error message if something goes wrong during player querying

lib/pages/player_page.dart

@@ -72,6 +72,11 @@ class _PlayerPageState extends State<PlayerPage> {
  () => playerInfo.watchable.player.getSource(playerInfo.watchable)
  ),
  builder: (context, snapshot) {
+ if (snapshot.hasError) {
+ Future.microtask(() => this._errorPlaying());
+ return const Center(child: CircularProgressIndicator());
+ }
+
  if (snapshot.connectionState != ConnectionState.done)
  return const Center(child: CircularProgressIndicator());
 
@@ -88,6 +93,24 @@ class _PlayerPageState extends State<PlayerPage> {
  );
  }
 
+ Future<void> _errorPlaying() async {
+ await showDialog(
+ context: super.context,
+ builder: (context) => AlertDialog(
+ title: const Text('Errore imprevisto'),
+ content: const Text('Si è verificato un errore durante la riproduzione, riprova più tardi.'),
+ actions: [
+ TextButton(
+ onPressed: () => Navigator.of(super.context).pop(),
+ child: const Text('Torna indietro')
+ )
+ ],
+ )
+ );
+ if(super.mounted)
+ Navigator.of(super.context).pop();
+ }
+
  void _exitPlayer() {
  this._exited = true;
  if(this._playerInfo.hasStarted)