Fix keep screen on

app/src/main/res/layout/activity_exo_player.xml

@@ -5,7 +5,8 @@
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:background="@android:color/black"
-    android:gravity="center">
+    android:gravity="center"
+    android:keepScreenOn="true">
 
     <com.google.android.exoplayer2.ui.AspectRatioFrameLayout
         android:id="@+id/aspectRatioLayout"