FLUTTER：如何显示用户特定页面？

Question

Trying to implement user-specific login: After login, If the user is type-A a different Homepage should be displayed and if the user is type-B then a separate Homepage.
Following is the code of the Login widget:

class LogInWidget extends StatefulWidget {
  @override
  _LogInWidgetState createState() => _LogInWidgetState();
}

class _LogInWidgetState extends State<LogInWidget> {
  var _formKey = GlobalKey<FormState>();
  bool hide = true;
  bool forgotPassword = false;
  bool isLoginPressed = false;
  final FirebaseAuth _auth = FirebaseAuth.instance;
  final AuthMethods _authMethods = AuthMethods();
  TextEditingController email = TextEditingController();
  TextEditingController password = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return isLoginPressed
        ? Center(
            child: CircularProgressIndicator(),
          )
        : Scaffold(
            backgroundColor: UniversalVariables.blackColor,
            body: Padding(
              padding: EdgeInsets.symmetric(horizontal: 24.0),
              child: ListView(
                children: <Widget>[
                  SizedBox(
                    height: 80,
                  ),
                  !forgotPassword
                      ? Form(
                          key: _formKey,
                          child: Column(
                            mainAxisAlignment: MainAxisAlignment.center,
                            crossAxisAlignment: CrossAxisAlignment.stretch,
                            children: <Widget>[
                              Text(
                                'Sign In',
                                style: TextStyle(
                                    color: Colors.white,
                                    fontSize: 60,
                                    fontWeight: FontWeight.w700),
                                textAlign: TextAlign.center,
                              ),
                              SizedBox(
                                height: 48.0,
                              ),
                              Material(
                                borderRadius: BorderRadius.circular(10.0),
                                elevation: 0.0,
                                color: Colors.white.withOpacity(0.2),
                                child: TextFormField(
                                  cursorColor: Colors.white,
                                  controller: email,
                                  textAlign: TextAlign.center,
                                  keyboardType: TextInputType.emailAddress,
                                  // ignore: missing_return
                                  validator: (String value) {
                                    if (value.isEmpty) {
                                      return "please enter a value";
                                    }
                                  },
                                  style: TextStyle(
                                    color: Colors.white,
                                  ),
                                  decoration: kTextFieldDecoration.copyWith(
                                      hintText: 'Enter your email',
                                      prefixIcon: Icon(Icons.alternate_email,
                                          color: Colors.white)),
                                ),
                              ),
                              SizedBox(
                                height: 8.0,
                              ),
                              Material(
                                borderRadius: BorderRadius.circular(10.0),
                                elevation: 0.0,
                                color: Colors.white.withOpacity(0.2),
                                child: TextFormField(
                                  cursorColor: Colors.white,
                                  controller: password,
                                  textAlign: TextAlign.center,
                                  obscureText: hide,
                                  // ignore: missing_return
                                  validator: (String value) {
                                    if (value.isEmpty) {
                                      return "The password field cannot be empty";
                                    }
                                  },
                                  style: TextStyle(
                                    color: Colors.white,
                                  ),
                                  decoration: kTextFieldDecoration.copyWith(
                                    hintText: 'Enter your password',
                                    prefixIcon: Icon(
                                      Icons.lock_outline,
                                      color: Colors.white,
                                    ),
                                    suffixIcon: IconButton(
                                      icon: Icon(
                                        !hide
                                            ? Icons.remove_red_eye_outlined
                                            : Icons.remove_red_eye,
                                        color: Colors.white,
                                      ),
                                      onPressed: () {
                                        setState(() {
                                          hide = !hide;
                                        });
                                      },
                                    ),
                                  ),
                                ),
                              ),
                              Padding(
                                padding: const EdgeInsets.only(
                                    top: 15, right: 8, bottom: 8),
                                child: InkWell(
                                  onTap: () {
                                    setState(() {
                                      forgotPassword = true;
                                    });
                                  },
                                  child: Text(
                                    'Forgot Password?',
                                    textAlign: TextAlign.right,
                                    style: TextStyle(
                                      color: Colors.white,
                                    ),
                                  ),
                                ),
                              ),
                              SizedBox(
                                height: 18.0,
                              ),
                              Padding(
                                  padding: EdgeInsets.symmetric(vertical: 16.0),
                                  child: Material(
                                    color: Colors.white,
                                    borderRadius: BorderRadius.circular(30.0),
                                    elevation: 2.0,
                                    child: MaterialButton(
                                      onPressed: () async {
                                        if (_formKey.currentState.validate()) {
                                          performLogin();
                                        }
                                      },
                                      minWidth: 200.0,
                                      height: 42.0,
                                      child: Text(
                                        'Sign In',
                                        style: TextStyle(color: Colors.black),
                                      ),
                                    ),
                                  )),
                              Padding(
                                padding: const EdgeInsets.all(8.0),
                                child: Text(
                                  '-OR-',
                                  textAlign: TextAlign.center,
                                  style: TextStyle(
                                    color: Colors.white,
                                  ),
                                ),
                              ),
                              Padding(
                                padding: const EdgeInsets.all(8.0),
                                child: Text(
                                  'sign in with',
                                  textAlign: TextAlign.center,
                                  style: TextStyle(
                                      color: Colors.white,
                                      fontWeight: FontWeight.w600,
                                      fontSize: 17),
                                ),
                              ),
                              googleSignInButton(),
                            ],
                          ))
                      : Column(
                          mainAxisAlignment: MainAxisAlignment.center,
                          crossAxisAlignment: CrossAxisAlignment.stretch,
                          children: [
                            Material(
                              borderRadius: BorderRadius.circular(10.0),
                              elevation: 0.0,
                              color: Colors.white.withOpacity(0.2),
                              child: Form(
                                key: _formKey,
                                child: TextFormField(
                                  // ignore: missing_return
                                  validator: (String value) {
                                    if (value.isEmpty) {
                                      return "please enter a value";
                                    }
                                  },
                                  controller: email,
                                  textAlign: TextAlign.center,
                                  keyboardType: TextInputType.emailAddress,
                                  style: TextStyle(
                                    color: Colors.white,
                                  ),
                                  decoration: kTextFieldDecoration.copyWith(
                                      hintText: 'Enter your email',
                                      prefixIcon: Icon(Icons.alternate_email,
                                          color: Colors.white)),
                                ),
                              ),
                            ),
                            SizedBox(
                              height: 18.0,
                            ),
                            Padding(
                                padding: EdgeInsets.symmetric(vertical: 16.0),
                                child: Material(
                                  color: Colors.white,
                                  borderRadius: BorderRadius.circular(30.0),
                                  elevation: 2.0,
                                  child: MaterialButton(
                                    onPressed: () async {
                                      if (_formKey.currentState.validate()) {
                                        ForgotPassword();
                                      }
                                    },
                                    minWidth: 200.0,
                                    height: 42.0,
                                    child: Text(
                                      'Continue',
                                      style: TextStyle(color: Colors.black),
                                    ),
                                  ),
                                )),
                            Padding(
                              padding: const EdgeInsets.only(
                                  top: 15, right: 8, bottom: 8),
                              child: Center(
                                child: InkWell(
                                  onTap: () {
                                    setState(() {
                                      forgotPassword = false;
                                    });
                                  },
                                  child: Text(
                                    'Sign In',
                                    textAlign: TextAlign.right,
                                    style: TextStyle(
                                      color: Colors.white,
                                    ),
                                  ),
                                ),
                              ),
                            ),
                          ],
                        ),
                ],
              ),
            ));
  }

