Fix more warnings

QuickPlay/MainActivity.cs

@@ -152,7 +152,7 @@ namespace QuickPlay
             await currentPlayer.Play(song);
         } 
 
-        public async void OnResume()
+        protected override async void OnResume()
         {
             base.OnResume();
 
@@ -170,7 +170,7 @@ namespace QuickPlay
             // Refresh player info
             OnPlayerUpdate();
         }
-        public void OnDestroy()
+        protected override void OnDestroy()
         {
             base.OnDestroy();