ListView.java revision 24443ea3992e372e47daa50266b0f2ec38cac388
1/* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.widget; 18 19import android.content.Context; 20import android.content.res.TypedArray; 21import android.graphics.Canvas; 22import android.graphics.Rect; 23import android.graphics.PixelFormat; 24import android.graphics.drawable.Drawable; 25import android.graphics.drawable.ColorDrawable; 26import android.os.Parcel; 27import android.os.Parcelable; 28import android.util.AttributeSet; 29import android.util.SparseBooleanArray; 30import android.view.FocusFinder; 31import android.view.KeyEvent; 32import android.view.MotionEvent; 33import android.view.View; 34import android.view.ViewDebug; 35import android.view.ViewGroup; 36import android.view.ViewParent; 37import android.view.SoundEffectConstants; 38 39import com.google.android.collect.Lists; 40import com.android.internal.R; 41 42import java.util.ArrayList; 43 44/* 45 * Implementation Notes: 46 * 47 * Some terminology: 48 * 49 * index - index of the items that are currently visible 50 * position - index of the items in the cursor 51 */ 52 53 54/** 55 * A view that shows items in a vertically scrolling list. The items 56 * come from the {@link ListAdapter} associated with this view. 57 * 58 * @attr ref android.R.styleable#ListView_entries 59 * @attr ref android.R.styleable#ListView_divider 60 * @attr ref android.R.styleable#ListView_dividerHeight 61 * @attr ref android.R.styleable#ListView_choiceMode 62 * @attr ref android.R.styleable#ListView_headerDividersEnabled 63 * @attr ref android.R.styleable#ListView_footerDividersEnabled 64 */ 65public class ListView extends AbsListView { 66 /** 67 * Used to indicate a no preference for a position type. 68 */ 69 static final int NO_POSITION = -1; 70 71 /** 72 * Normal list that does not indicate choices 73 */ 74 public static final int CHOICE_MODE_NONE = 0; 75 76 /** 77 * The list allows up to one choice 78 */ 79 public static final int CHOICE_MODE_SINGLE = 1; 80 81 /** 82 * The list allows multiple choices 83 */ 84 public static final int CHOICE_MODE_MULTIPLE = 2; 85 86 /** 87 * When arrow scrolling, ListView will never scroll more than this factor 88 * times the height of the list. 89 */ 90 private static final float MAX_SCROLL_FACTOR = 0.33f; 91 92 /** 93 * When arrow scrolling, need a certain amount of pixels to preview next 94 * items. This is usually the fading edge, but if that is small enough, 95 * we want to make sure we preview at least this many pixels. 96 */ 97 private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; 98 99 /** 100 * A class that represents a fixed view in a list, for example a header at the top 101 * or a footer at the bottom. 102 */ 103 public class FixedViewInfo { 104 /** The view to add to the list */ 105 public View view; 106 /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ 107 public Object data; 108 /** <code>true</code> if the fixed view should be selectable in the list */ 109 public boolean isSelectable; 110 } 111 112 private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); 113 private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); 114 115 Drawable mDivider; 116 int mDividerHeight; 117 118 private boolean mIsCacheColorOpaque; 119 private boolean mDividerIsOpaque; 120 private boolean mClipDivider; 121 122 private boolean mHeaderDividersEnabled; 123 private boolean mFooterDividersEnabled; 124 125 private boolean mAreAllItemsSelectable = true; 126 127 private boolean mItemsCanFocus = false; 128 129 private int mChoiceMode = CHOICE_MODE_NONE; 130 131 private SparseBooleanArray mCheckStates; 132 133 // used for temporary calculations. 134 private final Rect mTempRect = new Rect(); 135 136 // the single allocated result per list view; kinda cheesey but avoids 137 // allocating these thingies too often. 138 private ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); 139 140 public ListView(Context context) { 141 this(context, null); 142 } 143 144 public ListView(Context context, AttributeSet attrs) { 145 this(context, attrs, com.android.internal.R.attr.listViewStyle); 146 } 147 148 public ListView(Context context, AttributeSet attrs, int defStyle) { 149 super(context, attrs, defStyle); 150 151 TypedArray a = context.obtainStyledAttributes(attrs, 152 com.android.internal.R.styleable.ListView, defStyle, 0); 153 154 CharSequence[] entries = a.getTextArray( 155 com.android.internal.R.styleable.ListView_entries); 156 if (entries != null) { 157 setAdapter(new ArrayAdapter<CharSequence>(context, 158 com.android.internal.R.layout.simple_list_item_1, entries)); 159 } 160 161 final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider); 162 if (d != null) { 163 // If a divider is specified use its intrinsic height for divider height 164 setDivider(d); 165 } 166 167 // Use the height specified, zero being the default 168 final int dividerHeight = a.getDimensionPixelSize( 169 com.android.internal.R.styleable.ListView_dividerHeight, 0); 170 if (dividerHeight != 0) { 171 setDividerHeight(dividerHeight); 172 } 173 174 mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); 175 mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); 176 177 a.recycle(); 178 } 179 180 /** 181 * @return The maximum amount a list view will scroll in response to 182 * an arrow event. 183 */ 184 public int getMaxScrollAmount() { 185 return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop)); 186 } 187 188 /** 189 * Make sure views are touching the top or bottom edge, as appropriate for 190 * our gravity 191 */ 192 private void adjustViewsUpOrDown() { 193 final int childCount = getChildCount(); 194 int delta; 195 196 if (childCount > 0) { 197 View child; 198 199 if (!mStackFromBottom) { 200 // Uh-oh -- we came up short. Slide all views up to make them 201 // align with the top 202 child = getChildAt(0); 203 delta = child.getTop() - mListPadding.top; 204 if (mFirstPosition != 0) { 205 // It's OK to have some space above the first item if it is 206 // part of the vertical spacing 207 delta -= mDividerHeight; 208 } 209 if (delta < 0) { 210 // We only are looking to see if we are too low, not too high 211 delta = 0; 212 } 213 } else { 214 // we are too high, slide all views down to align with bottom 215 child = getChildAt(childCount - 1); 216 delta = child.getBottom() - (getHeight() - mListPadding.bottom); 217 218 if (mFirstPosition + childCount < mItemCount) { 219 // It's OK to have some space below the last item if it is 220 // part of the vertical spacing 221 delta += mDividerHeight; 222 } 223 224 if (delta > 0) { 225 delta = 0; 226 } 227 } 228 229 if (delta != 0) { 230 offsetChildrenTopAndBottom(-delta); 231 } 232 } 233 } 234 235 /** 236 * Add a fixed view to appear at the top of the list. If addHeaderView is 237 * called more than once, the views will appear in the order they were 238 * added. Views added using this call can take focus if they want. 239 * <p> 240 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 241 * the supplied cursor with one that that will also account for header 242 * views. 243 * 244 * @param v The view to add. 245 * @param data Data to associate with this view 246 * @param isSelectable whether the item is selectable 247 */ 248 public void addHeaderView(View v, Object data, boolean isSelectable) { 249 250 if (mAdapter != null) { 251 throw new IllegalStateException( 252 "Cannot add header view to list -- setAdapter has already been called."); 253 } 254 255 FixedViewInfo info = new FixedViewInfo(); 256 info.view = v; 257 info.data = data; 258 info.isSelectable = isSelectable; 259 mHeaderViewInfos.add(info); 260 } 261 262 /** 263 * Add a fixed view to appear at the top of the list. If addHeaderView is 264 * called more than once, the views will appear in the order they were 265 * added. Views added using this call can take focus if they want. 266 * <p> 267 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 268 * the supplied cursor with one that that will also account for header 269 * views. 270 * 271 * @param v The view to add. 272 */ 273 public void addHeaderView(View v) { 274 addHeaderView(v, null, true); 275 } 276 277 @Override 278 public int getHeaderViewsCount() { 279 return mHeaderViewInfos.size(); 280 } 281 282 /** 283 * Removes a previously-added header view. 284 * 285 * @param v The view to remove 286 * @return true if the view was removed, false if the view was not a header 287 * view 288 */ 289 public boolean removeHeaderView(View v) { 290 if (mHeaderViewInfos.size() > 0) { 291 boolean result = false; 292 if (((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 293 mDataSetObserver.onChanged(); 294 result = true; 295 } 296 removeFixedViewInfo(v, mHeaderViewInfos); 297 return result; 298 } 299 return false; 300 } 301 302 private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { 303 int len = where.size(); 304 for (int i = 0; i < len; ++i) { 305 FixedViewInfo info = where.get(i); 306 if (info.view == v) { 307 where.remove(i); 308 break; 309 } 310 } 311 } 312 313 /** 314 * Add a fixed view to appear at the bottom of the list. If addFooterView is 315 * called more than once, the views will appear in the order they were 316 * added. Views added using this call can take focus if they want. 317 * <p> 318 * NOTE: Call this before calling setAdapter. This is so ListView can wrap 319 * the supplied cursor with one that that will also account for header 320 * views. 321 * 322 * @param v The view to add. 323 * @param data Data to associate with this view 324 * @param isSelectable true if the footer view can be selected 325 */ 326 public void addFooterView(View v, Object data, boolean isSelectable) { 327 FixedViewInfo info = new FixedViewInfo(); 328 info.view = v; 329 info.data = data; 330 info.isSelectable = isSelectable; 331 mFooterViewInfos.add(info); 332 333 // in the case of re-adding a footer view, or adding one later on, 334 // we need to notify the observer 335 if (mDataSetObserver != null) { 336 mDataSetObserver.onChanged(); 337 } 338 } 339 340 /** 341 * Add a fixed view to appear at the bottom of the list. If addFooterView is called more 342 * than once, the views will appear in the order they were added. Views added using 343 * this call can take focus if they want. 344 * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied 345 * cursor with one that that will also account for header views. 346 * 347 * 348 * @param v The view to add. 349 */ 350 public void addFooterView(View v) { 351 addFooterView(v, null, true); 352 } 353 354 @Override 355 public int getFooterViewsCount() { 356 return mFooterViewInfos.size(); 357 } 358 359 /** 360 * Removes a previously-added footer view. 361 * 362 * @param v The view to remove 363 * @return 364 * true if the view was removed, false if the view was not a footer view 365 */ 366 public boolean removeFooterView(View v) { 367 if (mFooterViewInfos.size() > 0) { 368 boolean result = false; 369 if (((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 370 mDataSetObserver.onChanged(); 371 result = true; 372 } 373 removeFixedViewInfo(v, mFooterViewInfos); 374 return result; 375 } 376 return false; 377 } 378 379 /** 380 * Returns the adapter currently in use in this ListView. The returned adapter 381 * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but 382 * might be a {@link WrapperListAdapter}. 383 * 384 * @return The adapter currently used to display data in this ListView. 385 * 386 * @see #setAdapter(ListAdapter) 387 */ 388 @Override 389 public ListAdapter getAdapter() { 390 return mAdapter; 391 } 392 393 /** 394 * Sets the data behind this ListView. 395 * 396 * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter}, 397 * depending on the ListView features currently in use. For instance, adding 398 * headers and/or footers will cause the adapter to be wrapped. 