flutter - 未处理的异常 : type '_InternalLinkedHashMap' is not a subtype of type 'String

Question

点击登录按钮后出现错误->未处理的异常:类型“_InternalLinkedHashMap ”不是类型“String

”的子类型

} 捕获(e){扔 e;//这里}请帮助我，我不明白如何解决

未处理的异常:类型“_InternalLinkedHashMap ”不是类型“String”的子类型

这是我的auth.dart

import 'package:http/http.dart' as http;

import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:login_and_signup/Utils/api.dart';

class Auth with ChangeNotifier {
  var MainUrl = Api.authUrl;

  Future<void> Authentication(String user_name, String user_email,
      String mobile_no, String password, String action) async {
    try {
      var url = Uri.parse('$MainUrl&action=$action');
      print(url);

      if (action == 'registration') {
        final responce = await http.post(url, headers: {
          "Accept": "Application/json"
        }, body: {
          "user_name": user_name,
          'user_email': user_email,
          "mobile_no": mobile_no,
          "password": password,
        });

        print("Response" + responce.body);
        final responceData = json.decode(responce.body);
        print("responceData" + responceData);

      } else {
        final responce = await http.post(url, headers: {
          "Accept": "Application/json"
        }, body: {
          "user_name": user_name,
          'user_email': user_email,
          "username": mobile_no,
          "password": password,
        });

        print("Response" + responce.body);
        final responceData = json.decode(responce.body);
        print("responceData" + responceData);
       
      }
      notifyListeners();

    } catch (e) {
      throw e;
    }
  }

  Future<void> login(
      String user_name, String user_email, String mobile_no, String password) {
    return Authentication(user_name, user_email, mobile_no, password, 'login');
  }

  Future<void> signUp(
      String user_name, String user_email, String mobile_no, String password) {
    return Authentication(
        user_name, user_email, mobile_no, password, 'registration');
  }
}

这是我的 login.dart 页面

// import 'package:flutter/material.dart';
// import 'package:login_signup_with_api/Providers/auth.dart';
// import 'package:login_signup_with_api/Screens/signup.dart';
// import 'package:login_signup_with_api/Utils/http_exception.dart';
import 'package:flutter/material.dart';
import 'package:login_and_signup/Providers/auth.dart';
import 'package:login_and_signup/Screens/home_screen.dart';
// import 'package:login_and_signup/Providers/login_auth.dart';
import 'package:login_and_signup/Screens/signup.dart';
import 'package:login_and_signup/Utils/http_exception.dart';
import 'package:provider/provider.dart';

class LoginScreen extends StatefulWidget {
  static const String routeName = "/login";

  @override
  _LoginScreenState createState() => _LoginScreenState();
}

class _LoginScreenState extends State<LoginScreen> {
  final GlobalKey<FormState> _formKey = GlobalKey();

  TextEditingController _mobileController = new TextEditingController();
  TextEditingController _passwordController = new TextEditingController();

  Map<String, String> _authData = {
    'user_name': '',
    'user_email': '',
    'username': '',
    'password': ''
  };

  Future _submit() async {
    print('aa' + _authData['username']!);
    if (!_formKey.currentState!.validate()) {

      return;
    }
    _formKey.currentState!.save();
    try {
      await Provider.of<Auth>(context, listen: false)
          .login(_authData['user_name']!, _authData['user_email']!,
              _authData['username']!, _authData['password']!)
          .then((_) {
        Navigator.of(context).pushReplacement(
            MaterialPageRoute(builder: (context) => HomeScreen()));
      });

      print('aaaa' + _authData['username']!);
      
