Flutter => showDialog / AlertDialog => No MaterialLocalizations found

Question

just new to Flutter but very impressed. I want to show a Dialog if a PushNotification arrives via Firebase \"onMessage\".

But every Time I get a Exception \"No MaterialL

Answer 1

Flutter 1.0, Dart 2.x

This solution works on both StatelessWidget widget and StatefulWidget widget.

On the top, in your declaration you can create a static navKey:

class MyApp extends StatefulWidget {
  final String title; // sample var you want to pass to your widget
  static final navKey = new GlobalKey<NavigatorState>();
  const MyApp({Key navKey, this.title}) : super(key: navKey);
  @override
  State<StatefulWidget> createState() => _MyAppState();
}

On the layout part you should use the key:

return MaterialApp(
        navigatorKey:MyApp.navKey,
        title: widget.title,
        ...

So, when you need the current context for your dialog or other widget, in the state part you can do :

@override
  void initState() {
  final context = MyApp.navKey.currentState.overlay.context;
  showMyCustomDialog(context);
  ...
  super.initState();
}

Answer 2

In Order to Fix the error, You need to Call Your Main class as a home parameter of MaterialAppas Like Below.

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Welcome to Flutter',
      debugShowCheckedModeBanner: false,
      home: Main(),
    );
  }
}

& update your Build Method in Main Class as:

@override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Welcome to Flutter'),
      ),
      body: Column(children: <Widget>[
        Center(
          child: Text('Hello World'),
        ),
        RaisedButton(
          onPressed: () {
            print("pushed?");
            _showPushDialog(context);
          },
          child: Text("press me"),
        )
      ]),
    );
  }

Answer 3

check your MaterialApp() widget, if you set localizationsDelegates ,may be you well get this problem. it works when i delete those code.

              localizationsDelegates: [
                  DefaultCupertinoLocalizations.delegate,
              ],

my codes.

MaterialApp(
              navigatorKey: navigatorKey,
              title: 'test',
              theme: ThemeData(
                  platform: TargetPlatform.iOS,
                  backgroundColor: Color(0xfff1f1f1),
                  accentColor: AppStyle.colorPrimary,
                  primaryColor: AppStyle.colorPrimary,
                  buttonColor: AppStyle.colorPrimary,
                  iconTheme: IconThemeData(color: Colors.white),
                  textTheme: TextTheme(
                      title: TextStyle(color: Colors.white),
                  ),
                  primaryTextTheme: TextTheme(title: TextStyle(color: Colors.white)),
                  primaryIconTheme: const IconThemeData.fallback().copyWith(
                      color: Colors.white,
                  ),
                  appBarTheme: AppBarTheme().copyWith(brightness: Brightness.dark),
              ),
              home: LoginPage(),
              debugShowCheckedModeBanner: false,
              onGenerateRoute: AppRouter.router.generator,
          )