FloatingActionButtonScrollBehavior.java

package com.liyu.fakeweather.widgets;

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;

/**
 * Created by liyu on 2016/11/29.
 */

public class FloatingActionButtonScrollBehavior extends FloatingActionButton.Behavior {

    public FloatingActionButtonScrollBehavior(Context context, AttributeSet attrs) {
        super();
    }

    @Override
    public boolean onStartNestedScroll(final CoordinatorLayout coordinatorLayout, final
    FloatingActionButton child, final View directTargetChild, final View target, final int
                                               nestedScrollAxes) {
        // 确保是竖直判断的滚动
        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) {
            /** design lib 升级到 25.1.0 导致 child.hide() 效果失效，法克哟
             *  http://stackoverflow.com/questions/41761736/android-design-library-25-1-0-causes-floatingactionbutton-behavior-to-stop-worki
             */
            child.hide(new FloatingActionButton.OnVisibilityChangedListener() {
                @Override
                public void onHidden(FloatingActionButton fab) {
                    super.onHidden(fab);
                    fab.setVisibility(View.INVISIBLE);
                }
            });
        } else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
            child.show();
        }
    }
}