 2246 return true; 2247 } 2248 } 2249 // we are blocking the key from being handled (by returning true) 2250 // if the global result is going to be some other view within this 2251 // list. this is to acheive the overall goal of having 2252 // horizontal d-pad navigation remain in the current item. 2253 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2254 (ViewGroup) getRootView(), currentFocus, direction); 2255 if (globalNextFocus != null) { 2256 return isViewAncestorOf(globalNextFocus, this); 2257 } 2258 } 2259 } 2260 return false; 2261 } 2262 2263 /** 2264 * Scrolls to the next or previous item if possible. 2265 * 2266 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2267 * 2268 * @return whether selection was moved 2269 */ 2270 boolean arrowScroll(int direction) { 2271 try { 2272 mInLayout = true; 2273 final boolean handled = arrowScrollImpl(direction); 2274 if (handled) { 2275 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2276 } 2277 return handled; 2278 } finally { 2279 mInLayout = false; 2280 } 2281 } 2282 2283 /** 2284 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2285 * whether there are focusable items etc. 2286 * 2287 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2288 * @return Whether any scrolling, selection or focus change occured. 2289 */ 2290 private boolean arrowScrollImpl(int direction) { 2291 if (getChildCount() <= 0) { 2292 return false; 2293 } 2294 2295 View selectedView = getSelectedView(); 2296 int selectedPos = mSelectedPosition; 2297 2298 int nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 2299 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2300 2301 // if we are moving focus, we may OVERRIDE the default behavior 2302 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2303 if (focusResult != null) { 2304 nextSelectedPosition = focusResult.getSelectedPosition(); 2305 amountToScroll = focusResult.getAmountToScroll(); 2306 } 2307 2308 boolean needToRedraw = focusResult != null; 2309 if (nextSelectedPosition != INVALID_POSITION) { 2310 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2311 setSelectedPositionInt(nextSelectedPosition); 2312 setNextSelectedPositionInt(nextSelectedPosition); 2313 selectedView = getSelectedView(); 2314 selectedPos = nextSelectedPosition; 2315 if (mItemsCanFocus && focusResult == null) { 2316 // there was no new view found to take focus, make sure we 2317 // don't leave focus with the old selection 2318 final View focused = getFocusedChild(); 2319 if (focused != null) { 2320 focused.clearFocus(); 2321 } 2322 } 2323 needToRedraw = true; 2324 checkSelectionChanged(); 2325 } 2326 2327 if (amountToScroll > 0) { 2328 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2329 needToRedraw = true; 2330 } 2331 2332 // if we didn't find a new focusable, make sure any existing focused 2333 // item that was panned off screen gives up focus. 2334 if (mItemsCanFocus && (focusResult == null) 2335 && selectedView != null && selectedView.hasFocus()) { 2336 final View focused = selectedView.findFocus(); 2337 if (distanceToView(focused) > 0) { 2338 focused.clearFocus(); 2339 } 2340 } 2341 2342 // if the current selection is panned off, we need to remove the selection 2343 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2344 && !isViewAncestorOf(selectedView, this)) { 2345 selectedView = null; 2346 hideSelector(); 2347 2348 // but we don't want to set the ressurect position (that would make subsequent 2349 // unhandled key events bring back the item we just scrolled off!) 2350 mResurrectToPosition = INVALID_POSITION; 2351 } 2352 2353 if (needToRedraw) { 2354 if (selectedView != null) { 2355 positionSelector(selectedPos, selectedView); 2356 mSelectedTop = selectedView.getTop(); 2357 } 2358 if (!awakenScrollBars()) { 2359 invalidate(); 2360 } 2361 invokeOnItemScrollListener(); 2362 return true; 2363 } 2364 2365 return false; 2366 } 2367 2368 /** 2369 * When selection changes, it is possible that the previously selected or the 2370 * next selected item will change its size. If so, we need to offset some folks, 2371 * and re-layout the items as appropriate. 2372 * 2373 * @param selectedView The currently selected view (before changing selection). 2374 * should be <code>null</code> if there was no previous selection. 2375 * @param direction Either {@link android.view.View#FOCUS_UP} or 2376 * {@link android.view.View#FOCUS_DOWN}. 2377 * @param newSelectedPosition The position of the next selection. 2378 * @param newFocusAssigned whether new focus was assigned. This matters because 2379 * when something has focus, we don't want to show selection (ugh). 