问题描述
我正在使用Chopper和BLoC系统在Flutter应用上实现登录身份验证。我的完整代码是here。 LoginForm中的BlocListner运作良好,可以在身份验证后将我导航到主页,但是存在两个问题:
问题1: 这是我要的main.dart:
void main() async {
WidgetsFlutterBinding.ensureInitialized();
setupLocator();
runApp(MultiBlocProvider(providers: [
BlocProvider(create: (BuildContext context) {
return dispatchBloc();
}),BlocProvider(create: (BuildContext context) {
return HistoryBloc();
}),BlocProvider(create: (BuildContext context) {
return LoginBloc();
}),],child: MyApp()));
}
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
LoginBloc loginBloc;
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'dispatch Executive App',theme: ThemeData(
primarySwatch: Colors.green,textTheme: Theme.of(context).textTheme.apply(
fontSizeDelta: 1.5,)),// home: LoginPage(),routes: {
'/': (context) {
return BlocListener<LoginBloc,LoginState>(
cubit: loginBloc,listener: (BuildContext context,state) {},child: BlocBuilder<LoginBloc,LoginState>(
builder: (BuildContext context,LoginState state) {
if (state is LoadedLoginState) {
print("loaded log in from home!");
return Home(token: state.login.token);
} else {
print(state);
return LoginPage();
}
//return Home();
},),);
},'/home': (context) => Home(),},// home: LoginPage(),//change this for testing
);
}
问题2: 身份验证成功并且导航器进入主页后,This issue 会显示2秒钟 这就是我用于登录表单的内容。 BlocListener和BlocBuilder在这里工作正常!
BlocBuilder(
cubit: loginBloc,builder: (context,state) {
if (state is LoadingLoginState) {
return Center(
child: CircularProgressIndicator(),);
}
if (state is LoadedLoginState) {
print(state);
print("in login form");
print(state.login.token);
Navigator.pushReplacementNamed(context,'/home');
return Text("Success " + state.login.token);
}
if (state is ErrorLoginState) {
return Text("Error" + state.error);
} else {
return SizedBox(width: 20.0);
}
},
请帮助!非常感谢。
解决方法
对于第一个问题,您应该将密钥保存在手机内存中。为此,您可以使用来自flutter的shared_preferences
包。
这里是例子。
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'SharedPreferences Demo',home: SharedPreferencesDemo(),);
}
}
class SharedPreferencesDemo extends StatefulWidget {
SharedPreferencesDemo({Key key}) : super(key: key);
@override
SharedPreferencesDemoState createState() => SharedPreferencesDemoState();
}
class SharedPreferencesDemoState extends State<SharedPreferencesDemo> {
Future<SharedPreferences> _prefs = SharedPreferences.getInstance();
Future<int> _counter;
Future<void> _incrementCounter() async {
final SharedPreferences prefs = await _prefs;
final int counter = (prefs.getInt('counter') ?? 0) + 1;
setState(() {
_counter = prefs.setInt("counter",counter).then((bool success) {
return counter;
});
});
}
@override
void initState() {
super.initState();
_counter = _prefs.then((SharedPreferences prefs) {
return (prefs.getInt('counter') ?? 0);
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("SharedPreferences Demo"),),body: Center(
child: FutureBuilder<int>(
future: _counter,builder: (BuildContext context,AsyncSnapshot<int> snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.waiting:
return const CircularProgressIndicator();
default:
if (snapshot.hasError) {
return Text('Error: ${snapshot.error}');
} else {
return Text(
'Button tapped ${snapshot.data} time${snapshot.data == 1 ? '' : 's'}.\n\n'
'This should persist across restarts.',);
}
}
})),floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,tooltip: 'Increment',child: const Icon(Icons.add),);
}
}
第二期,