399 * 400 * @param adapter The ListAdapter which is responsible for maintaining the 401 * data backing this list and for producing a view to represent an 402 * item in that data set. 403 * 404 * @see #getAdapter() 405 */ 406 @Override 407 public void setAdapter(ListAdapter adapter) { 408 if (null != mAdapter) { 409 mAdapter.unregisterDataSetObserver(mDataSetObserver); 410 } 411 412 resetList(); 413 mRecycler.clear(); 414 415 if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) { 416 mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); 417 } else { 418 mAdapter = adapter; 419 } 420 421 mOldSelectedPosition = INVALID_POSITION; 422 mOldSelectedRowId = INVALID_ROW_ID; 423 if (mAdapter != null) { 424 mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); 425 mOldItemCount = mItemCount; 426 mItemCount = mAdapter.getCount(); 427 checkFocus(); 428 429 mDataSetObserver = new AdapterDataSetObserver(); 430 mAdapter.registerDataSetObserver(mDataSetObserver); 431 432 mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); 433 434 int position; 435 if (mStackFromBottom) { 436 position = lookForSelectablePosition(mItemCount - 1, false); 437 } else { 438 position = lookForSelectablePosition(0, true); 439 } 440 setSelectedPositionInt(position); 441 setNextSelectedPositionInt(position); 442 443 if (mItemCount == 0) { 444 // Nothing selected 445 checkSelectionChanged(); 446 } 447 448 } else { 449 mAreAllItemsSelectable = true; 450 checkFocus(); 451 // Nothing selected 452 checkSelectionChanged(); 453 } 454 455 if (mCheckStates != null) { 456 mCheckStates.clear(); 457 } 458 459 requestLayout(); 460 } 461 462 463 /** 464 * The list is empty. Clear everything out. 465 */ 466 @Override 467 void resetList() { 468 // The parent's resetList() will remove all views from the layout so we need to 469 // cleanup the state of our footers and headers 470 clearRecycledState(mHeaderViewInfos); 471 clearRecycledState(mFooterViewInfos); 472 473 super.resetList(); 474 475 mLayoutMode = LAYOUT_NORMAL; 476 } 477 478 private void clearRecycledState(ArrayList<FixedViewInfo> infos) { 479 if (infos != null) { 480 final int count = infos.size(); 481 482 for (int i = 0; i < count; i++) { 483 final View child = infos.get(i).view; 484 final LayoutParams p = (LayoutParams) child.getLayoutParams(); 485 if (p != null) { 486 p.recycledHeaderFooter = false; 487 } 488 } 489 } 490 } 491 492 /** 493 * @return Whether the list needs to show the top fading edge 494 */ 495 private boolean showingTopFadingEdge() { 496 final int listTop = mScrollY + mListPadding.top; 497 return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); 498 } 499 500 /** 501 * @return Whether the list needs to show the bottom fading edge 502 */ 503 private boolean showingBottomFadingEdge() { 504 final int childCount = getChildCount(); 505 final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 506 final int lastVisiblePosition = mFirstPosition + childCount - 1; 507 508 final int listBottom = mScrollY + getHeight() - mListPadding.bottom; 509 510 return (lastVisiblePosition < mItemCount - 1) 511 || (bottomOfBottomChild < listBottom); 512 } 513 514 515 @Override 516 public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { 517 518 int rectTopWithinChild = rect.top; 519 520 // offset so rect is in coordinates of the this view 521 rect.offset(child.getLeft(), child.getTop()); 522 rect.offset(-child.getScrollX(), -child.getScrollY()); 523 524 final int height = getHeight(); 525 int listUnfadedTop = getScrollY(); 526 int listUnfadedBottom = listUnfadedTop + height; 527 final int fadingEdge = getVerticalFadingEdgeLength(); 528 529 if (showingTopFadingEdge()) { 530 // leave room for top fading edge as long as rect isn't at very top 531 if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { 532 listUnfadedTop += fadingEdge; 533 } 534 } 535 536 int childCount = getChildCount(); 537 int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); 538 539 if (showingBottomFadingEdge()) { 540 // leave room for bottom fading edge as long as rect isn't at very bottom 541 if ((mSelectedPosition < mItemCount - 1) 542 || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { 543 listUnfadedBottom -= fadingEdge; 544 } 545 } 546 547 int scrollYDelta = 0; 548 549 if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { 550 // need to MOVE DOWN to get it in view: move down just enough so 551 // that the entire rectangle is in view (or at least the first 552 // screen size chunk). 553 554 if (rect.height() > height) { 555 // just enough to get screen size chunk on 556 scrollYDelta += (rect.top - listUnfadedTop); 557 } else { 558 // get entire rect at bottom of screen 559 scrollYDelta += (rect.bottom - listUnfadedBottom); 560 } 561 562 // make sure we aren't scrolling beyond the end of our children 563 int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; 564 scrollYDelta = Math.min(scrollYDelta, distanceToBottom); 565 } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { 566 // need to MOVE UP to get it in view: move up just enough so that 567 // entire rectangle is in view (or at least the first screen 568 // size chunk of it). 569 570 if (rect.height() > height) { 571 // screen size chunk 572 scrollYDelta -= (listUnfadedBottom - rect.bottom); 573 } else { 574 // entire rect at top 575 scrollYDelta -= (listUnfadedTop - rect.top); 576 } 577 578 // make sure we aren't scrolling any further than the top our children 579 int top = getChildAt(0).getTop(); 580 int deltaToTop = top - listUnfadedTop; 581 scrollYDelta = Math.max(scrollYDelta, deltaToTop); 582 } 583 584 final boolean scroll = scrollYDelta != 0; 585 if (scroll) { 586 scrollListItemsBy(-scrollYDelta); 587 positionSelector(child); 588 mSelectedTop = child.getTop(); 589 invalidate(); 590 } 591 return scroll; 592 } 593 594 /** 595 * {@inheritDoc} 596 */ 597 @Override 598 void fillGap(boolean down) { 599 final int count = getChildCount(); 600 if (down) { 601 final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : 602 getListPaddingTop(); 603 fillDown(mFirstPosition + count, startOffset); 604 correctTooHigh(getChildCount()); 605 } else { 606 final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : 607 getHeight() - getListPaddingBottom(); 608 fillUp(mFirstPosition - 1, startOffset); 609 correctTooLow(getChildCount()); 610 } 611 } 612 613 /** 614 * Fills the list from pos down to the end of the list view. 615 * 616 * @param pos The first position to put in the list 617 * 618 * @param nextTop The location where the top of the item associated with pos 619 * should be drawn 620 * 621 * @return The view that is currently selected, if it happens to be in the 622 * range that we draw. 623 */ 624 private View fillDown(int pos, int nextTop) { 625 View selectedView = null; 626 627 int end = (mBottom - mTop) - mListPadding.bottom; 628 629 while (nextTop < end && pos < mItemCount) { 630 // is this the selected item? 631 boolean selected = pos == mSelectedPosition; 632 View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); 633 634 nextTop = child.getBottom() + mDividerHeight; 635 if (selected) { 636 selectedView = child; 637 } 638 pos++; 639 } 640 641 return selectedView; 642 } 643 644 /** 645 * Fills the list from pos up to the top of the list view. 646 * 647 * @param pos The first position to put in the list 648 * 649 * @param nextBottom The location where the bottom of the item associated 650 * with pos should be drawn 651 * 652 * @return The view that is currently selected 653 */ 654 private View fillUp(int pos, int nextBottom) { 655 View selectedView = null; 656 657 int end = mListPadding.top; 658 659 while (nextBottom > end && pos >= 0) { 660 // is this the selected item? 661 boolean selected = pos == mSelectedPosition; 662 View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); 663 nextBottom = child.getTop() - mDividerHeight; 664 if (selected) { 665 selectedView = child; 666 } 667 pos--; 668 } 669 670 mFirstPosition = pos + 1; 671 672 return selectedView; 673 } 674 675 /** 676 * Fills the list from top to bottom, starting with mFirstPosition 677 * 678 * @param nextTop The location where the top of the first item should be 679 * drawn 680 * 681 * @return The view that is currently selected 682 */ 683 private View fillFromTop(int nextTop) { 684 mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); 685 mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); 686 if (mFirstPosition < 0) { 687 mFirstPosition = 0; 688 } 689 return fillDown(mFirstPosition, nextTop); 690 } 691 692 693 /** 694 * Put mSelectedPosition in the middle of the screen and then build up and 695 * down from there. This method forces mSelectedPosition to the center. 696 * 697 * @param childrenTop Top of the area in which children can be drawn, as 698 * measured in pixels 699 * @param childrenBottom Bottom of the area in which children can be drawn, 700 * as measured in pixels 701 * @return Currently selected view 702 */ 703 private View fillFromMiddle(int childrenTop, int childrenBottom) { 704 int height = childrenBottom - childrenTop; 705 706 int position = reconcileSelectedPosition(); 707 708 View sel = makeAndAddView(position, childrenTop, true, 709 mListPadding.left, true); 710 mFirstPosition = position; 711 712 int selHeight = sel.getMeasuredHeight(); 713 if (selHeight <= height) { 714 sel.offsetTopAndBottom((height - selHeight) / 2); 715 } 716 717 fillAboveAndBelow(sel, position); 718 719 if (!mStackFromBottom) { 720 correctTooHigh(getChildCount()); 721 } else { 722 correctTooLow(getChildCount()); 723 } 724 725 return sel; 726 } 727 728 /** 729 * Once the selected view as been placed, fill up the visible area above and 730 * below it. 731 * 732 * @param sel The selected view 733 * @param position The position corresponding to sel 734 */ 735 private void fillAboveAndBelow(View sel, int position) { 736 final int dividerHeight = mDividerHeight; 737 if (!mStackFromBottom) { 738 fillUp(position - 1, sel.getTop() - dividerHeight); 739 adjustViewsUpOrDown(); 740 fillDown(position + 1, sel.getBottom() + dividerHeight); 741 } else { 742 fillDown(position + 1, sel.getBottom() + dividerHeight); 743 adjustViewsUpOrDown(); 744 fillUp(position - 1, sel.getTop() - dividerHeight); 745 } 746 } 747 748 749 /** 750 * Fills the grid based on positioning the new selection at a specific 751 * location. The selection may be moved so that it does not intersect the 752 * faded edges. The grid is then filled upwards and downwards from there. 753 * 754 * @param selectedTop Where the selected item should be 755 * @param childrenTop Where to start drawing children 756 * @param childrenBottom Last pixel where children can be drawn 757 * @return The view that currently has selection 758 */ 759 private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { 760 int fadingEdgeLength = getVerticalFadingEdgeLength(); 761 final int selectedPosition = mSelectedPosition; 762 763 View sel; 764 765 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 766 selectedPosition); 767 final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, 768 selectedPosition); 769 770 sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); 771 772 773 // Some of the newly selected item extends below the bottom of the list 774 if (sel.getBottom() > bottomSelectionPixel) { 775 // Find space available above the selection into which we can scroll 776 // upwards 777 final int spaceAbove = sel.getTop() - topSelectionPixel; 778 779 // Find space required to bring the bottom of the selected item 780 // fully into view 781 final int spaceBelow = sel.getBottom() - bottomSelectionPixel; 782 final int offset = Math.min(spaceAbove, spaceBelow); 783 784 // Now offset the selected item to get it into view 785 sel.offsetTopAndBottom(-offset); 786 } else if (sel.getTop() < topSelectionPixel) { 787 // Find space required to bring the top of the selected item fully 788 // into view 789 final int spaceAbove = topSelectionPixel - sel.getTop(); 790 791 // Find space available below the selection into which we can scroll 792 // downwards 793 final int spaceBelow = bottomSelectionPixel - sel.getBottom(); 794 final int offset = Math.min(spaceAbove, spaceBelow); 795 796 // Offset the selected item to get it into view 797 sel.offsetTopAndBottom(offset); 798 } 799 800 // Fill in views above and below 801 fillAboveAndBelow(sel, selectedPosition); 802 803 if (!mStackFromBottom) { 804 correctTooHigh(getChildCount()); 805 } else { 806 correctTooLow(getChildCount()); 807 } 808 809 return sel; 810 } 811 812 /** 813 * Calculate the bottom-most pixel we can draw the selection into 814 * 815 * @param childrenBottom Bottom pixel were children can be drawn 816 * @param fadingEdgeLength Length of the fading edge in pixels, if present 817 * @param selectedPosition The position that will be selected 818 * @return The bottom-most pixel we can draw the selection into 819 */ 820 private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, 821 int selectedPosition) { 822 int bottomSelectionPixel = childrenBottom; 823 if (selectedPosition != mItemCount - 1) { 824 bottomSelectionPixel -= fadingEdgeLength; 825 } 826 return bottomSelectionPixel; 827 } 828 829 /** 830 * Calculate the top-most pixel we can draw the selection into 831 * 832 * @param childrenTop Top pixel were children can be drawn 833 * @param fadingEdgeLength Length of the fading edge in pixels, if present 834 * @param selectedPosition The position that will be selected 835 * @return The top-most pixel we can draw the selection into 836 */ 837 private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { 838 // first pixel we can draw the selection into 839 int topSelectionPixel = childrenTop; 840 if (selectedPosition > 0) { 841 topSelectionPixel += fadingEdgeLength; 842 } 843 return topSelectionPixel; 844 } 845 846 847 /** 848 * Fills the list based on positioning the new selection relative to the old 849 * selection. The new selection will be placed at, above, or below the 850 * location of the new selection depending on how the selection is moving. 851 * The selection will then be pinned to the visible part of the screen, 852 * excluding the edges that are faded. The list is then filled upwards and 853 * downwards from there. 