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我有一个浮动操作按钮，它使用自定义行为在 RecyclerView 上显示或隐藏。无论如何，当我从列表中选择一些项目时（所以当 ActionMode 处于活动状态时），我也希望隐藏 FAB。当 ActionMode 启动 (onCreateActionMode) 时，我实际上隐藏了 FAB，但如果我滚动列表，它会重新出现。有任何想法吗？

布局：

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/coordinator">

    <android.support.v7.widget.RecyclerView
        android:scrollbars="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/list" />

    <android.support.design.widget.FloatingActionButton
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:layout_gravity="bottom|end"
        android:src="@drawable/ic_add"
        app:layout_behavior="package.Layout.FABScrollBehavior"
        app:backgroundTint="@color/accent"
        android:id="@+id/fab"/>
</android.support.design.widget.CoordinatorLayout>

行为：

public class FABScrollBehavior extends FloatingActionButton.Behavior {
    public FABScrollBehavior(Context context, AttributeSet attributeSet){
        super();
    }

    @Override
    public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
        return dependency instanceof RecyclerView;
    }

    @Override
    public void onNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
        super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
        if(dyConsumed > 0 && child.getVisibility() == View.VISIBLE){
            child.hide();
        } else if(dyConsumed < 0 && child.getVisibility() == View.GONE){
            child.show();
        }
    }

    @Override
    public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child, View directTargetChild, View target, int nestedScrollAxes) {
        return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL;
    }
}
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