GridLayoutManager.java revision 4a6588a5160206fc7063e5a140a405dfd84f0cc9
1/* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 5 * in compliance with the License. You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software distributed under the License 10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express 11 * or implied. See the License for the specific language governing permissions and limitations under 12 * the License. 13 */ 14package android.support.v17.leanback.widget; 15 16import android.content.Context; 17import android.graphics.PointF; 18import android.graphics.Rect; 19import android.os.Bundle; 20import android.os.Parcel; 21import android.os.Parcelable; 22import android.support.v4.view.ViewCompat; 23import android.support.v7.widget.LinearSmoothScroller; 24import android.support.v7.widget.RecyclerView; 25import android.support.v7.widget.RecyclerView.Recycler; 26import android.support.v7.widget.RecyclerView.State; 27 28import static android.support.v7.widget.RecyclerView.NO_ID; 29import static android.support.v7.widget.RecyclerView.NO_POSITION; 30import static android.support.v7.widget.RecyclerView.HORIZONTAL; 31import static android.support.v7.widget.RecyclerView.VERTICAL; 32 33import android.util.AttributeSet; 34import android.util.Log; 35import android.view.FocusFinder; 36import android.view.Gravity; 37import android.view.View; 38import android.view.ViewParent; 39import android.view.View.MeasureSpec; 40import android.view.ViewGroup.MarginLayoutParams; 41import android.view.ViewGroup; 42 43import java.io.PrintWriter; 44import java.io.StringWriter; 45import java.util.ArrayList; 46import java.util.List; 47 48final class GridLayoutManager extends RecyclerView.LayoutManager { 49 50 /* 51 * LayoutParams for {@link HorizontalGridView} and {@link VerticalGridView}. 52 * The class currently does two internal jobs: 53 * - Saves optical bounds insets. 54 * - Caches focus align view center. 55 */ 56 static class LayoutParams extends RecyclerView.LayoutParams { 57 58 // The view is saved only during animation. 59 private View mView; 60 61 // For placement 62 private int mLeftInset; 63 private int mTopInset; 64 private int mRightInset; 65 private int mBottomInset; 66 67 // For alignment 68 private int mAlignX; 69 private int mAlignY; 70 71 public LayoutParams(Context c, AttributeSet attrs) { 72 super(c, attrs); 73 } 74 75 public LayoutParams(int width, int height) { 76 super(width, height); 77 } 78 79 public LayoutParams(MarginLayoutParams source) { 80 super(source); 81 } 82 83 public LayoutParams(ViewGroup.LayoutParams source) { 84 super(source); 85 } 86 87 public LayoutParams(RecyclerView.LayoutParams source) { 88 super(source); 89 } 90 91 public LayoutParams(LayoutParams source) { 92 super(source); 93 } 94 95 int getAlignX() { 96 return mAlignX; 97 } 98 99 int getAlignY() { 100 return mAlignY; 101 } 102 103 int getOpticalLeft(View view) { 104 return view.getLeft() + mLeftInset; 105 } 106 107 int getOpticalTop(View view) { 108 return view.getTop() + mTopInset; 109 } 110 111 int getOpticalRight(View view) { 112 return view.getRight() - mRightInset; 113 } 114 115 int getOpticalBottom(View view) { 116 return view.getBottom() - mBottomInset; 117 } 118 119 int getOpticalWidth(View view) { 120 return view.getWidth() - mLeftInset - mRightInset; 121 } 122 123 int getOpticalHeight(View view) { 124 return view.getHeight() - mTopInset - mBottomInset; 125 } 126 127 int getOpticalLeftInset() { 128 return mLeftInset; 129 } 130 131 int getOpticalRightInset() { 132 return mRightInset; 133 } 134 135 int getOpticalTopInset() { 136 return mTopInset; 137 } 138 139 int getOpticalBottomInset() { 140 return mBottomInset; 141 } 142 143 void setAlignX(int alignX) { 144 mAlignX = alignX; 145 } 146 147 void setAlignY(int alignY) { 148 mAlignY = alignY; 149 } 150 151 void setOpticalInsets(int leftInset, int topInset, int rightInset, int bottomInset) { 152 mLeftInset = leftInset; 153 mTopInset = topInset; 154 mRightInset = rightInset; 155 mBottomInset = bottomInset; 156 } 157 158 private void invalidateItemDecoration() { 159 ViewParent parent = mView.getParent(); 160 if (parent instanceof RecyclerView) { 161 // TODO: we only need invalidate parent if it has ItemDecoration 162 ((RecyclerView) parent).invalidate(); 163 } 164 } 165 } 166 167 private static final String TAG = "GridLayoutManager"; 168 private static final boolean DEBUG = false; 169 170 private String getTag() { 171 return TAG + ":" + mBaseGridView.getId(); 172 } 173 174 private final BaseGridView mBaseGridView; 175 176 /** 177 * Note on conventions in the presence of RTL layout directions: 178 * Many properties and method names reference entities related to the 179 * beginnings and ends of things. In the presence of RTL flows, 180 * it may not be clear whether this is intended to reference a 181 * quantity that changes direction in RTL cases, or a quantity that 182 * does not. Here are the conventions in use: 183 * 184 * start/end: coordinate quantities - do reverse 185 * (optical) left/right: coordinate quantities - do not reverse 186 * low/high: coordinate quantities - do not reverse 187 * min/max: coordinate quantities - do not reverse 188 * scroll offset - coordinate quantities - do not reverse 189 * first/last: positional indices - do not reverse 190 * front/end: positional indices - do not reverse 191 * prepend/append: related to positional indices - do not reverse 192 * 193 * Note that although quantities do not reverse in RTL flows, their 194 * relationship does. In LTR flows, the first positional index is 195 * leftmost; in RTL flows, it is rightmost. Thus, anywhere that 196 * positional quantities are mapped onto coordinate quantities, 197 * the flow must be checked and the logic reversed. 198 */ 199 200 /** 201 * The orientation of a "row". 202 */ 203 private int mOrientation = HORIZONTAL; 204 205 private RecyclerView.State mState; 206 private RecyclerView.Recycler mRecycler; 207 208 private boolean mInLayout = false; 209 private boolean mInSelection = false; 210 211 private OnChildSelectedListener mChildSelectedListener = null; 212 213 /** 214 * The focused position, it's not the currently visually aligned position 215 * but it is the final position that we intend to focus on. If there are 216 * multiple setSelection() called, mFocusPosition saves last value. 217 */ 218 private int mFocusPosition = NO_POSITION; 219 220 /** 221 * The offset to be applied to mFocusPosition, due to adapter change, on the next 222 * layout. Set to Integer.MIN_VALUE means item was removed. 223 * TODO: This is somewhat duplication of RecyclerView getOldPosition() which is 224 * unfortunately cleared after prelayout. 225 */ 226 private int mFocusPositionOffset = 0; 227 228 /** 229 * Force a full layout under certain situations. 230 */ 231 private boolean mForceFullLayout; 232 233 /** 234 * True if layout is enabled. 235 */ 236 private boolean mLayoutEnabled = true; 237 238 /** 239 * override child visibility 240 */ 241 private int mChildVisibility = -1; 242 243 /** 244 * The scroll offsets of the viewport relative to the entire view. 245 */ 246 private int mScrollOffsetPrimary; 247 private int mScrollOffsetSecondary; 248 249 /** 250 * User-specified row height/column width. Can be WRAP_CONTENT. 251 */ 252 private int mRowSizeSecondaryRequested; 253 254 /** 255 * The fixed size of each grid item in the secondary direction. This corresponds to 256 * the row height, equal for all rows. Grid items may have variable length 257 * in the primary direction. 258 */ 259 private int mFixedRowSizeSecondary; 260 261 /** 262 * Tracks the secondary size of each row. 263 */ 264 private int[] mRowSizeSecondary; 265 266 /** 267 * Flag controlling whether the current/next layout should 268 * be updating the secondary size of rows. 269 */ 270 private boolean mRowSecondarySizeRefresh; 271 272 /** 273 * The maximum measured size of the view. 274 */ 275 private int mMaxSizeSecondary; 276 277 /** 278 * Margin between items. 279 */ 280 private int mHorizontalMargin; 281 /** 282 * Margin between items vertically. 283 */ 284 private int mVerticalMargin; 285 /** 286 * Margin in main direction. 287 */ 288 private int mMarginPrimary; 289 /** 290 * Margin in second direction. 291 */ 292 private int mMarginSecondary; 293 /** 294 * How to position child in secondary direction. 295 */ 296 private int mGravity = Gravity.START | Gravity.TOP; 297 /** 298 * The number of rows in the grid. 299 */ 300 private int mNumRows; 301 /** 302 * Number of rows requested, can be 0 to be determined by parent size and 303 * rowHeight. 304 */ 305 private int mNumRowsRequested = 1; 306 307 /** 308 * Tracking start/end position of each row for visible items. 309 */ 310 private StaggeredGrid.Row[] mRows; 311 312 /** 313 * Saves grid information of each view. 314 */ 315 private StaggeredGrid mGrid; 316 /** 317 * Position of first item (included) that has attached views. 318 */ 319 private int mFirstVisiblePos; 320 /** 321 * Position of last item (included) that has attached views. 322 */ 323 private int mLastVisiblePos; 324 325 /** 326 * Focus Scroll strategy. 327 */ 328 private int mFocusScrollStrategy = BaseGridView.FOCUS_SCROLL_ALIGNED; 329 /** 330 * Defines how item view is aligned in the window. 331 */ 332 private final WindowAlignment mWindowAlignment = new WindowAlignment(); 333 334 /** 335 * Defines how item view is aligned. 336 */ 337 private final ItemAlignment mItemAlignment = new ItemAlignment(); 338 339 /** 340 * Dimensions of the view, width or height depending on orientation. 341 */ 342 private int mSizePrimary; 343 344 /** 345 * Allow DPAD key to navigate out at the front of the View (where position = 0), 346 * default is false. 347 */ 348 private boolean mFocusOutFront; 349 350 /** 351 * Allow DPAD key to navigate out at the end of the view, default is false. 352 */ 353 private boolean mFocusOutEnd; 354 355 /** 356 * True if focus search is disabled. 357 */ 358 private boolean mFocusSearchDisabled; 359 360 /** 361 * True if prune child, might be disabled during transition. 362 */ 363 private boolean mPruneChild = true; 364 365 /** 366 * True if scroll content, might be disabled during transition. 367 */ 368 private boolean mScrollEnabled = true; 369 370 private int[] mTempDeltas = new int[2]; 371 372 /** 373 * Set to true for RTL layout in horizontal orientation 374 */ 375 private boolean mReverseFlowPrimary = false; 376 377 /** 378 * Set to true for RTL layout in vertical orientation 379 */ 380 private boolean mReverseFlowSecondary = false; 381 382 /** 383 * Temporaries used for measuring. 