Wie blende ich die Toolbar aus, wenn ich Inhalte in Android nach oben scrolle?

Ich versuche, meine Werkzeugleiste auszublenden, wenn ich meinen Text und mein Bild mit Inhalten scrolle. Hier verwende ich ScrollView, um Bildlaufinhalte zu erhalten 

hier mein Xml-Code

content_main.XML

<Android.support.v4.widget.NestedScrollView
xmlns:app="http://schemas.Android.com/apk/res-auto"
Android:layout_width="match_parent"
Android:layout_height="match_parent"
xmlns:Android="http://schemas.Android.com/apk/res/Android"
app:layout_behavior="@string/appbar_scrolling_view_behavior">


<LinearLayout
    Android:orientation="vertical"
    Android:layout_width="match_parent"
    Android:layout_height="match_parent">

<LinearLayout
    Android:paddingTop="?android:attr/actionBarSize"
    Android:orientation="vertical"
    Android:layout_width="match_parent"
    Android:layout_height="match_parent">

    <TextView
        Android:layout_marginLeft="10dp"
        Android:layout_marginRight="10dp"
        Android:id="@+id/textone"
        Android:layout_width="match_parent"
        Android:layout_height="match_parent"
        Android:textSize="23dp"
        Android:textStyle="bold"
        Android:text="hello world jheds sdjhs jds sjbs skjs ksjs kksjs ksj sdd dskd js sk "/>

    <ImageView
        Android:id="@+id/imge"
        Android:layout_width="match_parent"
        Android:layout_height="250dp"
        Android:src="@drawable/imag_bg"/>


    <TextView
        Android:id="@+id/texttwo"
        Android:layout_width="match_parent"
        Android:layout_height="match_parent"
        Android:layout_marginLeft="10dp"
        Android:layout_marginRight="10dp"
        Android:text="Pretty good, the Toolbar is moving along with the list and getting back just as we expect it to. This is thanks to the restrictions that we put on the mToolbarOffset variable.
        If we would omit checking if it’s bigger than 0 and lower than mToolbarHeight then when
        we would scroll
         up our list, the Toolbar would move along far away off the screen, so to show it back you
         would have to scroll the list down to 0. Right now it just scrolls up to mToolbarHeight
         position and not more so it’s “sitting” right above the list all of the time and if we
         start scrolling down, we can see it immediately showing.



          up our list, the Toolbar would move along far away off the screen, so to show it back you
         would have to scroll the list down to 0. Right now it just scrolls up to mToolbarHeight
         position and not more so it’s “sitting” right above the list all of the time and if we
         start scrolling down, we can see it immediately showing

          up our list, the Toolbar would move along far away off the screen, so to show it back you
         would have to scroll the list down to 0. Right now it just scrolls up to mToolbarHeight
         position and not more so it’s “sitting” right above the list all of the time and if we
         start scrolling down, we can see it immediately showing

          up our list, the Toolbar would move along far away off the screen, so to show it back you
         would have to scroll the list down to 0. Right now it just scrolls up to mToolbarHeight
         position and not more so it’s “sitting” right above the list all of the time and if we
         start scrolling down, we can see it immediately showing

          up our list, the Toolbar would move along far away off the screen, so to show it back you
         would have to scroll the list down to 0. Right now it just scrolls up to mToolbarHeight
         position and not more so it’s “sitting” right above the list all of the time and if we
         start scrolling down, we can see it immediately showing

          up our list, the Toolbar would move along far away off the screen, so to show it back you
         would have to scroll the list down to 0. Right now it just scrolls up to mToolbarHeight
         position and not more so it’s “sitting” right above the list all of the time and if we
         start scrolling down, we can see it immediately showing
        It works pretty well, but this is not what we want. It feels weird that you can
        stop it in the middle of
        the

         scroll and the Toolbar will stay half visible. Actually this is how it’s done in Google Play
         Games app
        which I consider as a bug

        It works pretty well, but this is not what we want. It feels weird that you can
        stop it in the middle of
        the
         scroll and the Toolbar will stay half visible. Actually this is how it’s done in Google Play
         Games app
        which I consider as a bug
        It works pretty well, but this is not what we want. It feels weird that you can
        stop it in the middle of
        the
         scroll and the Toolbar will stay half visible. Actually this is how it’s done in Google Play
         Games app
        which I consider as a bug."/>




</LinearLayout>

<View
    Android:layout_width="wrap_content"
    Android:layout_height="30dp" />
<LinearLayout

    Android:layout_width="match_parent"
    Android:layout_height="match_parent">
    <Button
         Android:text="hai"
         Android:layout_width="160dp"
         Android:layout_height="match_parent" />
    <Button
         Android:text="hello"
         Android:layout_width="160dp"
         Android:layout_height="match_parent" />


</LinearLayout>

activity_main.XML

<Android.support.design.widget.AppBarLayout
    Android:layout_height="wrap_content"
    Android:layout_width="match_parent" 
    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:popupTheme="@style/AppTheme.PopupOverlay" />

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

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