android - 工具栏不会隐藏在 Android 4 的 CoordinatorLayout 中

Question

我的布局是：

<android.support.v4.widget.DrawerLayout
    android:id="@+id/drawer_layout"
    xmlns:ads="http://schemas.android.com/tools"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/transparent"
    tools:context=".MainActivity">
    <!--Content of Main-->
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/menu_background"
        android:orientation="vertical"
        >

        <android.support.design.widget.CoordinatorLayout
            android:id="@+id/coordinator"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="2"
            >
            <!-- Frame where is Grid View -->
            <FrameLayout
                android:id="@+id/sample_content_fragment"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_weight="2"
                android:background="@color/menu_background"
                app:layout_behavior="@string/appbar_scrolling_view_behavior"
                android:nestedScrollingEnabled="true">
            </FrameLayout>

            <android.support.design.widget.AppBarLayout
                android:id="@+id/app_bar_layout"
                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"
                    app:layout_scrollFlags="scroll|enterAlways"/>
            </android.support.design.widget.AppBarLayout>


        </android.support.design.widget.CoordinatorLayout>

        <LinearLayout
            android:id="@+id/l_edds"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
        </LinearLayout>
    </LinearLayout>
    <!--End of Content of Main -->
    <!--DrawerView-->
    <LinearLayout
        android:id="@+id/left_RelativeLayout"
        android:layout_width="240dp"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:background="@color/default_color"
        android:orientation="vertical">

        <EditText
            android:id="@+id/left_search"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="5dip"
            android:layout_marginLeft="15dip"
            android:layout_marginRight="15dip"
            android:layout_marginTop="15dip"
            android:background="@drawable/edit_field"
            android:drawableRight="@drawable/ic_search"
            android:hint="@string/text_search"
            android:imeOptions="actionSearch"
            android:inputType="textNoSuggestions"
            android:lines="1"
            android:padding="5dip"
            android:textColor="@color/action_bar_color"
            android:textColorHint="@color/edit_search_hint_color"
            android:textSize="14sp"/>

        <ListView
            android:id="@+id/left_drawer"
            android:layout_width="match_parent"
            android:layout_height="match_parent"

            android:layout_below="@+id/editText"
            android:background="@color/default_color"
            android:choiceMode="singleChoice"
            android:divider="@android:color/transparent"
            android:dividerHeight="0dp"
            android:listSelector="@drawable/selector_bg_key"/>

    </LinearLayout>
    <!--End of DrawerView-->
</android.support.v4.widget.DrawerLayout>

我的活动是：

    import android.support.v7.app.AppCompatActivity;
    public class MainActivity extends AppCompatActivity
     {
 protected void onCreate(Bundle savedInstanceState) {
 FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
            fragment = SlidingTabsColorsFragment.newInstance();
            transaction.replace(R.id.sample_content_fragment, fragment, FRAGMENT_TAG);
            transaction.commit();
    ...
    }

在 Android 5 上，当我在 SlidingTabsColorsFragment 中滚动 gridView 时，工具栏隐藏在 MainActivity

但在 Android 4 上它不起作用，工具栏不会隐藏。 如何解决？