Flutter dark mode

...
MaterialApp(
    themeMode: ThemeMode.light, // Change it as you want
    theme: ThemeData(
        // next line is important!
        systemOverlayStyle: SystemUiOverlayStyle.dark,
    darkTheme: ThemeData( 
      appBarTheme: AppBarTheme(
        systemOverlayStyle: SystemUiOverlayStyle.light,
...

      WidgetsBinding.instance.addPostFrameCallback((_) {
        // set after AppBar apply style, 400ms is magic number
        Future.delayed(const Duration(milliseconds: 400)).then((value) {
          SystemChrome.setSystemUIOverlayStyle(const SystemUiOverlayStyle(
            statusBarBrightness: Brightness.dark, // for ios
            statusBarIconBrightness: Brightness.dark, // for android
          ));
        });
      });