Java 类android.support.v4.view.ScrollingView 实例源码

/**
 * Find out the scrollable child view from a ViewGroup.
 */
private void findScrollView(ViewGroup viewGroup) {
    scrollChild = viewGroup;
    if (viewGroup.getChildCount() > 0) {
        int count = viewGroup.getChildCount();
        View child;
        for (int i = 0; i < count; i++) {
            child = viewGroup.getChildAt(i);
            if (child instanceof ScrollingView ||
                child instanceof AbsListView ||
                child instanceof ScrollView ||
                child instanceof ViewPager ||
                child instanceof WebView) {
                scrollChild = child;
                return;
            }
        }
    }
}

protected View findScrollableViewInternal(View content, boolean selfable) {
    View scrollableView = null;
    Queue<View> views = new LinkedBlockingQueue<>(Collections.singletonList(content));
    while (!views.isEmpty() && scrollableView == null) {
        View view = views.poll();
        if (view != null) {
            if ((selfable || view != content) && (view instanceof AbsListView
                    || view instanceof ScrollView
                    || view instanceof ScrollingView
                    || view instanceof NestedScrollingChild
                    || view instanceof NestedScrollingParent
                    || view instanceof WebView
                    || view instanceof ViewPager)) {
                scrollableView = view;
            } else if (view instanceof ViewGroup) {
                ViewGroup group = (ViewGroup) view;
                for (int j = 0; j < group.getChildCount(); j++) {
                    views.add(group.getChildAt(j));
                }
            }
        }
    }
    return scrollableView;
}

private View findScrollableViewInternal(View content, boolean selfable) {
    View scrollableView = null;
    Queue<View> views = new LinkedBlockingQueue<>(Collections.singletonList(content));
    while (!views.isEmpty() && scrollableView == null) {
        View view = views.poll();
        if (view != null) {
            if ((selfable || view != content) && (view instanceof AbsListView
                    || view instanceof ScrollView
                    || view instanceof ScrollingView
                    || view instanceof NestedScrollingChild
                    || view instanceof NestedScrollingParent
                    || view instanceof WebView
                    || view instanceof ViewPager)) {
                scrollableView = view;
            } else if (view instanceof ViewGroup) {
                ViewGroup group = (ViewGroup) view;
                for (int j = 0; j < group.getChildCount(); j++) {
                    views.add(group.getChildAt(j));
                }
            }
        }
    }
    return scrollableView;
}

private void findOffset(ViewGroup root) {
  for (int index = 0; index < root.getChildCount(); index++) {
    View child = root.getChildAt(index);
    if (child instanceof ScrollView || child instanceof ScrollingView || child instanceof AbsListView || child instanceof WebView) {
      int widSpec = View.MeasureSpec.makeMeasureSpec(originalWidth, View.MeasureSpec.EXACTLY);
      int heightSpec = View.MeasureSpec.makeMeasureSpec(BIG_ENOUGH_HEIGHT, View.MeasureSpec.AT_MOST);
      child.measure(widSpec, heightSpec);

      if (child.getMeasuredHeight() == BIG_ENOUGH_HEIGHT) {
        heightSpec = View.MeasureSpec.makeMeasureSpec(BIG_ENOUGH_HEIGHT, View.MeasureSpec.UNSPECIFIED);
        child.measure(widSpec, heightSpec);
      }
      updateOffset(child.getHeight(), child.getMeasuredHeight(), child);
    } else if (child instanceof ZoomPanLayout) {
      updateOffset(child.getHeight(), ((ZoomPanLayout) child).getScaledHeight(), child);
    } else if (child instanceof ViewGroup) {
      findOffset((ViewGroup) child);
    }
  }
}

