Flutter initState not working when pushing navigator-CodePudding

This is the code where the initState is not working

class _MyAppState extends State<MyApp> {
  late bool _nightMode;

  Future<void> _loadNightMode() async {
    final prefs = await SharedPreferences.getInstance();
    setState(() {
      _nightMode = (prefs.getBool('nightMode') ?? false);
    });
  }

  @override
  void initState() {
    super.initState();
    _loadNightMode();
    print("HELLO");
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.light(),
      darkTheme: ThemeData.dark(),
      themeMode: _nightMode ? ThemeMode.dark : ThemeMode.light,
      debugShowCheckedModeBanner: false,
      home: const LandingPage(),
    );
  }
}

I tried printing HELLO as a testing but it resulted in nothing actually.

This is how I call it.


  logout() {
    FirebaseAuth.instance.signOut();
    Navigator.of(context).push(
      MaterialPageRoute(
        builder: (BuildContext context) {
          return const MyApp();
        },
      ),
    );
  }

As you can see, I am trying to pass the sharedpreferences to get a bool but with the initState not working it's actually not getting passed. There is also no error popping out.

CodePudding user response：

Navigator use context and when initstate called context not ready yet so don't use navigator or any context related work in initstate

CodePudding user response：

Try to add _loadNightMode() method call in callback inside initState method because of context not available yet:

WidgetsBinding.instance.addPostFrameCallback((_) async {
  _loadNightMode();
});

Second options is move _loadNightMode() into didChangeDependencies() widget lifecycle callback function.