2380 */ 2381 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2382 boolean newFocusAssigned) { 2383 if (newSelectedPosition == INVALID_POSITION) { 2384 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2385 } 2386 2387 // whether or not we are moving down or up, we want to preserve the 2388 // top of whatever view is on top: 2389 // - moving down: the view that had selection 2390 // - moving up: the view that is getting selection 2391 View topView; 2392 View bottomView; 2393 int topViewIndex, bottomViewIndex; 2394 boolean topSelected = false; 2395 final int selectedIndex = mSelectedPosition - mFirstPosition; 2396 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2397 if (direction == View.FOCUS_UP) { 2398 topViewIndex = nextSelectedIndex; 2399 bottomViewIndex = selectedIndex; 2400 topView = getChildAt(topViewIndex); 2401 bottomView = selectedView; 2402 topSelected = true; 2403 } else { 2404 topViewIndex = selectedIndex; 2405 bottomViewIndex = nextSelectedIndex; 2406 topView = selectedView; 2407 bottomView = getChildAt(bottomViewIndex); 2408 } 2409 2410 final int numChildren = getChildCount(); 2411 2412 // start with top view: is it changing size? 2413 if (topView != null) { 2414 topView.setSelected(!newFocusAssigned && topSelected); 2415 measureAndAdjustDown(topView, topViewIndex, numChildren); 2416 } 2417 2418 // is the bottom view changing size? 2419 if (bottomView != null) { 2420 bottomView.setSelected(!newFocusAssigned && !topSelected); 2421 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2422 } 2423 } 2424 2425 /** 2426 * Re-measure a child, and if its height changes, lay it out preserving its 2427 * top, and adjust the children below it appropriately. 2428 * @param child The child 2429 * @param childIndex The view group index of the child. 2430 * @param numChildren The number of children in the view group. 2431 */ 2432 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2433 int oldHeight = child.getHeight(); 2434 measureItem(child); 2435 if (child.getMeasuredHeight() != oldHeight) { 2436 // lay out the view, preserving its top 2437 relayoutMeasuredItem(child); 2438 2439 // adjust views below appropriately 2440 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2441 for (int i = childIndex + 1; i < numChildren; i++) { 2442 getChildAt(i).offsetTopAndBottom(heightDelta); 2443 } 2444 } 2445 } 2446 2447 /** 2448 * Measure a particular list child. 2449 * TODO: unify with setUpChild. 2450 * @param child The child. 2451 */ 2452 private void measureItem(View child) { 2453 ViewGroup.LayoutParams p = child.getLayoutParams(); 2454 if (p == null) { 2455 p = new ViewGroup.LayoutParams( 2456 ViewGroup.LayoutParams.MATCH_PARENT, 2457 ViewGroup.LayoutParams.WRAP_CONTENT); 2458 } 2459 2460 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2461 mListPadding.left + mListPadding.right, p.width); 2462 int lpHeight = p.height; 2463 int childHeightSpec; 2464 if (lpHeight > 0) { 2465 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2466 } else { 2467 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2468 } 2469 child.measure(childWidthSpec, childHeightSpec); 2470 } 2471 2472 /** 2473 * Layout a child that has been measured, preserving its top position. 2474 * TODO: unify with setUpChild. 2475 * @param child The child. 2476 */ 2477 private void relayoutMeasuredItem(View child) { 2478 final int w = child.getMeasuredWidth(); 2479 final int h = child.getMeasuredHeight(); 2480 final int childLeft = mListPadding.left; 2481 final int childRight = childLeft + w; 2482 final int childTop = child.getTop(); 2483 final int childBottom = childTop + h; 2484 child.layout(childLeft, childTop, childRight, childBottom); 2485 } 2486 2487 /** 2488 * @return The amount to preview next items when arrow srolling. 2489 */ 2490 private int getArrowScrollPreviewLength() { 2491 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2492 } 2493 2494 /** 2495 * Determine how much we need to scroll in order to get the next selected view 2496 * visible, with a fading edge showing below as applicable. The amount is 2497 * capped at {@link #getMaxScrollAmount()} . 2498 * 2499 * @param direction either {@link android.view.View#FOCUS_UP} or 2500 * {@link android.view.View#FOCUS_DOWN}. 2501 * @param nextSelectedPosition The position of the next selection, or 2502 * {@link #INVALID_POSITION} if there is no next selectable position 2503 * @return The amount to scroll. Note: this is always positive! Direction 2504 * needs to be taken into account when actually scrolling. 