384 */ 385 private int[] mMeasuredDimension = new int[2]; 386 387 final ViewsStateBundle mChildrenStates = new ViewsStateBundle(); 388 389 public GridLayoutManager(BaseGridView baseGridView) { 390 mBaseGridView = baseGridView; 391 } 392 393 public void setOrientation(int orientation) { 394 if (orientation != HORIZONTAL && orientation != VERTICAL) { 395 if (DEBUG) Log.v(getTag(), "invalid orientation: " + orientation); 396 return; 397 } 398 399 mOrientation = orientation; 400 mWindowAlignment.setOrientation(orientation); 401 mItemAlignment.setOrientation(orientation); 402 mForceFullLayout = true; 403 } 404 405 public void onRtlPropertiesChanged(int layoutDirection) { 406 if (mOrientation == HORIZONTAL) { 407 mReverseFlowPrimary = layoutDirection == View.LAYOUT_DIRECTION_RTL; 408 mReverseFlowSecondary = false; 409 } else { 410 mReverseFlowSecondary = layoutDirection == View.LAYOUT_DIRECTION_RTL; 411 mReverseFlowPrimary = false; 412 } 413 mWindowAlignment.setLayoutDirection(layoutDirection); 414 } 415 416 public int getFocusScrollStrategy() { 417 return mFocusScrollStrategy; 418 } 419 420 public void setFocusScrollStrategy(int focusScrollStrategy) { 421 mFocusScrollStrategy = focusScrollStrategy; 422 } 423 424 public void setWindowAlignment(int windowAlignment) { 425 mWindowAlignment.mainAxis().setWindowAlignment(windowAlignment); 426 } 427 428 public int getWindowAlignment() { 429 return mWindowAlignment.mainAxis().getWindowAlignment(); 430 } 431 432 public void setWindowAlignmentOffset(int alignmentOffset) { 433 mWindowAlignment.mainAxis().setWindowAlignmentOffset(alignmentOffset); 434 } 435 436 public int getWindowAlignmentOffset() { 437 return mWindowAlignment.mainAxis().getWindowAlignmentOffset(); 438 } 439 440 public void setWindowAlignmentOffsetPercent(float offsetPercent) { 441 mWindowAlignment.mainAxis().setWindowAlignmentOffsetPercent(offsetPercent); 442 } 443 444 public float getWindowAlignmentOffsetPercent() { 445 return mWindowAlignment.mainAxis().getWindowAlignmentOffsetPercent(); 446 } 447 448 public void setItemAlignmentOffset(int alignmentOffset) { 449 mItemAlignment.mainAxis().setItemAlignmentOffset(alignmentOffset); 450 updateChildAlignments(); 451 } 452 453 public int getItemAlignmentOffset() { 454 return mItemAlignment.mainAxis().getItemAlignmentOffset(); 455 } 456 457 public void setItemAlignmentOffsetWithPadding(boolean withPadding) { 458 mItemAlignment.mainAxis().setItemAlignmentOffsetWithPadding(withPadding); 459 updateChildAlignments(); 460 } 461 462 public boolean isItemAlignmentOffsetWithPadding() { 463 return mItemAlignment.mainAxis().isItemAlignmentOffsetWithPadding(); 464 } 465 466 public void setItemAlignmentOffsetPercent(float offsetPercent) { 467 mItemAlignment.mainAxis().setItemAlignmentOffsetPercent(offsetPercent); 468 updateChildAlignments(); 469 } 470 471 public float getItemAlignmentOffsetPercent() { 472 return mItemAlignment.mainAxis().getItemAlignmentOffsetPercent(); 473 } 474 475 public void setItemAlignmentViewId(int viewId) { 476 mItemAlignment.mainAxis().setItemAlignmentViewId(viewId); 477 updateChildAlignments(); 478 } 479 480 public int getItemAlignmentViewId() { 481 return mItemAlignment.mainAxis().getItemAlignmentViewId(); 482 } 483 484 public void setFocusOutAllowed(boolean throughFront, boolean throughEnd) { 485 mFocusOutFront = throughFront; 486 mFocusOutEnd = throughEnd; 487 } 488 489 public void setNumRows(int numRows) { 490 if (numRows < 0) throw new IllegalArgumentException(); 491 mNumRowsRequested = numRows; 492 mForceFullLayout = true; 493 } 494 495 /** 496 * Set the row height. May be WRAP_CONTENT, or a size in pixels. 497 */ 498 public void setRowHeight(int height) { 499 if (height >= 0 || height == ViewGroup.LayoutParams.WRAP_CONTENT) { 500 mRowSizeSecondaryRequested = height; 501 } else { 502 throw new IllegalArgumentException("Invalid row height: " + height); 503 } 504 } 505 506 public void setItemMargin(int margin) { 507 mVerticalMargin = mHorizontalMargin = margin; 508 mMarginPrimary = mMarginSecondary = margin; 509 } 510 511 public void setVerticalMargin(int margin) { 512 if (mOrientation == HORIZONTAL) { 513 mMarginSecondary = mVerticalMargin = margin; 514 } else { 515 mMarginPrimary = mVerticalMargin = margin; 516 } 517 } 518 519 public void setHorizontalMargin(int margin) { 520 if (mOrientation == HORIZONTAL) { 521 mMarginPrimary = mHorizontalMargin = margin; 522 } else { 523 mMarginSecondary = mHorizontalMargin = margin; 524 } 525 } 526 527 public int getVerticalMargin() { 528 return mVerticalMargin; 529 } 530 531 public int getHorizontalMargin() { 532 return mHorizontalMargin; 533 } 534 535 public void setGravity(int gravity) { 536 mGravity = gravity; 537 } 538 539 protected boolean hasDoneFirstLayout() { 540 return mGrid != null; 541 } 542 543 public void setOnChildSelectedListener(OnChildSelectedListener listener) { 544 mChildSelectedListener = listener; 545 } 546 547 private int getPositionByView(View view) { 548 if (view == null) { 549 return NO_POSITION; 550 } 551 LayoutParams params = (LayoutParams) view.getLayoutParams(); 552 if (params == null || params.isItemRemoved()) { 553 // when item is removed, the position value can be any value. 554 return NO_POSITION; 555 } 556 return params.getViewPosition(); 557 } 558 559 private int getPositionByIndex(int index) { 560 return getPositionByView(getChildAt(index)); 561 } 562 563 private void dispatchChildSelected() { 564 if (mChildSelectedListener == null) { 565 return; 566 } 567 if (mFocusPosition != NO_POSITION) { 568 View view = findViewByPosition(mFocusPosition); 569 if (view != null) { 570 RecyclerView.ViewHolder vh = mBaseGridView.getChildViewHolder(view); 571 mChildSelectedListener.onChildSelected(mBaseGridView, view, mFocusPosition, 572 vh == null? NO_ID: vh.getItemId()); 573 return; 574 } 575 } 576 mChildSelectedListener.onChildSelected(mBaseGridView, null, NO_POSITION, NO_ID); 577 } 578 579 @Override 580 public boolean canScrollHorizontally() { 581 // We can scroll horizontally if we have horizontal orientation, or if 582 // we are vertical and have more than one column. 583 return mOrientation == HORIZONTAL || mNumRows > 1; 584 } 585 586 @Override 587 public boolean canScrollVertically() { 588 // We can scroll vertically if we have vertical orientation, or if we 589 // are horizontal and have more than one row. 590 return mOrientation == VERTICAL || mNumRows > 1; 591 } 592 593 @Override 594 public RecyclerView.LayoutParams generateDefaultLayoutParams() { 595 return new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, 596 ViewGroup.LayoutParams.WRAP_CONTENT); 597 } 598 599 @Override 600 public RecyclerView.LayoutParams generateLayoutParams(Context context, AttributeSet attrs) { 601 return new LayoutParams(context, attrs); 602 } 603 604 @Override 605 public RecyclerView.LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) { 606 if (lp instanceof LayoutParams) { 607 return new LayoutParams((LayoutParams) lp); 608 } else if (lp instanceof RecyclerView.LayoutParams) { 609 return new LayoutParams((RecyclerView.LayoutParams) lp); 610 } else if (lp instanceof MarginLayoutParams) { 611 return new LayoutParams((MarginLayoutParams) lp); 612 } else { 613 return new LayoutParams(lp); 614 } 615 } 616 617 protected View getViewForPosition(int position) { 618 return mRecycler.getViewForPosition(position); 619 } 620 621 final int getOpticalLeft(View v) { 622 return ((LayoutParams) v.getLayoutParams()).getOpticalLeft(v); 623 } 624 625 final int getOpticalRight(View v) { 626 return ((LayoutParams) v.getLayoutParams()).getOpticalRight(v); 627 } 628 629 final int getOpticalTop(View v) { 630 return ((LayoutParams) v.getLayoutParams()).getOpticalTop(v); 631 } 632 633 final int getOpticalBottom(View v) { 634 return ((LayoutParams) v.getLayoutParams()).getOpticalBottom(v); 635 } 636 637 private int getViewMin(View v) { 638 return (mOrientation == HORIZONTAL) ? getOpticalLeft(v) : getOpticalTop(v); 639 } 640 641 private int getViewMax(View v) { 642 return (mOrientation == HORIZONTAL) ? getOpticalRight(v) : getOpticalBottom(v); 643 } 644 645 private int getViewCenter(View view) { 646 return (mOrientation == HORIZONTAL) ? getViewCenterX(view) : getViewCenterY(view); 647 } 648 649 private int getViewCenterSecondary(View view) { 650 return (mOrientation == HORIZONTAL) ? getViewCenterY(view) : getViewCenterX(view); 651 } 652 653 private int getViewCenterX(View v) { 654 LayoutParams p = (LayoutParams) v.getLayoutParams(); 655 return p.getOpticalLeft(v) + p.getAlignX(); 656 } 657 658 private int getViewCenterY(View v) { 659 LayoutParams p = (LayoutParams) v.getLayoutParams(); 660 return p.getOpticalTop(v) + p.getAlignY(); 661 } 662 663 /** 664 * Save Recycler and State for convenience. Must be paired with leaveContext(). 665 */ 666 private void saveContext(Recycler recycler, State state) { 667 if (mRecycler != null || mState != null) { 668 Log.e(TAG, "Recycler information was not released, bug!"); 669 } 670 mRecycler = recycler; 671 mState = state; 672 } 673 674 /** 675 * Discard saved Recycler and State. 676 */ 677 private void leaveContext() { 678 mRecycler = null; 679 mState = null; 680 } 681 682 /** 683 * Re-initialize data structures for a data change or handling invisible 684 * selection. The method tries its best to preserve position information so 685 * that staggered grid looks same before and after re-initialize. 686 * @param focusPosition The initial focusPosition that we would like to 687 * focus on. 688 * @return Actual position that can be focused on. 689 */ 690 private int init(int focusPosition) { 691 692 final int newItemCount = mState.getItemCount(); 693 694 // Force the re-init path in the following conditional 695 if (newItemCount == 0) { 696 focusPosition = NO_POSITION; 697 } else if (focusPosition == NO_POSITION && newItemCount > 0) { 698 // if focus position is never set before, initialize it to 0 699 focusPosition = 0; 700 } 701 702 // If adapter has changed then caches are invalid; otherwise, 703 // we try to maintain each row's position if number of rows keeps the same 704 // and existing mGrid contains the focusPosition. 705 if (mRows != null && mNumRows == mRows.length && 706 mGrid != null && mGrid.getSize() > 0 && focusPosition >= 0 && 707 focusPosition >= mGrid.getFirstIndex() && 708 focusPosition <= mGrid.getLastIndex()) { 709 // strip mGrid to a subset (like a column) that contains focusPosition 710 mGrid.stripDownTo(focusPosition); 711 // make sure that remaining items do not exceed new adapter size 712 int firstIndex = mGrid.getFirstIndex(); 713 int lastIndex = mGrid.getLastIndex(); 714 if (DEBUG) { 715 Log .v(getTag(), "mGrid firstIndex " + firstIndex + " lastIndex " + lastIndex); 716 } 717 for (int i = lastIndex; i >=firstIndex; i--) { 718 if (i >= newItemCount) { 719 mGrid.removeLast(); 720 } 721 } 722 if (mGrid.getSize() == 0) { 723 focusPosition = newItemCount - 1; 724 // initialize row start locations 725 for (int i = 0; i < mNumRows; i++) { 726 mRows[i].low = 0; 727 mRows[i].high = 0; 728 } 729 if (DEBUG) Log.v(getTag(), "mGrid zero size"); 730 } else { 731 // initialize row start locations 732 for (int i = 0; i < mNumRows; i++) { 733 mRows[i].low = Integer.MAX_VALUE; 734 mRows[i].high = Integer.MIN_VALUE; 735 } 736 firstIndex = mGrid.getFirstIndex(); 737 lastIndex = mGrid.getLastIndex(); 738 if (focusPosition > lastIndex) { 739 focusPosition = mGrid.getLastIndex(); 740 } 741 if (DEBUG) { 742 Log.v(getTag(), "mGrid firstIndex " + firstIndex + " lastIndex " 743 + lastIndex + " focusPosition " + focusPosition); 744 } 745 // fill rows with minimal view positions of the subset 746 for (int i = firstIndex; i <= lastIndex; i++) { 747 View v = findViewByPosition(i); 748 if (v == null) { 749 continue; 750 } 751 int row = mGrid.getLocation(i).row; 752 int low = getViewMin(v) + mScrollOffsetPrimary; 753 if (low < mRows[row].low) { 754 mRows[row].low = mRows[row].high = low; 755 } 756 } 757 int firstItemRowPosition = mRows[mGrid.getLocation(firstIndex).row].low; 758 if (firstItemRowPosition == Integer.MAX_VALUE) { 759 firstItemRowPosition = 0; 760 } 761 if (mState.didStructureChange()) { 762 // if there is structure change, the removed item might be in the 763 // subset, so it is meaningless to maintain the low locations. 