ViewPager的列表向下滚动时，工具栏无法自动隐藏

Question

I use CoordinatorLayout and AppBarLayout to try get the effect that the toolbar hides automatically as the ListView contained in the viewPager's Fragment scrolling down,but it doesn't work!The Toolbar never hide as I wish!Any of your suggestion will be appreciated! xml code:

 <android.support.design.widget.CoordinatorLayout
        android:id="@+id/main_content"
        android:orientation = "vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.design.widget.AppBarLayout xmlns:android="http://schemas.android.com/apk/res/android"
            xmlns:app="http://schemas.android.com/apk/res-auto"
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:layout_scrollFlags="scroll|enterAlways"
                />
            <android.support.design.widget.TabLayout
                android:id="@+id/tabs"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="@color/md_primary_green"
                app:tabGravity="fill"
                app:tabMode="fixed"
                app:tabSelectedTextColor="#ff0000"
                app:tabTextColor="@color/md_text"/>
        </android.support.design.widget.AppBarLayout>


        <!--<LinearLayout-->
            <!--android:layout_width="match_parent"-->
            <!--android:layout_height="match_parent"-->
            <!--android:orientation="vertical"-->
            <!--android:scrollbars="none"-->
             <!-->-->

            <android.support.v4.view.ViewPager
                android:id="@+id/viewgroup"
                android:layout_height="match_parent"
                app:layout_behavior="@string/appbar_scrolling_view_behavior"
                android:layout_width="match_parent">
            </android.support.v4.view.ViewPager>
        <!--</LinearLayout>-->
    </android.support.design.widget.CoordinatorLayout>

Answer 1

原因是AppBarLayout无法与旧控件完全兼容。当我用RecycleView替换ListView时，它运行良好。