ScrollAwareFABBehavior.java 文件源码

@Override
public void onNestedScroll(@NonNull CoordinatorLayout coordinatorLayout,
                           @NonNull FloatingActionButton child,
                           @NonNull View target,
                           int dxConsumed,
                           int dyConsumed,
                           int dxUnconsumed,
                           int dyUnconsumed) {
    super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);

    //child -> Floating Action Button
    if (dyConsumed > 0) {
        Log.d("Scrolling", "Up");
        CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) child.getLayoutParams();
        int fab_bottomMargin = layoutParams.bottomMargin;
        child.animate().translationY(child.getHeight() + fab_bottomMargin).setInterpolator(new LinearInterpolator()).start();
    } else if (dyConsumed < 0) {
        Log.d("Scrolling", "down");
        child.animate().translationY(0).setInterpolator(new LinearInterpolator()).start();
    }
}