Java Code Examples for android.support.v7.widget.RecyclerView#computeVerticalScrollRange()

private void fireScrollEvent(RecyclerView recyclerView, int offsetX, int offsetY) {
  int contentWidth = recyclerView.getMeasuredWidth() + recyclerView.computeHorizontalScrollRange();
  int contentHeight = recyclerView.computeVerticalScrollRange();

  Map<String, Object> event = new HashMap<>(2);
  Map<String, Object> contentSize = new HashMap<>(2);
  Map<String, Object> contentOffset = new HashMap<>(2);

  contentSize.put(Constants.Name.WIDTH, WXViewUtils.getWebPxByWidth(contentWidth, getInstance().getInstanceViewPortWidth()));
  contentSize.put(Constants.Name.HEIGHT, WXViewUtils.getWebPxByWidth(contentHeight, getInstance().getInstanceViewPortWidth()));

  contentOffset.put(Constants.Name.X, - WXViewUtils.getWebPxByWidth(offsetX, getInstance().getInstanceViewPortWidth()));
  contentOffset.put(Constants.Name.Y, - WXViewUtils.getWebPxByWidth(offsetY, getInstance().getInstanceViewPortWidth()));
  event.put(Constants.Name.CONTENT_SIZE, contentSize);
  event.put(Constants.Name.CONTENT_OFFSET, contentOffset);

  fireEvent(Constants.Event.SCROLL, event);
}
 

@Override public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
    if (scrollerView.isSelected()) return;
    int verticalScrollOffset = recyclerView.computeVerticalScrollOffset();
    int verticalScrollRange = recyclerView.computeVerticalScrollRange();
    float proportion = (float) verticalScrollOffset / ((float) verticalScrollRange - height);
    setScrollerHeight(height * proportion);
}
 

private static int getOffsetOfGoal(int position, RecyclerView mRecyclerView, RecyclerView.Adapter mRecyclerAdapter) {
    int scrollPosition = mRecyclerView.computeVerticalScrollOffset();
    int goalPosition;
    if (position == 0) { // we are at the top
        goalPosition = 0;
    } else if (position == mRecyclerAdapter.getItemCount() - 1) {
        goalPosition = mRecyclerView.computeVerticalScrollRange();
    } else {
        goalPosition = 100000000; // this will cause scrollToPosition() to be called, which we want
    }
    return Math.abs(scrollPosition - goalPosition);
}
 

@Override
public void onScrolled(final RecyclerView recyclerView, final int dx, final int dy) {
    if (bubble == null || handle.isSelected())
        return;
    final int verticalScrollOffset = recyclerView.computeVerticalScrollOffset();
    final int verticalScrollRange = recyclerView.computeVerticalScrollRange();
    float proportion = (float) verticalScrollOffset / ((float) verticalScrollRange - height);
    setBubbleAndHandlePosition(height * proportion);
}
 

@Override
public void onScrolled(final RecyclerView recyclerView, final int dx, final int dy) {
  if (handle.isSelected()) return;
  final int   offset      = recyclerView.computeVerticalScrollOffset();
  final int   range       = recyclerView.computeVerticalScrollRange();
  final int   extent      = recyclerView.computeVerticalScrollExtent();
  final int   offsetRange = Math.max(range - extent, 1);
  setBubbleAndHandlePosition((float) Util.clamp(offset, 0, offsetRange) / offsetRange);
}
 

private void computeOffsetWith(RecyclerView recyclerView) {
    if (recyclerView.getAdapter() == null) {
        setTranslationY(getMeasuredHeight());
        return;
    }
    int lastPosition = recyclerView.getAdapter().getItemCount() - 1;
    RecyclerView.ViewHolder viewHolder = recyclerView.findViewHolderForAdapterPosition(lastPosition);
    if (viewHolder != null && viewHolder.itemView != null && viewHolder.itemView.isShown()) {
        int scrollRange = recyclerView.computeVerticalScrollRange();
        int currentScroll = recyclerView.computeVerticalScrollOffset();
        int rHeight = recyclerView.getHeight();
        int rPadTop = recyclerView.getPaddingTop();
        int offset = scrollRange - currentScroll - rHeight + getHeight() + rPadTop;

        checkAutoLoad();
        setTranslationY(offset);
        if (offset < 0) {
            dispatchOverScroll(offset, recyclerView.getScrollState());
        }
    } else if (recyclerView.getAdapter().getItemCount() == 0) {//no item
        setTranslationY(-recyclerView.getHeight() / 2 + getMeasuredHeight() / 2);
        checkAutoLoad();

    } else {
        setTranslationY(getMeasuredHeight());
    }
}
 

public static boolean isScrollable(RecyclerView recyclerView) {
  return recyclerView.computeHorizontalScrollRange() > recyclerView.getWidth() ||
    recyclerView.computeVerticalScrollRange() > recyclerView.getHeight();
}
 

private boolean isScrollToEnd(RecyclerView view){
    if (view == null) return false;
    if (view.computeVerticalScrollExtent() + view.computeVerticalScrollOffset() >= view.computeVerticalScrollRange())
        return true;
    return false;
}
 

private float getScrollProportion(RecyclerView recyclerView) {
  final int verticalScrollOffset = recyclerView.computeVerticalScrollOffset();
  final int verticalScrollRange = recyclerView.computeVerticalScrollRange();
  float proportion = (float) verticalScrollOffset / ((float) verticalScrollRange - mHeight);
  return mHeight * proportion;
}
 

/**
 * 判断recyclerview是否滑到底部
 * <p>
 * 原理：判断滑过的距离加上屏幕上的显示的区域是否比整个控件高度高
 *
 * @return
 */
public static boolean isScrollToBottom(@NonNull RecyclerView recyclerView) {
    return recyclerView != null && recyclerView.computeVerticalScrollExtent() + recyclerView.computeVerticalScrollOffset() >= recyclerView.computeVerticalScrollRange();
}