2505 */ 2506 private int amountToScroll(int direction, int nextSelectedPosition) { 2507 final int listBottom = getHeight() - mListPadding.bottom; 2508 final int listTop = mListPadding.top; 2509 2510 final int numChildren = getChildCount(); 2511 2512 if (direction == View.FOCUS_DOWN) { 2513 int indexToMakeVisible = numChildren - 1; 2514 if (nextSelectedPosition != INVALID_POSITION) { 2515 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2516 } 2517 2518 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2519 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2520 2521 int goalBottom = listBottom; 2522 if (positionToMakeVisible < mItemCount - 1) { 2523 goalBottom -= getArrowScrollPreviewLength(); 2524 } 2525 2526 if (viewToMakeVisible.getBottom() <= goalBottom) { 2527 // item is fully visible. 2528 return 0; 2529 } 2530 2531 if (nextSelectedPosition != INVALID_POSITION 2532 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2533 // item already has enough of it visible, changing selection is good enough 2534 return 0; 2535 } 2536 2537 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2538 2539 if ((mFirstPosition + numChildren) == mItemCount) { 2540 // last is last in list -> make sure we don't scroll past it 2541 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2542 amountToScroll = Math.min(amountToScroll, max); 2543 } 2544 2545 return Math.min(amountToScroll, getMaxScrollAmount()); 2546 } else { 2547 int indexToMakeVisible = 0; 2548 if (nextSelectedPosition != INVALID_POSITION) { 2549 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2550 } 2551 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2552 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2553 int goalTop = listTop; 2554 if (positionToMakeVisible > 0) { 2555 goalTop += getArrowScrollPreviewLength(); 2556 } 2557 if (viewToMakeVisible.getTop() >= goalTop) { 2558 // item is fully visible. 2559 return 0; 2560 } 2561 2562 if (nextSelectedPosition != INVALID_POSITION && 2563 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2564 // item already has enough of it visible, changing selection is good enough 2565 return 0; 2566 } 2567 2568 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2569 if (mFirstPosition == 0) { 2570 // first is first in list -> make sure we don't scroll past it 2571 final int max = listTop - getChildAt(0).getTop(); 2572 amountToScroll = Math.min(amountToScroll, max); 2573 } 2574 return Math.min(amountToScroll, getMaxScrollAmount()); 2575 } 2576 } 2577 2578 /** 2579 * Holds results of focus aware arrow scrolling. 2580 */ 2581 static private class ArrowScrollFocusResult { 2582 private int mSelectedPosition; 2583 private int mAmountToScroll; 2584 2585 /** 2586 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2587 */ 2588 void populate(int selectedPosition, int amountToScroll) { 2589 mSelectedPosition = selectedPosition; 2590 mAmountToScroll = amountToScroll; 2591 } 2592 2593 public int getSelectedPosition() { 2594 return mSelectedPosition; 2595 } 2596 2597 public int getAmountToScroll() { 2598 return mAmountToScroll; 2599 } 2600 } 2601 2602 /** 2603 * @param direction either {@link android.view.View#FOCUS_UP} or 2604 * {@link android.view.View#FOCUS_DOWN}. 2605 * @return The position of the next selectable position of the views that 2606 * are currently visible, taking into account the fact that there might 2607 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2608 * selectable view on screen in the given direction. 2609 */ 2610 private int lookForSelectablePositionOnScreen(int direction) { 2611 final int firstPosition = mFirstPosition; 2612 if (direction == View.FOCUS_DOWN) { 2613 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2614 mSelectedPosition + 1 : 2615 firstPosition; 2616 if (startPos >= mAdapter.getCount()) { 2617 return INVALID_POSITION; 2618 } 2619 if (startPos < firstPosition) { 2620 startPos = firstPosition; 2621 } 2622 2623 final int lastVisiblePos = getLastVisiblePosition(); 2624 final ListAdapter adapter = getAdapter(); 2625 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2626 if (adapter.isEnabled(pos) 2627 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2628 return pos; 2629 } 2630 } 2631 } else { 2632 int last = firstPosition + getChildCount() - 1; 2633 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2634 mSelectedPosition - 1 : 2635 firstPosition + getChildCount() - 1; 2636 if (startPos < 0) { 2637 return INVALID_POSITION; 2638 } 2639 if (startPos > last) { 2640 startPos = last; 2641 } 2642 2643 final ListAdapter adapter = getAdapter(); 2644 for (int pos = startPos; pos >= firstPosition; pos--) { 2645 if (adapter.isEnabled(pos) 2646 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2647 return pos; 2648 } 2649 } 2650 } 2651 return INVALID_POSITION; 2652 } 2653 2654 /** 2655 * Do an arrow scroll based on focus searching. If a new view is 2656 * given focus, return the selection delta and amount to scroll via 2657 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2658 * 2659 * @param direction either {@link android.view.View#FOCUS_UP} or 2660 * {@link android.view.View#FOCUS_DOWN}. 