feat(example): establishing connection improvements

example/lib/components/peer_widget.dart

@@ -7,21 +7,30 @@ class PeerWidget extends StatelessWidget {
     required this.device,
     required this.isIosBrowser,
     required this.onConnect,
+    required this.communicationChannelState,
   });
 
   final NearbyDevice device;
   final bool isIosBrowser;
   final ValueChanged<NearbyDevice> onConnect;
+  final CommunicationChannelState communicationChannelState;
 
   @override
   Widget build(BuildContext context) {
+    final connectedStateCaption = communicationChannelState.isLoading
+        ? 'Wait for connection'
+        : 'Tap to chat';
+
     final status =
-        device.status.isConnected ? 'Tap to chat' : device.status.name;
+        device.status.isConnected ? connectedStateCaption : device.status.name;
+
+    final canTap = !communicationChannelState.isLoading;
+
     return ListTile(
       title: Text(
         '${isIosBrowser ? 'Found device' : 'Pending invitation'} | ${device.info.displayName} | $status',
       ),
-      onTap: () => onConnect(device),
+      onTap: canTap ? () => onConnect(device) : null,
       tileColor: Colors.blueAccent,
       textColor: Colors.white,
     );

example/lib/main.dart

@@ -57,10 +57,11 @@ class AppBody extends StatefulWidget {
 
 class _AppBodyState extends State<AppBody> {
   /// Our service
-  final _nearbyService = NearbyService.getInstance(
+  late final _nearbyService = NearbyService.getInstance(
     /// Define log level here
     logLevel: NearbyServiceLogLevel.debug,
-  );
+  )..communicationChannelState.addListener(() => setState(() {}));
+
   AppState _state = AppState.idle;
 
   /// Browser OR Advertiser for IOS
@@ -116,6 +117,7 @@ class _AppBodyState extends State<AppBody> {
               device: e,
               isIosBrowser: _isIosBrowser,
               onConnect: _connect,
+              communicationChannelState: _communicationChannelState,
             ),
           ),
         ],
@@ -155,6 +157,10 @@ class _AppBodyState extends State<AppBody> {
     return Container();
   }
 
+  CommunicationChannelState get _communicationChannelState {
+    return _nearbyService.communicationChannelState.value;
+  }
+
   Future<void> _initialize() async {
     await _nearbyService.initialize();
   }
@@ -199,30 +205,42 @@ class _AppBodyState extends State<AppBody> {
     // double connection may be unnecessary
     final result = await _nearbyService.connect(device);
     if (result || device.status.isConnected) {
-      _connectionCheckTimer = Timer.periodic(
+      final channelStarting = _tryCommunicate(device);
-        const Duration(seconds: 3),
+      if (!channelStarting) {
-        (_) {
+        _connectionCheckTimer = Timer.periodic(
-          NearbyDevice? selectedDevice;
+          const Duration(seconds: 3),
-          try {
+          (_) => _tryCommunicate(device),
-            selectedDevice = _peers.firstWhere(
+        );
-              (element) => element.info.id == device.info.id,
+      }
-            );
-          } finally {}
-
-          if (selectedDevice.status.isConnected) {
-            try {
-              _startCommunicationChannel(device);
-            } finally {
-              _connectionCheckTimer?.cancel();
-              _connectionCheckTimer = null;
-            }
-          }
-        },
-      );
     }
   }
 
+  bool _tryCommunicate(NearbyDevice device) {
+    NearbyDevice? selectedDevice;
+
+    try {
+      selectedDevice = _peers.firstWhere(
+        (element) => element.info.id == device.info.id,
+      );
+    } catch (_) {
+      return false;
+    }
+
+    if (selectedDevice.status.isConnected) {
+      try {
+        _startCommunicationChannel(device);
+      } finally {
+        _connectionCheckTimer?.cancel();
+        _connectionCheckTimer = null;
+      }
+      return true;
+    }
+    return false;
+  }
+
   void _startCommunicationChannel(NearbyDevice device) {
+    if (!_communicationChannelState.isNotConnected) return;
+
     _nearbyService.startCommunicationChannel(
       NearbyCommunicationChannelData(
         device.info.id,
@@ -260,6 +278,7 @@ class _AppBodyState extends State<AppBody> {
       await _nearbyService.stopDiscovery();
       await _peersSubscription?.cancel();
       setState(() {
+        _peers = [];
         _state = AppState.idle;
       });
     }

example/lib/utils/app_snack_bar.dart

@@ -24,6 +24,7 @@ class AppSnackBar {
       SnackBar(
         content: content,
         action: action,
+        duration: Duration(seconds: action != null ? 10 : 2),
       ),
     );
     return messenger.closed.then((value) => null);