Toolbar will not collapse with Scrollview as child of CoordinatorLayout

The ScrollView does not cooperate with the CoordinatorLayout. You have to use NestedScrollView instead of ScrollView

Use NestedScrollView to collapse your scrollview as a child of Coordinator Layout. Replace your code with this code:

<android.support.design.widget.CoordinatorLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v4.widget.NestedScrollView
        android:layout_width="match_parent"
                 android:layout_height="match_parent"
                 app:layout_behavior="@string/appbar_scrolling_view_behavior">

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

        <TextView
            android:id="@+id/tv_View"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_gravity="center"
            android:gravity="center"
            android:text="@string/filler"
            style="@style/TextAppearance.AppCompat.Large"
            />

    </LinearLayout>
    </android.support.v4.widget.NestedScrollView>

    <android.support.design.widget.AppBarLayout
        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>

You can keep the ScrollView and add this XML property : android:nestedScrollingEnabled="true" so it knows the CoordinatorLayout as a sibling and keep in mind this property is supported just in lollipop version and above.