Question

遵循本教程。 https://itnext.io/app-theming-in-flutter-dark-mode-light-mode-27d9adf3cee

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  SystemChrome.setPreferredOrientations([
    DeviceOrientation.portraitUp,
    DeviceOrientation.portraitDown,
  ]);
  runApp(
    ChangeNotifierProvider<AppStateNotifier>(
      builder: (context) => AppStateNotifier(), //<--COMPILER ERROR, details below.
      child: MyApp(),
    ),
  );
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return Consumer<AppStateNotifier>(
      builder: (context, appState, child) {
        return MaterialApp(
          title: 'Lockify',
          debugShowCheckedModeBanner: false,
          theme: AppTheme.lightTheme, 
          darkTheme:
              AppTheme.darkTheme, 
          home: MyHomePage(),
          themeMode: appState.isDarkModeOn ? ThemeMode.dark : ThemeMode.light,
        );
      },
    );
  }
}

错误：编译器消息： lib / main.dart：16：29：错误：无法将类型为“ AppStateNotifier”的值分配给类型为“小部件”的变量。

“ AppStateNotifier”来自“ package：lockify / appstatenotifier.dart”（“ lib / appstatenotifier.dart”）。
“小部件”来自“ package：flutter / src / widgets / framework.dart”（“ ../../ Developer / flutter / packages / flutter / lib / src / widgets / framework.dart”）。构建器：（上下文）=> AppStateNotifier（），

lib / main.dart：16：16：错误：参数类型'Widget Function（BuildContext）'无法分配给参数类型'Widget Function（BuildContext，Widget）'。

“小部件”来自“ package：flutter / src / widgets / framework.dart”（“ ../../ Developer / flutter / packages / flutter / lib / src / widgets / framework.dart”）。 / li>
“ BuildContext”来自“ package：flutter / src / widgets / framework.dart”（“ ../../ Developer / flutter / packages / flutter / lib / src / widgets / framework.dart”）。构建器：（上下文）=> AppStateNotifier（），

Answer 1

尝试在builder小部件上将create更改为ChangeNotifierProvider。

错误：无法将'AppStateNotifier'类型的值分配给'Widget类型的变量

1 个答案: