android：折叠工具栏在向上滚动时反弹

<android.support.design.widget.CoordinatorLayout
    android:id="@+id/rootLayout"
    xmlns:android="http://scheR_317_11845@as.android.com/apk/res/android"
    xmlns:app="http://scheR_317_11845@as.android.com/apk/res-auto"
    xmlns:cardview="http://scheR_317_11845@as.android.com/apk/res-auto"
    android:BACkground="@color/white"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:fitsSystemWindows="true"
        android:layout_width="match_parent"
        android:layout_height="250dp">

         <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:minHeight="?attr/actionBarSize"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            android:fitsSystemWindows="true">

                <RelativeLayout 
                    xmlns:android="http://scheR_317_11845@as.android.com/apk/res/android"
                    android:id="@+id/layout_toolbar"
                    android:layout_width="fill_parent"
                    android:orientation="vertical"
                    app:layout_collapseMode="parallax" 
                    android:layout_height="match_parent">

                        <com.android.volley.toolBox.VolleyImageView 
                            android:id="@+id/image_toolbar"
                            android:layout_width="fill_parent"
                            android:layout_height="match_parent"
                            android:scaleType="centerCrop"/>

                        .... some text views aligned over image...
                </RelativeLayout>

                <android.support.v7.widget.Toolbar
                    android:id="@+id/tool_bar"
                    android:layout_width="match_parent"
                    android:layout_height="?attr/actionBarSize"
                    app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
                    app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />


        </android.support.design.widget.CollapsingToolbarLayout>
    </android.support.design.widget.AppBarLayout>

        <android.support.v7.widget.RecyclerView
        android:id="@+id/lisT_Brands"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layouT_Behavior="@String/appbar_scrolling_view_behavior"/>
</android.support.design.widget.CoordinatorLayout>

当我在回收站视图中快速向上滚动时,折叠的工具栏无法顺利打开,但会跳出并关闭.我不知道什么是错的.我正在关注this文章.

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