Add a scrollbar

I use VerticalGridView to replace RecycleView in Android TV app and set scrollbar for VerticalGridView in xml as below. But in the end the scrollbar is not showing.

`
android:scrollbarSize="@dimen/sw_3dp"
android:scrollbarStyle="outsideInset"
android:scrollbarThumbVertical="@color/white"
android:scrollbarTrackVertical="@color/color_B0B0B0"
android:scrollbars="vertical"
`
After I added the following code, the scroll bar can be displayed. But the scrollbar only shows the track but not the thumb.
`
android:fadeScrollbars="false"
android:background="@color/transparent"
android:scrollbarAlwaysDrawVerticalTrack="true"
`
Can help me?

Start by reproducing the reported VerticalGridView behavior in an Android TV app using the XML scrollbar attributes shown in the issue. Confirm that the vertical scrollbar displays both its track and thumb; the issue names no source file or test, so the relevant implementation and test location must first be identified.

Written by the indexing model from the issue text.