764 for (int i = 0; i < mNumRows; i++) { 765 mRows[i].low = firstItemRowPosition; 766 mRows[i].high = firstItemRowPosition; 767 } 768 } else { 769 // fill other rows that does not include the subset using first item 770 for (int i = 0; i < mNumRows; i++) { 771 if (mRows[i].low == Integer.MAX_VALUE) { 772 mRows[i].low = mRows[i].high = firstItemRowPosition; 773 } 774 } 775 } 776 } 777 778 // Same adapter, we can reuse any attached views 779 detachAndScrapAttachedViews(mRecycler); 780 781 } else { 782 // otherwise recreate data structure 783 mRows = new StaggeredGrid.Row[mNumRows]; 784 785 for (int i = 0; i < mNumRows; i++) { 786 mRows[i] = new StaggeredGrid.Row(); 787 } 788 mGrid = new StaggeredGridDefault(); 789 if (newItemCount == 0) { 790 focusPosition = NO_POSITION; 791 } else if (focusPosition >= newItemCount) { 792 focusPosition = newItemCount - 1; 793 } 794 795 // Adapter may have changed so remove all attached views permanently 796 removeAndRecycleAllViews(mRecycler); 797 798 mScrollOffsetPrimary = 0; 799 mScrollOffsetSecondary = 0; 800 mWindowAlignment.reset(); 801 } 802 803 mGrid.setProvider(mGridProvider); 804 // mGrid share the same Row array information 805 mGrid.setRows(mRows); 806 mFirstVisiblePos = mLastVisiblePos = NO_POSITION; 807 808 initScrollController(); 809 updateScrollSecondAxis(); 810 811 return focusPosition; 812 } 813 814 private int getRowSizeSecondary(int rowIndex) { 815 if (mFixedRowSizeSecondary != 0) { 816 return mFixedRowSizeSecondary; 817 } 818 if (mRowSizeSecondary == null) { 819 return 0; 820 } 821 return mRowSizeSecondary[rowIndex]; 822 } 823 824 private int getRowStartSecondary(int rowIndex) { 825 int start = 0; 826 // Iterate from left to right, which is a different index traversal 827 // in RTL flow 828 if (mReverseFlowSecondary) { 829 for (int i = mNumRows-1; i > rowIndex; i--) { 830 start += getRowSizeSecondary(i) + mMarginSecondary; 831 } 832 } else { 833 for (int i = 0; i < rowIndex; i++) { 834 start += getRowSizeSecondary(i) + mMarginSecondary; 835 } 836 } 837 return start; 838 } 839 840 private int getSizeSecondary() { 841 int rightmostIndex = mReverseFlowSecondary ? 0 : mNumRows - 1; 842 return getRowStartSecondary(rightmostIndex) + getRowSizeSecondary(rightmostIndex); 843 } 844 845 private void measureScrapChild(int position, int widthSpec, int heightSpec, 846 int[] measuredDimension) { 847 View view = mRecycler.getViewForPosition(position); 848 if (view != null) { 849 LayoutParams p = (LayoutParams) view.getLayoutParams(); 850 int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec, 851 getPaddingLeft() + getPaddingRight(), p.width); 852 int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec, 853 getPaddingTop() + getPaddingBottom(), p.height); 854 view.measure(childWidthSpec, childHeightSpec); 855 measuredDimension[0] = view.getMeasuredWidth(); 856 measuredDimension[1] = view.getMeasuredHeight(); 857 mRecycler.recycleView(view); 858 } 859 } 860 861 private boolean processRowSizeSecondary(boolean measure) { 862 if (mFixedRowSizeSecondary != 0) { 863 return false; 864 } 865 866 List<Integer>[] rows = mGrid == null ? null : 867 mGrid.getItemPositionsInRows(mFirstVisiblePos, mLastVisiblePos); 868 boolean changed = false; 869 int scrapChildWidth = -1; 870 int scrapChildHeight = -1; 871 872 for (int rowIndex = 0; rowIndex < mNumRows; rowIndex++) { 873 final int rowItemCount = rows == null ? 0 : rows[rowIndex].size(); 874 if (DEBUG) Log.v(getTag(), "processRowSizeSecondary row " + rowIndex + 875 " rowItemCount " + rowItemCount); 876 877 int rowSize = -1; 878 for (int i = 0; i < rowItemCount; i++) { 879 final View view = findViewByPosition(rows[rowIndex].get(i)); 880 if (view == null) { 881 continue; 882 } 883 if (measure && view.isLayoutRequested()) { 884 measureChild(view); 885 } 886 final int secondarySize = mOrientation == HORIZONTAL ? 887 view.getMeasuredHeight() : view.getMeasuredWidth(); 888 if (secondarySize > rowSize) { 889 rowSize = secondarySize; 890 } 891 } 892 893 final int itemCount = mState.getItemCount(); 894 if (measure && rowSize < 0 && itemCount > 0) { 895 if (scrapChildWidth < 0 && scrapChildHeight < 0) { 896 int position; 897 if (mFocusPosition == NO_POSITION) { 898 position = 0; 899 } else if (mFocusPosition >= itemCount) { 900 position = itemCount - 1; 901 } else { 902 position = mFocusPosition; 903 } 904 measureScrapChild(position, 905 MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), 906 MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), 907 mMeasuredDimension); 908 scrapChildWidth = mMeasuredDimension[0]; 909 scrapChildHeight = mMeasuredDimension[1]; 910 if (DEBUG) Log.v(TAG, "measured scrap child: " + scrapChildWidth + 911 " " + scrapChildHeight); 912 } 913 rowSize = mOrientation == HORIZONTAL ? scrapChildHeight : scrapChildWidth; 914 } 915 916 if (rowSize < 0) { 917 rowSize = 0; 918 } 919 920 if (DEBUG) Log.v(getTag(), "row " + rowIndex + " rowItemCount " + rowItemCount + 921 " rowSize " + rowSize); 922 923 if (mRowSizeSecondary[rowIndex] != rowSize) { 924 if (DEBUG) Log.v(getTag(), "row size secondary changed: " + mRowSizeSecondary[rowIndex] + 925 ", " + rowSize); 926 927 mRowSizeSecondary[rowIndex] = rowSize; 928 changed = true; 929 } 930 } 931 932 return changed; 933 } 934 935 /** 936 * Checks if we need to update row secondary sizes. 937 */ 938 private void updateRowSecondarySizeRefresh() { 939 mRowSecondarySizeRefresh = processRowSizeSecondary(false); 940 if (mRowSecondarySizeRefresh) { 941 if (DEBUG) Log.v(getTag(), "mRowSecondarySizeRefresh now set"); 942 forceRequestLayout(); 943 } 944 } 945 946 private void forceRequestLayout() { 947 if (DEBUG) Log.v(getTag(), "forceRequestLayout"); 948 // RecyclerView prevents us from requesting layout in many cases 949 // (during layout, during scroll, etc.) 950 // For secondary row size wrap_content support we currently need a 951 // second layout pass to update the measured size after having measured 952 // and added child views in layoutChildren. 953 // Force the second layout by posting a delayed runnable. 954 // TODO: investigate allowing a second layout pass, 955 // or move child add/measure logic to the measure phase. 956 ViewCompat.postOnAnimation(mBaseGridView, mRequestLayoutRunnable); 957 } 958 959 private final Runnable mRequestLayoutRunnable = new Runnable() { 960 @Override 961 public void run() { 962 if (DEBUG) Log.v(getTag(), "request Layout from runnable"); 963 requestLayout(); 964 } 965 }; 966 967 @Override 968 public void onMeasure(Recycler recycler, State state, int widthSpec, int heightSpec) { 969 saveContext(recycler, state); 970 971 int sizePrimary, sizeSecondary, modeSecondary, paddingSecondary; 972 int measuredSizeSecondary; 973 if (mOrientation == HORIZONTAL) { 974 sizePrimary = MeasureSpec.getSize(widthSpec); 975 sizeSecondary = MeasureSpec.getSize(heightSpec); 976 modeSecondary = MeasureSpec.getMode(heightSpec); 977 paddingSecondary = getPaddingTop() + getPaddingBottom(); 978 } else { 979 sizeSecondary = MeasureSpec.getSize(widthSpec); 980 sizePrimary = MeasureSpec.getSize(heightSpec); 981 modeSecondary = MeasureSpec.getMode(widthSpec); 982 paddingSecondary = getPaddingLeft() + getPaddingRight(); 983 } 984 if (DEBUG) Log.v(getTag(), "onMeasure widthSpec " + Integer.toHexString(widthSpec) + 985 " heightSpec " + Integer.toHexString(heightSpec) + 986 " modeSecondary " + Integer.toHexString(modeSecondary) + 987 " sizeSecondary " + sizeSecondary + " " + this); 988 989 mMaxSizeSecondary = sizeSecondary; 990 991 if (mRowSizeSecondaryRequested == ViewGroup.LayoutParams.WRAP_CONTENT) { 992 mNumRows = mNumRowsRequested == 0 ? 1 : mNumRowsRequested; 993 mFixedRowSizeSecondary = 0; 994 995 if (mRowSizeSecondary == null || mRowSizeSecondary.length != mNumRows) { 996 mRowSizeSecondary = new int[mNumRows]; 997 } 998 999 // Measure all current children and update cached row heights 1000 processRowSizeSecondary(true); 1001 1002 switch (modeSecondary) { 1003 case MeasureSpec.UNSPECIFIED: 1004 measuredSizeSecondary = getSizeSecondary() + paddingSecondary; 1005 break; 1006 case MeasureSpec.AT_MOST: 1007 measuredSizeSecondary = Math.min(getSizeSecondary() + paddingSecondary, 1008 mMaxSizeSecondary); 1009 break; 1010 case MeasureSpec.EXACTLY: 1011 measuredSizeSecondary = mMaxSizeSecondary; 1012 break; 1013 default: 1014 throw new IllegalStateException("wrong spec"); 1015 } 1016 1017 } else { 1018 switch (modeSecondary) { 1019 case MeasureSpec.UNSPECIFIED: 1020 if (mRowSizeSecondaryRequested == 0) { 1021 if (mOrientation == HORIZONTAL) { 1022 throw new IllegalStateException("Must specify rowHeight or view height"); 1023 } else { 1024 throw new IllegalStateException("Must specify columnWidth or view width"); 1025 } 1026 } 1027 mFixedRowSizeSecondary = mRowSizeSecondaryRequested; 1028 mNumRows = mNumRowsRequested == 0 ? 1 : mNumRowsRequested; 1029 measuredSizeSecondary = mFixedRowSizeSecondary * mNumRows + mMarginSecondary 1030 * (mNumRows - 1) + paddingSecondary; 1031 break; 1032 case MeasureSpec.AT_MOST: 1033 case MeasureSpec.EXACTLY: 1034 if (mNumRowsRequested == 0 && mRowSizeSecondaryRequested == 0) { 1035 mNumRows = 1; 1036 mFixedRowSizeSecondary = sizeSecondary - paddingSecondary; 1037 } else if (mNumRowsRequested == 0) { 1038 mFixedRowSizeSecondary = mRowSizeSecondaryRequested; 1039 mNumRows = (sizeSecondary + mMarginSecondary) 1040 / (mRowSizeSecondaryRequested + mMarginSecondary); 1041 } else if (mRowSizeSecondaryRequested == 0) { 1042 mNumRows = mNumRowsRequested; 1043 mFixedRowSizeSecondary = (sizeSecondary - paddingSecondary - mMarginSecondary 1044 * (mNumRows - 1)) / mNumRows; 1045 } else { 1046 mNumRows = mNumRowsRequested; 1047 mFixedRowSizeSecondary = mRowSizeSecondaryRequested; 1048 } 1049 measuredSizeSecondary = sizeSecondary; 1050 if (modeSecondary == MeasureSpec.AT_MOST) { 1051 int childrenSize = mFixedRowSizeSecondary * mNumRows + mMarginSecondary 1052 * (mNumRows - 1) + paddingSecondary; 1053 if (childrenSize < measuredSizeSecondary) { 1054 measuredSizeSecondary = childrenSize; 1055 } 1056 } 1057 break; 1058 default: 1059 throw new IllegalStateException("wrong spec"); 1060 } 1061 } 1062 if (mOrientation == HORIZONTAL) { 1063 setMeasuredDimension(sizePrimary, measuredSizeSecondary); 1064 } else { 1065 setMeasuredDimension(measuredSizeSecondary, sizePrimary); 1066 } 1067 if (DEBUG) { 1068 Log.v(getTag(), "onMeasure sizePrimary " + sizePrimary + 1069 " measuredSizeSecondary " + measuredSizeSecondary + 1070 " mFixedRowSizeSecondary " + mFixedRowSizeSecondary + 1071 " mNumRows " + mNumRows); 1072 } 1073 1074 leaveContext(); 1075 } 1076 1077 private void measureChild(View child) { 1078 final ViewGroup.LayoutParams lp = child.getLayoutParams(); 1079 final int secondarySpec = (mRowSizeSecondaryRequested == ViewGroup.LayoutParams.WRAP_CONTENT) ? 