  // ignore: non_constant_identifier_names
  void ForgotPassword() async {
    setState(() {
      isLoginPressed = true;
    });
    try {
      await _auth.sendPasswordResetEmail(email: email.text);
      setState(() {
        isLoginPressed = false;
      });
      Fluttertoast.showToast(
          msg: 'email sent successfully!!',
          textColor: Colors.black,
          backgroundColor: Colors.white);
      showSuccessDialog(context, "email Sent",
          'An email has been sent to your registered email id for resetting password',
          () {
        setState(() {
          forgotPassword = false;
        });
        Navigator.pop(context);
      });
    } catch (e) {
      setState(() {
        isLoginPressed = false;
      });
      Fluttertoast.showToast(
          msg: 'Please provide correct email',
          textColor: Colors.black,
          backgroundColor: Colors.white);
      print(e);
    }
  }

  Widget googleSignInButton() {
    return GestureDetector(
      onTap: () {
        performGoogleLogin();
      },
      child: Center(
        child: CircleAvatar(
          radius: 35.0,
          backgroundImage: AssetImage("assets/google.png"),
        ),
      ),
    );
  }

  void performGoogleLogin() async {
    setState(() {
      isLoginPressed = true;
    });

    FirebaseUser user = await _authMethods.signInWithGoogle();

    if (user != null) {
      authenticateUser(user);
    }
    setState(() {
      isLoginPressed = false;
    });
  }

  void performLogin() async {
    setState(() {
      isLoginPressed = true;
    });

    FirebaseUser user = await _authMethods.signIn(email, password);

    if (user != null) {
      authenticateUser(user);
    }
    setState(() {
      isLoginPressed = false;
    });
  }

  void authenticateUser(FirebaseUser user) {
    _authMethods.authenticateUser(user).then((isNewUser) {
      setState(() {
        isLoginPressed = false;
      });

      if (isNewUser) {
        _authMethods.addDataToDb(user).then((value) {
          Navigator.pushReplacement(context,
              MaterialPageRoute(builder: (context) {
            return HomeScreen();
          }));
        });
      } else {
        Navigator.pushReplacement(context,
            MaterialPageRoute(builder: (context) {
          return HomeScreen();
        }));
      }
    });
  }
}

This code displays same Homepage for both user. How can I convert this code to show 2 different Homepages depending upon the user? UPDATE: need to check a field from firebase db and then redirect them to different pages depending upon value inside the field.

Answer 1

There are multiple ways you could do this. I would recommend using a StreamProvider (from the Provider package ) which contains the state of a user. You could use an Enum for example:

enum UserState{
    FIREBASE_AUTH,
    GOOGLE
}

and when the user is logged in with a specific method you add an event to the stream which will update the provider and thereby update the screen based on the value of the stream.

I would also take this approach in case you want to use the users auth status elsewhere in the app you can easily access it.

Please let me know if that helps or I misunderstood you!