Java Code Examples for android.support.v7.widget.RecyclerView#NO_POSITION

@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
                           RecyclerView.State state) {
    super.getItemOffsets(outRect, view, parent, state);
    if (mDivider == null) {
        return;
    }

    int position = parent.getChildAdapterPosition(view);
    if (position == RecyclerView.NO_POSITION || (position == 0)) {
        return;
    }

    if (mOrientation == -1) {
        getOrientation(parent);
    }

    if (mOrientation == LinearLayoutManager.VERTICAL) {
        outRect.top = mDivider.getIntrinsicHeight();
    } else {
        outRect.left = mDivider.getIntrinsicWidth();
    }
}
 

@Override
public int findTargetSnapPosition(RecyclerView.LayoutManager layoutManager, int velocityX, int velocityY) {

    View centerView = findSnapView(layoutManager);
    if (centerView == null)
        return RecyclerView.NO_POSITION;

    int position = layoutManager.getPosition(centerView);
    int targetPosition = -1;
    if (layoutManager.canScrollHorizontally()) {
        if (velocityX < 0) {
            targetPosition = position - 1;
        } else {
            targetPosition = position + 1;
        }
    }

    if (layoutManager.canScrollVertically()) {
        if (velocityY < 0) {
            targetPosition = position - 1;
        } else {
            targetPosition = position + 1;
        }
    }

    final int firstItem = 0;
    final int lastItem = layoutManager.getItemCount() - 1;
    targetPosition = Math.min(lastItem, Math.max(targetPosition, firstItem));
    if(targetPosition >= 0) recyclerSnapItemListener.onItemSnap(targetPosition);
    return targetPosition;
}
 

private void changeItem(View view) {
    int position = mRecyclerView.getChildAdapterPosition(view);
    if (position != RecyclerView.NO_POSITION) {
        int color = generateColor();
        mColors.set(position, color);
        notifyItemChanged(position);
    }
}
 

@Override
public void onClick(final View view) {
  if (getAdapterPosition() == RecyclerView.NO_POSITION) {
    return;
  }
  final TodoItem item = todoItems.get(getAdapterPosition());
  itemUpdater.updateChecked(item.getId(), taskCheckbox.isChecked());
}
 

@Override
public boolean onLongClick(View v) {
    if (mListener != null && getAdapterPosition() != RecyclerView.NO_POSITION) {
        mListener.onLongClick(getAdapterPosition());
    }
    return true;
}
 

/**
 * Finds the above the fold view.
 * @return The view for above the fold or null, if it is not present.
 */
public NewTabPageLayout findAboveTheFoldView() {
    int position = getNewTabPageAdapter().getAboveTheFoldPosition();
    if (position == RecyclerView.NO_POSITION) return null;

    ViewHolder viewHolder = findViewHolderForAdapterPosition(position);
    if (viewHolder == null) return null;

    View view = viewHolder.itemView;
    if (!(view instanceof NewTabPageLayout)) return null;

    return (NewTabPageLayout) view;
}
 

private void collapseExpandedComment() {
    if (!isCommentReplyExpanded()) return;
    notifyItemChanged(expandedCommentPosition, CommentAnimator.COLLAPSE_COMMENT);
    notifyItemRemoved(expandedCommentPosition + 1);
    replyToCommentFocused = false;
    expandedCommentPosition = RecyclerView.NO_POSITION;
    updateFabVisibility();
}
 

/**
 * Finds the view holder for the first header.
 * @return The {@code ViewHolder} of the header, or null if it is not present.
 */
private SectionHeaderViewHolder findFirstHeader() {
    int position = getNewTabPageAdapter().getFirstHeaderPosition();
    if (position == RecyclerView.NO_POSITION) return null;

    ViewHolder viewHolder = findViewHolderForAdapterPosition(position);
    if (!(viewHolder instanceof SectionHeaderViewHolder)) return null;

    return (SectionHeaderViewHolder) viewHolder;
}
 

/**
 * 滑动到底部.
 */
public int findLastCompletelyVisibleItemPosition() {
    LayoutManager layoutManager = getLayoutManager();
    if (layoutManager != null) {
        if (layoutManager instanceof LinearLayoutManager) {
            return ((LinearLayoutManager) layoutManager).findLastCompletelyVisibleItemPosition();
        }
        if (layoutManager instanceof GridLayoutManager) {
            return ((GridLayoutManager) layoutManager).findLastCompletelyVisibleItemPosition();
        }
    }
    return RecyclerView.NO_POSITION;
}
 

