Example usage for android.widget ScrollView computeVerticalScrollOffset

Introduction

In this page you can find the example usage for android.widget ScrollView computeVerticalScrollOffset.

Prototype

@Override
    protected int computeVerticalScrollOffset() 

Source Link

Usage

From source file:com.my.seams_carv.util.ScrollableViewUtil.java

/**
 * Return true if the given scrollable view is over scrolling in terms of
 * the given y momentum./*from w  w w  .  j av  a  2  s  . c o  m*/
 * <br/>
 * Usually it is called in the {@code dispatchTouchEvent}, {@code onTouchEvent},
 * or the {@code onInterceptTouchEvent}.
 *
 * @param view the scrollable view.
 * @param dy The y momentum.
 * @return true if the view is over scrolling in the vertical direction.
 */
public static boolean ifOverScrollingVertically(View view, float dy) {
    if (view == null || dy == 0)
        return false;

    // TODO: Test it.
    if (view instanceof ScrollView) {
        final ScrollView scrollView = (ScrollView) view;
        final View child = scrollView.getChildAt(0);
        if (scrollView.getHeight() >= child.getHeight())
            return true;

        if (dy > 0) {
            // Slide the thumb down to scroll up the list.
            return scrollView.getScrollY() == 0;
        } else {
            // Slide the thumb up to scroll down the list.
            MarginLayoutParams params = (MarginLayoutParams) child.getLayoutParams();

            return child.getHeight() - scrollView.getScrollY() == scrollView.getHeight()
                    - (params.topMargin + params.bottomMargin);
        }
        //        } else if (view instanceof WebView) {
        //            WebView webView = (WebView) view;
        //
        //            // TODO: Complete it.
        //            if (dy > 0) {
        //                // Slide the thumb down to scroll up the list.
        //                return webView.computeHorizontalScrollOffset() == 0.f;
        //            } else {
        //                // Slide the thumb up to scroll down the list.
        //                return false;
        //            }
    } else if (view instanceof NestedScrollView) {
        final NestedScrollView scrollView = (NestedScrollView) view;
        final int scrollRange = scrollView.computeVerticalScrollRange()
                - scrollView.computeVerticalScrollExtent();

        if (scrollRange <= 0)
            return true;

        if (dy > 0) {
            // Slide the thumb down to scroll up the list.
            return scrollView.computeVerticalScrollOffset() == 0.f;
        } else {
            // Slide the thumb up to scroll down the list.
            return scrollView.computeVerticalScrollOffset() == scrollRange;
        }
    } else if (view instanceof ListView) {
        final ListView listView = (ListView) view;
        if (listView.getAdapter().getCount() == 0)
            return true;

        // TODO: Complete it.
        if (dy > 0) {
            // Slide the thumb down to scroll up the list.
            return listView.getScrollY() == 0;
        } else {
            // Slide the thumb up to scroll down the list.
            return false;
        }
    } else if (view instanceof RecyclerView) {
        final RecyclerView recyclerView = (RecyclerView) view;
        if (recyclerView.getAdapter().getItemCount() == 0)
            return true;

        final int scrollRange = recyclerView.computeVerticalScrollRange()
                - recyclerView.computeVerticalScrollExtent();

        if (dy > 0) {
            // Slide the thumb down to scroll up the list.
            return recyclerView.computeVerticalScrollOffset() == 0.f;
        } else {
            // Slide the thumb up to scroll down the list.
            return recyclerView.computeVerticalScrollOffset() == scrollRange;
        }
    }
    // TODO: Support more scrollable view.

    // Return true for the unsupported view because the dy is non-zero.
    return true;
}

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