flutter json.decode()意外的输入结束(在字符1处)

06odsfpq  于 2023-10-22  发布在  Flutter
关注(0)|答案(8)|浏览(169)

登录用户时，我在flutter中遇到了一个匿名关闭错误。它工作了几天前，但现在它不工作，我不知道为什么。所以请帮助并提前感谢。.每当我填写详细信息并点击登录按钮时，它会抛出以下错误-

E/flutter ( 2914): [ERROR:flutter/shell/common/shell.cc(184)] Dart Error: Unhandled exception:
E/flutter ( 2914): FormatException: Unexpected end of input (at character 1)
E/flutter ( 2914): 
E/flutter ( 2914): ^
E/flutter ( 2914): 
E/flutter ( 2914): #0      _ChunkedJsonParser.fail (dart:convert/runtime/libconvert_patch.dart:1358:5)
E/flutter ( 2914): #1      _ChunkedJsonParser.close (dart:convert/runtime/libconvert_patch.dart:511:7)
E/flutter ( 2914): #2      _parseJson (dart:convert/runtime/libconvert_patch.dart:30:10)
E/flutter ( 2914): #3      JsonDecoder.convert (dart:convert/json.dart:540:36)
E/flutter ( 2914): #4      JsonCodec.decode (dart:convert/json.dart:167:41)
E/flutter ( 2914): #5      _SignInState._login.<anonymous closure> (package:restaurant_app/signin.dart:81:23)
import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:restaurant_app/globalVar.dart';
import 'package:restaurant_app/homescreen.dart';
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 import 'package:restaurant_app/signup.dart';
import 'package:http/http.dart' as http;
import 'package:flutter_html_view/html_parser.dart';

class SignIn extends StatefulWidget {
 @override
_SignInState createState() => _SignInState();
}

class _SignInState extends State<SignIn> with SingleTickerProviderStateMixin 
{
TabController controller;
TextEditingController _email = new TextEditingController();
TextEditingController _password = new TextEditingController();
bool loading;

 final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState> 
();

@override
void initState() {
// TODO: implement initState
super.initState();
controller = new TabController(length: 2, vsync: this);
loading = false;
_email = new TextEditingController(text: "rajeshvishnani");
_password = new TextEditingController(text: "Rajesh@MaaKiRasoi");
}

@override
void dispose() {
// TODO: implement dispose
super.dispose();
controller.dispose();
setState(() {
  loading = false;
});
_email.dispose();
_password.dispose();
}

final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
bool _autoValidate = false;

Future _writer(String username, String password, String token) async {
final storage = new FlutterSecureStorage();
await storage.write(key: authTokenKeys, value: token);
print(await storage.read(key: authTokenKeys));
await storage.write(key: nameKeys, value: username);
print(await storage.read(key: nameKeys));
await storage.write(key: passwordKeys, value: password);
}

  static final String authTokenKeys = 'auth_token';
static final String nameKeys = 'username';
static final String passwordKeys = 'password';

_login(username, password) async {
setState(() {
  loading = true;
});

var body = json.encode({
  "username": username,
  "password": password,
});

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

await http
    .post("${GlobalVar.Ip}/wp-json/jwt-auth/v1/token",
        body: body, headers: headers)
    .then((response) {
  var body = json.decode(response.body);

  if (response.statusCode == 200) {
    // TODO: you need to store body['token'] to use in some authentication
    loading = false;
    _writer(_email.text, _password.text, body['token']);
    Navigator.pushReplacement(context,
        MaterialPageRoute(builder: (BuildContext ctx) => HomePage()));
  } else {
    // TODO: alert message
    final snackBar = SnackBar(
      content: Text(body['message']),
    );
    _scaffoldKey.currentState.showSnackBar(snackBar);
  }
  setState(() {
    loading = false;
  });
  });
}