private int getHeaderTop(RecyclerView parent, View child, View header,
                         int adapterPos, int layoutPos) {
    int headerHeight = getHeaderHeightForLayout(header);
    int top = ((int) child.getY()) - headerHeight;
    if (layoutPos == 0) {
        final int count = parent.getChildCount();
        final long currentId = mAdapter.getHeaderId(adapterPos);
        // find next view with header and compute the offscreen push if needed
        for (int i = 1; i < count; i++) {
            int adapterPosHere = parent.getChildAdapterPosition(parent.getChildAt(i));
            if (adapterPosHere != RecyclerView.NO_POSITION) {
                long nextId = mAdapter.getHeaderId(adapterPosHere);
                if (nextId != currentId) {
                    final View next = parent.getChildAt(i);
                    final int offset = ((int) next.getY()) - (headerHeight +
                            getHeader(parent, adapterPosHere).itemView.getHeight());
                    if (offset < 0) {
                        return offset;
                    } else {
                        break;
                    }
                }
            }
        }
        top = Math.max(0, top);
    }
    return top;
}
 

/**
 * onViewRecycled
 * @param holder
 */
@Override
public void onViewRecycled(CardViewHolder holder)
{
    detachClickListeners(holder);
    if (holder.position >= 0 && (holder.position < TODAY_POSITION - 1 || holder.position > TODAY_POSITION + 2)) {
        data.remove(holder.position);
    }
    holder.position = RecyclerView.NO_POSITION;
}
 

@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
  super.getItemOffsets(outRect, view, parent, state);
  int itemPosition = parent.getChildAdapterPosition(view);
  if (itemPosition == RecyclerView.NO_POSITION) {
      return;
  }
  if (mHeaderPositionCalculator.hasNewHeader(itemPosition, mOrientationProvider.isReverseLayout(parent))) {
    View header = getHeaderView(parent, itemPosition);
    setItemOffsetsForHeader(outRect, header, mOrientationProvider.getOrientation(parent));
  }
}
 

/**
 * 滑动到底部.
 */
public int findLastCompletelyVisibleItemPosition() {
    LayoutManager layoutManager = getLayoutManager();
    if (layoutManager != null) {
        if (layoutManager instanceof LinearLayoutManager) {
            return ((LinearLayoutManager) layoutManager).findLastCompletelyVisibleItemPosition();
        }
        if (layoutManager instanceof GridLayoutManager) {
            return ((GridLayoutManager) layoutManager).findLastCompletelyVisibleItemPosition();
        }
    }
    return RecyclerView.NO_POSITION;
}
 

@Override
public final void onBindViewHolder(VH holder, int groupPosition) {
	if (DEBUG) Log.d(LOG_TAG,  this+" onBindViewHolder(pos="+groupPosition+") expanded="+expandedPosition+" count="+expandedChildCount);

	holder.setExpandHandler(this);

	if (expandedPosition == RecyclerView.NO_POSITION || groupPosition <= expandedPosition) {
		holder.isSelected = groupPosition == recyclerView.selectedGroup;
		onBindGroupView(holder, groupPosition);
		setExpandedViewHolder(holder, groupPosition == expandedPosition, true);
	} else if (groupPosition <= expandedPosition + expandedChildCount) {
		holder.isSelected = expandedPosition == recyclerView.selectedGroup;
		if (!BuildConfig.DEBUG) {
			try {
				onBindChildView(holder, expandedPosition, groupPosition - expandedPosition - 1);
			} catch (ClassCastException e) {
				Log.e(LOG_TAG, this + " failed onBindViewHolder(pos=" + groupPosition + ") expanded=" + expandedPosition + " count=" + expandedChildCount, e);
			}
		} else {
			onBindChildView(holder, expandedPosition, groupPosition - expandedPosition - 1);
		}
	} else {
		holder.isSelected = groupPosition == recyclerView.selectedGroup;
		onBindGroupView(holder, groupPosition - expandedChildCount);
		setExpandedViewHolder(holder, false, true);
	}
}
 

@Override
public boolean onLongClick(View v) {
    int index = getAdapterPosition();
    return index != RecyclerView.NO_POSITION && onItemLongClickListener != null &&
        onItemLongClickListener.onItemLongClick(adapter.itemAt(index));
}
 

@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
    initScriptDirection(recyclerView);

    switch (newState) {
        case RecyclerView.SCROLL_STATE_DRAGGING:
            // distinct drag to improve accuracy, init mDraggingStart and mDraggingEnd here
            mDragging = true;
            final int[] range = AbstractLayoutManagerUtils.getVisibleRange(recyclerView);
            mDraggingStart = range[0];
            mDraggingEnd = range[1];
            break;
        case RecyclerView.SCROLL_STATE_SETTLING:
            mDragging = false;
            break;
        case RecyclerView.SCROLL_STATE_IDLE:
            mDragging = false;