2661 * @return The result if focus has changed, or <code>null</code>. 2662 */ 2663 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2664 final View selectedView = getSelectedView(); 2665 View newFocus; 2666 if (selectedView != null && selectedView.hasFocus()) { 2667 View oldFocus = selectedView.findFocus(); 2668 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2669 } else { 2670 if (direction == View.FOCUS_DOWN) { 2671 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2672 final int listTop = mListPadding.top + 2673 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2674 final int ySearchPoint = 2675 (selectedView != null && selectedView.getTop() > listTop) ? 2676 selectedView.getTop() : 2677 listTop; 2678 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2679 } else { 2680 final boolean bottomFadingEdgeShowing = 2681 (mFirstPosition + getChildCount() - 1) < mItemCount; 2682 final int listBottom = getHeight() - mListPadding.bottom - 2683 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2684 final int ySearchPoint = 2685 (selectedView != null && selectedView.getBottom() < listBottom) ? 2686 selectedView.getBottom() : 2687 listBottom; 2688 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2689 } 2690 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2691 } 2692 2693 if (newFocus != null) { 2694 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2695 2696 // if the focus change is in a different new position, make sure 2697 // we aren't jumping over another selectable position 2698 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2699 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2700 if (selectablePosition != INVALID_POSITION && 2701 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2702 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2703 return null; 2704 } 2705 } 2706 2707 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2708 2709 final int maxScrollAmount = getMaxScrollAmount(); 2710 if (focusScroll < maxScrollAmount) { 2711 // not moving too far, safe to give next view focus 2712 newFocus.requestFocus(direction); 2713 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2714 return mArrowScrollFocusResult; 2715 } else if (distanceToView(newFocus) < maxScrollAmount){ 2716 // Case to consider: 2717 // too far to get entire next focusable on screen, but by going 2718 // max scroll amount, we are getting it at least partially in view, 2719 // so give it focus and scroll the max ammount. 2720 newFocus.requestFocus(direction); 2721 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2722 return mArrowScrollFocusResult; 2723 } 2724 } 2725 return null; 2726 } 2727 2728 /** 2729 * @param newFocus The view that would have focus. 2730 * @return the position that contains newFocus 2731 */ 2732 private int positionOfNewFocus(View newFocus) { 2733 final int numChildren = getChildCount(); 2734 for (int i = 0; i < numChildren; i++) { 2735 final View child = getChildAt(i); 2736 if (isViewAncestorOf(newFocus, child)) { 2737 return mFirstPosition + i; 2738 } 2739 } 2740 throw new IllegalArgumentException("newFocus is not a child of any of the" 2741 + " children of the list!"); 2742 } 2743 2744 /** 2745 * Return true if child is an ancestor of parent, (or equal to the parent). 2746 */ 2747 private boolean isViewAncestorOf(View child, View parent) { 2748 if (child == parent) { 2749 return true; 2750 } 2751 2752 final ViewParent theParent = child.getParent(); 2753 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2754 } 2755 2756 /** 2757 * Determine how much we need to scroll in order to get newFocus in view. 2758 * @param direction either {@link android.view.View#FOCUS_UP} or 2759 * {@link android.view.View#FOCUS_DOWN}. 2760 * @param newFocus The view that would take focus. 2761 * @param positionOfNewFocus The position of the list item containing newFocus 2762 * @return The amount to scroll. Note: this is always positive! Direction 2763 * needs to be taken into account when actually scrolling. 