854 * 855 * @param oldSel The old selected view. Useful for trying to put the new 856 * selection in the same place 857 * @param newSel The view that is to become selected. Useful for trying to 858 * put the new selection in the same place 859 * @param delta Which way we are moving 860 * @param childrenTop Where to start drawing children 861 * @param childrenBottom Last pixel where children can be drawn 862 * @return The view that currently has selection 863 */ 864 private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, 865 int childrenBottom) { 866 int fadingEdgeLength = getVerticalFadingEdgeLength(); 867 final int selectedPosition = mSelectedPosition; 868 869 View sel; 870 871 final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, 872 selectedPosition); 873 final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, 874 selectedPosition); 875 876 if (delta > 0) { 877 /* 878 * Case 1: Scrolling down. 879 */ 880 881 /* 882 * Before After 883 * | | | | 884 * +-------+ +-------+ 885 * | A | | A | 886 * | 1 | => +-------+ 887 * +-------+ | B | 888 * | B | | 2 | 889 * +-------+ +-------+ 890 * | | | | 891 * 892 * Try to keep the top of the previously selected item where it was. 893 * oldSel = A 894 * sel = B 895 */ 896 897 // Put oldSel (A) where it belongs 898 oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, 899 mListPadding.left, false); 900 901 final int dividerHeight = mDividerHeight; 902 903 // Now put the new selection (B) below that 904 sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, 905 mListPadding.left, true); 906 907 // Some of the newly selected item extends below the bottom of the list 908 if (sel.getBottom() > bottomSelectionPixel) { 909 910 // Find space available above the selection into which we can scroll upwards 911 int spaceAbove = sel.getTop() - topSelectionPixel; 912 913 // Find space required to bring the bottom of the selected item fully into view 914 int spaceBelow = sel.getBottom() - bottomSelectionPixel; 915 916 // Don't scroll more than half the height of the list 917 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 918 int offset = Math.min(spaceAbove, spaceBelow); 919 offset = Math.min(offset, halfVerticalSpace); 920 921 // We placed oldSel, so offset that item 922 oldSel.offsetTopAndBottom(-offset); 923 // Now offset the selected item to get it into view 924 sel.offsetTopAndBottom(-offset); 925 } 926 927 // Fill in views above and below 928 if (!mStackFromBottom) { 929 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 930 adjustViewsUpOrDown(); 931 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 932 } else { 933 fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); 934 adjustViewsUpOrDown(); 935 fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); 936 } 937 } else if (delta < 0) { 938 /* 939 * Case 2: Scrolling up. 940 */ 941 942 /* 943 * Before After 944 * | | | | 945 * +-------+ +-------+ 946 * | A | | A | 947 * +-------+ => | 1 | 948 * | B | +-------+ 949 * | 2 | | B | 950 * +-------+ +-------+ 951 * | | | | 952 * 953 * Try to keep the top of the item about to become selected where it was. 954 * newSel = A 955 * olSel = B 956 */ 957 958 if (newSel != null) { 959 // Try to position the top of newSel (A) where it was before it was selected 960 sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, 961 true); 962 } else { 963 // If (A) was not on screen and so did not have a view, position 964 // it above the oldSel (B) 965 sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, 966 true); 967 } 968 969 // Some of the newly selected item extends above the top of the list 970 if (sel.getTop() < topSelectionPixel) { 971 // Find space required to bring the top of the selected item fully into view 972 int spaceAbove = topSelectionPixel - sel.getTop(); 973 974 // Find space available below the selection into which we can scroll downwards 975 int spaceBelow = bottomSelectionPixel - sel.getBottom(); 976 977 // Don't scroll more than half the height of the list 978 int halfVerticalSpace = (childrenBottom - childrenTop) / 2; 979 int offset = Math.min(spaceAbove, spaceBelow); 980 offset = Math.min(offset, halfVerticalSpace); 981 982 // Offset the selected item to get it into view 983 sel.offsetTopAndBottom(offset); 984 } 985 986 // Fill in views above and below 987 fillAboveAndBelow(sel, selectedPosition); 988 } else { 989 990 int oldTop = oldSel.getTop(); 991 992 /* 993 * Case 3: Staying still 994 */ 995 sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); 996 997 // We're staying still... 998 if (oldTop < childrenTop) { 999 // ... but the top of the old selection was off screen. 1000 // (This can happen if the data changes size out from under us) 1001 int newBottom = sel.getBottom(); 1002 if (newBottom < childrenTop + 20) { 1003 // Not enough visible -- bring it onscreen 1004 sel.offsetTopAndBottom(childrenTop - sel.getTop()); 1005 } 1006 } 1007 1008 // Fill in views above and below 1009 fillAboveAndBelow(sel, selectedPosition); 1010 } 1011 1012 return sel; 1013 } 1014 1015 @Override 1016 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 1017 // Sets up mListPadding 1018 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 1019 1020 int widthMode = MeasureSpec.getMode(widthMeasureSpec); 1021 int heightMode = MeasureSpec.getMode(heightMeasureSpec); 1022 int widthSize = MeasureSpec.getSize(widthMeasureSpec); 1023 int heightSize = MeasureSpec.getSize(heightMeasureSpec); 1024 1025 int childWidth = 0; 1026 int childHeight = 0; 1027 1028 mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); 1029 if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || 1030 heightMode == MeasureSpec.UNSPECIFIED)) { 1031 final View child = obtainView(0); 1032 1033 measureScrapChild(child, 0, widthMeasureSpec); 1034 1035 childWidth = child.getMeasuredWidth(); 1036 childHeight = child.getMeasuredHeight(); 1037 1038 if (recycleOnMeasure()) { 1039 mRecycler.addScrapView(child); 1040 } 1041 } 1042 1043 if (widthMode == MeasureSpec.UNSPECIFIED) { 1044 widthSize = mListPadding.left + mListPadding.right + childWidth + 1045 getVerticalScrollbarWidth(); 1046 } 1047 1048 if (heightMode == MeasureSpec.UNSPECIFIED) { 1049 heightSize = mListPadding.top + mListPadding.bottom + childHeight + 1050 getVerticalFadingEdgeLength() * 2; 1051 } 1052 1053 if (heightMode == MeasureSpec.AT_MOST) { 1054 // TODO: after first layout we should maybe start at the first visible position, not 0 1055 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); 1056 } 1057 1058 setMeasuredDimension(widthSize, heightSize); 1059 mWidthMeasureSpec = widthMeasureSpec; 1060 } 1061 1062 private void measureScrapChild(View child, int position, int widthMeasureSpec) { 1063 LayoutParams p = (LayoutParams) child.getLayoutParams(); 1064 if (p == null) { 1065 p = new LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 1066 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1067 child.setLayoutParams(p); 1068 } 1069 p.viewType = mAdapter.getItemViewType(position); 1070 1071 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, 1072 mListPadding.left + mListPadding.right, p.width); 1073 int lpHeight = p.height; 1074 int childHeightSpec; 1075 if (lpHeight > 0) { 1076 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1077 } else { 1078 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1079 } 1080 child.measure(childWidthSpec, childHeightSpec); 1081 } 1082 1083 /** 1084 * @return True to recycle the views used to measure this ListView in 1085 * UNSPECIFIED/AT_MOST modes, false otherwise. 1086 * @hide 1087 */ 1088 @ViewDebug.ExportedProperty 1089 protected boolean recycleOnMeasure() { 1090 return true; 1091 } 1092 1093 /** 1094 * Measures the height of the given range of children (inclusive) and 1095 * returns the height with this ListView's padding and divider heights 1096 * included. If maxHeight is provided, the measuring will stop when the 1097 * current height reaches maxHeight. 1098 * 1099 * @param widthMeasureSpec The width measure spec to be given to a child's 1100 * {@link View#measure(int, int)}. 1101 * @param startPosition The position of the first child to be shown. 1102 * @param endPosition The (inclusive) position of the last child to be 1103 * shown. Specify {@link #NO_POSITION} if the last child should be 1104 * the last available child from the adapter. 1105 * @param maxHeight The maximum height that will be returned (if all the 1106 * children don't fit in this value, this value will be 1107 * returned). 1108 * @param disallowPartialChildPosition In general, whether the returned 1109 * height should only contain entire children. This is more 1110 * powerful--it is the first inclusive position at which partial 1111 * children will not be allowed. Example: it looks nice to have 1112 * at least 3 completely visible children, and in portrait this 1113 * will most likely fit; but in landscape there could be times 1114 * when even 2 children can not be completely shown, so a value 1115 * of 2 (remember, inclusive) would be good (assuming 1116 * startPosition is 0). 1117 * @return The height of this ListView with the given children. 1118 */ 1119 final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, 1120 final int maxHeight, int disallowPartialChildPosition) { 1121 1122 final ListAdapter adapter = mAdapter; 1123 if (adapter == null) { 1124 return mListPadding.top + mListPadding.bottom; 1125 } 1126 1127 // Include the padding of the list 1128 int returnedHeight = mListPadding.top + mListPadding.bottom; 1129 final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; 1130 // The previous height value that was less than maxHeight and contained 1131 // no partial children 1132 int prevHeightWithoutPartialChild = 0; 1133 int i; 1134 View child; 1135 1136 // mItemCount - 1 since endPosition parameter is inclusive 1137 endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; 1138 final AbsListView.RecycleBin recycleBin = mRecycler; 1139 final boolean recyle = recycleOnMeasure(); 1140 1141 for (i = startPosition; i <= endPosition; ++i) { 1142 child = obtainView(i); 1143 1144 measureScrapChild(child, i, widthMeasureSpec); 1145 1146 if (i > 0) { 1147 // Count the divider for all but one child 1148 returnedHeight += dividerHeight; 1149 } 1150 1151 // Recycle the view before we possibly return from the method 1152 if (recyle) { 1153 recycleBin.addScrapView(child); 1154 } 1155 1156 returnedHeight += child.getMeasuredHeight(); 1157 1158 if (returnedHeight >= maxHeight) { 1159 // We went over, figure out which height to return. If returnedHeight > maxHeight, 1160 // then the i'th position did not fit completely. 1161 return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) 1162 && (i > disallowPartialChildPosition) // We've past the min pos 1163 && (prevHeightWithoutPartialChild > 0) // We have a prev height 1164 && (returnedHeight != maxHeight) // i'th child did not fit completely 1165 ? prevHeightWithoutPartialChild 1166 : maxHeight; 1167 } 1168 1169 if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { 1170 prevHeightWithoutPartialChild = returnedHeight; 1171 } 1172 } 1173 1174 // At this point, we went through the range of children, and they each 1175 // completely fit, so return the returnedHeight 1176 return returnedHeight; 1177 } 1178 1179 @Override 1180 int findMotionRow(int y) { 1181 int childCount = getChildCount(); 1182 if (childCount > 0) { 1183 for (int i = 0; i < childCount; i++) { 1184 View v = getChildAt(i); 1185 if (y <= v.getBottom()) { 1186 return mFirstPosition + i; 1187 } 1188 } 1189 return mFirstPosition + childCount - 1; 1190 } 1191 return INVALID_POSITION; 1192 } 1193 1194 /** 1195 * Put a specific item at a specific location on the screen and then build 1196 * up and down from there. 1197 * 1198 * @param position The reference view to use as the starting point 1199 * @param top Pixel offset from the top of this view to the top of the 1200 * reference view. 1201 * 1202 * @return The selected view, or null if the selected view is outside the 1203 * visible area. 1204 */ 1205 private View fillSpecific(int position, int top) { 1206 boolean tempIsSelected = position == mSelectedPosition; 1207 View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); 1208 // Possibly changed again in fillUp if we add rows above this one. 1209 mFirstPosition = position; 1210 1211 View above; 1212 View below; 1213 1214 final int dividerHeight = mDividerHeight; 1215 if (!mStackFromBottom) { 1216 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1217 // This will correct for the top of the first view not touching the top of the list 1218 adjustViewsUpOrDown(); 1219 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1220 int childCount = getChildCount(); 1221 if (childCount > 0) { 1222 correctTooHigh(childCount); 1223 } 1224 } else { 1225 below = fillDown(position + 1, temp.getBottom() + dividerHeight); 1226 // This will correct for the bottom of the last view not touching the bottom of the list 1227 adjustViewsUpOrDown(); 1228 above = fillUp(position - 1, temp.getTop() - dividerHeight); 1229 int childCount = getChildCount(); 1230 if (childCount > 0) { 1231 correctTooLow(childCount); 1232 } 1233 } 1234 1235 if (tempIsSelected) { 1236 return temp; 1237 } else if (above != null) { 1238 return above; 1239 } else { 1240 return below; 1241 } 1242 } 1243 1244 /** 1245 * Check if we have dragged the bottom of the list too high (we have pushed the 1246 * top element off the top of the screen when we did not need to). Correct by sliding 1247 * everything back down. 1248 * 1249 * @param childCount Number of children 1250 */ 1251 private void correctTooHigh(int childCount) { 1252 // First see if the last item is visible. If it is not, it is OK for the 1253 // top of the list to be pushed up. 1254 int lastPosition = mFirstPosition + childCount - 1; 1255 if (lastPosition == mItemCount - 1 && childCount > 0) { 1256 1257 // Get the last child ... 