1080 MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED) : 1081 MeasureSpec.makeMeasureSpec(mFixedRowSizeSecondary, MeasureSpec.EXACTLY); 1082 int widthSpec, heightSpec; 1083 1084 if (mOrientation == HORIZONTAL) { 1085 widthSpec = ViewGroup.getChildMeasureSpec( 1086 MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), 1087 0, lp.width); 1088 heightSpec = ViewGroup.getChildMeasureSpec(secondarySpec, 0, lp.height); 1089 } else { 1090 heightSpec = ViewGroup.getChildMeasureSpec( 1091 MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), 1092 0, lp.height); 1093 widthSpec = ViewGroup.getChildMeasureSpec(secondarySpec, 0, lp.width); 1094 } 1095 1096 child.measure(widthSpec, heightSpec); 1097 1098 if (DEBUG) Log.v(getTag(), "measureChild secondarySpec " + Integer.toHexString(secondarySpec) + 1099 " widthSpec " + Integer.toHexString(widthSpec) + 1100 " heightSpec " + Integer.toHexString(heightSpec) + 1101 " measuredWidth " + child.getMeasuredWidth() + 1102 " measuredHeight " + child.getMeasuredHeight()); 1103 if (DEBUG) Log.v(getTag(), "child lp width " + lp.width + " height " + lp.height); 1104 } 1105 1106 private StaggeredGrid.Provider mGridProvider = new StaggeredGrid.Provider() { 1107 1108 @Override 1109 public int getCount() { 1110 return mState.getItemCount(); 1111 } 1112 1113 @Override 1114 public void createItem(int index, int rowIndex, boolean append) { 1115 View v = getViewForPosition(index); 1116 if (mFirstVisiblePos >= 0) { 1117 // when StaggeredGrid append or prepend item, we must guarantee 1118 // that sibling item has created views already. 1119 if (append && index != mLastVisiblePos + 1) { 1120 throw new RuntimeException(); 1121 } else if (!append && index != mFirstVisiblePos - 1) { 1122 throw new RuntimeException(); 1123 } 1124 } 1125 1126 // See recyclerView docs: we don't need re-add scraped view if it was removed. 1127 if (!((RecyclerView.LayoutParams) v.getLayoutParams()).isItemRemoved()) { 1128 if (append) { 1129 addView(v); 1130 } else { 1131 addView(v, 0); 1132 } 1133 if (mChildVisibility != -1) { 1134 v.setVisibility(mChildVisibility); 1135 } 1136 1137 // View is added first or it won't be found by dispatchChildSelected. 1138 if (mInLayout && index == mFocusPosition) { 1139 dispatchChildSelected(); 1140 } 1141 1142 measureChild(v); 1143 } 1144 1145 int length = mOrientation == HORIZONTAL ? v.getMeasuredWidth() : v.getMeasuredHeight(); 1146 int start, end; 1147 final boolean rowIsEmpty = mRows[rowIndex].high == mRows[rowIndex].low; 1148 boolean addLow = (!mReverseFlowPrimary) ? append : !append; 1149 int lowVisiblePos = (!mReverseFlowPrimary) ? mFirstVisiblePos : mLastVisiblePos; 1150 int highVisiblePos = (!mReverseFlowPrimary) ? mLastVisiblePos : mFirstVisiblePos; 1151 if (addLow) { 1152 if (!rowIsEmpty) { 1153 // if there are existing item in the row, add margin between 1154 start = mRows[rowIndex].high + mMarginPrimary; 1155 } else { 1156 if (highVisiblePos >= 0) { 1157 int lastRow = mGrid.getLocation(highVisiblePos).row; 1158 // if the last visible item is not last row, align to beginning, 1159 // otherwise start a new column after. 1160 if (lastRow < mNumRows - 1) { 1161 start = mRows[lastRow].low; 1162 } else { 1163 start = mRows[lastRow].high + mMarginPrimary; 1164 } 1165 } else { 1166 start = 0; 1167 } 1168 mRows[rowIndex].low = start; 1169 } 1170 end = start + length; 1171 mRows[rowIndex].high = end; 1172 } else { 1173 if (!rowIsEmpty) { 1174 // if there are existing item in the row, add margin between 1175 end = mRows[rowIndex].low - mMarginPrimary; 1176 start = end - length; 1177 } else { 1178 if (lowVisiblePos >= 0) { 1179 int firstRow = mGrid.getLocation(lowVisiblePos).row; 1180 // if the first visible item is not first row, align to beginning, 1181 // otherwise start a new column before. 1182 if (firstRow > 0) { 1183 start = mRows[firstRow].low; 1184 end = start + length; 1185 } else { 1186 end = mRows[firstRow].low - mMarginPrimary; 1187 start = end - length; 1188 } 1189 } else { 1190 start = 0; 1191 end = length; 1192 } 1193 mRows[rowIndex].high = end; 1194 } 1195 mRows[rowIndex].low = start; 1196 } 1197 if (mFirstVisiblePos < 0) { 1198 mFirstVisiblePos = mLastVisiblePos = index; 1199 } else { 1200 if (append) { 1201 mLastVisiblePos++; 1202 } else { 1203 mFirstVisiblePos--; 1204 } 1205 } 1206 if (DEBUG) Log.v(getTag(), "start " + start + " end " + end); 1207 int startSecondary = getRowStartSecondary(rowIndex) - mScrollOffsetSecondary; 1208 mChildrenStates.loadView(v, index); 1209 layoutChild(rowIndex, v, start - mScrollOffsetPrimary, end - mScrollOffsetPrimary, 1210 startSecondary); 1211 if (DEBUG) { 1212 Log.d(getTag(), "addView " + index + " " + v); 1213 } 1214 if (index == mFirstVisiblePos) { 1215 if (!mReverseFlowPrimary) { 1216 updateScrollMin(); 1217 } else { 1218 updateScrollMax(); 1219 } 1220 } 1221 if (index == mLastVisiblePos) { 1222 if (!mReverseFlowPrimary) { 1223 updateScrollMax(); 1224 } else { 1225 updateScrollMin(); 1226 } 1227 } 1228 } 1229 }; 1230 1231 private void layoutChild(int rowIndex, View v, int start, int end, int startSecondary) { 1232 int sizeSecondary = mOrientation == HORIZONTAL ? v.getMeasuredHeight() 1233 : v.getMeasuredWidth(); 1234 if (mFixedRowSizeSecondary > 0) { 1235 sizeSecondary = Math.min(sizeSecondary, mFixedRowSizeSecondary); 1236 } 1237 final int verticalGravity = mGravity & Gravity.VERTICAL_GRAVITY_MASK; 1238 final int horizontalGravity = (mReverseFlowPrimary || mReverseFlowSecondary) ? 1239 Gravity.getAbsoluteGravity(mGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK, View.LAYOUT_DIRECTION_RTL) : 1240 mGravity & Gravity.HORIZONTAL_GRAVITY_MASK; 1241 if (mOrientation == HORIZONTAL && verticalGravity == Gravity.TOP 1242 || mOrientation == VERTICAL && horizontalGravity == Gravity.LEFT) { 1243 // do nothing 1244 } else if (mOrientation == HORIZONTAL && verticalGravity == Gravity.BOTTOM 1245 || mOrientation == VERTICAL && horizontalGravity == Gravity.RIGHT) { 1246 startSecondary += getRowSizeSecondary(rowIndex) - sizeSecondary; 1247 } else if (mOrientation == HORIZONTAL && verticalGravity == Gravity.CENTER_VERTICAL 1248 || mOrientation == VERTICAL && horizontalGravity == Gravity.CENTER_HORIZONTAL) { 1249 startSecondary += (getRowSizeSecondary(rowIndex) - sizeSecondary) / 2; 1250 } 1251 int left, top, right, bottom; 1252 if (mOrientation == HORIZONTAL) { 1253 left = start; 1254 top = startSecondary; 1255 right = end; 1256 bottom = startSecondary + sizeSecondary; 1257 } else { 1258 top = start; 1259 left = startSecondary; 1260 bottom = end; 1261 right = startSecondary + sizeSecondary; 1262 } 1263 v.layout(left, top, right, bottom); 1264 updateChildOpticalInsets(v, left, top, right, bottom); 1265 updateChildAlignments(v); 1266 } 1267 1268 private void updateChildOpticalInsets(View v, int left, int top, int right, int bottom) { 1269 LayoutParams p = (LayoutParams) v.getLayoutParams(); 1270 p.setOpticalInsets(left - v.getLeft(), top - v.getTop(), 1271 v.getRight() - right, v.getBottom() - bottom); 1272 } 1273 1274 private void updateChildAlignments(View v) { 1275 LayoutParams p = (LayoutParams) v.getLayoutParams(); 1276 p.setAlignX(mItemAlignment.horizontal.getAlignmentPosition(v)); 1277 p.setAlignY(mItemAlignment.vertical.getAlignmentPosition(v)); 1278 } 1279 1280 private void updateChildAlignments() { 1281 for (int i = 0, c = getChildCount(); i < c; i++) { 1282 updateChildAlignments(getChildAt(i)); 1283 } 1284 } 1285 1286 private boolean needsAppendVisibleItem() { 1287 if (mLastVisiblePos < mFocusPosition) { 1288 return true; 1289 } 1290 if (mReverseFlowPrimary) { 1291 for (int i = 0; i < mNumRows; i++) { 1292 if (mRows[i].low == mRows[i].high) { 1293 if (mRows[i].low > mScrollOffsetPrimary) { 1294 return true; 1295 } 1296 } else if (mRows[i].low - mMarginPrimary > mScrollOffsetPrimary) { 1297 return true; 1298 } 1299 } 1300 } else { 1301 int right = mScrollOffsetPrimary + mSizePrimary; 1302 for (int i = 0; i < mNumRows; i++) { 1303 if (mRows[i].low == mRows[i].high) { 1304 if (mRows[i].high < right) { 1305 return true; 1306 } 1307 } else if (mRows[i].high < right - mMarginPrimary) { 1308 return true; 1309 } 1310 } 1311 } 1312 return false; 1313 } 1314 1315 private boolean needsPrependVisibleItem() { 1316 if (mFirstVisiblePos > mFocusPosition) { 1317 return true; 1318 } 1319 if (mReverseFlowPrimary) { 1320 int right = mScrollOffsetPrimary + mSizePrimary; 1321 for (int i = 0; i < mNumRows; i++) { 1322 if (mRows[i].low == mRows[i].high) { 1323 if (mRows[i].high < right) { 1324 return true; 1325 } 1326 } else if (mRows[i].high < right - mMarginPrimary) { 1327 return true; 1328 } 1329 } 1330 } else { 1331 for (int i = 0; i < mNumRows; i++) { 1332 if (mRows[i].low == mRows[i].high) { 1333 if (mRows[i].low > mScrollOffsetPrimary) { 1334 return true; 1335 } 1336 } else if (mRows[i].low - mMarginPrimary > mScrollOffsetPrimary) { 1337 return true; 1338 } 1339 } 1340 } 1341 return false; 1342 } 1343 1344 // Append one column if possible and return true if reach end. 1345 private boolean appendOneVisibleItem() { 1346 while (true) { 1347 if (mLastVisiblePos != NO_POSITION && mLastVisiblePos < mState.getItemCount() -1 && 1348 mLastVisiblePos < mGrid.getLastIndex()) { 1349 // append invisible view of saved location till last row 1350 final int index = mLastVisiblePos + 1; 1351 final int row = mGrid.getLocation(index).row; 1352 mGridProvider.createItem(index, row, true); 1353 if (row == mNumRows - 1) { 1354 return false; 1355 } 1356 } else if ((mLastVisiblePos == NO_POSITION && mState.getItemCount() > 0) || 1357 (mLastVisiblePos != NO_POSITION && 1358 mLastVisiblePos < mState.getItemCount() - 1)) { 1359 mGrid.appendItems(mScrollOffsetPrimary + mSizePrimary); 1360 return false; 1361 } else { 1362 return true; 1363 } 1364 } 1365 } 1366 1367 private void appendVisibleItems() { 1368 while (needsAppendVisibleItem()) { 1369 if (appendOneVisibleItem()) { 1370 break; 1371 } 1372 } 1373 } 1374 1375 // Prepend one column if possible and return true if reach end. 1376 private boolean prependOneVisibleItem() { 1377 while (true) { 1378 if (mFirstVisiblePos > 0) { 1379 if (mFirstVisiblePos > mGrid.getFirstIndex()) { 1380 // prepend invisible view of saved location till first row 1381 final int index = mFirstVisiblePos - 1; 1382 final int row = mGrid.getLocation(index).row; 1383 mGridProvider.createItem(index, row, false); 1384 if (row == 0) { 1385 return false; 1386 } 1387 } else { 1388 mGrid.prependItems(mScrollOffsetPrimary); 1389 return false; 1390 } 1391 } else { 1392 return true; 1393 } 1394 } 1395 } 1396 1397 private void prependVisibleItems() { 1398 while (needsPrependVisibleItem()) { 1399 if (prependOneVisibleItem()) { 1400 break; 1401 } 1402 } 1403 } 1404 1405 private void removeChildAt(int position) { 1406 View v = findViewByPosition(position); 1407 if (v != null) { 1408 if (DEBUG) { 1409 Log.d(getTag(), "removeAndRecycleViewAt " + position + " " + v); 1410 } 1411 mChildrenStates.saveOffscreenView(v, position); 1412 removeAndRecycleView(v, mRecycler); 1413 } 1414 } 1415 1416 private void removeInvisibleViewsAtEnd() { 1417 if (!mPruneChild) { 1418 return; 1419 } 1420 boolean update = false; 1421 while(mLastVisiblePos > mFirstVisiblePos && mLastVisiblePos > mFocusPosition) { 1422 View view = findViewByPosition(mLastVisiblePos); 1423 boolean offEnd = (!mReverseFlowPrimary) ? getViewMin(view) > mSizePrimary : 1424 getViewMax(view) < 0; 1425 if (offEnd) { 1426 removeChildAt(mLastVisiblePos); 1427 mLastVisiblePos--; 1428 update = true; 1429 } else { 1430 break; 1431 } 1432 } 1433 if (update) { 1434 updateRowsMinMax(); 1435 } 1436 } 1437 1438 private void removeInvisibleViewsAtFront() { 1439 if (!mPruneChild) { 1440 return; 1441 } 1442 boolean update = false; 1443 while(mLastVisiblePos > mFirstVisiblePos && mFirstVisiblePos < mFocusPosition) { 1444 View view = findViewByPosition(mFirstVisiblePos); 1445 boolean offFront = (!mReverseFlowPrimary) ? getViewMax(view) < 0: 1446 getViewMin(view) > mSizePrimary; 1447 if (offFront) { 1448 removeChildAt(mFirstVisiblePos); 1449 mFirstVisiblePos++; 1450 update = true; 1451 } else { 1452 break; 1453 } 1454 } 1455 if (update) { 1456 updateRowsMinMax(); 1457 } 1458 } 1459 1460 private void updateRowsMinMax() { 1461 if (mFirstVisiblePos < 0) { 1462 return; 1463 } 1464 for (int i = 0; i < mNumRows; i++) { 1465 mRows[i].low = Integer.MAX_VALUE; 1466 mRows[i].high = Integer.MIN_VALUE; 1467 } 1468 for (int i = mFirstVisiblePos; i <= mLastVisiblePos; i++) { 1469 View view = findViewByPosition(i); 1470 int row = mGrid.getLocation(i).row; 1471 int low = getViewMin(view) + mScrollOffsetPrimary; 1472 if (low < mRows[row].low) { 1473 mRows[row].low = low; 1474 } 1475 int high = getViewMax(view) + mScrollOffsetPrimary; 1476 if (high > mRows[row].high) { 1477 mRows[row].high = high; 1478 } 1479 } 1480 } 1481 1482 // Fast layout when there is no structure change, adapter change, etc. 1483 protected void fastRelayout(boolean scrollToFocus) { 1484 initScrollController(); 1485 1486 List<Integer>[] rows = mGrid.getItemPositionsInRows(mFirstVisiblePos, mLastVisiblePos); 1487 1488 // relayout and repositioning views on each row 1489 for (int i = 0; i < mNumRows; i++) { 1490 List<Integer> row = rows[i]; 1491 final int startSecondary = getRowStartSecondary(i) - mScrollOffsetSecondary; 1492 for (int j = 0, size = row.size(); j < size; j++) { 1493 final int position = row.get(j); 1494 View view = findViewByPosition(position); 1495 int primaryDelta, end; 1496 1497 int start = getViewMin(view); 1498 int oldPrimarySize = (mOrientation == HORIZONTAL) ? 