            // perform final update on the range we have ever visited
            updateVisibleRange(recyclerView);
            AbstractLogUtils.e(this, "==>  visible range: [" + mDraggingStart + ", " + mDraggingEnd + "]");
            MeasurableRecyclerViewHelper.notifyMeasurableViewHolderDataRangeChanged(recyclerView, mDraggingStart, mDraggingEnd);

            // reset mDraggingStart and mDraggingEnd here
            mDraggingStart = RecyclerView.NO_POSITION;
            mDraggingEnd = RecyclerView.NO_POSITION;

            final int state = ScriptDirectionChecker.checkSelfScriptDirection(recyclerView.getContext());
            if (mScriptDirectionState != ScriptDirectionChecker.UNSPECIFIED
                    && state != ScriptDirectionChecker.UNSPECIFIED
                    && mScriptDirectionState != state) {
                /*
                 * [ANDROID-1778]
                 *
                 * immediately flush the statistics if user change between a ltr and rtl language
                 * on the fly; do the check in here for better performance
                 */
                final List<IMeasurableViewHolder> holders =
                        MeasurableRecyclerViewHelper.getViewHolders(recyclerView, IMeasurableViewHolder.class);
                for (IMeasurableViewHolder holder : holders) {
                    holder.flush();
                }

                if (AbstractLayoutManagerUtils.getOrientation(recyclerView.getLayoutManager())
                        == OrientationHelper.HORIZONTAL) {
                    AbstractLayoutManagerUtils.setReverseLayout(recyclerView.getLayoutManager(),
                            state == ScriptDirectionChecker.RIGHT_TO_LEFT);
                }
                mScriptDirectionState = state;
            }
            break;
        default:
            break;
    }
}
 

/**
 * find highest & lowest views among visible attached views
 */
@Override
public void findBorderViews() {
    topView = null;
    bottomView = null;
    leftView = null;
    rightView = null;
    minPositionOnScreen = RecyclerView.NO_POSITION;
    maxPositionOnScreen = RecyclerView.NO_POSITION;

    isFirstItemAdded = false;

    if (lm.getChildCount() > 0) {
        View initView = lm.getChildAt(0);
        topView = initView;
        bottomView = initView;
        leftView = initView;
        rightView = initView;

        for (View view : childViews) {
            int position = lm.getPosition(view);

            if (!isInside(view)) continue;

            if (lm.getDecoratedTop(view) < lm.getDecoratedTop(topView)) {
                topView = view;
            }

            if (lm.getDecoratedBottom(view) > lm.getDecoratedBottom(bottomView)) {
                bottomView = view;
            }

            if (lm.getDecoratedLeft(view) < lm.getDecoratedLeft(leftView)) {
                leftView = view;
            }

            if (lm.getDecoratedRight(view) > lm.getDecoratedRight(rightView)) {
                rightView = view;
            }

            if (minPositionOnScreen == RecyclerView.NO_POSITION || position < minPositionOnScreen) {
                minPositionOnScreen = position;
            }

            if (maxPositionOnScreen == RecyclerView.NO_POSITION || position > maxPositionOnScreen) {
                maxPositionOnScreen = position;
            }

            if (position == 0) {
                isFirstItemAdded = true;
            }
        }
    }
}
 

public void clearSelection() {
  int prev = selectedPosition;
  selectedPosition = RecyclerView.NO_POSITION;
  notifyItemChanged(prev);
}
 

public FocusableLinearLayoutManager(Context context) {
    super(context, VERTICAL, false);

    mContext = context;
    mUiHandler = new Handler();

    mOnCentralPositionChangedListeners = new ArrayList<>();
    mPreviousCentral = RecyclerView.NO_POSITION;

    mScrollOffset = INVALID_SCROLL_OFFSET;

    mAppBarScrollController = new AppBarScrollController(mTicklableRecyclerView);

    setInFocusState(false);
}
 

/**
 * Returns the adapter position of the last visible view. This position does not include
 * adapter changes that were dispatched after the last layout pass.
 *
 * @return The adapter position of the last visible view or {@link RecyclerView#NO_POSITION} if
 * there aren't any visible items
 */
public int findLastVisibleItemPosition() {
    final View child = findOneVisibleChild(layoutManager.getChildCount() - 1, -1, false, true);
    return child == null ? RecyclerView.NO_POSITION : recyclerView.getChildAdapterPosition(child);
}