1258 final View lastChild = getChildAt(childCount - 1); 1259 1260 // ... and its bottom edge 1261 final int lastBottom = lastChild.getBottom(); 1262 1263 // This is bottom of our drawable area 1264 final int end = (mBottom - mTop) - mListPadding.bottom; 1265 1266 // This is how far the bottom edge of the last view is from the bottom of the 1267 // drawable area 1268 int bottomOffset = end - lastBottom; 1269 View firstChild = getChildAt(0); 1270 final int firstTop = firstChild.getTop(); 1271 1272 // Make sure we are 1) Too high, and 2) Either there are more rows above the 1273 // first row or the first row is scrolled off the top of the drawable area 1274 if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { 1275 if (mFirstPosition == 0) { 1276 // Don't pull the top too far down 1277 bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); 1278 } 1279 // Move everything down 1280 offsetChildrenTopAndBottom(bottomOffset); 1281 if (mFirstPosition > 0) { 1282 // Fill the gap that was opened above mFirstPosition with more rows, if 1283 // possible 1284 fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); 1285 // Close up the remaining gap 1286 adjustViewsUpOrDown(); 1287 } 1288 1289 } 1290 } 1291 } 1292 1293 /** 1294 * Check if we have dragged the bottom of the list too low (we have pushed the 1295 * bottom element off the bottom of the screen when we did not need to). Correct by sliding 1296 * everything back up. 1297 * 1298 * @param childCount Number of children 1299 */ 1300 private void correctTooLow(int childCount) { 1301 // First see if the first item is visible. If it is not, it is OK for the 1302 // bottom of the list to be pushed down. 1303 if (mFirstPosition == 0 && childCount > 0) { 1304 1305 // Get the first child ... 1306 final View firstChild = getChildAt(0); 1307 1308 // ... and its top edge 1309 final int firstTop = firstChild.getTop(); 1310 1311 // This is top of our drawable area 1312 final int start = mListPadding.top; 1313 1314 // This is bottom of our drawable area 1315 final int end = (mBottom - mTop) - mListPadding.bottom; 1316 1317 // This is how far the top edge of the first view is from the top of the 1318 // drawable area 1319 int topOffset = firstTop - start; 1320 View lastChild = getChildAt(childCount - 1); 1321 final int lastBottom = lastChild.getBottom(); 1322 int lastPosition = mFirstPosition + childCount - 1; 1323 1324 // Make sure we are 1) Too low, and 2) Either there are more rows below the 1325 // last row or the last row is scrolled off the bottom of the drawable area 1326 if (topOffset > 0 && (lastPosition < mItemCount - 1 || lastBottom > end)) { 1327 if (lastPosition == mItemCount - 1 ) { 1328 // Don't pull the bottom too far up 1329 topOffset = Math.min(topOffset, lastBottom - end); 1330 } 1331 // Move everything up 1332 offsetChildrenTopAndBottom(-topOffset); 1333 if (lastPosition < mItemCount - 1) { 1334 // Fill the gap that was opened below the last position with more rows, if 1335 // possible 1336 fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); 1337 // Close up the remaining gap 1338 adjustViewsUpOrDown(); 1339 } 1340 } 1341 } 1342 } 1343 1344 @Override 1345 protected void layoutChildren() { 1346 final boolean blockLayoutRequests = mBlockLayoutRequests; 1347 if (!blockLayoutRequests) { 1348 mBlockLayoutRequests = true; 1349 } else { 1350 return; 1351 } 1352 1353 try { 1354 super.layoutChildren(); 1355 1356 invalidate(); 1357 1358 if (mAdapter == null) { 1359 resetList(); 1360 invokeOnItemScrollListener(); 1361 return; 1362 } 1363 1364 int childrenTop = mListPadding.top; 1365 int childrenBottom = mBottom - mTop - mListPadding.bottom; 1366 1367 int childCount = getChildCount(); 1368 int index; 1369 int delta = 0; 1370 1371 View sel; 1372 View oldSel = null; 1373 View oldFirst = null; 1374 View newSel = null; 1375 1376 View focusLayoutRestoreView = null; 1377 1378 // Remember stuff we will need down below 1379 switch (mLayoutMode) { 1380 case LAYOUT_SET_SELECTION: 1381 index = mNextSelectedPosition - mFirstPosition; 1382 if (index >= 0 && index < childCount) { 1383 newSel = getChildAt(index); 1384 } 1385 break; 1386 case LAYOUT_FORCE_TOP: 1387 case LAYOUT_FORCE_BOTTOM: 1388 case LAYOUT_SPECIFIC: 1389 case LAYOUT_SYNC: 1390 break; 1391 case LAYOUT_MOVE_SELECTION: 1392 default: 1393 // Remember the previously selected view 1394 index = mSelectedPosition - mFirstPosition; 1395 if (index >= 0 && index < childCount) { 1396 oldSel = getChildAt(index); 1397 } 1398 1399 // Remember the previous first child 1400 oldFirst = getChildAt(0); 1401 1402 if (mNextSelectedPosition >= 0) { 1403 delta = mNextSelectedPosition - mSelectedPosition; 1404 } 1405 1406 // Caution: newSel might be null 1407 newSel = getChildAt(index + delta); 1408 } 1409 1410 1411 boolean dataChanged = mDataChanged; 1412 if (dataChanged) { 1413 handleDataChanged(); 1414 } 1415 1416 // Handle the empty set by removing all views that are visible 1417 // and calling it a day 1418 if (mItemCount == 0) { 1419 resetList(); 1420 invokeOnItemScrollListener(); 1421 return; 1422 } else if (mItemCount != mAdapter.getCount()) { 1423 throw new IllegalStateException("The content of the adapter has changed but " 1424 + "ListView did not receive a notification. Make sure the content of " 1425 + "your adapter is not modified from a background thread, but only " 1426 + "from the UI thread."); 1427 } 1428 1429 setSelectedPositionInt(mNextSelectedPosition); 1430 1431 // Pull all children into the RecycleBin. 1432 // These views will be reused if possible 1433 final int firstPosition = mFirstPosition; 1434 final RecycleBin recycleBin = mRecycler; 1435 1436 // reset the focus restoration 1437 View focusLayoutRestoreDirectChild = null; 1438 1439 1440 // Don't put header or footer views into the Recycler. Those are 1441 // already cached in mHeaderViews; 1442 if (dataChanged) { 1443 for (int i = 0; i < childCount; i++) { 1444 recycleBin.addScrapView(getChildAt(i)); 1445 if (ViewDebug.TRACE_RECYCLER) { 1446 ViewDebug.trace(getChildAt(i), 1447 ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i); 1448 } 1449 } 1450 } else { 1451 recycleBin.fillActiveViews(childCount, firstPosition); 1452 } 1453 1454 // take focus back to us temporarily to avoid the eventual 1455 // call to clear focus when removing the focused child below 1456 // from messing things up when ViewRoot assigns focus back 1457 // to someone else 1458 final View focusedChild = getFocusedChild(); 1459 if (focusedChild != null) { 1460 // TODO: in some cases focusedChild.getParent() == null 1461 1462 // we can remember the focused view to restore after relayout if the 1463 // data hasn't changed, or if the focused position is a header or footer 1464 if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { 1465 focusLayoutRestoreDirectChild = focusedChild; 1466 // remember the specific view that had focus 1467 focusLayoutRestoreView = findFocus(); 1468 if (focusLayoutRestoreView != null) { 1469 // tell it we are going to mess with it 1470 focusLayoutRestoreView.onStartTemporaryDetach(); 1471 } 1472 } 1473 requestFocus(); 1474 } 1475 1476 // Clear out old views 1477 //removeAllViewsInLayout(); 1478 detachAllViewsFromParent(); 1479 1480 switch (mLayoutMode) { 1481 case LAYOUT_SET_SELECTION: 1482 if (newSel != null) { 1483 sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); 1484 } else { 1485 sel = fillFromMiddle(childrenTop, childrenBottom); 1486 } 1487 break; 1488 case LAYOUT_SYNC: 1489 sel = fillSpecific(mSyncPosition, mSpecificTop); 1490 break; 1491 case LAYOUT_FORCE_BOTTOM: 1492 sel = fillUp(mItemCount - 1, childrenBottom); 1493 adjustViewsUpOrDown(); 1494 break; 1495 case LAYOUT_FORCE_TOP: 1496 mFirstPosition = 0; 1497 sel = fillFromTop(childrenTop); 1498 adjustViewsUpOrDown(); 1499 break; 1500 case LAYOUT_SPECIFIC: 1501 sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); 1502 break; 1503 case LAYOUT_MOVE_SELECTION: 1504 sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); 1505 break; 1506 default: 1507 if (childCount == 0) { 1508 if (!mStackFromBottom) { 1509 final int position = lookForSelectablePosition(0, true); 1510 setSelectedPositionInt(position); 1511 sel = fillFromTop(childrenTop); 1512 } else { 1513 final int position = lookForSelectablePosition(mItemCount - 1, false); 1514 setSelectedPositionInt(position); 1515 sel = fillUp(mItemCount - 1, childrenBottom); 1516 } 1517 } else { 1518 if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { 1519 sel = fillSpecific(mSelectedPosition, 1520 oldSel == null ? childrenTop : oldSel.getTop()); 1521 } else if (mFirstPosition < mItemCount) { 1522 sel = fillSpecific(mFirstPosition, 1523 oldFirst == null ? childrenTop : oldFirst.getTop()); 1524 } else { 1525 sel = fillSpecific(0, childrenTop); 1526 } 1527 } 1528 break; 1529 } 1530 1531 // Flush any cached views that did not get reused above 1532 recycleBin.scrapActiveViews(); 1533 1534 if (sel != null) { 1535 // the current selected item should get focus if items 1536 // are focusable 1537 if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { 1538 final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && 1539 focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); 1540 if (!focusWasTaken) { 1541 // selected item didn't take focus, fine, but still want 1542 // to make sure something else outside of the selected view 1543 // has focus 1544 final View focused = getFocusedChild(); 1545 if (focused != null) { 1546 focused.clearFocus(); 1547 } 1548 positionSelector(sel); 1549 } else { 1550 sel.setSelected(false); 1551 mSelectorRect.setEmpty(); 1552 } 1553 } else { 1554 positionSelector(sel); 1555 } 1556 mSelectedTop = sel.getTop(); 1557 } else { 1558 mSelectedTop = 0; 1559 mSelectorRect.setEmpty(); 1560 1561 // even if there is not selected position, we may need to restore 1562 // focus (i.e. something focusable in touch mode) 1563 if (hasFocus() && focusLayoutRestoreView != null) { 1564 focusLayoutRestoreView.requestFocus(); 1565 } 1566 } 1567 1568 // tell focus view we are done mucking with it, if it is still in 1569 // our view hierarchy. 1570 if (focusLayoutRestoreView != null 1571 && focusLayoutRestoreView.getWindowToken() != null) { 1572 focusLayoutRestoreView.onFinishTemporaryDetach(); 1573 } 1574 1575 mLayoutMode = LAYOUT_NORMAL; 1576 mDataChanged = false; 1577 mNeedSync = false; 1578 setNextSelectedPositionInt(mSelectedPosition); 1579 1580 updateScrollIndicators(); 1581 1582 if (mItemCount > 0) { 1583 checkSelectionChanged(); 1584 } 1585 1586 invokeOnItemScrollListener(); 1587 } finally { 1588 if (!blockLayoutRequests) { 1589 mBlockLayoutRequests = false; 1590 } 1591 } 1592 } 1593 1594 /** 1595 * @param child a direct child of this list. 1596 * @return Whether child is a header or footer view. 1597 */ 1598 private boolean isDirectChildHeaderOrFooter(View child) { 1599 1600 final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; 1601 final int numHeaders = headers.size(); 1602 for (int i = 0; i < numHeaders; i++) { 1603 if (child == headers.get(i).view) { 1604 return true; 1605 } 1606 } 1607 final ArrayList<FixedViewInfo> footers = mFooterViewInfos; 1608 final int numFooters = footers.size(); 1609 for (int i = 0; i < numFooters; i++) { 1610 if (child == footers.get(i).view) { 1611 return true; 1612 } 1613 } 1614 return false; 1615 } 1616 1617 /** 1618 * Obtain the view and add it to our list of children. The view can be made 1619 * fresh, converted from an unused view, or used as is if it was in the 1620 * recycle bin. 1621 * 1622 * @param position Logical position in the list 1623 * @param y Top or bottom edge of the view to add 1624 * @param flow If flow is true, align top edge to y. If false, align bottom 1625 * edge to y. 1626 * @param childrenLeft Left edge where children should be positioned 1627 * @param selected Is this position selected? 1628 * @return View that was added 1629 */ 1630 private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, 1631 boolean selected) { 1632 View child; 1633 1634 1635 if (!mDataChanged) { 1636 // Try to use an exsiting view for this position 1637 child = mRecycler.getActiveView(position); 1638 if (child != null) { 1639 if (ViewDebug.TRACE_RECYCLER) { 1640 ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, 1641 position, getChildCount()); 1642 } 1643 1644 // Found it -- we're using an existing child 1645 // This just needs to be positioned 1646 setupChild(child, position, y, flow, childrenLeft, selected, true); 1647 1648 return child; 1649 } 1650 } 1651 1652 // Make a new view for this position, or convert an unused view if possible 1653 child = obtainView(position); 1654 1655 // This needs to be positioned and measured 1656 setupChild(child, position, y, flow, childrenLeft, selected, false); 1657 1658 return child; 1659 } 1660 1661 /** 1662 * Add a view as a child and make sure it is measured (if necessary) and 1663 * positioned properly. 1664 * 1665 * @param child The view to add 1666 * @param position The position of this child 1667 * @param y The y position relative to which this view will be positioned 1668 * @param flowDown If true, align top edge to y. If false, align bottom 1669 * edge to y. 1670 * @param childrenLeft Left edge where children should be positioned 1671 * @param selected Is this position selected? 1672 * @param recycled Has this view been pulled from the recycle bin? If so it 1673 * does not need to be remeasured. 