1499 view.getMeasuredWidth() : 1500 view.getMeasuredHeight(); 1501 1502 LayoutParams lp = (LayoutParams) view.getLayoutParams(); 1503 if (lp.viewNeedsUpdate()) { 1504 int index = mBaseGridView.indexOfChild(view); 1505 detachAndScrapView(view, mRecycler); 1506 view = getViewForPosition(position); 1507 addView(view, index); 1508 } 1509 1510 if (view.isLayoutRequested()) { 1511 measureChild(view); 1512 } 1513 1514 if (mOrientation == HORIZONTAL) { 1515 end = start + view.getMeasuredWidth(); 1516 primaryDelta = view.getMeasuredWidth() - oldPrimarySize; 1517 if (primaryDelta != 0) { 1518 for (int k = j + 1; k < size; k++) { 1519 findViewByPosition(row.get(k)).offsetLeftAndRight(primaryDelta); 1520 } 1521 } 1522 } else { 1523 end = start + view.getMeasuredHeight(); 1524 primaryDelta = view.getMeasuredHeight() - oldPrimarySize; 1525 if (primaryDelta != 0) { 1526 for (int k = j + 1; k < size; k++) { 1527 findViewByPosition(row.get(k)).offsetTopAndBottom(primaryDelta); 1528 } 1529 } 1530 } 1531 layoutChild(i, view, start, end, startSecondary); 1532 } 1533 } 1534 1535 updateRowsMinMax(); 1536 appendVisibleItems(); 1537 prependVisibleItems(); 1538 1539 updateRowsMinMax(); 1540 updateScrollMin(); 1541 updateScrollMax(); 1542 updateScrollSecondAxis(); 1543 1544 if (scrollToFocus) { 1545 View focusView = findViewByPosition(mFocusPosition == NO_POSITION ? 0 : mFocusPosition); 1546 scrollToView(focusView, false); 1547 } 1548 } 1549 1550 public void removeAndRecycleAllViews(RecyclerView.Recycler recycler) { 1551 if (DEBUG) Log.v(TAG, "removeAndRecycleAllViews " + getChildCount()); 1552 for (int i = getChildCount() - 1; i >= 0; i--) { 1553 removeAndRecycleViewAt(i, recycler); 1554 } 1555 } 1556 1557 // Lays out items based on the current scroll position 1558 @Override 1559 public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) { 1560 if (DEBUG) { 1561 Log.v(getTag(), "layoutChildren start numRows " + mNumRows + " mScrollOffsetSecondary " 1562 + mScrollOffsetSecondary + " mScrollOffsetPrimary " + mScrollOffsetPrimary 1563 + " inPreLayout " + state.isPreLayout() 1564 + " didStructureChange " + state.didStructureChange() 1565 + " mForceFullLayout " + mForceFullLayout); 1566 Log.v(getTag(), "width " + getWidth() + " height " + getHeight()); 1567 } 1568 1569 if (mNumRows == 0) { 1570 // haven't done measure yet 1571 return; 1572 } 1573 final int itemCount = state.getItemCount(); 1574 if (itemCount < 0) { 1575 return; 1576 } 1577 1578 if (!mLayoutEnabled) { 1579 discardLayoutInfo(); 1580 removeAndRecycleAllViews(recycler); 1581 return; 1582 } 1583 mInLayout = true; 1584 1585 final boolean scrollToFocus = !isSmoothScrolling() 1586 && mFocusScrollStrategy == BaseGridView.FOCUS_SCROLL_ALIGNED; 1587 if (mFocusPosition != NO_POSITION && mFocusPositionOffset != Integer.MIN_VALUE) { 1588 mFocusPosition = mFocusPosition + mFocusPositionOffset; 1589 mFocusPositionOffset = 0; 1590 } 1591 saveContext(recycler, state); 1592 1593 // Track the old focus view so we can adjust our system scroll position 1594 // so that any scroll animations happening now will remain valid. 1595 // We must use same delta in Pre Layout (if prelayout exists) and second layout. 1596 // So we cache the deltas in PreLayout and use it in second layout. 1597 int delta = 0, deltaSecondary = 0; 1598 if (mFocusPosition != NO_POSITION && scrollToFocus 1599 && mBaseGridView.getScrollState() != RecyclerView.SCROLL_STATE_IDLE) { 1600 // FIXME: we should get the remaining scroll animation offset from RecyclerView 1601 View focusView = findViewByPosition(mFocusPosition); 1602 if (focusView != null) { 1603 delta = mWindowAlignment.mainAxis().getSystemScrollPos(mScrollOffsetPrimary 1604 + getViewCenter(focusView), false, false) - mScrollOffsetPrimary; 1605 deltaSecondary = mWindowAlignment.secondAxis().getSystemScrollPos( 1606 mScrollOffsetSecondary + getViewCenterSecondary(focusView), 1607 false, false) - mScrollOffsetSecondary; 1608 } 1609 } 1610 1611 final boolean hasDoneFirstLayout = hasDoneFirstLayout(); 1612 int savedFocusPos = mFocusPosition; 1613 boolean fastRelayout = false; 1614 if (!mState.didStructureChange() && !mForceFullLayout && hasDoneFirstLayout) { 1615 fastRelayout = true; 1616 fastRelayout(scrollToFocus); 1617 } else { 1618 boolean hadFocus = mBaseGridView.hasFocus(); 1619 1620 mFocusPosition = init(mFocusPosition); 1621 if (mFocusPosition != savedFocusPos) { 1622 if (DEBUG) Log.v(getTag(), "savedFocusPos " + savedFocusPos + 1623 " mFocusPosition " + mFocusPosition); 1624 } 1625 if (mFocusPosition == NO_POSITION) { 1626 mBaseGridView.clearFocus(); 1627 } 1628 1629 mWindowAlignment.mainAxis().invalidateScrollMin(); 1630 mWindowAlignment.mainAxis().invalidateScrollMax(); 1631 // depending on result of init(), either recreating everything 1632 // or try to reuse the row start positions near mFocusPosition 1633 if (mGrid.getSize() == 0) { 1634 // this is a fresh creating all items, starting from 1635 // mFocusPosition with a estimated row index. 1636 mGrid.setStart(mFocusPosition, StaggeredGrid.START_DEFAULT); 1637 1638 // Can't track the old focus view 1639 delta = deltaSecondary = 0; 1640 1641 } else { 1642 // mGrid remembers Locations for the column that 1643 // contains mFocusePosition and also mRows remembers start 1644 // positions of each row. 1645 // Manually re-create child views for that column 1646 int firstIndex = mGrid.getFirstIndex(); 1647 int lastIndex = mGrid.getLastIndex(); 1648 for (int i = firstIndex; i <= lastIndex; i++) { 1649 mGridProvider.createItem(i, mGrid.getLocation(i).row, true); 1650 } 1651 } 1652 1653 // add visible views at end until reach the end of window 1654 appendVisibleItems(); 1655 // add visible views at front until reach the start of window 1656 prependVisibleItems(); 1657 // multiple rounds: scrollToView of first round may drag first/last child into 1658 // "visible window" and we update scrollMin/scrollMax then run second scrollToView 1659 int oldFirstVisible; 1660 int oldLastVisible; 1661 do { 1662 updateScrollMin(); 1663 updateScrollMax(); 1664 oldFirstVisible = mFirstVisiblePos; 1665 oldLastVisible = mLastVisiblePos; 1666 View focusView = findViewByPosition(mFocusPosition); 1667 // we need force to initialize the child view's position 1668 scrollToView(focusView, false); 1669 if (focusView != null && hadFocus) { 1670 focusView.requestFocus(); 1671 } 1672 appendVisibleItems(); 1673 prependVisibleItems(); 1674 removeInvisibleViewsAtFront(); 1675 removeInvisibleViewsAtEnd(); 1676 } while (mFirstVisiblePos != oldFirstVisible || mLastVisiblePos != oldLastVisible); 1677 } 1678 mForceFullLayout = false; 1679 1680 if (scrollToFocus) { 1681 scrollDirectionPrimary(-delta); 1682 scrollDirectionSecondary(-deltaSecondary); 1683 } 1684 appendVisibleItems(); 1685 prependVisibleItems(); 1686 removeInvisibleViewsAtFront(); 1687 removeInvisibleViewsAtEnd(); 1688 1689 if (DEBUG) { 1690 StringWriter sw = new StringWriter(); 1691 PrintWriter pw = new PrintWriter(sw); 1692 mGrid.debugPrint(pw); 1693 Log.d(getTag(), sw.toString()); 1694 } 1695 1696 if (mRowSecondarySizeRefresh) { 1697 mRowSecondarySizeRefresh = false; 1698 } else { 1699 updateRowSecondarySizeRefresh(); 1700 } 1701 1702 if (fastRelayout && mFocusPosition != savedFocusPos) { 1703 dispatchChildSelected(); 1704 } 1705 mInLayout = false; 1706 leaveContext(); 1707 if (DEBUG) Log.v(getTag(), "layoutChildren end"); 1708 } 1709 1710 private void offsetChildrenSecondary(int increment) { 1711 final int childCount = getChildCount(); 1712 if (mOrientation == HORIZONTAL) { 1713 for (int i = 0; i < childCount; i++) { 1714 getChildAt(i).offsetTopAndBottom(increment); 1715 } 1716 } else { 1717 for (int i = 0; i < childCount; i++) { 1718 getChildAt(i).offsetLeftAndRight(increment); 1719 } 1720 } 1721 } 1722 1723 private void offsetChildrenPrimary(int increment) { 1724 final int childCount = getChildCount(); 1725 if (mOrientation == VERTICAL) { 1726 for (int i = 0; i < childCount; i++) { 1727 getChildAt(i).offsetTopAndBottom(increment); 1728 } 1729 } else { 1730 for (int i = 0; i < childCount; i++) { 1731 getChildAt(i).offsetLeftAndRight(increment); 1732 } 1733 } 1734 } 1735 1736 @Override 1737 public int scrollHorizontallyBy(int dx, Recycler recycler, RecyclerView.State state) { 1738 if (DEBUG) Log.v(getTag(), "scrollHorizontallyBy " + dx); 1739 if (!mLayoutEnabled || !hasDoneFirstLayout()) { 1740 return 0; 1741 } 1742 saveContext(recycler, state); 1743 int result; 1744 if (mOrientation == HORIZONTAL) { 1745 result = scrollDirectionPrimary(dx); 1746 } else { 1747 result = scrollDirectionSecondary(dx); 1748 } 1749 leaveContext(); 1750 return result; 1751 } 1752 1753 @Override 1754 public int scrollVerticallyBy(int dy, Recycler recycler, RecyclerView.State state) { 1755 if (DEBUG) Log.v(getTag(), "scrollVerticallyBy " + dy); 1756 if (!mLayoutEnabled || !hasDoneFirstLayout()) { 1757 return 0; 1758 } 1759 saveContext(recycler, state); 1760 int result; 1761 if (mOrientation == VERTICAL) { 1762 result = scrollDirectionPrimary(dy); 1763 } else { 1764 result = scrollDirectionSecondary(dy); 1765 } 1766 leaveContext(); 1767 return result; 1768 } 1769 1770 // scroll in main direction may add/prune views 1771 private int scrollDirectionPrimary(int da) { 1772 boolean isMaxUnknown = false, isMinUnknown = false; 1773 int minScroll = 0, maxScroll = 0; 1774 if (da > 0) { 1775 isMaxUnknown = mWindowAlignment.mainAxis().isMaxUnknown(); 1776 if (!isMaxUnknown) { 1777 maxScroll = mWindowAlignment.mainAxis().getMaxScroll(); 1778 if (mScrollOffsetPrimary + da > maxScroll) { 1779 da = maxScroll - mScrollOffsetPrimary; 1780 } 1781 } 1782 } else if (da < 0) { 1783 isMinUnknown = mWindowAlignment.mainAxis().isMinUnknown(); 1784 if (!isMinUnknown) { 1785 minScroll = mWindowAlignment.mainAxis().getMinScroll(); 1786 if (mScrollOffsetPrimary + da < minScroll) { 1787 da = minScroll - mScrollOffsetPrimary; 1788 } 1789 } 1790 } 1791 if (da == 0) { 1792 return 0; 1793 } 1794 offsetChildrenPrimary(-da); 1795 mScrollOffsetPrimary += da; 1796 if (mInLayout) { 1797 return da; 1798 } 1799 1800 int childCount = getChildCount(); 1801 boolean updated; 1802 1803 if (da > 0) { 1804 if (mReverseFlowPrimary) { 1805 prependVisibleItems(); 1806 } else { 1807 appendVisibleItems(); 1808 } 1809 } else if (da < 0) { 1810 if (mReverseFlowPrimary) { 1811 appendVisibleItems(); 1812 } else { 1813 prependVisibleItems(); 1814 } 1815 } 1816 updated = getChildCount() > childCount; 1817 childCount = getChildCount(); 1818 1819 if (da > 0) { 1820 if (mReverseFlowPrimary) { 1821 removeInvisibleViewsAtEnd(); 1822 } else { 1823 removeInvisibleViewsAtFront(); 1824 } 1825 } else if (da < 0) { 1826 if (mReverseFlowPrimary) { 1827 removeInvisibleViewsAtFront(); 1828 } else { 1829 removeInvisibleViewsAtEnd(); 1830 } 1831 } 1832 updated |= getChildCount() < childCount; 1833 1834 if (updated) { 1835 updateRowSecondarySizeRefresh(); 1836 } 1837 1838 mBaseGridView.invalidate(); 1839 return da; 1840 } 1841 1842 // scroll in second direction will not add/prune views 1843 private int scrollDirectionSecondary(int dy) { 1844 if (dy == 0) { 1845 return 0; 1846 } 1847 offsetChildrenSecondary(-dy); 1848 mScrollOffsetSecondary += dy; 1849 mBaseGridView.invalidate(); 1850 return dy; 1851 } 1852 1853 private void updateScrollMax() { 1854 int highVisiblePos = (!mReverseFlowPrimary) ? mLastVisiblePos : mFirstVisiblePos; 1855 int highMaxPos = (!mReverseFlowPrimary) ? mState.getItemCount() - 1 : 0; 1856 if (highVisiblePos < 0) { 1857 return; 1858 } 1859 final boolean highAvailable = highVisiblePos == highMaxPos; 1860 final boolean maxUnknown = mWindowAlignment.mainAxis().isMaxUnknown(); 1861 if (!highAvailable && maxUnknown) { 1862 return; 1863 } 1864 int maxEdge = Integer.MIN_VALUE; 1865 int rowIndex = -1; 1866 for (int i = 0; i < mRows.length; i++) { 1867 if (mRows[i].high > maxEdge) { 1868 maxEdge = mRows[i].high; 1869 rowIndex = i; 1870 } 1871 } 1872 int maxScroll = Integer.MAX_VALUE; 1873 for (int i = mFirstVisiblePos; i <= mLastVisiblePos; i++) { 1874 int pos = mReverseFlowPrimary ? i : mLastVisiblePos-i+mFirstVisiblePos; 1875 StaggeredGrid.Location location = mGrid.getLocation(pos); 1876 if (location != null && location.row == rowIndex) { 1877 int savedMaxEdge = mWindowAlignment.mainAxis().getMaxEdge(); 1878 mWindowAlignment.mainAxis().setMaxEdge(maxEdge); 1879 maxScroll = getPrimarySystemScrollPosition(findViewByPosition(pos)); 1880 mWindowAlignment.mainAxis().setMaxEdge(savedMaxEdge); 1881 break; 1882 } 1883 } 1884 if (highAvailable) { 1885 mWindowAlignment.mainAxis().setMaxEdge(maxEdge); 1886 mWindowAlignment.mainAxis().setMaxScroll(maxScroll); 1887 if (DEBUG) Log.v(getTag(), "updating scroll maxEdge to " + maxEdge + 1888 " scrollMax to " + maxScroll); 1889 } else { 1890 // the maxScroll for currently last visible item is larger, 1891 // so we must invalidate the max scroll value. 1892 if (maxScroll > mWindowAlignment.mainAxis().getMaxScroll()) { 1893 mWindowAlignment.mainAxis().invalidateScrollMax(); 1894 if (DEBUG) Log.v(getTag(), "Invalidate scrollMax since it should be " 1895 + "greater than " + maxScroll); 1896 } 1897 } 1898 } 1899 1900 private void updateScrollMin() { 1901 int lowVisiblePos = (!mReverseFlowPrimary) ? mFirstVisiblePos : mLastVisiblePos; 1902 int lowMinPos = (!mReverseFlowPrimary) ? 0 : mState.getItemCount() - 1; 1903 if (lowVisiblePos < 0) { 1904 return; 1905 } 1906 final boolean lowAvailable = lowVisiblePos == lowMinPos; 1907 final boolean minUnknown = mWindowAlignment.mainAxis().isMinUnknown(); 1908 if (!lowAvailable && minUnknown) { 1909 return; 1910 } 1911 int minEdge = Integer.MAX_VALUE; 1912 int rowIndex = -1; 1913 for (int i = 0; i < mRows.length; i++) { 1914 if (mRows[i].low < minEdge) { 1915 minEdge = mRows[i].low; 1916 rowIndex = i; 1917 } 1918 } 1919 int minScroll = Integer.MIN_VALUE; 1920 for (int i = mFirstVisiblePos; i <= mLastVisiblePos; i++) { 1921 int pos = mReverseFlowPrimary ? mLastVisiblePos-i+mFirstVisiblePos : i; 1922 StaggeredGrid.Location location = mGrid.getLocation(pos); 1923 if (location != null && location.row == rowIndex) { 1924 int savedMinEdge = mWindowAlignment.mainAxis().getMinEdge(); 1925 mWindowAlignment.mainAxis().setMinEdge(minEdge); 1926 minScroll = getPrimarySystemScrollPosition(findViewByPosition(pos)); 1927 mWindowAlignment.mainAxis().setMinEdge(savedMinEdge); 1928 break; 1929 } 1930 } 1931 if (lowAvailable) { 1932 mWindowAlignment.mainAxis().setMinEdge(minEdge); 1933 mWindowAlignment.mainAxis().setMinScroll(minScroll); 1934 if (DEBUG) Log.v(getTag(), "updating scroll minEdge to " + minEdge + 1935 " scrollMin to " + minScroll); 1936 } else { 1937 // the minScroll for currently first visible item is smaller, 1938 // so we must invalidate the min scroll value. 1939 if (minScroll < mWindowAlignment.mainAxis().getMinScroll()) { 1940 mWindowAlignment.mainAxis().invalidateScrollMin(); 1941 if (DEBUG) Log.v(getTag(), "Invalidate scrollMin, since it should be " 1942 + "less than " + minScroll); 1943 } 1944 } 1945 } 1946 1947 private void updateScrollSecondAxis() { 1948 mWindowAlignment.secondAxis().setMinEdge(0); 1949 mWindowAlignment.secondAxis().setMaxEdge(getSizeSecondary()); 1950 } 1951 1952 private void initScrollController() { 1953 // mScrollOffsetPrimary and mScrollOffsetSecondary includes the padding. 1954 // e.g. when topPadding is 16 for horizontal grid view, the initial 1955 // mScrollOffsetSecondary is -16. fastLayout() put views based on offsets(not padding), 1956 // when padding changes to 20, we also need update mScrollOffsetSecondary to -20 before 1957 // fastLayout() is performed 1958 int paddingPrimaryDiff, paddingSecondaryDiff; 1959 if (mOrientation == HORIZONTAL) { 1960 paddingPrimaryDiff = getPaddingLeft() - mWindowAlignment.horizontal.getPaddingLow(); 1961 paddingSecondaryDiff = getPaddingTop() - mWindowAlignment.vertical.getPaddingLow(); 1962 } else { 1963 paddingPrimaryDiff = getPaddingTop() - mWindowAlignment.vertical.getPaddingLow(); 1964 paddingSecondaryDiff = getPaddingLeft() - mWindowAlignment.horizontal.getPaddingLow(); 1965 } 1966 mScrollOffsetPrimary -= paddingPrimaryDiff; 1967 mScrollOffsetSecondary -= paddingSecondaryDiff; 1968 1969 mWindowAlignment.horizontal.setSize(getWidth()); 1970 mWindowAlignment.vertical.setSize(getHeight()); 1971 mWindowAlignment.horizontal.setPadding(getPaddingLeft(), getPaddingRight()); 1972 mWindowAlignment.vertical.setPadding(getPaddingTop(), getPaddingBottom()); 1973 mSizePrimary = mWindowAlignment.mainAxis().getSize(); 1974 1975 if (DEBUG) { 1976 Log.v(getTag(), "initScrollController mSizePrimary " + mSizePrimary 1977 + " mWindowAlignment " + mWindowAlignment); 1978 } 1979 } 1980 1981 public void setSelection(RecyclerView parent, int position) { 1982 setSelection(parent, position, false); 1983 } 1984 1985 public void setSelectionSmooth(RecyclerView parent, int position) { 1986 setSelection(parent, position, true); 1987 } 1988 1989 public int getSelection() { 1990 return mFocusPosition; 1991 } 1992 1993 public void setSelection(RecyclerView parent, int position, boolean smooth) { 1994 if (mFocusPosition != position && position != NO_POSITION) { 1995 scrollToSelection(parent, position, smooth); 1996 } 1997 } 1998 1999 private void scrollToSelection(RecyclerView parent, int position, boolean smooth) { 2000 View view = findViewByPosition(position); 2001 if (view != null) { 2002 mInSelection = true; 2003 scrollToView(view, smooth); 2004 mInSelection = false; 2005 } else { 2006 mFocusPosition = position; 2007 mFocusPositionOffset = 0; 2008 if (!mLayoutEnabled) { 2009 return; 2010 } 2011 if (smooth) { 2012 if (!hasDoneFirstLayout()) { 2013 Log.w(getTag(), "setSelectionSmooth should " + 2014 "not be called before first layout pass"); 2015 return; 2016 } 2017 LinearSmoothScroller linearSmoothScroller = 2018 new LinearSmoothScroller(parent.getContext()) { 2019 @Override 2020 public PointF computeScrollVectorForPosition(int targetPosition) { 2021 if (getChildCount() == 0) { 2022 return null; 2023 } 2024 final int firstChildPos = getPosition(getChildAt(0)); 2025 // TODO We should be able to deduce direction from bounds of current and target focus, 2026 // rather than making assumptions about positions and directionality 2027 final boolean isStart = mReverseFlowPrimary ? targetPosition > firstChildPos : targetPosition < firstChildPos; 2028 final int direction = isStart ? -1 : 1; 2029 if (mOrientation == HORIZONTAL) { 2030 return new PointF(direction, 0); 2031 } else { 2032 return new PointF(0, direction); 2033 } 2034 } 2035 @Override 2036 protected void onTargetFound(View targetView, 2037 RecyclerView.State state, Action action) { 2038 if (hasFocus()) { 2039 targetView.requestFocus(); 2040 } 2041 dispatchChildSelected(); 2042 if (getScrollPosition(targetView, mTempDeltas)) { 2043 int dx, dy; 2044 if (mOrientation == HORIZONTAL) { 2045 dx = mTempDeltas[0]; 2046 dy = mTempDeltas[1]; 2047 } else { 2048 dx = mTempDeltas[1]; 2049 dy = mTempDeltas[0]; 2050 } 2051 final int distance = (int) Math.sqrt(dx * dx + dy * dy); 2052 final int time = calculateTimeForDeceleration(distance); 2053 action.update(dx, dy, time, mDecelerateInterpolator); 2054 } 2055 } 2056 }; 2057 linearSmoothScroller.setTargetPosition(position); 2058 startSmoothScroll(linearSmoothScroller); 2059 } else { 2060 mForceFullLayout = true; 2061 parent.requestLayout(); 2062 } 2063 } 2064 } 2065 2066 @Override 2067 public void onItemsAdded(RecyclerView recyclerView, int positionStart, int itemCount) { 2068 if (DEBUG) Log.v(getTag(), "onItemsAdded positionStart " 2069 + positionStart + " itemCount " + itemCount); 2070 if (mFocusPosition != NO_POSITION && mFocusPositionOffset != Integer.MIN_VALUE 2071 && getChildAt(mFocusPosition) != null) { 2072 int pos = mFocusPosition + mFocusPositionOffset; 2073 if (positionStart <= pos) { 2074 mFocusPositionOffset += itemCount; 2075 } 2076 } 2077 mChildrenStates.clear(); 2078 } 2079 2080 @Override 2081 public void onItemsChanged(RecyclerView recyclerView) { 2082 if (DEBUG) Log.v(getTag(), "onItemsChanged"); 2083 mFocusPositionOffset = 0; 2084 mChildrenStates.clear(); 2085 } 2086 2087 @Override 2088 public void onItemsRemoved(RecyclerView recyclerView, int positionStart, int itemCount) { 2089 if (DEBUG) Log.v(getTag(), "onItemsRemoved positionStart " 2090 + positionStart + " itemCount " + itemCount); 2091 if (mFocusPosition != NO_POSITION && mFocusPositionOffset != Integer.MIN_VALUE 2092 && getChildAt(mFocusPosition) != null) { 2093 int pos = mFocusPosition + mFocusPositionOffset; 2094 if (positionStart <= pos) { 2095 if (positionStart + itemCount > pos) { 2096 // stop updating offset after the focus item was removed 2097 mFocusPositionOffset = Integer.MIN_VALUE; 2098 } else { 2099 mFocusPositionOffset -= itemCount; 2100 } 2101 } 2102 } 2103 mChildrenStates.clear(); 2104 } 2105 2106 @Override 2107 public void onItemsMoved(RecyclerView recyclerView, int fromPosition, int toPosition, 2108 int itemCount) { 2109 if (DEBUG) Log.v(getTag(), "onItemsMoved fromPosition " 2110 + fromPosition + " toPosition " + toPosition); 2111 if (mFocusPosition != NO_POSITION && mFocusPositionOffset != Integer.MIN_VALUE 2112 && getChildAt(mFocusPosition) != null) { 2113 int pos = mFocusPosition + mFocusPositionOffset; 2114 if (fromPosition <= pos && pos < fromPosition + itemCount) { 2115 // moved items include focused position 2116 mFocusPositionOffset += toPosition - fromPosition; 2117 } else if (fromPosition < pos && toPosition > pos - itemCount) { 2118 // move items before focus position to after focused position 2119 mFocusPositionOffset -= itemCount; 2120 } else if (fromPosition > pos && toPosition < pos) { 2121 // move items after focus position to before focused position 2122 mFocusPositionOffset += itemCount; 2123 } 2124 } 2125 mChildrenStates.clear(); 2126 } 2127 2128 @Override 2129 public void onItemsUpdated(RecyclerView recyclerView, int positionStart, int itemCount) { 2130 if (DEBUG) Log.v(getTag(), "onItemsUpdated positionStart " 2131 + positionStart + " itemCount " + itemCount); 2132 for (int i = positionStart, end = positionStart + itemCount; i < end; i++) { 2133 mChildrenStates.remove(i); 2134 } 2135 } 2136 2137 @Override 2138 public boolean onRequestChildFocus(RecyclerView parent, View child, View focused) { 2139 if (mFocusSearchDisabled) { 2140 return true; 2141 } 2142 if (getPositionByView(child) == NO_POSITION) { 2143 // This shouldn't happen, but in case it does be sure not to attempt a 2144 // scroll to a view whose item has been removed. 