Flutter: [FirebaseFirestore][I-FST000001] Error closes App when using StreamBuilder and no internet connection

Question

I'm building an App on Flutter which includes a Chat for the users with Firebase. To show the data updates in real time I get the data through a StreamBuilder. Everything works fine, but when I decide to turn off WIFI and Inte.net connection on an Iphone XI get the following error and the app closes ( NOTE that on the emulator none of the errors appear and it doesn't close ):

THE CODE FOR BUILDING THE STREAM BUILDER:

chatList(){
    return StreamBuilder<QuerySnapshot>(
      stream: DatabaseService(uid: FirebaseAuth.instance.currentUser!.uid).getChatInfo(),
      builder: (context, snapshot){
        //make some checks
        if(snapshot.hasData){
          var docs = snapshot.data!.docs;
          if(docs.isNotEmpty){
            return ListView.separated(
              itemCount: docs.length,
              itemBuilder: (context, index) {
                var doc = docs[index];
                return ChatTile(
                  bondName: (doc['bondNames'][0] == userName)?  doc['bondNames'][1] : doc['bondNames'][0], 
                  chatId: doc['chatId'],
                  sender: checkSender(doc['sentById'].toString()),
                  lastMessage: doc['lastMessage'].toString(),
                  elapsedTime: calculateElapsedTime((doc['sentAt'] as Timestamp).toDate()),
                  read: doc['read'],
                  userId: userId ,
                );
              },
              separatorBuilder: (context, index) {
                return const Divider();
              },
            );
          }else{
            return noChatWidget();
          }
        }else{
          return Center(
            child: CircularProgressIndicator(
              color: Theme.of(context).primaryColor,
              )
            );
        }
      },
    );

  }

THE ERROR ON PHYSICAL DEVICE:

+88312 ms] 10.2.0 - [FirebaseFirestore][I-FST000001] WatchStream
(102d1d448) Stream error: 'Unavailable: Network connectivity changed'
[   +1 ms] 10.2.0 - [FirebaseFirestore][I-FST000001] WriteStream
(102d79128) Stream error: 'Unavailable: Network connectivity changed'
[+16360 ms] 10.2.0 - [FirebaseFirestore][I-FST000001] WatchStream
(102d1d448) Stream error: 'Unavailable: Network connectivity changed'
[   +8 ms] 10.2.0 - [FirebaseFirestore][I-FST000001] WatchStream
(102d1d448) Stream error: 'Unavailable: DNS resolution failed for
firestore.googleapis.com: UNKNOWN: nodename nor servname provided, or not
known'
[+4007 ms] 10.2.0 - [FirebaseFirestore][I-FST000001] WatchStream
(102d1d448) Stream error: 'Unavailable: DNS resolution failed for
firestore.googleapis.com: UNKNOWN: nodename nor servname provided, or not
known'
[  +11 ms] 10.2.0 - [FirebaseFirestore][I-FST000001] WatchStream
(102d1d448) Stream error: 'Unavailable: DNS resolution failed for
firestore.googleapis.com: UNKNOWN: nodename nor servname provided, or not
known'
[+1306 ms] Service protocol connection closed.
[        ] Lost connection to device.
[   +9 ms] DevFS: Deleting filesystem on the device
(file:///private/var/mobile/Containers/Data/Application/4D1F7639-FEF1-4A33
-866E-734CC70BE773/tmp/binderpC3ghF/binder/)
[ +253 ms] Ignored error while cleaning up DevFS: TimeoutException after
0:00:00.250000: Future not completed
[  +22 ms] "flutter run" took 1.660.540ms.
[  +31 ms] ensureAnalyticsSent: 13ms
[   +1 ms] Running shutdown hooks
[        ] Shutdown hooks complete
[   +1 ms] exiting with code 0

I've tried checking for inte.net connection and returning null when there is no connection on the stream builder, but I still get the error crashing the App. I've searched everywhere and I still cannot find why I get the error knowing that Firebase should even give me an Offline option and it only happens on physical device. Thanks!!

Answer 1

use the ConnectionState property of the StreamBuilder to check the state of the stream and show an appropriate message or widget when the stream is in the ConnectionState.none state.