@override
 Widget build(BuildContext context) {
return Scaffold(
  key: _scaffoldKey,
  resizeToAvoidBottomPadding: false,
  body: Container(
    decoration: BoxDecoration(
      image: DecorationImage(
        image: AssetImage('images/art.png'),
        fit: BoxFit.fill,
        colorFilter: ColorFilter.mode(
            Colors.white12.withOpacity(0.2), BlendMode.dstATop),
      ),
    ),
    child: ListView(
      shrinkWrap: true,
      physics: BouncingScrollPhysics(),
      children: <Widget>[
        SizedBox(
          height: MediaQuery.of(context).size.height / 30,
        ),
        Align(
          alignment: Alignment.topCenter,
          child: CircleAvatar(
            backgroundColor: Colors.grey,
            radius: 55.0,
            backgroundImage: AssetImage('images/logo.png'),
          ),
        ),
        SizedBox(
          height: MediaQuery.of(context).size.height / 30,
        ),
        Stack(
          alignment: Alignment.center,
          children: <Widget>[
            SizedBox(
              height: MediaQuery.of(context).size.height / 300,
              child: new Center(
                child: new Container(
                  height: 10.0,
                  color: Colors.black12,
                ),
              ),
            ),
            Row(
              children: <Widget>[
                SizedBox(
                  width: MediaQuery.of(context).size.width / 4,
                ),
                Chip(
                  label: Text(
                    "SIGN IN",
                    style: TextStyle(color: Colors.white, fontSize: 18.0),
                  ),
                  backgroundColor: Color(0xFFD1A155),
                ),
                SizedBox(
                  width: MediaQuery.of(context).size.width / 35,
                  child: Container(
                    width: MediaQuery.of(context).size.height / 12,
                    height: 2.0,
                    color: Colors.white,
                  ),
                ),
                Chip(
                  label: Text(
                    "SIGN UP",
                    style: TextStyle(color: Colors.white, fontSize: 18.0),
                  ),
                  backgroundColor: Colors.black87,
                ),
              ],
            )
          ],
        ),
        SizedBox(
          height: MediaQuery.of(context).size.height / 35,
        ),
        Align(
            alignment: Alignment.center,
            child: Text(
              "Welcome back!",
              style: TextStyle(
                fontSize: 20.0,
                color: Color(0xFFD1A155),
              ),
            )),
        SizedBox(
          height: MediaQuery.of(context).size.height / 30,
        ),
        Form(
          key: _formKey,
          autovalidate: _autoValidate,
          child: Column(
            children: <Widget>[
              Theme(
                data: ThemeData(
                  hintColor: Colors.black26,
                  primaryColor: Color(0xFFD1A155),
                ),
                child: Padding(
                  padding: const EdgeInsets.only(left: 15.0, right: 15.0),
                  child: TextFormField(
                    keyboardType: TextInputType.emailAddress,
                    //validator: _email.text.isEmpty?:null,
                    controller: _email,

