Check out example codes for "exoplayer how to put loader while video is still loading android java". It will help you in understanding the concepts better.

Code Example 1

<com.google.android.exoplayer2.ui.PlayerView
        android:id="@+id/player_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:show_buffering="always"/>

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