2145 return true; 2146 } 2147 if (!mInLayout && !mInSelection) { 2148 scrollToView(child, true); 2149 } 2150 return true; 2151 } 2152 2153 @Override 2154 public boolean requestChildRectangleOnScreen(RecyclerView parent, View view, Rect rect, 2155 boolean immediate) { 2156 if (DEBUG) Log.v(getTag(), "requestChildRectangleOnScreen " + view + " " + rect); 2157 return false; 2158 } 2159 2160 int getScrollOffsetX() { 2161 return mOrientation == HORIZONTAL ? mScrollOffsetPrimary : mScrollOffsetSecondary; 2162 } 2163 2164 int getScrollOffsetY() { 2165 return mOrientation == HORIZONTAL ? mScrollOffsetSecondary : mScrollOffsetPrimary; 2166 } 2167 2168 public void getViewSelectedOffsets(View view, int[] offsets) { 2169 if (mOrientation == HORIZONTAL) { 2170 offsets[0] = getPrimarySystemScrollPosition(view) - mScrollOffsetPrimary; 2171 offsets[1] = getSecondarySystemScrollPosition(view) - mScrollOffsetSecondary; 2172 } else { 2173 offsets[1] = getPrimarySystemScrollPosition(view) - mScrollOffsetPrimary; 2174 offsets[0] = getSecondarySystemScrollPosition(view) - mScrollOffsetSecondary; 2175 } 2176 } 2177 2178 private int getPrimarySystemScrollPosition(View view) { 2179 int viewCenterPrimary = mScrollOffsetPrimary + getViewCenter(view); 2180 int pos = getPositionByView(view); 2181 StaggeredGrid.Location location = mGrid.getLocation(pos); 2182 final int row = location.row; 2183 boolean isFirst = mFirstVisiblePos == 0; 2184 // TODO: change to use State object in onRequestChildFocus() 2185 boolean isLast = mLastVisiblePos == (mState == null ? 2186 getItemCount() : mState.getItemCount()) - 1; 2187 if (isFirst || isLast) { 2188 for (int i = getChildCount() - 1; i >= 0; i--) { 2189 int position = getPositionByIndex(i); 2190 StaggeredGrid.Location loc = mGrid.getLocation(position); 2191 // TODO RTL logic here? 2192 if (loc != null && loc.row == row) { 2193 if (position < pos) { 2194 isFirst = false; 2195 } else if (position > pos) { 2196 isLast = false; 2197 } 2198 } 2199 } 2200 } 2201 return mWindowAlignment.mainAxis().getSystemScrollPos(viewCenterPrimary, isFirst, isLast); 2202 } 2203 2204 private int getSecondarySystemScrollPosition(View view) { 2205 int viewCenterSecondary = mScrollOffsetSecondary + getViewCenterSecondary(view); 2206 int pos = getPositionByView(view); 2207 StaggeredGrid.Location location = mGrid.getLocation(pos); 2208 final int row = location.row; 2209 boolean isFirst = row == 0; 2210 boolean isLast = row == mGrid.getNumRows() - 1; 2211 return mWindowAlignment.secondAxis().getSystemScrollPos(viewCenterSecondary, 2212 isFirst, isLast); 2213 } 2214 2215 /** 2216 * Scroll to a given child view and change mFocusPosition. 2217 */ 2218 private void scrollToView(View view, boolean smooth) { 2219 int newFocusPosition = getPositionByView(view); 2220 if (newFocusPosition != mFocusPosition) { 2221 mFocusPosition = newFocusPosition; 2222 mFocusPositionOffset = 0; 2223 if (!mInLayout) { 2224 dispatchChildSelected(); 2225 } 2226 } 2227 if (mBaseGridView.isChildrenDrawingOrderEnabledInternal()) { 2228 mBaseGridView.invalidate(); 2229 } 2230 if (view == null) { 2231 return; 2232 } 2233 if (!view.hasFocus() && mBaseGridView.hasFocus()) { 2234 // transfer focus to the child if it does not have focus yet (e.g. triggered 2235 // by setSelection()) 2236 view.requestFocus(); 2237 } 2238 if (!mScrollEnabled) { 2239 return; 2240 } 2241 if (getScrollPosition(view, mTempDeltas)) { 2242 scrollGrid(mTempDeltas[0], mTempDeltas[1], smooth); 2243 } 2244 } 2245 2246 private boolean getScrollPosition(View view, int[] deltas) { 2247 switch (mFocusScrollStrategy) { 2248 case BaseGridView.FOCUS_SCROLL_ALIGNED: 2249 default: 2250 return getAlignedPosition(view, deltas); 2251 case BaseGridView.FOCUS_SCROLL_ITEM: 2252 case BaseGridView.FOCUS_SCROLL_PAGE: 2253 return getNoneAlignedPosition(view, deltas); 2254 } 2255 } 2256 2257 private boolean getNoneAlignedPosition(View view, int[] deltas) { 2258 int pos = getPositionByView(view); 2259 int viewMin = getViewMin(view); 2260 int viewMax = getViewMax(view); 2261 // we either align "firstView" to left/top padding edge 2262 // or align "lastView" to right/bottom padding edge 2263 View firstView = null; 2264 View lastView = null; 2265 int paddingLow = mWindowAlignment.mainAxis().getPaddingLow(); 2266 int clientSize = mWindowAlignment.mainAxis().getClientSize(); 2267 final int row = mGrid.getLocation(pos).row; 2268 if (viewMin < paddingLow) { 2269 // view enters low padding area: 2270 firstView = view; 2271 if (mFocusScrollStrategy == BaseGridView.FOCUS_SCROLL_PAGE) { 2272 // scroll one "page" left/top, 2273 // align first visible item of the "page" at the low padding edge. 2274 while (!prependOneVisibleItem()) { 2275 List<Integer> positions = 2276 mGrid.getItemPositionsInRows(mFirstVisiblePos, pos)[row]; 2277 firstView = findViewByPosition(positions.get(0)); 2278 if (viewMax - getViewMin(firstView) > clientSize) { 2279 if (positions.size() > 1) { 2280 firstView = findViewByPosition(positions.get(1)); 2281 } 2282 break; 2283 } 2284 } 2285 } 2286 } else if (viewMax > clientSize + paddingLow) { 2287 // view enters high padding area: 2288 if (mFocusScrollStrategy == BaseGridView.FOCUS_SCROLL_PAGE) { 2289 // scroll whole one page right/bottom, align view at the low padding edge. 2290 firstView = view; 2291 do { 2292 List<Integer> positions = 2293 mGrid.getItemPositionsInRows(pos, mLastVisiblePos)[row]; 2294 lastView = findViewByPosition(positions.get(positions.size() - 1)); 2295 if (getViewMax(lastView) - viewMin > clientSize) { 2296 lastView = null; 2297 break; 2298 } 2299 } while (!appendOneVisibleItem()); 2300 if (lastView != null) { 2301 // however if we reached end, we should align last view. 2302 firstView = null; 2303 } 2304 } else { 2305 lastView = view; 2306 } 2307 } 2308 int scrollPrimary = 0; 2309 int scrollSecondary = 0; 2310 if (firstView != null) { 2311 scrollPrimary = getViewMin(firstView) - paddingLow; 2312 } else if (lastView != null) { 2313 scrollPrimary = getViewMax(lastView) - (paddingLow + clientSize); 2314 } 2315 View secondaryAlignedView; 2316 if (firstView != null) { 2317 secondaryAlignedView = firstView; 2318 } else if (lastView != null) { 2319 secondaryAlignedView = lastView; 2320 } else { 2321 secondaryAlignedView = view; 2322 } 2323 scrollSecondary = getSecondarySystemScrollPosition(secondaryAlignedView); 2324 scrollSecondary -= mScrollOffsetSecondary; 2325 if (scrollPrimary != 0 || scrollSecondary != 0) { 2326 deltas[0] = scrollPrimary; 2327 deltas[1] = scrollSecondary; 2328 return true; 2329 } 2330 return false; 2331 } 2332 2333 private boolean getAlignedPosition(View view, int[] deltas) { 2334 int scrollPrimary = getPrimarySystemScrollPosition(view); 2335 int scrollSecondary = getSecondarySystemScrollPosition(view); 2336 if (DEBUG) { 2337 Log.v(getTag(), "getAlignedPosition " + scrollPrimary + " " + scrollSecondary 2338 + " " + mWindowAlignment); 2339 Log.v(getTag(), "getAlignedPosition " + mScrollOffsetPrimary + " " + mScrollOffsetSecondary); 2340 } 2341 scrollPrimary -= mScrollOffsetPrimary; 2342 scrollSecondary -= mScrollOffsetSecondary; 2343 if (scrollPrimary != 0 || scrollSecondary != 0) { 2344 deltas[0] = scrollPrimary; 2345 deltas[1] = scrollSecondary; 2346 return true; 2347 } 2348 return false; 2349 } 2350 2351 private void scrollGrid(int scrollPrimary, int scrollSecondary, boolean smooth) { 2352 if (mInLayout) { 2353 scrollDirectionPrimary(scrollPrimary); 2354 scrollDirectionSecondary(scrollSecondary); 2355 } else { 2356 int scrollX; 2357 int scrollY; 2358 if (mOrientation == HORIZONTAL) { 2359 scrollX = scrollPrimary; 2360 scrollY = scrollSecondary; 2361 } else { 2362 scrollX = scrollSecondary; 2363 scrollY = scrollPrimary; 2364 } 2365 if (smooth) { 2366 mBaseGridView.smoothScrollBy(scrollX, scrollY); 2367 } else { 2368 mBaseGridView.scrollBy(scrollX, scrollY); 2369 } 2370 } 2371 } 2372 2373 public void setPruneChild(boolean pruneChild) { 2374 if (mPruneChild != pruneChild) { 2375 mPruneChild = pruneChild; 2376 if (mPruneChild) { 2377 requestLayout(); 2378 } 2379 } 2380 } 2381 2382 public boolean getPruneChild() { 2383 return mPruneChild; 2384 } 2385 2386 public void setScrollEnabled(boolean scrollEnabled) { 2387 if (mScrollEnabled != scrollEnabled) { 2388 mScrollEnabled = scrollEnabled; 2389 if (mScrollEnabled && mFocusScrollStrategy == BaseGridView.FOCUS_SCROLL_ALIGNED 2390 && mFocusPosition != NO_POSITION) { 2391 scrollToSelection(mBaseGridView, mFocusPosition, true); 2392 } 2393 } 2394 } 2395 2396 public boolean isScrollEnabled() { 2397 return mScrollEnabled; 2398 } 2399 2400 private int findImmediateChildIndex(View view) { 2401 while (view != null && view != mBaseGridView) { 2402 int index = mBaseGridView.indexOfChild(view); 2403 if (index >= 0) { 2404 return index; 2405 } 2406 view = (View) view.getParent(); 2407 } 2408 return NO_POSITION; 2409 } 2410 2411 void setFocusSearchDisabled(boolean disabled) { 2412 mFocusSearchDisabled = disabled; 2413 } 2414 2415 boolean isFocusSearchDisabled() { 2416 return mFocusSearchDisabled; 2417 } 2418 2419 @Override 2420 public View onInterceptFocusSearch(View focused, int direction) { 2421 if (mFocusSearchDisabled) { 2422 return focused; 2423 } 2424 return null; 2425 } 2426 2427 boolean hasPreviousViewInSameRow(int pos) { 2428 if (mGrid == null || pos == NO_POSITION) { 2429 return false; 2430 } 2431 if (mFirstVisiblePos > 0) { 2432 return true; 2433 } 2434 final int focusedRow = mGrid.getLocation(pos).row; 2435 for (int i = getChildCount() - 1; i >= 0; i--) { 2436 int position = getPositionByIndex(i); 2437 StaggeredGrid.Location loc = mGrid.getLocation(position); 2438 if (loc != null && loc.row == focusedRow) { 2439 if (position < pos) { 2440 return true; 2441 } 2442 } 2443 } 2444 return false; 2445 } 2446 2447 @Override 2448 public boolean onAddFocusables(RecyclerView recyclerView, 2449 ArrayList<View> views, int direction, int focusableMode) { 2450 if (mFocusSearchDisabled) { 2451 return true; 2452 } 2453 // If this viewgroup or one of its children currently has focus then we 2454 // consider our children for focus searching in main direction on the same row. 2455 // If this viewgroup has no focus and using focus align, we want the system 2456 // to ignore our children and pass focus to the viewgroup, which will pass 2457 // focus on to its children appropriately. 2458 // If this viewgroup has no focus and not using focus align, we want to 2459 // consider the child that does not overlap with padding area. 2460 if (recyclerView.hasFocus()) { 2461 final int movement = getMovement(direction); 2462 if (movement != PREV_ITEM && movement != NEXT_ITEM) { 2463 // Move on secondary direction uses default addFocusables(). 