2764 */ 2765 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2766 int amountToScroll = 0; 2767 newFocus.getDrawingRect(mTempRect); 2768 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2769 if (direction == View.FOCUS_UP) { 2770 if (mTempRect.top < mListPadding.top) { 2771 amountToScroll = mListPadding.top - mTempRect.top; 2772 if (positionOfNewFocus > 0) { 2773 amountToScroll += getArrowScrollPreviewLength(); 2774 } 2775 } 2776 } else { 2777 final int listBottom = getHeight() - mListPadding.bottom; 2778 if (mTempRect.bottom > listBottom) { 2779 amountToScroll = mTempRect.bottom - listBottom; 2780 if (positionOfNewFocus < mItemCount - 1) { 2781 amountToScroll += getArrowScrollPreviewLength(); 2782 } 2783 } 2784 } 2785 return amountToScroll; 2786 } 2787 2788 /** 2789 * Determine the distance to the nearest edge of a view in a particular 2790 * direction. 2791 * 2792 * @param descendant A descendant of this list. 2793 * @return The distance, or 0 if the nearest edge is already on screen. 2794 */ 2795 private int distanceToView(View descendant) { 2796 int distance = 0; 2797 descendant.getDrawingRect(mTempRect); 2798 offsetDescendantRectToMyCoords(descendant, mTempRect); 2799 final int listBottom = mBottom - mTop - mListPadding.bottom; 2800 if (mTempRect.bottom < mListPadding.top) { 2801 distance = mListPadding.top - mTempRect.bottom; 2802 } else if (mTempRect.top > listBottom) { 2803 distance = mTempRect.top - listBottom; 2804 } 2805 return distance; 2806 } 2807 2808 2809 /** 2810 * Scroll the children by amount, adding a view at the end and removing 2811 * views that fall off as necessary. 2812 * 2813 * @param amount The amount (positive or negative) to scroll. 2814 */ 2815 private void scrollListItemsBy(int amount) { 2816 offsetChildrenTopAndBottom(amount); 2817 2818 final int listBottom = getHeight() - mListPadding.bottom; 2819 final int listTop = mListPadding.top; 2820 final AbsListView.RecycleBin recycleBin = mRecycler; 2821 2822 if (amount < 0) { 2823 // shifted items up 2824 2825 // may need to pan views into the bottom space 2826 int numChildren = getChildCount(); 2827 View last = getChildAt(numChildren - 1); 2828 while (last.getBottom() < listBottom) { 2829 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2830 if (lastVisiblePosition < mItemCount - 1) { 2831 last = addViewBelow(last, lastVisiblePosition); 2832 numChildren++; 2833 } else { 2834 break; 2835 } 2836 } 2837 2838 // may have brought in the last child of the list that is skinnier 2839 // than the fading edge, thereby leaving space at the end. need 2840 // to shift back 2841 if (last.getBottom() < listBottom) { 2842 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2843 } 2844 2845 // top views may be panned off screen 2846 View first = getChildAt(0); 2847 while (first.getBottom() < listTop) { 2848 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2849 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2850 detachViewFromParent(first); 2851 recycleBin.addScrapView(first, mFirstPosition); 2852 } else { 2853 removeViewInLayout(first); 2854 } 2855 first = getChildAt(0); 2856 mFirstPosition++; 2857 } 2858 } else { 2859 // shifted items down 2860 View first = getChildAt(0); 2861 2862 // may need to pan views into top 2863 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2864 first = addViewAbove(first, mFirstPosition); 2865 mFirstPosition--; 2866 } 2867 2868 // may have brought the very first child of the list in too far and 2869 // need to shift it back 2870 if (first.getTop() > listTop) { 2871 offsetChildrenTopAndBottom(listTop - first.getTop()); 2872 } 2873 2874 int lastIndex = getChildCount() - 1; 2875 View last = getChildAt(lastIndex); 2876 2877 // bottom view may be panned off screen 2878 while (last.getTop() > listBottom) { 2879 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 2880 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2881 detachViewFromParent(last); 2882 recycleBin.addScrapView(last, mFirstPosition+lastIndex); 2883 } else { 2884 removeViewInLayout(last); 2885 } 2886 last = getChildAt(--lastIndex); 2887 } 2888 } 2889 } 2890 2891 private View addViewAbove(View theView, int position) { 2892 int abovePosition = position - 1; 2893 View view = obtainView(abovePosition, mIsScrap); 2894 int edgeOfNewChild = theView.getTop() - mDividerHeight; 2895 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, 2896 false, mIsScrap[0]); 2897 return view; 2898 } 2899 2900 private View addViewBelow(View theView, int position) { 2901 int belowPosition = position + 1; 2902 View view = obtainView(belowPosition, mIsScrap); 2903 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 2904 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, 2905 false, mIsScrap[0]); 2906 return view; 2907 } 2908 2909 /** 2910 * Indicates that the views created by the ListAdapter can contain focusable 2911 * items. 