1674 */ 1675 private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, 1676 boolean selected, boolean recycled) { 1677 final boolean isSelected = selected && shouldShowSelector(); 1678 final boolean updateChildSelected = isSelected != child.isSelected(); 1679 final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); 1680 1681 // Respect layout params that are already in the view. Otherwise make some up... 1682 // noinspection unchecked 1683 AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); 1684 if (p == null) { 1685 p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 1686 ViewGroup.LayoutParams.WRAP_CONTENT, 0); 1687 } 1688 p.viewType = mAdapter.getItemViewType(position); 1689 1690 if (recycled || (p.recycledHeaderFooter && 1691 p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { 1692 attachViewToParent(child, flowDown ? -1 : 0, p); 1693 } else { 1694 if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { 1695 p.recycledHeaderFooter = true; 1696 } 1697 addViewInLayout(child, flowDown ? -1 : 0, p, true); 1698 } 1699 1700 if (updateChildSelected) { 1701 child.setSelected(isSelected); 1702 } 1703 1704 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 1705 if (child instanceof Checkable) { 1706 ((Checkable) child).setChecked(mCheckStates.get(position)); 1707 } 1708 } 1709 1710 if (needToMeasure) { 1711 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 1712 mListPadding.left + mListPadding.right, p.width); 1713 int lpHeight = p.height; 1714 int childHeightSpec; 1715 if (lpHeight > 0) { 1716 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 1717 } else { 1718 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 1719 } 1720 child.measure(childWidthSpec, childHeightSpec); 1721 } else { 1722 cleanupLayoutState(child); 1723 } 1724 1725 final int w = child.getMeasuredWidth(); 1726 final int h = child.getMeasuredHeight(); 1727 final int childTop = flowDown ? y : y - h; 1728 1729 if (needToMeasure) { 1730 final int childRight = childrenLeft + w; 1731 final int childBottom = childTop + h; 1732 child.layout(childrenLeft, childTop, childRight, childBottom); 1733 } else { 1734 child.offsetLeftAndRight(childrenLeft - child.getLeft()); 1735 child.offsetTopAndBottom(childTop - child.getTop()); 1736 } 1737 1738 if (mCachingStarted && !child.isDrawingCacheEnabled()) { 1739 child.setDrawingCacheEnabled(true); 1740 } 1741 } 1742 1743 @Override 1744 protected boolean canAnimate() { 1745 return super.canAnimate() && mItemCount > 0; 1746 } 1747 1748 /** 1749 * Sets the currently selected item. If in touch mode, the item will not be selected 1750 * but it will still be positioned appropriately. If the specified selection position 1751 * is less than 0, then the item at position 0 will be selected. 1752 * 1753 * @param position Index (starting at 0) of the data item to be selected. 1754 */ 1755 @Override 1756 public void setSelection(int position) { 1757 setSelectionFromTop(position, 0); 1758 } 1759 1760 /** 1761 * Sets the selected item and positions the selection y pixels from the top edge 1762 * of the ListView. (If in touch mode, the item will not be selected but it will 1763 * still be positioned appropriately.) 1764 * 1765 * @param position Index (starting at 0) of the data item to be selected. 1766 * @param y The distance from the top edge of the ListView (plus padding) that the 1767 * item will be positioned. 1768 */ 1769 public void setSelectionFromTop(int position, int y) { 1770 if (mAdapter == null) { 1771 return; 1772 } 1773 1774 if (!isInTouchMode()) { 1775 position = lookForSelectablePosition(position, true); 1776 if (position >= 0) { 1777 setNextSelectedPositionInt(position); 1778 } 1779 } else { 1780 mResurrectToPosition = position; 1781 } 1782 1783 if (position >= 0) { 1784 mLayoutMode = LAYOUT_SPECIFIC; 1785 mSpecificTop = mListPadding.top + y; 1786 1787 if (mNeedSync) { 1788 mSyncPosition = position; 1789 mSyncRowId = mAdapter.getItemId(position); 1790 } 1791 1792 requestLayout(); 1793 } 1794 } 1795 1796 /** 1797 * Makes the item at the supplied position selected. 1798 * 1799 * @param position the position of the item to select 1800 */ 1801 @Override 1802 void setSelectionInt(int position) { 1803 setNextSelectedPositionInt(position); 1804 layoutChildren(); 1805 } 1806 1807 /** 1808 * Find a position that can be selected (i.e., is not a separator). 1809 * 1810 * @param position The starting position to look at. 1811 * @param lookDown Whether to look down for other positions. 1812 * @return The next selectable position starting at position and then searching either up or 1813 * down. Returns {@link #INVALID_POSITION} if nothing can be found. 1814 */ 1815 @Override 1816 int lookForSelectablePosition(int position, boolean lookDown) { 1817 final ListAdapter adapter = mAdapter; 1818 if (adapter == null || isInTouchMode()) { 1819 return INVALID_POSITION; 1820 } 1821 1822 final int count = adapter.getCount(); 1823 if (!mAreAllItemsSelectable) { 1824 if (lookDown) { 1825 position = Math.max(0, position); 1826 while (position < count && !adapter.isEnabled(position)) { 1827 position++; 1828 } 1829 } else { 1830 position = Math.min(position, count - 1); 1831 while (position >= 0 && !adapter.isEnabled(position)) { 1832 position--; 1833 } 1834 } 1835 1836 if (position < 0 || position >= count) { 1837 return INVALID_POSITION; 1838 } 1839 return position; 1840 } else { 1841 if (position < 0 || position >= count) { 1842 return INVALID_POSITION; 1843 } 1844 return position; 1845 } 1846 } 1847 1848 /** 1849 * setSelectionAfterHeaderView set the selection to be the first list item 1850 * after the header views. 1851 */ 1852 public void setSelectionAfterHeaderView() { 1853 final int count = mHeaderViewInfos.size(); 1854 if (count > 0) { 1855 mNextSelectedPosition = 0; 1856 return; 1857 } 1858 1859 if (mAdapter != null) { 1860 setSelection(count); 1861 } else { 1862 mNextSelectedPosition = count; 1863 mLayoutMode = LAYOUT_SET_SELECTION; 1864 } 1865 1866 } 1867 1868 @Override 1869 public boolean dispatchKeyEvent(KeyEvent event) { 1870 // Dispatch in the normal way 1871 boolean handled = super.dispatchKeyEvent(event); 1872 if (!handled) { 1873 // If we didn't handle it... 1874 View focused = getFocusedChild(); 1875 if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { 1876 // ... and our focused child didn't handle it 1877 // ... give it to ourselves so we can scroll if necessary 1878 handled = onKeyDown(event.getKeyCode(), event); 1879 } 1880 } 1881 return handled; 1882 } 1883 1884 @Override 1885 public boolean onKeyDown(int keyCode, KeyEvent event) { 1886 return commonKey(keyCode, 1, event); 1887 } 1888 1889 @Override 1890 public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { 1891 return commonKey(keyCode, repeatCount, event); 1892 } 1893 1894 @Override 1895 public boolean onKeyUp(int keyCode, KeyEvent event) { 1896 return commonKey(keyCode, 1, event); 1897 } 1898 1899 private boolean commonKey(int keyCode, int count, KeyEvent event) { 1900 if (mAdapter == null) { 1901 return false; 1902 } 1903 1904 if (mDataChanged) { 1905 layoutChildren(); 1906 } 1907 1908 boolean handled = false; 1909 int action = event.getAction(); 1910 1911 if (action != KeyEvent.ACTION_UP) { 1912 if (mSelectedPosition < 0) { 1913 switch (keyCode) { 1914 case KeyEvent.KEYCODE_DPAD_UP: 1915 case KeyEvent.KEYCODE_DPAD_DOWN: 1916 case KeyEvent.KEYCODE_DPAD_CENTER: 1917 case KeyEvent.KEYCODE_ENTER: 1918 case KeyEvent.KEYCODE_SPACE: 1919 if (resurrectSelection()) { 1920 return true; 1921 } 1922 } 1923 } 1924 switch (keyCode) { 1925 case KeyEvent.KEYCODE_DPAD_UP: 1926 if (!event.isAltPressed()) { 1927 while (count > 0) { 1928 handled = arrowScroll(FOCUS_UP); 1929 count--; 1930 } 1931 } else { 1932 handled = fullScroll(FOCUS_UP); 1933 } 1934 break; 1935 1936 case KeyEvent.KEYCODE_DPAD_DOWN: 1937 if (!event.isAltPressed()) { 1938 while (count > 0) { 1939 handled = arrowScroll(FOCUS_DOWN); 1940 count--; 1941 } 1942 } else { 1943 handled = fullScroll(FOCUS_DOWN); 1944 } 1945 break; 1946 1947 case KeyEvent.KEYCODE_DPAD_LEFT: 1948 handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); 1949 break; 1950 case KeyEvent.KEYCODE_DPAD_RIGHT: 1951 handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); 1952 break; 1953 1954 case KeyEvent.KEYCODE_DPAD_CENTER: 1955 case KeyEvent.KEYCODE_ENTER: 1956 if (mItemCount > 0 && event.getRepeatCount() == 0) { 1957 keyPressed(); 1958 } 1959 handled = true; 1960 break; 1961 1962 case KeyEvent.KEYCODE_SPACE: 1963 if (mPopup == null || !mPopup.isShowing()) { 1964 if (!event.isShiftPressed()) { 1965 pageScroll(FOCUS_DOWN); 1966 } else { 1967 pageScroll(FOCUS_UP); 1968 } 1969 handled = true; 1970 } 1971 break; 1972 } 1973 } 1974 1975 if (!handled) { 1976 handled = sendToTextFilter(keyCode, count, event); 1977 } 1978 1979 if (handled) { 1980 return true; 1981 } else { 1982 switch (action) { 1983 case KeyEvent.ACTION_DOWN: 1984 return super.onKeyDown(keyCode, event); 1985 1986 case KeyEvent.ACTION_UP: 1987 return super.onKeyUp(keyCode, event); 1988 1989 case KeyEvent.ACTION_MULTIPLE: 1990 return super.onKeyMultiple(keyCode, count, event); 1991 1992 default: // shouldn't happen 1993 return false; 1994 } 1995 } 1996 } 1997 1998 /** 1999 * Scrolls up or down by the number of items currently present on screen. 2000 * 2001 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2002 * @return whether selection was moved 2003 */ 2004 boolean pageScroll(int direction) { 2005 int nextPage = -1; 2006 boolean down = false; 2007 2008 if (direction == FOCUS_UP) { 2009 nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); 2010 } else if (direction == FOCUS_DOWN) { 2011 nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); 2012 down = true; 2013 } 2014 2015 if (nextPage >= 0) { 2016 int position = lookForSelectablePosition(nextPage, down); 2017 if (position >= 0) { 2018 mLayoutMode = LAYOUT_SPECIFIC; 2019 mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength(); 2020 2021 if (down && position > mItemCount - getChildCount()) { 2022 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2023 } 2024 2025 if (!down && position < getChildCount()) { 2026 mLayoutMode = LAYOUT_FORCE_TOP; 2027 } 2028 2029 setSelectionInt(position); 2030 invokeOnItemScrollListener(); 2031 invalidate(); 2032 2033 return true; 2034 } 2035 } 2036 2037 return false; 2038 } 2039 2040 /** 2041 * Go to the last or first item if possible (not worrying about panning across or navigating 2042 * within the internal focus of the currently selected item.) 2043 * 2044 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2045 * 2046 * @return whether selection was moved 2047 */ 2048 boolean fullScroll(int direction) { 2049 boolean moved = false; 2050 if (direction == FOCUS_UP) { 2051 if (mSelectedPosition != 0) { 2052 int position = lookForSelectablePosition(0, true); 2053 if (position >= 0) { 2054 mLayoutMode = LAYOUT_FORCE_TOP; 2055 setSelectionInt(position); 2056 invokeOnItemScrollListener(); 2057 } 2058 moved = true; 2059 } 2060 } else if (direction == FOCUS_DOWN) { 2061 if (mSelectedPosition < mItemCount - 1) { 2062 int position = lookForSelectablePosition(mItemCount - 1, true); 2063 if (position >= 0) { 2064 mLayoutMode = LAYOUT_FORCE_BOTTOM; 2065 setSelectionInt(position); 2066 invokeOnItemScrollListener(); 2067 } 2068 moved = true; 2069 } 2070 } 2071 2072 if (moved) { 2073 invalidate(); 2074 } 2075 2076 return moved; 2077 } 2078 2079 /** 2080 * To avoid horizontal focus searches changing the selected item, we 2081 * manually focus search within the selected item (as applicable), and 2082 * prevent focus from jumping to something within another item. 2083 * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} 2084 * @return Whether this consumes the key event. 2085 */ 2086 private boolean handleHorizontalFocusWithinListItem(int direction) { 2087 if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { 2088 throw new IllegalArgumentException("direction must be one of" 2089 + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); 2090 } 2091 2092 final int numChildren = getChildCount(); 2093 if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { 2094 final View selectedView = getSelectedView(); 2095 if (selectedView != null && selectedView.hasFocus() && 2096 selectedView instanceof ViewGroup) { 2097 2098 final View currentFocus = selectedView.findFocus(); 2099 final View nextFocus = FocusFinder.getInstance().findNextFocus( 2100 (ViewGroup) selectedView, currentFocus, direction); 2101 if (nextFocus != null) { 2102 // do the math to get interesting rect in next focus' coordinates 2103 currentFocus.getFocusedRect(mTempRect); 2104 offsetDescendantRectToMyCoords(currentFocus, mTempRect); 2105 offsetRectIntoDescendantCoords(nextFocus, mTempRect); 2106 if (nextFocus.requestFocus(direction, mTempRect)) { 2107 return true; 2108 } 2109 } 2110 // we are blocking the key from being handled (by returning true) 2111 // if the global result is going to be some other view within this 2112 // list. this is to acheive the overall goal of having 2113 // horizontal d-pad navigation remain in the current item. 2114 final View globalNextFocus = FocusFinder.getInstance().findNextFocus( 2115 (ViewGroup) getRootView(), currentFocus, direction); 2116 if (globalNextFocus != null) { 2117 return isViewAncestorOf(globalNextFocus, this); 2118 } 2119 } 2120 } 2121 return false; 2122 } 2123 2124 /** 2125 * Scrolls to the next or previous item if possible. 