/**
 * @return {@code true} if child view almost scroll to bottom.
 */
public boolean isAlmostBottom() {
    if (null == mTarget) {
        return false;
    }

    if (mTarget instanceof AbsListView) {
        final AbsListView absListView = (AbsListView) mTarget;
        return absListView.getLastVisiblePosition() >= absListView.getCount() - 1;
    } else if (mTarget instanceof ScrollingView) {
        final ScrollingView scrollingView = (ScrollingView) mTarget;
        final int offset = scrollingView.computeVerticalScrollOffset();
        final int range = scrollingView.computeVerticalScrollRange() -
                scrollingView.computeVerticalScrollExtent();
        return offset >= range;
    } else {
        return !ViewCompat.canScrollVertically(mTarget, 1);
    }
}

@Override
public boolean onNestedFling(final CoordinatorLayout coordinatorLayout, final AppBarLayout child, final View target,
  final float velocityX, float velocityY, boolean consumed) {
  if (velocityY > 0 && !isPositive || velocityY < 0 && isPositive) {
    velocityY = velocityY * -1;
  }

  if (target instanceof SwipeRefreshLayout) {
    consumed = consumed((SwipeRefreshLayout) target, consumed);
  } else if (target instanceof RecyclerView) {
    consumed = consumed((RecyclerView) target);
  } else if (target instanceof ScrollingView) {
    consumed = target.getScrollY() < 0;
  }

  return super.onNestedFling(coordinatorLayout, child, target, velocityX, velocityY, consumed);
}

/**
 * is video controllerView in 'list' controllerView
 * @return
 */
public boolean inListView() {
    for (ViewParent vp = getParent(); vp != null; vp = vp.getParent()) {
        if (vp instanceof AbsListView || vp instanceof ScrollingView || vp instanceof ScrollView) {
            return true;
        }
    }
    return false;
}

protected boolean isScrollableView(View view) {
    return view instanceof AbsListView
            || view instanceof ScrollView
            || view instanceof ScrollingView
            || view instanceof NestedScrollingChild
            || view instanceof NestedScrollingParent
            || view instanceof WebView
            || view instanceof ViewPager;
}

protected boolean isScrollableView(View view) {
    return view instanceof AbsListView
            || view instanceof ScrollView
            || view instanceof ScrollingView
            || view instanceof NestedScrollingChild
            || view instanceof NestedScrollingParent
            || view instanceof WebView
            || view instanceof ViewPager;
}

@Override
public void run() {
    if (mScroller.computeScrollOffset()) {
        int dy = mScroller.getCurrY() - mLastFlingY;

        final int selfOffset = getTopAndBottomOffset();
        final int newSelfOffset = Math.max(mMinOffset, Math.min(mMaxOffset, selfOffset - dy));
        final int skipped = newSelfOffset - selfOffset + dy;

        final boolean selfFinished = !setTopAndBottomOffset(newSelfOffset);

        final int targetOffset;
        final boolean targetFinished;
        if (mTargetView instanceof ScrollingView) {
            targetOffset = ((ScrollingView) mTargetView).computeVerticalScrollOffset();
            mTargetView.scrollBy(0, skipped);
            targetFinished = (targetOffset == ((ScrollingView) mTargetView).computeVerticalScrollOffset());
        } else {
            targetOffset = mTargetView.getScrollY();
            mTargetView.scrollBy(0, skipped);
            targetFinished = (targetOffset == mTargetView.getScrollY());
        }

        final boolean scrollerFinished = mScroller.isFinished();

        if (scrollerFinished || (selfFinished && targetFinished)) {
            return;
        }

        mCoordinatorLayout.postOnAnimation(this);

        mLastFlingY = mScroller.getCurrY();
    }
}

private boolean consumed(final SwipeRefreshLayout swipeRefreshLayout, final boolean defaultValue) {
  if (swipeRefreshLayout.getChildCount() > 0) {
    if (swipeRefreshLayout.getChildAt(0) instanceof RecyclerView) {
      return consumed((RecyclerView) swipeRefreshLayout.getChildAt(0));
    } else if (swipeRefreshLayout.getChildAt(0) instanceof ScrollingView) {
      return swipeRefreshLayout.getScrollY() < 0;
    }
  }
  return defaultValue;
}