    } catch (error) {
    }
  }

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Scaffold(
      // backgroundColor: Colors.white,
      body: SingleChildScrollView(
        child: Container(
          child: Stack(
            children: <Widget>[
              Container(
                height: MediaQuery.of(context).size.height * 0.65,
                width: MediaQuery.of(context).size.width * 0.85,
                decoration: BoxDecoration(
                    borderRadius: BorderRadius.only(
                        topRight: Radius.circular(360),
                        bottomRight: Radius.circular(360)),
                    color: Colors.blue),
              ),
              Container(
                padding:
                    EdgeInsets.only(top: 50, left: 20, right: 20, bottom: 50),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    Text(
                      "Sign In",
                      style: TextStyle(
                          color: Colors.white,
                          fontWeight: FontWeight.bold,
                          fontSize: 40),
                    ),
                    SizedBox(
                      height: 10,
                    ),
                    Text(
                      "Sign in with your username or email",
                      style: TextStyle(
                          color: Colors.white,
                          fontWeight: FontWeight.bold,
                          fontSize: 10),
                    ),
                    Form(
                      key: _formKey,
                      child: Container(
                        padding: EdgeInsets.only(top: 50, left: 20, right: 20),
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: <Widget>[
                            Text(
                              "username",
                              style: TextStyle(
                                  color: Colors.white,
                                  fontWeight: FontWeight.bold,
                                  fontSize: 12),
                            ),
                            TextFormField(
                              // obscureText: true,
                              controller: _mobileController,
                              style: TextStyle(color: Colors.white),
                              decoration: InputDecoration(
                                  enabledBorder: UnderlineInputBorder(
                                    borderSide: BorderSide(color: Colors.white),
                                  ),
                                  focusedBorder: UnderlineInputBorder(
                                    borderSide: BorderSide(color: Colors.white),
                                  ),
                                  prefixIcon: Icon(
                                    Icons.vpn_key,
                                    color: Colors.white,
                                  )),
                              validator: (value) {
                                if (value!.isEmpty || value.length < 1) {
                                  return 'valid no';
                                }
                              },
                              onSaved: (value) {
                                _authData['username'] = value!;
                              },
                            ),
                            SizedBox(
                              height: 10,
                            ),
                            
                            SizedBox(
                              height: 10,
                            ),
                            Text(
                              "Password",
                              style: TextStyle(
                                  color: Colors.white,
                                  fontWeight: FontWeight.bold,
                                  fontSize: 12),
                            ),
                            TextFormField(
                              controller: _passwordController,
                              obscureText: true,
                              style: TextStyle(color: Colors.white),
                              decoration: InputDecoration(
                                  enabledBorder: UnderlineInputBorder(
                                    borderSide: BorderSide(color: Colors.white),
                                  ),
                                  focusedBorder: UnderlineInputBorder(
                                    borderSide: BorderSide(color: Colors.white),
                                  ),
                                  prefixIcon: Icon(
                                    Icons.vpn_key,
                                    color: Colors.white,
                                  )),
                              validator: (value) {
                                if (value!.isEmpty || value.length < 5) {
                                  return 'Password is to Short';
                                }
                              },
                              onSaved: (value) {
                                _authData['password'] = value!;
                              },
                            ),
                            Container(
                              padding: EdgeInsets.only(top: 40),
                              width: 140,
                              child: RaisedButton(
                                  onPressed: () {
                                    print(_authData['username']);
                                    print(_authData['password']);
                                    _submit();
                                  },
                                  shape: RoundedRectangleBorder(
                                    borderRadius:
                                        new BorderRadius.circular(10.0),
                                  ),
                                  child: Text(
                                    'Sign In',
                                    style: TextStyle(color: Colors.white),
                                  ),
                                  color: Colors.green),
                            ),
                            Align(
                              alignment: Alignment.bottomRight,
                              child: InkWell(
                                onTap: () {
                                  Navigator.of(context).push(MaterialPageRoute(
                                      builder: (ctx) => SignUpScreen()));
                                },
                                child: Container(
                                  padding: EdgeInsets.only(top: 90),
                                  child: Text(
                                    "Create Account",
                                    style: TextStyle(
                                        decoration: TextDecoration.underline,
                                        color: Colors.blue,
                                        fontSize: 16),
                                  ),
                                ),
                              ),
                            )
                          ],
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  void _showerrorDialog(String message) {
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: Text(
          'An Error Occurs',
          style: TextStyle(color: Colors.blue),
        ),
        content: Text(message),
        actions: <Widget>[
          FlatButton(
            child: Text('Okay'),
            onPressed: () {
              Navigator.of(context).pop();
            },
          )
        ],
      ),
    );
  }
}

Answer 1

您应该使用 jsonEncode(requestBody) 对您的请求主体进行编码。同样在打印响应时使用 $ 和 String。

print("响应:${responce.body}");