                    decoration: InputDecoration(
                        border:
                            OutlineInputBorder(borderSide: BorderSide()),
                        prefixIcon: Icon(
                          Icons.email,
                          color: Color(0xFFD1A155),
                        ),
                        hintText: 'Email Address',
                        hintStyle: TextStyle(
                            color: Colors.black,
                            fontWeight: FontWeight.w400)),
                  ),
                ),
              ),
              SizedBox(
                height: MediaQuery.of(context).size.height / 45,
              ),
              Theme(
                data: ThemeData(
                    primaryColor: Color(0xFFD1A155),
                    hintColor: Colors.black26),
                child: Padding(
                  padding: const EdgeInsets.only(left: 15.0, right: 15.0),
                  child: TextFormField(
                    keyboardType: TextInputType.text,
                    obscureText: true,
                    controller: _password,
                  decoration: InputDecoration(
                        border:
                            OutlineInputBorder(borderSide: BorderSide()),
                        prefixIcon: Icon(
                          Icons.lock,
                          color: Color(0xFFD1A155),
                        ),
                        hintText: 'Password',
                        hintStyle: TextStyle(
                            color: Colors.black,
                            fontWeight: FontWeight.w400)),
                  ),
                ),
              ),
              Padding(
                padding: const EdgeInsets.only(right: 15.0, left: 10.0),
                child: Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: <Widget>[
                    Row(
                      children: <Widget>[
                        ActionChip(
                          onPressed: () {},
                          avatar: Checkbox(
                            value: false,
                            onChanged: (bool z) {
                              print(z);
                            },
                            activeColor: Color(0xFFD1A155),
                          ),
                          label: Text("Remember Me"),
                          backgroundColor: Colors.transparent,
                        ),
                      ],
                    ),
                    Text(
                      "Forgot Password?",
                      style: TextStyle(
                        color: Color(0xFFD1A155),
                      ),
                    ),
                  ],
                ),
              ),
              Padding(
                padding: const EdgeInsets.only(left: 15.0, right: 15.0),
                child: InkWell(
                  onTap: () {
                    _login(_email.text, _password.text);
         //                        Navigator.push(
        //                            context,
    //                            MaterialPageRoute(
     //                                builder: (context) => HomePage()));
                  },
                  child: loading
                      ? CircularProgressIndicator()
                      : Container(
                          height: MediaQuery.of(context).size.height / 13,
                          //width: MediaQuery.of(context).size.height / 1.8,
                          decoration: BoxDecoration(
                            color: Color(0xFFD1A155),
                            borderRadius: BorderRadius.circular(5.0),
                          ),
                          child: Center(
                            child: Text(
                              "LOGIN",
                              style: TextStyle(
                                  color: Colors.white, fontSize: 18.0),
                            ),
                          ),
                        ),
                ),
              )
            ],
          ),
        ),
        SizedBox(
          height: MediaQuery.of(context).size.height / 15,
        ),
        Stack(
          alignment: Alignment.center,
          children: <Widget>[
            SizedBox(
              height: 2.0,
              child: new Center(
                child: new Container(
                  height: 10.0,
                  color: Colors.black12,
                ),
              ),
            ),
            Container(
              height: MediaQuery.of(context).size.height / 18,
              width: MediaQuery.of(context).size.height / 11,
              decoration: BoxDecoration(
                  borderRadius: BorderRadius.circular(23.0),
                  color: Colors.white,
                  border: Border.all(color: Colors.black12)),
              child: Center(
                  child: Text(
                "OR",
                style: TextStyle(fontSize: 18.0),
              )),
            ),
          ],
        ),
        SizedBox(
          height: MediaQuery.of(context).size.height / 30,
        ),
        Padding(
          padding: const EdgeInsets.only(left: 15.0, right: 15.0),
          child: Row(
            children: <Widget>[
              Container(
                height: MediaQuery.of(context).size.height / 13,
                width: MediaQuery.of(context).size.width / 2.2,
                decoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(5.0),
                    color: Colors.white,
                    border: Border.all(color: Colors.black12)),
                child: Row(
                  children: <Widget>[
                    SizedBox(
                      width: 18.0,
                    ),
                    Icon(Icons.tag_faces),
                    SizedBox(
                      width: 10.0,
                    ),
                    Text(
                      "Facebook",
                      style: TextStyle(fontSize: 22.0, color: Colors.blue),
                    ),
                  ],
                ),
              ),
              SizedBox(
                width: MediaQuery.of(context).size.width / 40,
              ),
              Container(
                height: MediaQuery.of(context).size.height / 13,
                width: MediaQuery.of(context).size.width / 2.3,
                decoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(5.0),
                    color: Colors.white,
                    border: Border.all(color: Colors.black12)),
                child: Row(
                  children: <Widget>[
                    SizedBox(
                      width: 18.0,
                    ),
                    Icon(Icons.tag_faces),
                    SizedBox(
                      width: 10.0,
                    ),
                    Text(
                      "Google+",
                      style: TextStyle(fontSize: 22.0, color: Colors.red),
                    ),
                  ],
                ),
              ),
            ],
          ),
        ),
        SizedBox(
          height: MediaQuery.of(context).size.height / 20,
        ),
        Align(
          alignment: Alignment.center,
          child: InkWell(
            onTap: () => Navigator.push(
                context, MaterialPageRoute(builder: (context) => SignUp())),
            child: RichText(
                text: TextSpan(
                    text: "Don't have an account?",
                    style: TextStyle(fontSize: 20.0, color: Colors.black87),
                    children: <TextSpan>[
                  TextSpan(
                      text: ' Sign up',
                      style: TextStyle(
                          color: Color(0xFFD1A155),
                          fontWeight: FontWeight.bold)),
                ])),
          ),
        ),
        SizedBox(
          height: MediaQuery.of(context).size.height / 30,
        ),
      ],
    ),
  ),
  );
 }
}
flutter