2912 * 2913 * @param itemsCanFocus true if items can get focus, false otherwise 2914 */ 2915 public void setItemsCanFocus(boolean itemsCanFocus) { 2916 mItemsCanFocus = itemsCanFocus; 2917 if (!itemsCanFocus) { 2918 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 2919 } 2920 } 2921 2922 /** 2923 * @return Whether the views created by the ListAdapter can contain focusable 2924 * items. 2925 */ 2926 public boolean getItemsCanFocus() { 2927 return mItemsCanFocus; 2928 } 2929 2930 /** 2931 * @hide Pending API council approval. 2932 */ 2933 @Override 2934 public boolean isOpaque() { 2935 return (mCachingStarted && mIsCacheColorOpaque && mDividerIsOpaque && 2936 hasOpaqueScrollbars()) || super.isOpaque(); 2937 } 2938 2939 @Override 2940 public void setCacheColorHint(int color) { 2941 final boolean opaque = (color >>> 24) == 0xFF; 2942 mIsCacheColorOpaque = opaque; 2943 if (opaque) { 2944 if (mDividerPaint == null) { 2945 mDividerPaint = new Paint(); 2946 } 2947 mDividerPaint.setColor(color); 2948 } 2949 super.setCacheColorHint(color); 2950 } 2951 2952 @Override 2953 protected void dispatchDraw(Canvas canvas) { 2954 // Draw the dividers 2955 final int dividerHeight = mDividerHeight; 2956 final boolean drawDividers = dividerHeight > 0 && mDivider != null; 2957 2958 if (drawDividers) { 2959 // Only modify the top and bottom in the loop, we set the left and right here 2960 final Rect bounds = mTempRect; 2961 bounds.left = mPaddingLeft; 2962 bounds.right = mRight - mLeft - mPaddingRight; 2963 2964 final int count = getChildCount(); 2965 final int headerCount = mHeaderViewInfos.size(); 2966 final int itemCount = mItemCount; 2967 final int footerLimit = itemCount - mFooterViewInfos.size() - 1; 2968 final boolean headerDividers = mHeaderDividersEnabled; 2969 final boolean footerDividers = mFooterDividersEnabled; 2970 final int first = mFirstPosition; 2971 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 2972 final ListAdapter adapter = mAdapter; 2973 // If the list is opaque *and* the background is not, we want to 2974 // fill a rect where the dividers would be for non-selectable items 2975 // If the list is opaque and the background is also opaque, we don't 2976 // need to draw anything since the background will do it for us 2977 final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); 2978 2979 if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { 2980 mDividerPaint = new Paint(); 2981 mDividerPaint.setColor(getCacheColorHint()); 2982 } 2983 final Paint paint = mDividerPaint; 2984 2985 final int listBottom = mBottom - mTop - mListPadding.bottom + mScrollY; 2986 if (!mStackFromBottom) { 2987 int bottom; 2988 2989 for (int i = 0; i < count; i++) { 2990 if ((headerDividers || first + i >= headerCount) && 2991 (footerDividers || first + i < footerLimit)) { 2992 View child = getChildAt(i); 2993 bottom = child.getBottom(); 2994 // Don't draw dividers next to items that are not enabled 2995 if ((areAllItemsSelectable || 2996 (adapter.isEnabled(first + i) && (i == count - 1 || 2997 adapter.isEnabled(first + i + 1))))) { 2998 bounds.top = bottom; 2999 bounds.bottom = bottom + dividerHeight; 3000 drawDivider(canvas, bounds, i); 3001 } else if (fillForMissingDividers) { 3002 bounds.top = bottom; 3003 bounds.bottom = bottom + dividerHeight; 3004 canvas.drawRect(bounds, paint); 3005 } 3006 } 3007 } 3008 } else { 3009 int top; 3010 int listTop = mListPadding.top; 3011 3012 final int scrollY = mScrollY; 3013 3014 for (int i = 0; i < count; i++) { 3015 if ((headerDividers || first + i >= headerCount) && 3016 (footerDividers || first + i < footerLimit)) { 3017 View child = getChildAt(i); 3018 top = child.getTop(); 3019 // Don't draw dividers next to items that are not enabled 3020 if (top > listTop) { 3021 if ((areAllItemsSelectable || 3022 (adapter.isEnabled(first + i) && (i == count - 1 || 3023 adapter.isEnabled(first + i + 1))))) { 3024 bounds.top = top - dividerHeight; 3025 bounds.bottom = top; 3026 // Give the method the child ABOVE the divider, so we 3027 // subtract one from our child 3028 // position. Give -1 when there is no child above the 3029 // divider. 