avoid updating player bottom sheet when not visible

app/src/main/java/com/cappielloantonio/tempo/ui/fragment/PlayerBottomSheetFragment.java

@@ -3,6 +3,7 @@ package com.cappielloantonio.tempo.ui.fragment;
 import android.content.ComponentName;
 import android.os.Bundle;
 import android.os.Handler;
+import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -47,7 +48,7 @@ public class PlayerBottomSheetFragment extends Fragment {
     private PlayerBottomSheetViewModel playerBottomSheetViewModel;
     private ListenableFuture<MediaBrowser> mediaBrowserListenableFuture;
 
-    private Handler progressBarHandler;
+    private Handler progressBarHandler = null;
     private Runnable progressBarRunnable;
 
     @Nullable
@@ -66,6 +67,14 @@ public class PlayerBottomSheetFragment extends Fragment {
         return view;
     }
 
+    @Override
+    public void onResume() {
+        super.onResume();
+        if (progressBarHandler != null)
+            progressBarHandler.post(progressBarRunnable);
+        Log.d("Player", "resumed");
+    }
+
     @Override
     public void onStart() {
         super.onStart();
@@ -281,6 +290,10 @@ public class PlayerBottomSheetFragment extends Fragment {
     private void defineProgressBarHandler(MediaBrowser mediaBrowser) {
         progressBarHandler = new Handler();
         progressBarRunnable = () -> {
+            if (!isResumed()) {
+                Log.d("Player", "not resumed");
+                return;
+            }
             setProgress(mediaBrowser);
             progressBarHandler.postDelayed(progressBarRunnable, 1000);
         };