8条答案

按热度按时间
1bqhqjot

1bqhqjot1#

我也有类似类型的错误，确保.decode方法的参数不应该是空对象。而不是使用这一行：

var body = json.decode(response.body);

尝试

if(response.body.isNotEmpty) {
    json.decode(response.body);
}

试试这个，希望对你有用。

赞(0）分享  回复(0）举报  2023-10-22
vwoqyblh

vwoqyblh2#

打印你的身体和双重检查你不是试图解码一个数组，而不是对象。

赞(0）分享  回复(0）举报  2023-10-22
x33g5p2x

x33g5p2x3#

检查你的后端，它在响应体中返回null对象

赞(0）分享  回复(0）举报  2023-10-22
6rqinv9w

6rqinv9w4#

我可以通过添加.trim()来修复此错误

if (response.statusCode == 200) {
        final responseBody = response.body.trim(); 
       if (responseBody.isNotEmpty) {
       } else {};

当使用jsonDecode或json.decode时，它期望一个有效的JSON响应，即使它是一个空的JSON对象或数组。.trim（）函数从您的API中删除任何空白响应，并将其转换为空的JSON数据。
假设您正在从数据库发送http request到Create、Update或Delete数据，但您的API没有返回任何jsonData值，例如echo json_encode("Successful");
这是我的案子decode函数将响应视为无效的json响应。您要么需要修剪它并仅在响应不为空时解码，要么修改您的API以发送某种响应，而不管它正在执行什么操作。

赞(0）分享  回复(0）举报  2023-10-22
z0qdvdin

z0qdvdin5#

我有类似类型的问题，我尝试了一切，但最终的问题是，我使用的是http而不是使用https，即使api是在https中，我忘记在http中添加s。从http改为https后，错误就消失了。

赞(0）分享  回复(0）举报  2023-10-22
puruo6ea

puruo6ea6#

请检查你的头在http或dio在扑

headers: {
      'Content-Type': 'application/json',
      'Accept': 'application/json',
      'Authorization': 'Bearer $token',
    }
赞(0）分享  回复(0）举报  2023-10-22
xqnpmsa8

xqnpmsa87#

请检查您的标题，如果您正在发送JWT令牌

赞(0）分享  回复(0）举报  2023-10-22
368yc8dk

368yc8dk8#

我遇到这个问题是因为response.body是空的--在检查了主体是否为空之后，如上面Parag所提到的，导致了另一个偶尔的问题（Unhandled Exception: FormatException: Unexpected extension byte (at offset 5)）。
response.body是空的，因为PHP脚本没有回显结果，因为它不能json_encode它。发生这种情况的原因是它无法对数据库中某些行中的某些字符进行编码。
在PHP脚本中的修复是这样的：

// Connect to the MySQL database
$conn = new mysqli($host, $user, $password, $database);
// Set the charset to utf-8
$conn->set_charset("utf8");

这将字符集设置为“utf-8”，数据可以被编码和回显。

赞(0）分享  回复(0）举报  2023-10-22
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