3030 drawDivider(canvas, bounds, i - 1); 3031 } else if (fillForMissingDividers) { 3032 bounds.top = top - dividerHeight; 3033 bounds.bottom = top; 3034 canvas.drawRect(bounds, paint); 3035 } 3036 } 3037 } 3038 } 3039 3040 if (count > 0 && scrollY > 0) { 3041 bounds.top = listBottom; 3042 bounds.bottom = listBottom + dividerHeight; 3043 drawDivider(canvas, bounds, -1); 3044 } 3045 } 3046 } 3047 3048 // Draw the indicators (these should be drawn above the dividers) and children 3049 super.dispatchDraw(canvas); 3050 } 3051 3052 /** 3053 * Draws a divider for the given child in the given bounds. 3054 * 3055 * @param canvas The canvas to draw to. 3056 * @param bounds The bounds of the divider. 3057 * @param childIndex The index of child (of the View) above the divider. 3058 * This will be -1 if there is no child above the divider to be 3059 * drawn. 3060 */ 3061 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 3062 // This widget draws the same divider for all children 3063 final Drawable divider = mDivider; 3064 3065 divider.setBounds(bounds); 3066 divider.draw(canvas); 3067 } 3068 3069 /** 3070 * Returns the drawable that will be drawn between each item in the list. 3071 * 3072 * @return the current drawable drawn between list elements 3073 */ 3074 public Drawable getDivider() { 3075 return mDivider; 3076 } 3077 3078 /** 3079 * Sets the drawable that will be drawn between each item in the list. If the drawable does 3080 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 3081 * 3082 * @param divider The drawable to use. 3083 */ 3084 public void setDivider(Drawable divider) { 3085 if (divider != null) { 3086 mDividerHeight = divider.getIntrinsicHeight(); 3087 } else { 3088 mDividerHeight = 0; 3089 } 3090 mDivider = divider; 3091 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 3092 requestLayoutIfNecessary(); 3093 } 3094 3095 /** 3096 * @return Returns the height of the divider that will be drawn between each item in the list. 3097 */ 3098 public int getDividerHeight() { 3099 return mDividerHeight; 3100 } 3101 3102 /** 3103 * Sets the height of the divider that will be drawn between each item in the list. Calling 3104 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 3105 * 3106 * @param height The new height of the divider in pixels. 3107 */ 3108 public void setDividerHeight(int height) { 3109 mDividerHeight = height; 3110 requestLayoutIfNecessary(); 3111 } 3112 3113 /** 3114 * Enables or disables the drawing of the divider for header views. 3115 * 3116 * @param headerDividersEnabled True to draw the headers, false otherwise. 3117 * 3118 * @see #setFooterDividersEnabled(boolean) 3119 * @see #addHeaderView(android.view.View) 3120 */ 3121 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 3122 mHeaderDividersEnabled = headerDividersEnabled; 3123 invalidate(); 3124 } 3125 3126 /** 3127 * Enables or disables the drawing of the divider for footer views. 3128 * 3129 * @param footerDividersEnabled True to draw the footers, false otherwise. 3130 * 3131 * @see #setHeaderDividersEnabled(boolean) 3132 * @see #addFooterView(android.view.View) 3133 */ 3134 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 3135 mFooterDividersEnabled = footerDividersEnabled; 3136 invalidate(); 3137 } 3138 3139 @Override 3140 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 3141 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 3142 3143 int closetChildIndex = -1; 3144 if (gainFocus && previouslyFocusedRect != null) { 3145 previouslyFocusedRect.offset(mScrollX, mScrollY); 3146 3147 final ListAdapter adapter = mAdapter; 3148 // Don't cache the result of getChildCount or mFirstPosition here, 3149 // it could change in layoutChildren. 3150 if (adapter.getCount() < getChildCount() + mFirstPosition) { 3151 mLayoutMode = LAYOUT_NORMAL; 3152 layoutChildren(); 3153 } 3154 3155 // figure out which item should be selected based on previously 3156 // focused rect 3157 Rect otherRect = mTempRect; 3158 int minDistance = Integer.MAX_VALUE; 3159 final int childCount = getChildCount(); 3160 final int firstPosition = mFirstPosition; 3161 3162 for (int i = 0; i < childCount; i++) { 3163 // only consider selectable views 3164 if (!adapter.isEnabled(firstPosition + i)) { 3165 continue; 3166 } 3167 3168 View other = getChildAt(i); 3169 other.getDrawingRect(otherRect); 3170 offsetDescendantRectToMyCoords(other, otherRect); 3171 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 3172 3173 if (distance < minDistance) { 3174 minDistance = distance; 3175 closetChildIndex = i; 3176 } 3177 } 3178 } 3179 3180 if (closetChildIndex >= 0) { 3181 setSelection(closetChildIndex + mFirstPosition); 3182 } else { 3183 requestLayout(); 3184 } 3185 } 3186 3187 3188 /* 3189 * (non-Javadoc) 3190 * 3191 * Children specified in XML are assumed to be header views. After we have 3192 * parsed them move them out of the children list and into mHeaderViews. 