滚动时如何隐藏选项卡

我用的是 FrameLayout NestedScrollView 在上面我打开了一个有3个标签的片段。

ActionBar .

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    app:layout_scrollFlags="scroll|enterAlways"
    tools:context=".MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <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_collapseMode="pin"
            app:layout_scrollFlags="enterAlways|scroll" />

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

    <!--<include layout="@layout/content_main" />-->

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/main_container"
        android:background="@color/colorPrimary"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">
        <android.support.v4.widget.NestedScrollView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fillViewport="true">
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical">
                <!-- Your content here -->
            </LinearLayout>
        </android.support.v4.widget.NestedScrollView>
    </FrameLayout>

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        app:srcCompat="@android:drawable/ic_dialog_email" />

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