在Android中启用RecyclerView快速滚动来设置固定高度的滚动拇指

Question

我已经使用以下属性实现了RecyclerView快速滚动：

<android.support.v7.widget.RecyclerView
...
 app:fastScrollEnabled="true"
 app:fastScrollHorizontalThumbDrawable="@drawable/fast_scroll_thumb"
 app:fastScrollHorizontalTrackDrawable="@drawable/fast_scroll_track"
 app:fastScrollVerticalThumbDrawable="@drawable/fast_scroll_thumb"
 app:fastScrollVerticalTrackDrawable="@drawable/fast_scroll_track"/>

fast_scroll_thumb.xml

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true">
        <shape android:shape="rectangle">
            <solid android:color="@color/lightBlue" />
        </shape>
    </item>
    <item>
        <shape android:shape="rectangle">
            <solid android:color="@color/lightBlue" />
        </shape>
    </item>
</selector>

fast_scroll_track.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <solid android:color="@color/gray" />
</shape>

但是，快速滚动拇指大小取决于数据数量。随着RecyclerView数据的增加，拇指大小减小。有什么方法可以将拇指大小固定在固定高度上吗？