颤振：在没有互联网连接时返回一个页面

Question

i created flutter app that shows a taost message when no internet connection, but i was trying to return a page clarifies that no internet connection ( before entering the app) instead of toast message is there a way to do it?

 class _NotificationState extends State<Notification> { var subscription; var connectionStatus; @override void initState() { subscription = Connectivity().onConnectivityChanged.listen((ConnectivityResult result) { setState(() => connectionStatus = result); checkInternetConnectivity(); }); checkInternetConnectivity(); // checkLoginStatus(); super.initState(); } checkInternetConnectivity() { if (connectionStatus == ConnectivityResult.none) { return Fluttertoast.showToast( msg: "Check your internet connection", toastLength: Toast.LENGTH_LONG, gravity: ToastGravity.TOP, timeInSecForIosWeb: 10, backgroundColor: Colors.red, textColor: Colors.white, fontSize: 16.0 ); } } //PS: i tried to return Internet() page instead but it's not working @override dispose() { super.dispose(); subscription.cancel(); } Widget build(BuildContext context) {

Answer 1

Your initState method contains duplicate method calls to checkInternetConnectivity . Remove one of them:

@override
  void initState() {
subscription = Connectivity().onConnectivityChanged.listen((ConnectivityResult result) {         
        setState(() => connectionStatus = result);
        checkInternetConnectivity();
});
    
    // checkInternetConnectivity(); <--- Remove this
    // checkLoginStatus();
    
    super.initState();
  }

Finally, your method should look something like this:

void checkInternetConnectivity() {
   if (connectionStatus == ConnectivityResult.none) {
     Navigator.of(context).push(MaterialPageRoute(
       buider: (BuildContext context) => Internet(),
     )); 
   }
}

Answer 2

Two common ways of navigating from one page to another

1. Without the use of route

  Navigator.push(
        context,
        MaterialPageRoute(
        builder: (context) => InternetPage(
            // you can pass parameter here to the next page
            // remember to create instance of dataToNextPage at the page you are navigating to
            dataToNextPage: dataFromCurrentPage,
        ),
 ));

2. With the use of named Route. You need to specify the route you will be using link for more info

Navigator.pushNamed(context, '/internetPage', arguments: {});