2126 * 2127 * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} 2128 * 2129 * @return whether selection was moved 2130 */ 2131 boolean arrowScroll(int direction) { 2132 try { 2133 mInLayout = true; 2134 final boolean handled = arrowScrollImpl(direction); 2135 if (handled) { 2136 playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); 2137 } 2138 return handled; 2139 } finally { 2140 mInLayout = false; 2141 } 2142 } 2143 2144 /** 2145 * Handle an arrow scroll going up or down. Take into account whether items are selectable, 2146 * whether there are focusable items etc. 2147 * 2148 * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. 2149 * @return Whether any scrolling, selection or focus change occured. 2150 */ 2151 private boolean arrowScrollImpl(int direction) { 2152 if (getChildCount() <= 0) { 2153 return false; 2154 } 2155 2156 View selectedView = getSelectedView(); 2157 2158 int nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 2159 int amountToScroll = amountToScroll(direction, nextSelectedPosition); 2160 2161 // if we are moving focus, we may OVERRIDE the default behavior 2162 final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; 2163 if (focusResult != null) { 2164 nextSelectedPosition = focusResult.getSelectedPosition(); 2165 amountToScroll = focusResult.getAmountToScroll(); 2166 } 2167 2168 boolean needToRedraw = focusResult != null; 2169 if (nextSelectedPosition != INVALID_POSITION) { 2170 handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); 2171 setSelectedPositionInt(nextSelectedPosition); 2172 setNextSelectedPositionInt(nextSelectedPosition); 2173 selectedView = getSelectedView(); 2174 if (mItemsCanFocus && focusResult == null) { 2175 // there was no new view found to take focus, make sure we 2176 // don't leave focus with the old selection 2177 final View focused = getFocusedChild(); 2178 if (focused != null) { 2179 focused.clearFocus(); 2180 } 2181 } 2182 needToRedraw = true; 2183 checkSelectionChanged(); 2184 } 2185 2186 if (amountToScroll > 0) { 2187 scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); 2188 needToRedraw = true; 2189 } 2190 2191 // if we didn't find a new focusable, make sure any existing focused 2192 // item that was panned off screen gives up focus. 2193 if (mItemsCanFocus && (focusResult == null) 2194 && selectedView != null && selectedView.hasFocus()) { 2195 final View focused = selectedView.findFocus(); 2196 if (distanceToView(focused) > 0) { 2197 focused.clearFocus(); 2198 } 2199 } 2200 2201 // if the current selection is panned off, we need to remove the selection 2202 if (nextSelectedPosition == INVALID_POSITION && selectedView != null 2203 && !isViewAncestorOf(selectedView, this)) { 2204 selectedView = null; 2205 hideSelector(); 2206 2207 // but we don't want to set the ressurect position (that would make subsequent 2208 // unhandled key events bring back the item we just scrolled off!) 2209 mResurrectToPosition = INVALID_POSITION; 2210 } 2211 2212 if (needToRedraw) { 2213 if (selectedView != null) { 2214 positionSelector(selectedView); 2215 mSelectedTop = selectedView.getTop(); 2216 } 2217 invalidate(); 2218 invokeOnItemScrollListener(); 2219 return true; 2220 } 2221 2222 return false; 2223 } 2224 2225 /** 2226 * When selection changes, it is possible that the previously selected or the 2227 * next selected item will change its size. If so, we need to offset some folks, 2228 * and re-layout the items as appropriate. 2229 * 2230 * @param selectedView The currently selected view (before changing selection). 2231 * should be <code>null</code> if there was no previous selection. 2232 * @param direction Either {@link android.view.View#FOCUS_UP} or 2233 * {@link android.view.View#FOCUS_DOWN}. 2234 * @param newSelectedPosition The position of the next selection. 2235 * @param newFocusAssigned whether new focus was assigned. This matters because 2236 * when something has focus, we don't want to show selection (ugh). 2237 */ 2238 private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, 2239 boolean newFocusAssigned) { 2240 if (newSelectedPosition == INVALID_POSITION) { 2241 throw new IllegalArgumentException("newSelectedPosition needs to be valid"); 2242 } 2243 2244 // whether or not we are moving down or up, we want to preserve the 2245 // top of whatever view is on top: 2246 // - moving down: the view that had selection 2247 // - moving up: the view that is getting selection 2248 View topView; 2249 View bottomView; 2250 int topViewIndex, bottomViewIndex; 2251 boolean topSelected = false; 2252 final int selectedIndex = mSelectedPosition - mFirstPosition; 2253 final int nextSelectedIndex = newSelectedPosition - mFirstPosition; 2254 if (direction == View.FOCUS_UP) { 2255 topViewIndex = nextSelectedIndex; 2256 bottomViewIndex = selectedIndex; 2257 topView = getChildAt(topViewIndex); 2258 bottomView = selectedView; 2259 topSelected = true; 2260 } else { 2261 topViewIndex = selectedIndex; 2262 bottomViewIndex = nextSelectedIndex; 2263 topView = selectedView; 2264 bottomView = getChildAt(bottomViewIndex); 2265 } 2266 2267 final int numChildren = getChildCount(); 2268 2269 // start with top view: is it changing size? 2270 if (topView != null) { 2271 topView.setSelected(!newFocusAssigned && topSelected); 2272 measureAndAdjustDown(topView, topViewIndex, numChildren); 2273 } 2274 2275 // is the bottom view changing size? 2276 if (bottomView != null) { 2277 bottomView.setSelected(!newFocusAssigned && !topSelected); 2278 measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); 2279 } 2280 } 2281 2282 /** 2283 * Re-measure a child, and if its height changes, lay it out preserving its 2284 * top, and adjust the children below it appropriately. 2285 * @param child The child 2286 * @param childIndex The view group index of the child. 2287 * @param numChildren The number of children in the view group. 2288 */ 2289 private void measureAndAdjustDown(View child, int childIndex, int numChildren) { 2290 int oldHeight = child.getHeight(); 2291 measureItem(child); 2292 if (child.getMeasuredHeight() != oldHeight) { 2293 // lay out the view, preserving its top 2294 relayoutMeasuredItem(child); 2295 2296 // adjust views below appropriately 2297 final int heightDelta = child.getMeasuredHeight() - oldHeight; 2298 for (int i = childIndex + 1; i < numChildren; i++) { 2299 getChildAt(i).offsetTopAndBottom(heightDelta); 2300 } 2301 } 2302 } 2303 2304 /** 2305 * Measure a particular list child. 2306 * TODO: unify with setUpChild. 2307 * @param child The child. 2308 */ 2309 private void measureItem(View child) { 2310 ViewGroup.LayoutParams p = child.getLayoutParams(); 2311 if (p == null) { 2312 p = new ViewGroup.LayoutParams( 2313 ViewGroup.LayoutParams.FILL_PARENT, 2314 ViewGroup.LayoutParams.WRAP_CONTENT); 2315 } 2316 2317 int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, 2318 mListPadding.left + mListPadding.right, p.width); 2319 int lpHeight = p.height; 2320 int childHeightSpec; 2321 if (lpHeight > 0) { 2322 childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); 2323 } else { 2324 childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 2325 } 2326 child.measure(childWidthSpec, childHeightSpec); 2327 } 2328 2329 /** 2330 * Layout a child that has been measured, preserving its top position. 2331 * TODO: unify with setUpChild. 2332 * @param child The child. 2333 */ 2334 private void relayoutMeasuredItem(View child) { 2335 final int w = child.getMeasuredWidth(); 2336 final int h = child.getMeasuredHeight(); 2337 final int childLeft = mListPadding.left; 2338 final int childRight = childLeft + w; 2339 final int childTop = child.getTop(); 2340 final int childBottom = childTop + h; 2341 child.layout(childLeft, childTop, childRight, childBottom); 2342 } 2343 2344 /** 2345 * @return The amount to preview next items when arrow srolling. 2346 */ 2347 private int getArrowScrollPreviewLength() { 2348 return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); 2349 } 2350 2351 /** 2352 * Determine how much we need to scroll in order to get the next selected view 2353 * visible, with a fading edge showing below as applicable. The amount is 2354 * capped at {@link #getMaxScrollAmount()} . 2355 * 2356 * @param direction either {@link android.view.View#FOCUS_UP} or 2357 * {@link android.view.View#FOCUS_DOWN}. 2358 * @param nextSelectedPosition The position of the next selection, or 2359 * {@link #INVALID_POSITION} if there is no next selectable position 2360 * @return The amount to scroll. Note: this is always positive! Direction 2361 * needs to be taken into account when actually scrolling. 2362 */ 2363 private int amountToScroll(int direction, int nextSelectedPosition) { 2364 final int listBottom = getHeight() - mListPadding.bottom; 2365 final int listTop = mListPadding.top; 2366 2367 final int numChildren = getChildCount(); 2368 2369 if (direction == View.FOCUS_DOWN) { 2370 int indexToMakeVisible = numChildren - 1; 2371 if (nextSelectedPosition != INVALID_POSITION) { 2372 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2373 } 2374 2375 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2376 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2377 2378 int goalBottom = listBottom; 2379 if (positionToMakeVisible < mItemCount - 1) { 2380 goalBottom -= getArrowScrollPreviewLength(); 2381 } 2382 2383 if (viewToMakeVisible.getBottom() <= goalBottom) { 2384 // item is fully visible. 2385 return 0; 2386 } 2387 2388 if (nextSelectedPosition != INVALID_POSITION 2389 && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { 2390 // item already has enough of it visible, changing selection is good enough 2391 return 0; 2392 } 2393 2394 int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); 2395 2396 if ((mFirstPosition + numChildren) == mItemCount) { 2397 // last is last in list -> make sure we don't scroll past it 2398 final int max = getChildAt(numChildren - 1).getBottom() - listBottom; 2399 amountToScroll = Math.min(amountToScroll, max); 2400 } 2401 2402 return Math.min(amountToScroll, getMaxScrollAmount()); 2403 } else { 2404 int indexToMakeVisible = 0; 2405 if (nextSelectedPosition != INVALID_POSITION) { 2406 indexToMakeVisible = nextSelectedPosition - mFirstPosition; 2407 } 2408 final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; 2409 final View viewToMakeVisible = getChildAt(indexToMakeVisible); 2410 int goalTop = listTop; 2411 if (positionToMakeVisible > 0) { 2412 goalTop += getArrowScrollPreviewLength(); 2413 } 2414 if (viewToMakeVisible.getTop() >= goalTop) { 2415 // item is fully visible. 2416 return 0; 2417 } 2418 2419 if (nextSelectedPosition != INVALID_POSITION && 2420 (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { 2421 // item already has enough of it visible, changing selection is good enough 2422 return 0; 2423 } 2424 2425 int amountToScroll = (goalTop - viewToMakeVisible.getTop()); 2426 if (mFirstPosition == 0) { 2427 // first is first in list -> make sure we don't scroll past it 2428 final int max = listTop - getChildAt(0).getTop(); 2429 amountToScroll = Math.min(amountToScroll, max); 2430 } 2431 return Math.min(amountToScroll, getMaxScrollAmount()); 2432 } 2433 } 2434 2435 /** 2436 * Holds results of focus aware arrow scrolling. 2437 */ 2438 static private class ArrowScrollFocusResult { 2439 private int mSelectedPosition; 2440 private int mAmountToScroll; 2441 2442 /** 2443 * How {@link android.widget.ListView#arrowScrollFocused} returns its values. 2444 */ 2445 void populate(int selectedPosition, int amountToScroll) { 2446 mSelectedPosition = selectedPosition; 2447 mAmountToScroll = amountToScroll; 2448 } 2449 2450 public int getSelectedPosition() { 2451 return mSelectedPosition; 2452 } 2453 2454 public int getAmountToScroll() { 2455 return mAmountToScroll; 2456 } 2457 } 2458 2459 /** 2460 * @param direction either {@link android.view.View#FOCUS_UP} or 2461 * {@link android.view.View#FOCUS_DOWN}. 2462 * @return The position of the next selectable position of the views that 2463 * are currently visible, taking into account the fact that there might 2464 * be no selection. Returns {@link #INVALID_POSITION} if there is no 2465 * selectable view on screen in the given direction. 2466 */ 2467 private int lookForSelectablePositionOnScreen(int direction) { 2468 final int firstPosition = mFirstPosition; 2469 if (direction == View.FOCUS_DOWN) { 2470 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2471 mSelectedPosition + 1 : 2472 firstPosition; 2473 if (startPos >= mAdapter.getCount()) { 2474 return INVALID_POSITION; 2475 } 2476 if (startPos < firstPosition) { 2477 startPos = firstPosition; 2478 } 2479 2480 final int lastVisiblePos = getLastVisiblePosition(); 2481 final ListAdapter adapter = getAdapter(); 2482 for (int pos = startPos; pos <= lastVisiblePos; pos++) { 2483 if (adapter.isEnabled(pos) 2484 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2485 return pos; 2486 } 2487 } 2488 } else { 2489 int last = firstPosition + getChildCount() - 1; 2490 int startPos = (mSelectedPosition != INVALID_POSITION) ? 