如何让用户保持登录状态

Question

我昨天发布了这个问题，但没有得到任何有效答案。我目前的情况是我可以成功登录用户但是当我重新启动应用程序时我必须再次登录所以我需要将用户的详细信息保存在共享首选项中以便用户可以在整个会话期间保持登录状态直到 logout.But 我做不到，所以请帮助我。提前致谢

login.dart :

Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Color.fromRGBO(3, 9, 23, 1),
      body: Container(
          padding: EdgeInsets.only(
            top: 100,
            right: 30,
            left: 30,
          ),
          child: SingleChildScrollView(
            child: Form(
              key: _formKey,
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.center,
                mainAxisAlignment: MainAxisAlignment.center,
                children: <Widget>[
                  FadeAnimation(
                      1.2,
                      Container(
                        padding: EdgeInsets.all(70.0),
                        margin: EdgeInsets.only(bottom: 50.0),
                        decoration: BoxDecoration(
                            image: DecorationImage(
                                image: AssetImage(
                                    'assets/images/trakinglogo.png'))),
                      )),
                  SizedBox(
                    height: 30,
                  ),
                  FadeAnimation(
                      1.5,
                      Container(
                        padding: EdgeInsets.all(10),
                        decoration: BoxDecoration(
                            borderRadius: BorderRadius.circular(10),
                            color: Colors.white),
                        child: Column(
                          children: <Widget>[
                            Container(
                              decoration: BoxDecoration(
                                  border: Border(
                                      bottom:
                                          BorderSide(color: Colors.grey[300]))),
                              child: TextFormField(
                                controller: _emailController,
                                onFieldSubmitted: (_) =>
                                    FocusScope.of(context).nextFocus(),
                                textInputAction: TextInputAction.done,
                                validator: (value) {
                                  if (value.isEmpty) {
                                    return 'Email is required';
                                  }
                                  return null;
                                },
                                decoration: InputDecoration(
                                    border: InputBorder.none,
                                    hintStyle: TextStyle(
                                        color: Colors.grey.withOpacity(.8)),
                                    hintText: "Votre adresse mail"),
                              ),
                            ),
                            Container(
                              decoration: BoxDecoration(),
                              child: TextFormField(
                                controller: _passwordController,
                                validator: (value) {
                                  if (value.isEmpty) {
                                    return 'Password is required';
                                  }
                                  return null;
                                },
                                obscureText: _isHidden,
                                decoration: InputDecoration(
                                  border: InputBorder.none,
                                  hintStyle: TextStyle(
                                      color: Colors.grey.withOpacity(.8)),
                                  hintText: "Mot de passe",
                                  suffix: InkWell(
                                      onTap: _togglePasswordView,
                                      child: Icon(
                                        _isHidden
                                            ? (CommunityMaterialIcons
                                                .eye_outline)
                                            : (CommunityMaterialIcons.eye_off),
                                        color: Color(0xFF939394),
                      
                  SizedBox(
                    height: 40,
                  ),
                  FadeAnimation(
                      1.8,
                      Center(
                          child: Column(
                        children: [
                          Row(
                            mainAxisAlignment: MainAxisAlignment.center,
                            crossAxisAlignment: CrossAxisAlignment.center,
                            children: [
                              Container(
                                child: RaisedButton(
                                  textColor: Colors.white,
                                  color: kPrimaryColor,
                                  child: Text("Se connecter"),
                                  onPressed: () async {
                                    if (_formKey.currentState.validate()) {
                                      showDialog(
                                          context: context,
                                          builder: (BuildContext context) {
                                            return Center(
                                              child:
                                                  CircularProgressIndicator(),
                                            );
                                          });
                                      await loginUser();
                                    }
                                    /*  Navigator.push(
                                      context,
                                      MaterialPageRoute(
                                          builder: (context) => MyWidget()),
                                    );*/
                                    // Navigator.pushNamed(context, 'Mywidget');
                                  },
                                  shape: new RoundedRectangleBorder(
                                    borderRadius:
                                        new BorderRadius.circular(30.0),
                                  ),
                                ),
                                width: 250,
                                padding: EdgeInsets.all(15),
                              )
                            ],
                          ),
                          Row(
                            mainAxisAlignment: MainAxisAlignment.center,
                            children: [
                              AlreadyHaveAnAccountCheck(
                                press: () {
                                  Navigator.push(
                                    context,
                                    MaterialPageRoute(
                                      builder: (context) {
                                        return SignUp();

 void loginUser() async {
    // if (_formKey.currentState.validate()) {
    setState(() {
      _isLoading = true;
    });
    String email = _emailController.text;
    String password = _passwordController.text;

    authentication.login(email, password).then((user) {
      if (user != null)
        Navigator.push(
            context, MaterialPageRoute(builder: (context) => MyWidget()));
    }).catchError((error) {
      ScaffoldMessenger.of(context)
          .showSnackBar(SnackBar(content: Text(error.toString())));
    });

    setState(() {
      _isLoading = false;
    });
  }

这是登录功能：

Future<User> login(String email, String password) async {
  await checkInternet();