3193 */ 3194 @Override 3195 protected void onFinishInflate() { 3196 super.onFinishInflate(); 3197 3198 int count = getChildCount(); 3199 if (count > 0) { 3200 for (int i = 0; i < count; ++i) { 3201 addHeaderView(getChildAt(i)); 3202 } 3203 removeAllViews(); 3204 } 3205 } 3206 3207 /* (non-Javadoc) 3208 * @see android.view.View#findViewById(int) 3209 * First look in our children, then in any header and footer views that may be scrolled off. 3210 */ 3211 @Override 3212 protected View findViewTraversal(int id) { 3213 View v; 3214 v = super.findViewTraversal(id); 3215 if (v == null) { 3216 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3217 if (v != null) { 3218 return v; 3219 } 3220 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3221 if (v != null) { 3222 return v; 3223 } 3224 } 3225 return v; 3226 } 3227 3228 /* (non-Javadoc) 3229 * 3230 * Look in the passed in list of headers or footers for the view. 3231 */ 3232 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3233 if (where != null) { 3234 int len = where.size(); 3235 View v; 3236 3237 for (int i = 0; i < len; i++) { 3238 v = where.get(i).view; 3239 3240 if (!v.isRootNamespace()) { 3241 v = v.findViewById(id); 3242 3243 if (v != null) { 3244 return v; 3245 } 3246 } 3247 } 3248 } 3249 return null; 3250 } 3251 3252 /* (non-Javadoc) 3253 * @see android.view.View#findViewWithTag(String) 3254 * First look in our children, then in any header and footer views that may be scrolled off. 3255 */ 3256 @Override 3257 protected View findViewWithTagTraversal(Object tag) { 3258 View v; 3259 v = super.findViewWithTagTraversal(tag); 3260 if (v == null) { 3261 v = findViewTagInHeadersOrFooters(mHeaderViewInfos, tag); 3262 if (v != null) { 3263 return v; 3264 } 3265 3266 v = findViewTagInHeadersOrFooters(mFooterViewInfos, tag); 3267 if (v != null) { 3268 return v; 3269 } 3270 } 3271 return v; 3272 } 3273 3274 /* (non-Javadoc) 3275 * 3276 * Look in the passed in list of headers or footers for the view with the tag. 3277 */ 3278 View findViewTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3279 if (where != null) { 3280 int len = where.size(); 3281 View v; 3282 3283 for (int i = 0; i < len; i++) { 3284 v = where.get(i).view; 3285 3286 if (!v.isRootNamespace()) { 3287 v = v.findViewWithTag(tag); 3288 3289 if (v != null) { 3290 return v; 3291 } 3292 } 3293 } 3294 } 3295 return null; 3296 } 3297 3298 @Override 3299 public boolean onTouchEvent(MotionEvent ev) { 3300 if (mItemsCanFocus && ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { 3301 // Don't handle edge touches immediately -- they may actually belong to one of our 3302 // descendants. 3303 return false; 3304 } 3305 return super.onTouchEvent(ev); 3306 } 3307 3308 /** 3309 * Returns the set of checked items ids. The result is only valid if the 3310 * choice mode has not been set to {@link #CHOICE_MODE_NONE}. 3311 * 3312 * @return A new array which contains the id of each checked item in the 3313 * list. 3314 * 3315 * @deprecated Use {@link #getCheckedItemIds()} instead. 3316 */ 3317 @Deprecated 3318 public long[] getCheckItemIds() { 3319 // Use new behavior that correctly handles stable ID mapping. 3320 if (mAdapter != null && mAdapter.hasStableIds()) { 3321 return getCheckedItemIds(); 3322 } 3323 3324 // Old behavior was buggy, but would sort of work for adapters without stable IDs. 3325 // Fall back to it to support legacy apps. 3326 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3327 final SparseBooleanArray states = mCheckStates; 3328 final int count = states.size(); 3329 final long[] ids = new long[count]; 3330 final ListAdapter adapter = mAdapter; 3331 3332 int checkedCount = 0; 3333 for (int i = 0; i < count; i++) { 3334 if (states.valueAt(i)) { 3335 ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); 3336 } 3337 } 3338 3339 // Trim array if needed. mCheckStates may contain false values 3340 // resulting in checkedCount being smaller than count. 3341 if (checkedCount == count) { 3342 return ids; 3343 } else { 3344 final long[] result = new long[checkedCount]; 3345 System.arraycopy(ids, 0, result, 0, checkedCount); 3346 3347 return result; 3348 } 3349 } 3350 return new long[0]; 3351 } 3352} 3353