2491 mSelectedPosition - 1 : 2492 firstPosition + getChildCount() - 1; 2493 if (startPos < 0) { 2494 return INVALID_POSITION; 2495 } 2496 if (startPos > last) { 2497 startPos = last; 2498 } 2499 2500 final ListAdapter adapter = getAdapter(); 2501 for (int pos = startPos; pos >= firstPosition; pos--) { 2502 if (adapter.isEnabled(pos) 2503 && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { 2504 return pos; 2505 } 2506 } 2507 } 2508 return INVALID_POSITION; 2509 } 2510 2511 /** 2512 * Do an arrow scroll based on focus searching. If a new view is 2513 * given focus, return the selection delta and amount to scroll via 2514 * an {@link ArrowScrollFocusResult}, otherwise, return null. 2515 * 2516 * @param direction either {@link android.view.View#FOCUS_UP} or 2517 * {@link android.view.View#FOCUS_DOWN}. 2518 * @return The result if focus has changed, or <code>null</code>. 2519 */ 2520 private ArrowScrollFocusResult arrowScrollFocused(final int direction) { 2521 final View selectedView = getSelectedView(); 2522 View newFocus; 2523 if (selectedView != null && selectedView.hasFocus()) { 2524 View oldFocus = selectedView.findFocus(); 2525 newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); 2526 } else { 2527 if (direction == View.FOCUS_DOWN) { 2528 final boolean topFadingEdgeShowing = (mFirstPosition > 0); 2529 final int listTop = mListPadding.top + 2530 (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2531 final int ySearchPoint = 2532 (selectedView != null && selectedView.getTop() > listTop) ? 2533 selectedView.getTop() : 2534 listTop; 2535 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2536 } else { 2537 final boolean bottomFadingEdgeShowing = 2538 (mFirstPosition + getChildCount() - 1) < mItemCount; 2539 final int listBottom = getHeight() - mListPadding.bottom - 2540 (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); 2541 final int ySearchPoint = 2542 (selectedView != null && selectedView.getBottom() < listBottom) ? 2543 selectedView.getBottom() : 2544 listBottom; 2545 mTempRect.set(0, ySearchPoint, 0, ySearchPoint); 2546 } 2547 newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); 2548 } 2549 2550 if (newFocus != null) { 2551 final int positionOfNewFocus = positionOfNewFocus(newFocus); 2552 2553 // if the focus change is in a different new position, make sure 2554 // we aren't jumping over another selectable position 2555 if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { 2556 final int selectablePosition = lookForSelectablePositionOnScreen(direction); 2557 if (selectablePosition != INVALID_POSITION && 2558 ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || 2559 (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { 2560 return null; 2561 } 2562 } 2563 2564 int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); 2565 2566 final int maxScrollAmount = getMaxScrollAmount(); 2567 if (focusScroll < maxScrollAmount) { 2568 // not moving too far, safe to give next view focus 2569 newFocus.requestFocus(direction); 2570 mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); 2571 return mArrowScrollFocusResult; 2572 } else if (distanceToView(newFocus) < maxScrollAmount){ 2573 // Case to consider: 2574 // too far to get entire next focusable on screen, but by going 2575 // max scroll amount, we are getting it at least partially in view, 2576 // so give it focus and scroll the max ammount. 2577 newFocus.requestFocus(direction); 2578 mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); 2579 return mArrowScrollFocusResult; 2580 } 2581 } 2582 return null; 2583 } 2584 2585 /** 2586 * @param newFocus The view that would have focus. 2587 * @return the position that contains newFocus 2588 */ 2589 private int positionOfNewFocus(View newFocus) { 2590 final int numChildren = getChildCount(); 2591 for (int i = 0; i < numChildren; i++) { 2592 final View child = getChildAt(i); 2593 if (isViewAncestorOf(newFocus, child)) { 2594 return mFirstPosition + i; 2595 } 2596 } 2597 throw new IllegalArgumentException("newFocus is not a child of any of the" 2598 + " children of the list!"); 2599 } 2600 2601 /** 2602 * Return true if child is an ancestor of parent, (or equal to the parent). 2603 */ 2604 private boolean isViewAncestorOf(View child, View parent) { 2605 if (child == parent) { 2606 return true; 2607 } 2608 2609 final ViewParent theParent = child.getParent(); 2610 return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); 2611 } 2612 2613 /** 2614 * Determine how much we need to scroll in order to get newFocus in view. 2615 * @param direction either {@link android.view.View#FOCUS_UP} or 2616 * {@link android.view.View#FOCUS_DOWN}. 2617 * @param newFocus The view that would take focus. 2618 * @param positionOfNewFocus The position of the list item containing newFocus 2619 * @return The amount to scroll. Note: this is always positive! Direction 2620 * needs to be taken into account when actually scrolling. 2621 */ 2622 private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { 2623 int amountToScroll = 0; 2624 newFocus.getDrawingRect(mTempRect); 2625 offsetDescendantRectToMyCoords(newFocus, mTempRect); 2626 if (direction == View.FOCUS_UP) { 2627 if (mTempRect.top < mListPadding.top) { 2628 amountToScroll = mListPadding.top - mTempRect.top; 2629 if (positionOfNewFocus > 0) { 2630 amountToScroll += getArrowScrollPreviewLength(); 2631 } 2632 } 2633 } else { 2634 final int listBottom = getHeight() - mListPadding.bottom; 2635 if (mTempRect.bottom > listBottom) { 2636 amountToScroll = mTempRect.bottom - listBottom; 2637 if (positionOfNewFocus < mItemCount - 1) { 2638 amountToScroll += getArrowScrollPreviewLength(); 2639 } 2640 } 2641 } 2642 return amountToScroll; 2643 } 2644 2645 /** 2646 * Determine the distance to the nearest edge of a view in a particular 2647 * direciton. 2648 * @param descendant A descendant of this list. 2649 * @return The distance, or 0 if the nearest edge is already on screen. 2650 */ 2651 private int distanceToView(View descendant) { 2652 int distance = 0; 2653 descendant.getDrawingRect(mTempRect); 2654 offsetDescendantRectToMyCoords(descendant, mTempRect); 2655 final int listBottom = mBottom - mTop - mListPadding.bottom; 2656 if (mTempRect.bottom < mListPadding.top) { 2657 distance = mListPadding.top - mTempRect.bottom; 2658 } else if (mTempRect.top > listBottom) { 2659 distance = mTempRect.top - listBottom; 2660 } 2661 return distance; 2662 } 2663 2664 2665 /** 2666 * Scroll the children by amount, adding a view at the end and removing 2667 * views that fall off as necessary. 2668 * 2669 * @param amount The amount (positive or negative) to scroll. 2670 */ 2671 private void scrollListItemsBy(int amount) { 2672 offsetChildrenTopAndBottom(amount); 2673 2674 final int listBottom = getHeight() - mListPadding.bottom; 2675 final int listTop = mListPadding.top; 2676 final AbsListView.RecycleBin recycleBin = mRecycler; 2677 2678 if (amount < 0) { 2679 // shifted items up 2680 2681 // may need to pan views into the bottom space 2682 int numChildren = getChildCount(); 2683 View last = getChildAt(numChildren - 1); 2684 while (last.getBottom() < listBottom) { 2685 final int lastVisiblePosition = mFirstPosition + numChildren - 1; 2686 if (lastVisiblePosition < mItemCount - 1) { 2687 last = addViewBelow(last, lastVisiblePosition); 2688 numChildren++; 2689 } else { 2690 break; 2691 } 2692 } 2693 2694 // may have brought in the last child of the list that is skinnier 2695 // than the fading edge, thereby leaving space at the end. need 2696 // to shift back 2697 if (last.getBottom() < listBottom) { 2698 offsetChildrenTopAndBottom(listBottom - last.getBottom()); 2699 } 2700 2701 // top views may be panned off screen 2702 View first = getChildAt(0); 2703 while (first.getBottom() < listTop) { 2704 AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); 2705 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2706 removeViewInLayout(first); 2707 recycleBin.addScrapView(first); 2708 } else { 2709 detachViewFromParent(first); 2710 } 2711 first = getChildAt(0); 2712 mFirstPosition++; 2713 } 2714 } else { 2715 // shifted items down 2716 View first = getChildAt(0); 2717 2718 // may need to pan views into top 2719 while ((first.getTop() > listTop) && (mFirstPosition > 0)) { 2720 first = addViewAbove(first, mFirstPosition); 2721 mFirstPosition--; 2722 } 2723 2724 // may have brought the very first child of the list in too far and 2725 // need to shift it back 2726 if (first.getTop() > listTop) { 2727 offsetChildrenTopAndBottom(listTop - first.getTop()); 2728 } 2729 2730 int lastIndex = getChildCount() - 1; 2731 View last = getChildAt(lastIndex); 2732 2733 // bottom view may be panned off screen 2734 while (last.getTop() > listBottom) { 2735 AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); 2736 if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { 2737 removeViewInLayout(last); 2738 recycleBin.addScrapView(last); 2739 } else { 2740 detachViewFromParent(last); 2741 } 2742 last = getChildAt(--lastIndex); 2743 } 2744 } 2745 } 2746 2747 private View addViewAbove(View theView, int position) { 2748 int abovePosition = position - 1; 2749 View view = obtainView(abovePosition); 2750 int edgeOfNewChild = theView.getTop() - mDividerHeight; 2751 setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, false, false); 2752 return view; 2753 } 2754 2755 private View addViewBelow(View theView, int position) { 2756 int belowPosition = position + 1; 2757 View view = obtainView(belowPosition); 2758 int edgeOfNewChild = theView.getBottom() + mDividerHeight; 2759 setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, false, false); 2760 return view; 2761 } 2762 2763 /** 2764 * Indicates that the views created by the ListAdapter can contain focusable 2765 * items. 2766 * 2767 * @param itemsCanFocus true if items can get focus, false otherwise 2768 */ 2769 public void setItemsCanFocus(boolean itemsCanFocus) { 2770 mItemsCanFocus = itemsCanFocus; 2771 if (!itemsCanFocus) { 2772 setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); 2773 } 2774 } 2775 2776 /** 2777 * @return Whether the views created by the ListAdapter can contain focusable 2778 * items. 2779 */ 2780 public boolean getItemsCanFocus() { 2781 return mItemsCanFocus; 2782 } 2783 2784 @Override 2785 public boolean isOpaque() { 2786 return (mCachingStarted && mIsCacheColorOpaque && mDividerIsOpaque) || super.isOpaque(); 2787 } 2788 2789 @Override 2790 public void setCacheColorHint(int color) { 2791 mIsCacheColorOpaque = (color >>> 24) == 0xFF; 2792 super.setCacheColorHint(color); 2793 } 2794 2795 @Override 2796 protected void dispatchDraw(Canvas canvas) { 2797 // Draw the dividers 2798 final int dividerHeight = mDividerHeight; 2799 2800 if (dividerHeight > 0 && mDivider != null) { 2801 // Only modify the top and bottom in the loop, we set the left and right here 2802 final Rect bounds = mTempRect; 2803 bounds.left = mPaddingLeft; 2804 bounds.right = mRight - mLeft - mPaddingRight; 2805 2806 final int count = getChildCount(); 2807 final int headerCount = mHeaderViewInfos.size(); 2808 final int footerLimit = mItemCount - mFooterViewInfos.size() - 1; 2809 final boolean headerDividers = mHeaderDividersEnabled; 2810 final boolean footerDividers = mFooterDividersEnabled; 2811 final int first = mFirstPosition; 2812 final boolean areAllItemsSelectable = mAreAllItemsSelectable; 2813 final ListAdapter adapter = mAdapter; 2814 2815 if (!mStackFromBottom) { 2816 int bottom; 2817 int listBottom = mBottom - mTop - mListPadding.bottom; 2818 2819 for (int i = 0; i < count; i++) { 2820 if ((headerDividers || first + i >= headerCount) && 2821 (footerDividers || first + i < footerLimit)) { 2822 View child = getChildAt(i); 2823 bottom = child.getBottom(); 2824 // Don't draw dividers next to items that are not enabled 2825 if (bottom < listBottom && (areAllItemsSelectable || 2826 (adapter.isEnabled(first + i) && (i == count - 1 || 2827 adapter.isEnabled(first + i + 1))))) { 2828 bounds.top = bottom; 2829 bounds.bottom = bottom + dividerHeight; 2830 drawDivider(canvas, bounds, i); 2831 } 2832 } 2833 } 2834 } else { 2835 int top; 2836 int listTop = mListPadding.top; 2837 2838 for (int i = 0; i < count; i++) { 2839 if ((headerDividers || first + i >= headerCount) && 2840 (footerDividers || first + i < footerLimit)) { 2841 View child = getChildAt(i); 2842 top = child.getTop(); 2843 // Don't draw dividers next to items that are not enabled 2844 if (top > listTop && (areAllItemsSelectable || 2845 (adapter.isEnabled(first + i) && (i == count - 1 || 2846 adapter.isEnabled(first + i + 1))))) { 2847 bounds.top = top - dividerHeight; 2848 bounds.bottom = top; 2849 // Give the method the child ABOVE the divider, so we 2850 // subtract one from our child 2851 // position. Give -1 when there is no child above the 2852 // divider. 2853 drawDivider(canvas, bounds, i - 1); 2854 } 2855 } 2856 } 2857 } 2858 } 2859 2860 // Draw the indicators (these should be drawn above the dividers) and children 2861 super.dispatchDraw(canvas); 2862 } 2863 2864 /** 2865 * Draws a divider for the given child in the given bounds. 2866 * 2867 * @param canvas The canvas to draw to. 2868 * @param bounds The bounds of the divider. 2869 * @param childIndex The index of child (of the View) above the divider. 2870 * This will be -1 if there is no child above the divider to be 2871 * drawn. 2872 */ 2873 void drawDivider(Canvas canvas, Rect bounds, int childIndex) { 2874 // This widget draws the same divider for all children 2875 final Drawable divider = mDivider; 2876 final boolean clipDivider = mClipDivider; 2877 2878 if (!clipDivider) { 2879 divider.setBounds(bounds); 2880 } else { 2881 canvas.save(); 2882 canvas.clipRect(bounds); 2883 } 2884 2885 divider.draw(canvas); 2886 2887 if (clipDivider) { 2888 canvas.restore(); 2889 } 2890 } 2891 2892 /** 2893 * Returns the drawable that will be drawn between each item in the list. 2894 * 2895 * @return the current drawable drawn between list elements 2896 */ 2897 public Drawable getDivider() { 2898 return mDivider; 2899 } 2900 2901 /** 2902 * Sets the drawable that will be drawn between each item in the list. If the drawable does 2903 * not have an intrinsic height, you should also call {@link #setDividerHeight(int)} 2904 * 2905 * @param divider The drawable to use. 2906 */ 2907 public void setDivider(Drawable divider) { 2908 if (divider != null) { 2909 mDividerHeight = divider.getIntrinsicHeight(); 2910 mClipDivider = divider instanceof ColorDrawable; 2911 } else { 2912 mDividerHeight = 0; 2913 mClipDivider = false; 2914 } 2915 mDivider = divider; 2916 mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; 2917 requestLayoutIfNecessary(); 2918 } 2919 2920 /** 2921 * @return Returns the height of the divider that will be drawn between each item in the list. 2922 */ 2923 public int getDividerHeight() { 2924 return mDividerHeight; 2925 } 2926 2927 /** 2928 * Sets the height of the divider that will be drawn between each item in the list. Calling 2929 * this will override the intrinsic height as set by {@link #setDivider(Drawable)} 2930 * 2931 * @param height The new height of the divider in pixels. 2932 */ 2933 public void setDividerHeight(int height) { 2934 mDividerHeight = height; 2935 requestLayoutIfNecessary(); 2936 } 2937 2938 /** 2939 * Enables or disables the drawing of the divider for header views. 2940 * 2941 * @param headerDividersEnabled True to draw the headers, false otherwise. 2942 * 2943 * @see #setFooterDividersEnabled(boolean) 2944 * @see #addHeaderView(android.view.View) 2945 */ 2946 public void setHeaderDividersEnabled(boolean headerDividersEnabled) { 2947 mHeaderDividersEnabled = headerDividersEnabled; 2948 invalidate(); 2949 } 2950 2951 /** 2952 * Enables or disables the drawing of the divider for footer views. 2953 * 2954 * @param footerDividersEnabled True to draw the footers, false otherwise. 2955 * 2956 * @see #setHeaderDividersEnabled(boolean) 2957 * @see #addFooterView(android.view.View) 2958 */ 2959 public void setFooterDividersEnabled(boolean footerDividersEnabled) { 2960 mFooterDividersEnabled = footerDividersEnabled; 2961 invalidate(); 2962 } 2963 2964 @Override 2965 protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { 2966 super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); 2967 2968 int closetChildIndex = -1; 2969 if (gainFocus && previouslyFocusedRect != null) { 2970 previouslyFocusedRect.offset(mScrollX, mScrollY); 2971 2972 // figure out which item should be selected based on previously 2973 // focused rect 2974 Rect otherRect = mTempRect; 2975 int minDistance = Integer.MAX_VALUE; 2976 final int childCount = getChildCount(); 2977 final int firstPosition = mFirstPosition; 2978 final ListAdapter adapter = mAdapter; 2979 2980 for (int i = 0; i < childCount; i++) { 2981 // only consider selectable views 2982 if (!adapter.isEnabled(firstPosition + i)) { 2983 continue; 2984 } 2985 2986 View other = getChildAt(i); 2987 other.getDrawingRect(otherRect); 2988 offsetDescendantRectToMyCoords(other, otherRect); 2989 int distance = getDistance(previouslyFocusedRect, otherRect, direction); 2990 2991 if (distance < minDistance) { 2992 minDistance = distance; 2993 closetChildIndex = i; 2994 } 2995 } 2996 } 2997 2998 if (closetChildIndex >= 0) { 2999 setSelection(closetChildIndex + mFirstPosition); 3000 } else { 3001 requestLayout(); 3002 } 3003 } 3004 3005 3006 /* 3007 * (non-Javadoc) 3008 * 3009 * Children specified in XML are assumed to be header views. After we have 3010 * parsed them move them out of the children list and into mHeaderViews. 3011 */ 3012 @Override 3013 protected void onFinishInflate() { 3014 super.onFinishInflate(); 3015 3016 int count = getChildCount(); 3017 if (count > 0) { 3018 for (int i = 0; i < count; ++i) { 3019 addHeaderView(getChildAt(i)); 3020 } 3021 removeAllViews(); 3022 } 3023 } 3024 3025 /* (non-Javadoc) 3026 * @see android.view.View#findViewById(int) 3027 * First look in our children, then in any header and footer views that may be scrolled off. 3028 */ 3029 @Override 3030 protected View findViewTraversal(int id) { 3031 View v; 3032 v = super.findViewTraversal(id); 3033 if (v == null) { 3034 v = findViewInHeadersOrFooters(mHeaderViewInfos, id); 3035 if (v != null) { 3036 return v; 3037 } 3038 v = findViewInHeadersOrFooters(mFooterViewInfos, id); 3039 if (v != null) { 3040 return v; 3041 } 3042 } 3043 return v; 3044 } 3045 3046 /* (non-Javadoc) 3047 * 3048 * Look in the passed in list of headers or footers for the view. 3049 */ 3050 View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { 3051 if (where != null) { 3052 int len = where.size(); 3053 View v; 3054 3055 for (int i = 0; i < len; i++) { 3056 v = where.get(i).view; 3057 3058 if (!v.isRootNamespace()) { 3059 v = v.findViewById(id); 3060 3061 if (v != null) { 3062 return v; 3063 } 3064 } 3065 } 3066 } 3067 return null; 3068 } 3069 3070 /* (non-Javadoc) 3071 * @see android.view.View#findViewWithTag(String) 3072 * First look in our children, then in any header and footer views that may be scrolled off. 3073 */ 3074 @Override 3075 protected View findViewWithTagTraversal(Object tag) { 3076 View v; 3077 v = super.findViewWithTagTraversal(tag); 3078 if (v == null) { 3079 v = findViewTagInHeadersOrFooters(mHeaderViewInfos, tag); 3080 if (v != null) { 3081 return v; 3082 } 3083 3084 v = findViewTagInHeadersOrFooters(mFooterViewInfos, tag); 3085 if (v != null) { 3086 return v; 3087 } 3088 } 3089 return v; 3090 } 3091 3092 /* (non-Javadoc) 3093 * 3094 * Look in the passed in list of headers or footers for the view with the tag. 3095 */ 3096 View findViewTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { 3097 if (where != null) { 3098 int len = where.size(); 3099 View v; 3100 3101 for (int i = 0; i < len; i++) { 3102 v = where.get(i).view; 3103 3104 if (!v.isRootNamespace()) { 3105 v = v.findViewWithTag(tag); 3106 3107 if (v != null) { 3108 return v; 3109 } 3110 } 3111 } 3112 } 3113 return null; 3114 } 3115 3116 @Override 3117 public boolean onTouchEvent(MotionEvent ev) { 3118 if (mItemsCanFocus && ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { 3119 // Don't handle edge touches immediately -- they may actually belong to one of our 3120 // descendants. 3121 return false; 3122 } 3123 return super.onTouchEvent(ev); 3124 } 3125 3126 /** 3127 * @see #setChoiceMode(int) 3128 * 3129 * @return The current choice mode 3130 */ 3131 public int getChoiceMode() { 3132 return mChoiceMode; 3133 } 3134 3135 /** 3136 * Defines the choice behavior for the List. By default, Lists do not have any choice behavior 3137 * ({@link #CHOICE_MODE_NONE}). By setting the choiceMode to {@link #CHOICE_MODE_SINGLE}, the 3138 * List allows up to one item to be in a chosen state. By setting the choiceMode to 3139 * {@link #CHOICE_MODE_MULTIPLE}, the list allows any number of items to be chosen. 3140 * 3141 * @param choiceMode One of {@link #CHOICE_MODE_NONE}, {@link #CHOICE_MODE_SINGLE}, or 3142 * {@link #CHOICE_MODE_MULTIPLE} 3143 */ 3144 public void setChoiceMode(int choiceMode) { 3145 mChoiceMode = choiceMode; 3146 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates == null) { 3147 mCheckStates = new SparseBooleanArray(); 3148 } 3149 } 3150 3151 @Override 3152 public boolean performItemClick(View view, int position, long id) { 3153 boolean handled = false; 3154 3155 if (mChoiceMode != CHOICE_MODE_NONE) { 3156 handled = true; 3157 3158 if (mChoiceMode == CHOICE_MODE_MULTIPLE) { 3159 boolean oldValue = mCheckStates.get(position, false); 3160 mCheckStates.put(position, !oldValue); 3161 } else { 3162 boolean oldValue = mCheckStates.get(position, false); 3163 if (!oldValue) { 3164 mCheckStates.clear(); 3165 mCheckStates.put(position, true); 3166 } 3167 } 3168 3169 mDataChanged = true; 3170 rememberSyncState(); 3171 requestLayout(); 3172 } 3173 3174 handled |= super.performItemClick(view, position, id); 3175 3176 return handled; 3177 } 3178 3179 /** 3180 * Sets the checked state of the specified position. The is only valid if 3181 * the choice mode has been set to {@link #CHOICE_MODE_SINGLE} or 3182 * {@link #CHOICE_MODE_MULTIPLE}. 3183 * 3184 * @param position The item whose checked state is to be checked 3185 * @param value The new checked sate for the item 3186 */ 3187 public void setItemChecked(int position, boolean value) { 3188 if (mChoiceMode == CHOICE_MODE_NONE) { 3189 return; 3190 } 3191 3192 if (mChoiceMode == CHOICE_MODE_MULTIPLE) { 3193 mCheckStates.put(position, value); 3194 } else { 3195 boolean oldValue = mCheckStates.get(position, false); 3196 mCheckStates.clear(); 3197 if (!oldValue) { 3198 mCheckStates.put(position, true); 3199 } 3200 } 3201 3202 // Do not generate a data change while we are in the layout phase 3203 if (!mInLayout && !mBlockLayoutRequests) { 3204 mDataChanged = true; 3205 rememberSyncState(); 3206 requestLayout(); 3207 } 3208 } 3209 3210 /** 3211 * Returns the checked state of the specified position. The result is only 3212 * valid if the choice mode has not been set to {@link #CHOICE_MODE_SINGLE} 3213 * or {@link #CHOICE_MODE_MULTIPLE}. 3214 * 3215 * @param position The item whose checked state to return 3216 * @return The item's checked state 3217 * 3218 * @see #setChoiceMode(int) 3219 */ 3220 public boolean isItemChecked(int position) { 3221 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { 3222 return mCheckStates.get(position); 3223 } 3224 3225 return false; 3226 } 3227 3228 /** 3229 * Returns the currently checked item. The result is only valid if the choice 3230 * mode has not been set to {@link #CHOICE_MODE_SINGLE}. 3231 * 3232 * @return The position of the currently checked item or 3233 * {@link #INVALID_POSITION} if nothing is selected 3234 * 3235 * @see #setChoiceMode(int) 3236 */ 3237 public int getCheckedItemPosition() { 3238 if (mChoiceMode == CHOICE_MODE_SINGLE && mCheckStates != null && mCheckStates.size() == 1) { 3239 return mCheckStates.keyAt(0); 3240 } 3241 3242 return INVALID_POSITION; 3243 } 3244 3245 /** 3246 * Returns the set of checked items in the list. The result is only valid if 3247 * the choice mode has not been set to {@link #CHOICE_MODE_SINGLE}. 3248 * 3249 * @return A SparseBooleanArray which will return true for each call to 3250 * get(int position) where position is a position in the list. 3251 */ 3252 public SparseBooleanArray getCheckedItemPositions() { 3253 if (mChoiceMode != CHOICE_MODE_NONE) { 3254 return mCheckStates; 3255 } 3256 return null; 3257 } 3258 3259 /** 3260 * Returns the set of checked items ids. The result is only valid if 3261 * the choice mode has not been set to {@link #CHOICE_MODE_SINGLE}. 3262 * 3263 * @return A new array which contains the id of each checked item in the list. 3264 */ 3265 public long[] getCheckItemIds() { 3266 if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { 3267 final SparseBooleanArray states = mCheckStates; 3268 final int count = states.size(); 3269 final long[] ids = new long[count]; 3270 final ListAdapter adapter = mAdapter; 3271 3272 for (int i = 0; i < count; i++) { 3273 ids[i]= adapter.getItemId(states.keyAt(i)); 3274 } 3275 3276 return ids; 3277 } 3278 3279 return new long[0]; 3280 } 3281 3282 /** 3283 * Clear any choices previously set 3284 */ 3285 public void clearChoices() { 3286 if (mCheckStates != null) { 3287 mCheckStates.clear(); 3288 } 3289 } 3290 3291 static class SavedState extends BaseSavedState { 3292 SparseBooleanArray checkState; 3293 3294 /** 3295 * Constructor called from {@link ListView#onSaveInstanceState()} 3296 */ 3297 SavedState(Parcelable superState, SparseBooleanArray checkState) { 3298 super(superState); 3299 this.checkState = checkState; 3300 } 3301 3302 /** 3303 * Constructor called from {@link #CREATOR} 3304 */ 3305 private SavedState(Parcel in) { 3306 super(in); 3307 checkState = in.readSparseBooleanArray(); 3308 } 3309 3310 @Override 3311 public void writeToParcel(Parcel out, int flags) { 3312 super.writeToParcel(out, flags); 3313 out.writeSparseBooleanArray(checkState); 3314 } 3315 3316 @Override 3317 public String toString() { 3318 return "ListView.SavedState{" 3319 + Integer.toHexString(System.identityHashCode(this)) 3320 + " checkState=" + checkState + "}"; 3321 } 3322 3323 public static final Parcelable.Creator<SavedState> CREATOR 3324 = new Parcelable.Creator<SavedState>() { 3325 public SavedState createFromParcel(Parcel in) { 3326 return new SavedState(in); 3327 } 3328 3329 public SavedState[] newArray(int size) { 3330 return new SavedState[size]; 3331 } 3332 }; 3333 } 3334 3335 @Override 3336 public Parcelable onSaveInstanceState() { 3337 Parcelable superState = super.onSaveInstanceState(); 3338 return new SavedState(superState, mCheckStates); 3339 } 3340 3341 @Override 3342 public void onRestoreInstanceState(Parcelable state) { 3343 SavedState ss = (SavedState) state; 3344 3345 super.onRestoreInstanceState(ss.getSuperState()); 3346 3347 if (ss.checkState != null) { 3348 mCheckStates = ss.checkState; 3349 } 3350 3351 } 3352} 3353