package com.loopeer.codereader.ui.view; import android.content.Context; import android.support.design.widget.CoordinatorLayout; import android.support.design.widget.FloatingActionButton; import android.support.v4.view.ViewCompat; import android.util.AttributeSet; import android.view.View; public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior { public ScrollAwareFABBehavior(Context context, AttributeSet attrs) { super(); } @Override public boolean onStartNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child, final View directTargetChild, final View target, final int nestedScrollAxes) { // Ensure we react to vertical scrolling return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL || super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes); } @Override public void onNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child, final View target, final int dxConsumed, final int dyConsumed, final int dxUnconsumed, final int dyUnconsumed) { super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed); if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) { // User scrolled down and the FAB is currently visible -> hide the FAB child.hide(); } else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) { // User scrolled up and the FAB is currently not visible -> show the FAB child.show(); } } }