  Map<String, String> headers = {
    'Content-type': 'application/json',
    'Accept': 'application/json',
  };
  Map<String, String> body = {'email': email, 'password': password};

  var response = await http.post(Uri.parse(ApiUtil.AUTH_LOGIN),
      headers: headers, body: jsonEncode(body));
  switch (response.statusCode) {
    case 200:
      var body = jsonDecode(response.body);
      var data = body['user'];
      User user = User.fromJson(data);
      Track track = Track.fromJson(body);

      if (body['code'] == 0) {
        SharedPreferences localStorage =
        await SharedPreferences.getInstance();
        localStorage.setInt('id', body['user']['id']);
        localStorage.setString('adress', body['user']['adress']);
        localStorage.setString('phone', body['user']['phone']);
        localStorage.setString('access_token', body['access_token']);
        localStorage.setString('user', json.encode(body['user']));
        String user = localStorage.getString('user');

      }
      return user;
    case 500:
      throw ('Erreur serveur');
      break;

    case 400:
      throw LoginFailed();
    default:
      throw ('connection timeout');
      break;
  }
}

Answer 1

当我第一次登录时，我将数据保存在共享首选项中

 ApiRepository.get().login(LoginRequest(username: _emailController.text, password: _passwordController.text)).then((response) async {
  if (response != null) {
    //save on the shared preferences that the user is logged in
    SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setBool(SHARED_LOGGED, true);
    await prefs.setString(SHARED_USER, _emailController.text);
    await prefs.setString(SHARED_PASSWORD, _passwordController.text);
  }
}).catchError((error) { 
});

每次我打开应用程序时都会出现启动画面，在这里我进行了隐式登录，然后跳过登录页面并将用户带到主页

void checkUserIsLogged() async {
    final prefs = await SharedPreferences.getInstance();
    if ((prefs.getBool(SHARED_LOGGED) != null) && prefs.getBool(SHARED_LOGGED)) {
      ApiRepository.get().login(LoginRequest(username: prefs.getString(SHARED_USER), password: prefs.getString(SHARED_PASSWORD))).then((response) {
        if (response != null) {
          //"do something"
        }
      }).catchError((error) {
        
      });
    } else {

    }
  }

完整代码 SplashPageLoading.dart

class SplashPageLoading extends StatefulWidget {
  @override
  _SplashPageLoadingState createState() => _SplashPageLoadingState();
}

class _SplashPageLoadingState extends State<SplashPageLoading> {
  bool _doLogin = false;

  @override
  void initState() {
    super.initState();

    new Future.delayed(const Duration(seconds: 3), () => checkUserIsLogged());
  }

  void checkUserIsLogged() async {
    final prefs = await SharedPreferences.getInstance();
    if ((prefs.getBool(SHARED_LOGGED) != null) && prefs.getBool(SHARED_LOGGED)) {
      setState(() {
        _doLogin = true;
      });
      ApiRepository.get().login(LoginRequest(username: prefs.getString(SHARED_USER), password: prefs.getString(SHARED_PASSWORD))).then((response) {
        if (response != null) {
          Navigator.of(context).pushReplacementNamed(HomePage.routeName);
        }
      }).catchError((error) {
        Navigator.of(context).pushReplacementNamed(LoginPage.routeName);
      });
    } else {
      new Future.delayed(const Duration(seconds: 1), () => Navigator.of(context).pushReplacementNamed(LoginPage.routeName));
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Text(
          _doLogin ? "Login.." : "No data for login",
          style: TextStyle(color: Colors.black),
        ),
      ),
    );
  }
}

Strings.dart

const String SHARED_LOGGED = "USER_IS_LOGGED";
const String SHARED_USER = "USER";
const String SHARED_PASSWORD = "PASSWORD";

shared preferences library

Answer 2

SplashPageLoading.dart :

class SplashPageLoading extends StatefulWidget {
      @override
      _SplashPageLoadingState createState() => _SplashPageLoadingState();
    }
    
    class _SplashPageLoadingState extends State<SplashPageLoading> {
      bool _doLogin = false;
      Authentication authentication = Authentication();
    
      static const String SHARED_LOGGED = "USER_IS_LOGGED";
      static const String SHARED_USER = "USER";
      static const String SHARED_PASSWORD = "PASSWORD";
    
      @override
      void initState() {
        super.initState();
    
        new Future.delayed(const Duration(seconds: 3), () => checkUserIsLogged());
      }
    
      void checkUserIsLogged() async {
        final prefs = await SharedPreferences.getInstance();
        if ((prefs.getBool(SHARED_LOGGED) != null) &&
            prefs.getBool(SHARED_LOGGED)) {
          setState(() {
            _doLogin = true;
          });
          authentication
              .login(prefs.getString(SHARED_USER), prefs.getString(SHARED_PASSWORD))
              .then((user) {
            if (user != null) {
              Navigator.push(
                context,
                MaterialPageRoute(builder: (context) => MyWidget()),
              );
    
              // Navigator.of(context).pushReplacementNamed('/splash');
            }
          }).catchError((error) {
            Navigator.push(
              context,
              MaterialPageRoute(builder: (context) => MyWidget()),
            );
    
            //  Navigator.of(context).pushReplacementNamed('/splash');
          });
        } else {
          new Future.delayed(const Duration(seconds: 1),
              () => Navigator.of(context).pushReplacementNamed('/'));
        }
      }
    
      @override
      Widget build(BuildContext context) {
        return Text(
          _doLogin ? "Login.." : "",
          style: TextStyle(color: Colors.white),
        );
      }
    }

如何让用户保持登录状态

How keep user logged in flutter

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flutter-sharedpreference