2464 return false; 2465 } 2466 final View focused = recyclerView.findFocus(); 2467 final int focusedPos = getPositionByIndex(findImmediateChildIndex(focused)); 2468 // Add focusables of focused item. 2469 if (focusedPos != NO_POSITION) { 2470 findViewByPosition(focusedPos).addFocusables(views, direction, focusableMode); 2471 } 2472 final int focusedRow = mGrid != null && focusedPos != NO_POSITION ? 2473 mGrid.getLocation(focusedPos).row : NO_POSITION; 2474 // Add focusables of next neighbor of same row on the focus search direction. 2475 if (mGrid != null) { 2476 final int focusableCount = views.size(); 2477 for (int i = 0, count = getChildCount(); i < count; i++) { 2478 int index = movement == NEXT_ITEM ? i : count - 1 - i; 2479 final View child = getChildAt(index); 2480 if (child.getVisibility() != View.VISIBLE) { 2481 continue; 2482 } 2483 int position = getPositionByIndex(index); 2484 StaggeredGrid.Location loc = mGrid.getLocation(position); 2485 if (focusedRow == NO_POSITION || (loc != null && loc.row == focusedRow)) { 2486 if (focusedPos == NO_POSITION || 2487 (movement == NEXT_ITEM && position > focusedPos) 2488 || (movement == PREV_ITEM && position < focusedPos)) { 2489 child.addFocusables(views, direction, focusableMode); 2490 if (views.size() > focusableCount) { 2491 break; 2492 } 2493 } 2494 } 2495 } 2496 } 2497 } else { 2498 if (mFocusScrollStrategy != BaseGridView.FOCUS_SCROLL_ALIGNED) { 2499 // adding views not overlapping padding area to avoid scrolling in gaining focus 2500 int left = mWindowAlignment.mainAxis().getPaddingLow(); 2501 int right = mWindowAlignment.mainAxis().getClientSize() + left; 2502 int focusableCount = views.size(); 2503 for (int i = 0, count = getChildCount(); i < count; i++) { 2504 View child = getChildAt(i); 2505 if (child.getVisibility() == View.VISIBLE) { 2506 if (getViewMin(child) >= left && getViewMax(child) <= right) { 2507 child.addFocusables(views, direction, focusableMode); 2508 } 2509 } 2510 } 2511 // if we cannot find any, then just add all children. 2512 if (views.size() == focusableCount) { 2513 for (int i = 0, count = getChildCount(); i < count; i++) { 2514 View child = getChildAt(i); 2515 if (child.getVisibility() == View.VISIBLE) { 2516 child.addFocusables(views, direction, focusableMode); 2517 } 2518 } 2519 if (views.size() != focusableCount) { 2520 return true; 2521 } 2522 } else { 2523 return true; 2524 } 2525 // if still cannot find any, fall through and add itself 2526 } 2527 if (recyclerView.isFocusable()) { 2528 views.add(recyclerView); 2529 } 2530 } 2531 return true; 2532 } 2533 2534 @Override 2535 public View onFocusSearchFailed(View focused, int direction, Recycler recycler, 2536 RecyclerView.State state) { 2537 if (DEBUG) Log.v(getTag(), "onFocusSearchFailed direction " + direction); 2538 2539 View view = null; 2540 int movement = getMovement(direction); 2541 final boolean isScroll = mBaseGridView.getScrollState() != RecyclerView.SCROLL_STATE_IDLE; 2542 if (mNumRows == 1) { 2543 // for simple row, use LinearSmoothScroller to smooth animation. 2544 // It will stay at a fixed cap speed in continuous scroll. 2545 if (movement == NEXT_ITEM) { 2546 int newPos = mFocusPosition + mNumRows; 2547 if (newPos < getItemCount() && mScrollEnabled) { 2548 setSelectionSmooth(mBaseGridView, newPos); 2549 view = focused; 2550 } else { 2551 if (isScroll || !mFocusOutEnd) { 2552 view = focused; 2553 } 2554 } 2555 } else if (movement == PREV_ITEM){ 2556 int newPos = mFocusPosition - mNumRows; 2557 if (newPos >= 0 && mScrollEnabled) { 2558 setSelectionSmooth(mBaseGridView, newPos); 2559 view = focused; 2560 } else { 2561 if (isScroll || !mFocusOutFront) { 2562 view = focused; 2563 } 2564 } 2565 } 2566 } else if (mNumRows > 1) { 2567 // for possible staggered grid, we need guarantee focus to same row/column. 2568 // TODO: we may also use LinearSmoothScroller. 2569 saveContext(recycler, state); 2570 final FocusFinder ff = FocusFinder.getInstance(); 2571 if (movement == NEXT_ITEM) { 2572 while (view == null && !appendOneVisibleItem()) { 2573 view = ff.findNextFocus(mBaseGridView, focused, direction); 2574 } 2575 } else if (movement == PREV_ITEM){ 2576 while (view == null && !prependOneVisibleItem()) { 2577 view = ff.findNextFocus(mBaseGridView, focused, direction); 2578 } 2579 } 2580 if (view == null) { 2581 // returning the same view to prevent focus lost when scrolling past the end of the list 2582 if (movement == PREV_ITEM) { 2583 view = mFocusOutFront && !isScroll ? null : focused; 2584 } else if (movement == NEXT_ITEM){ 2585 view = mFocusOutEnd && !isScroll ? null : focused; 2586 } 2587 } 2588 leaveContext(); 2589 } 2590 if (DEBUG) Log.v(getTag(), "returning view " + view); 2591 return view; 2592 } 2593 2594 boolean gridOnRequestFocusInDescendants(RecyclerView recyclerView, int direction, 2595 Rect previouslyFocusedRect) { 2596 switch (mFocusScrollStrategy) { 2597 case BaseGridView.FOCUS_SCROLL_ALIGNED: 2598 default: 2599 return gridOnRequestFocusInDescendantsAligned(recyclerView, 2600 direction, previouslyFocusedRect); 2601 case BaseGridView.FOCUS_SCROLL_PAGE: 2602 case BaseGridView.FOCUS_SCROLL_ITEM: 2603 return gridOnRequestFocusInDescendantsUnaligned(recyclerView, 2604 direction, previouslyFocusedRect); 2605 } 2606 } 2607 2608 private boolean gridOnRequestFocusInDescendantsAligned(RecyclerView recyclerView, 2609 int direction, Rect previouslyFocusedRect) { 2610 View view = findViewByPosition(mFocusPosition); 2611 if (view != null) { 2612 boolean result = view.requestFocus(direction, previouslyFocusedRect); 2613 if (!result && DEBUG) { 2614 Log.w(getTag(), "failed to request focus on " + view); 2615 } 2616 return result; 2617 } 2618 return false; 2619 } 2620 2621 private boolean gridOnRequestFocusInDescendantsUnaligned(RecyclerView recyclerView, 2622 int direction, Rect previouslyFocusedRect) { 2623 // focus to view not overlapping padding area to avoid scrolling in gaining focus 2624 int index; 2625 int increment; 2626 int end; 2627 int count = getChildCount(); 2628 if ((direction & View.FOCUS_FORWARD) != 0) { 2629 index = 0; 2630 increment = 1; 2631 end = count; 2632 } else { 2633 index = count - 1; 2634 increment = -1; 2635 end = -1; 2636 } 2637 int left = mWindowAlignment.mainAxis().getPaddingLow(); 2638 int right = mWindowAlignment.mainAxis().getClientSize() + left; 2639 for (int i = index; i != end; i += increment) { 2640 View child = getChildAt(i); 2641 if (child.getVisibility() == View.VISIBLE) { 2642 if (getViewMin(child) >= left && getViewMax(child) <= right) { 2643 if (child.requestFocus(direction, previouslyFocusedRect)) { 2644 return true; 2645 } 2646 } 2647 } 2648 } 2649 return false; 2650 } 2651 2652 private final static int PREV_ITEM = 0; 2653 private final static int NEXT_ITEM = 1; 2654 private final static int PREV_ROW = 2; 2655 private final static int NEXT_ROW = 3; 2656 2657 private int getMovement(int direction) { 2658 int movement = View.FOCUS_LEFT; 2659 2660 if (mOrientation == HORIZONTAL) { 2661 switch(direction) { 2662 case View.FOCUS_LEFT: 2663 movement = (!mReverseFlowPrimary) ? PREV_ITEM : NEXT_ITEM; 2664 break; 2665 case View.FOCUS_RIGHT: 2666 movement = (!mReverseFlowPrimary) ? NEXT_ITEM : PREV_ITEM; 2667 break; 2668 case View.FOCUS_UP: 2669 movement = PREV_ROW; 2670 break; 2671 case View.FOCUS_DOWN: 2672 movement = NEXT_ROW; 2673 break; 2674 } 2675 } else if (mOrientation == VERTICAL) { 2676 switch(direction) { 2677 case View.FOCUS_LEFT: 2678 movement = (!mReverseFlowPrimary) ? PREV_ROW : NEXT_ROW; 2679 break; 2680 case View.FOCUS_RIGHT: 2681 movement = (!mReverseFlowPrimary) ? NEXT_ROW : PREV_ROW; 2682 break; 2683 case View.FOCUS_UP: 2684 movement = PREV_ITEM; 2685 break; 2686 case View.FOCUS_DOWN: 2687 movement = NEXT_ITEM; 2688 break; 2689 } 2690 } 2691 2692 return movement; 2693 } 2694 2695 int getChildDrawingOrder(RecyclerView recyclerView, int childCount, int i) { 2696 View view = findViewByPosition(mFocusPosition); 2697 if (view == null) { 2698 return i; 2699 } 2700 int focusIndex = recyclerView.indexOfChild(view); 2701 // supposely 0 1 2 3 4 5 6 7 8 9, 4 is the center item 2702 // drawing order is 0 1 2 3 9 8 7 6 5 4 2703 if (i < focusIndex) { 2704 return i; 2705 } else if (i < childCount - 1) { 2706 return focusIndex + childCount - 1 - i; 2707 } else { 2708 return focusIndex; 2709 } 2710 } 2711 2712 @Override 2713 public void onAdapterChanged(RecyclerView.Adapter oldAdapter, 2714 RecyclerView.Adapter newAdapter) { 2715 if (DEBUG) Log.v(getTag(), "onAdapterChanged to " + newAdapter); 2716 if (oldAdapter != null) { 2717 discardLayoutInfo(); 2718 mFocusPosition = NO_POSITION; 2719 mFocusPositionOffset = 0; 2720 mChildrenStates.clear(); 2721 } 2722 super.onAdapterChanged(oldAdapter, newAdapter); 2723 } 2724 2725 private void discardLayoutInfo() { 2726 mGrid = null; 2727 mRows = null; 2728 mRowSizeSecondary = null; 2729 mFirstVisiblePos = -1; 2730 mLastVisiblePos = -1; 2731 mRowSecondarySizeRefresh = false; 2732 } 2733 2734 public void setLayoutEnabled(boolean layoutEnabled) { 2735 if (mLayoutEnabled != layoutEnabled) { 2736 mLayoutEnabled = layoutEnabled; 2737 requestLayout(); 2738 } 2739 } 2740 2741 void setChildrenVisibility(int visiblity) { 2742 mChildVisibility = visiblity; 2743 if (mChildVisibility != -1) { 2744 int count = getChildCount(); 2745 for (int i= 0; i < count; i++) { 2746 getChildAt(i).setVisibility(mChildVisibility); 2747 } 2748 } 2749 } 2750 2751 final static class SavedState implements Parcelable { 2752 2753 int index; // index inside adapter of the current view 2754 Bundle childStates = Bundle.EMPTY; 2755 2756 @Override 2757 public void writeToParcel(Parcel out, int flags) { 2758 out.writeInt(index); 2759 out.writeBundle(childStates); 2760 } 2761 2762 @SuppressWarnings("hiding") 2763 public static final Parcelable.Creator<SavedState> CREATOR = 2764 new Parcelable.Creator<SavedState>() { 2765 @Override 2766 public SavedState createFromParcel(Parcel in) { 2767 return new SavedState(in); 2768 } 2769 2770 @Override 2771 public SavedState[] newArray(int size) { 2772 return new SavedState[size]; 2773 } 2774 }; 2775 2776 @Override 2777 public int describeContents() { 2778 return 0; 2779 } 2780 2781 SavedState(Parcel in) { 2782 index = in.readInt(); 2783 childStates = in.readBundle(GridLayoutManager.class.getClassLoader()); 2784 } 2785 2786 SavedState() { 2787 } 2788 } 2789 2790 @Override 2791 public Parcelable onSaveInstanceState() { 2792 if (DEBUG) Log.v(getTag(), "onSaveInstanceState getSelection() " + getSelection()); 2793 SavedState ss = new SavedState(); 2794 for (int i = 0, count = getChildCount(); i < count; i++) { 2795 View view = getChildAt(i); 2796 int position = getPositionByView(view); 2797 if (position != NO_POSITION) { 2798 mChildrenStates.saveOnScreenView(view, position); 2799 } 2800 } 2801 ss.index = getSelection(); 2802 ss.childStates = mChildrenStates.saveAsBundle(); 2803 return ss; 2804 } 2805 2806 @Override 2807 public void onRestoreInstanceState(Parcelable state) { 2808 if (!(state instanceof SavedState)) { 2809 return; 2810 } 2811 SavedState loadingState = (SavedState)state; 2812 mFocusPosition = loadingState.index; 2813 mFocusPositionOffset = 0; 2814 mChildrenStates.loadFromBundle(loadingState.childStates); 2815 mForceFullLayout = true; 2816 requestLayout(); 2817 if (DEBUG) Log.v(getTag(), "onRestoreInstanceState mFocusPosition " + mFocusPosition); 2818 } 2819} 2820