为什么我是未处理的异常:在颤振应用程序中输入'TextFormField‘错误？

Question

我试图创建一个认证的安多德应用程序使用颤振黑暗。我为登录注册路由创建了一个带有端点API的节点js服务器，它直接与阿特拉斯MongoDB数据库通信。我可以在邮递员中成功地发送POST请求，但是当我试图从颤振应用程序中调用它时，我会得到一个错误，如下所示

在3,634 in中重新启动应用程序。I/颤振(10513)：TextFormField I/颤振(10513)：TextFormField E/颤振(10513)：错误:flutter/lib/ui/ui_dart_state.cc(186个)未处理的异常:类型'TextFormField‘不是'String’的子类型[38;5；248 39/颤振(10513)：#0登录[39；49m包:cop_app/登录_e.dart][38；5；248 39/颤音(10513)]：#1 LoginSection.build。[39；49m包:cop_app_page.dart[38；5；5；248 38/颤振(10513)：#2 LoginSection.build。[39；49m包:cop_app/登录_page.dart][38；5；244 38/颤振(10513)：#3 ]

_InkResponseState._handleTap[39;49m包:颤振/…][38；5；244 38/颤振(10513)：#4 GestureRecognizer.invokeCallback[39;49m包:颤振/…]/手势/识别器[38；5；244 38/颤振(10513)：#5 TapGestureRecognizer.handleTapUp[39;49m包:颤振/…]/手势/踢踏舞[38；5；244 38/颤振(10513)：#6

BaseTapGestureRecognizer._checkUp[39;49m包:颤振/…]/手势/飞镖[38；5；244 38/颤振(10513)：#7

BaseTapGestureRecognizer.acceptGesture[39;49m包:颤振/…]/手势/踢踏舞[38；5；244 38/颤振(10513)：#8

GestureArenaManager.sweep[39;49m包:颤振/…]/手势/arena.dart[38；5；244 38/颤振(10513)：#9 GestureBinding.handleEvent[39;49m包:颤振/…]/手势/绑定.飞镖[38；5；244 38/颤振(10513)：#10 GestureBinding.dispatchEvent[39;49m包:颤振/…]/手势/绑定.飞镖[38；5；244 38/颤振(10513)：#11 RendererBinding.dispatchEvent[39;49m包:颤振/…]/呈现/绑定.10513[38；5；244…/颤振(10513)：#12 GestureBinding._handlePointerEventImmediately[39;49m包:flutter/…/手势/绑定.飞镖[38；5；244 38/颤振(10513)：#13 GestureBinding.handlePointerEvent[39;49m包:颤振/…]/手势/绑定.飞镖[38；5；244 38/颤振(10513)：#14 GestureBinding._flushPointerEventQueue[39;49m包:颤振/…]/手势/绑定.飞镖[38；5；244 38/颤振(10513)：#15 GestureBinding._handlePointerDataPacket[39;49m包:颤振/…/手势/绑定.飞镖[38;5；244 16/颤振(10513)：#16 _rootRunUnary (飞镖:异步/zone.dart:1370:13)[39；49m[38；5；54 16/颤振(10513)]：#17 _CustomZone.runUnary (飞镖:异步/飞镖:1265:19)[39；49m；5；244 16/颤振(10513)：#18 _CustomZone.runUnaryGuarded (飞镖:异步/zone.dart:1170:7)][39；49；49；5；5；244 20/颤振(10513)：#19 _invoke1 (飞镖:ui/钩子:180:10)[39；49m][38；5；244 20/颤振(10513)：#20

(dart:ui/platform_dispatcher.dart:276:7)[39;49m [38；5；244 39/颤振(10513)：#21 _dispatchPointerDataPacket (飞镖:ui/钩子:96:31)[39；49m E/颤振(10513)：

这是我的密码

import 'dart:convert';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';
import 'package:http/http.dart' as http;
import 'package:shared_preferences/shared_preferences.dart';
import 'profile.dart';

class LoginSection extends StatelessWidget {
  static const String id = "LoginSection";
  var uid;
  var password;
  @override
  Widget build(BuildContext context) {
    final logo = Hero(
      tag: 'hero',
      child: CircleAvatar(
        backgroundColor: Colors.transparent,
        radius: 48.0,
        child: Image.asset('assets/profile.png'),
      ),
    );

    final uid = TextFormField(
      textAlign: TextAlign.center,
      keyboardType: TextInputType.text,
      autofocus: false,
      initialValue: 'abc123',
      decoration: InputDecoration(
        hintText: 'Unique ID',
        contentPadding: EdgeInsets.fromLTRB(20.0, 10.0, 20.0, 10.0),
        border: OutlineInputBorder(borderRadius: BorderRadius.circular(32.0)),
      ),
    );

    final password = TextFormField(
      textAlign: TextAlign.center,
      autofocus: false,
      initialValue: '123abc',
      obscureText: true,
      decoration: InputDecoration(
        hintText: 'Password',
        contentPadding: EdgeInsets.fromLTRB(20.0, 10.0, 20.0, 10.0),
        border: OutlineInputBorder(borderRadius: BorderRadius.circular(32.0)),
      ),
    );

    final loginButton = Padding(
      padding: EdgeInsets.symmetric(vertical: 16.0),
      child: RaisedButton(
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(24),
        ),
        onPressed: () async {
          await login(uid, password);
          SharedPreferences prefs = await SharedPreferences.getInstance();
          String token = prefs.getString("token");
          print(token);
          if (token != null) {
            Navigator.popAndPushNamed(context, LandingScreen.id);
          }
        },
        padding: EdgeInsets.all(12),
        color: Colors.lightBlueAccent,
        child: Text('Log In', style: TextStyle(color: Colors.white)),
      ),
    );

    final forgotLabel = FlatButton(
      child: Text(
        'Forgot password?',
        style: TextStyle(color: Colors.black54),
      ),
      onPressed: () {},
    );
    return Scaffold(
      backgroundColor: Colors.white,
      body: Center(
        child: ListView(
          shrinkWrap: true,
          padding: EdgeInsets.only(left: 24.0, right: 24.0),
          children: <Widget>[
            logo,
            SizedBox(height: 48.0),
            uid,
            SizedBox(height: 8.0),
            password,
            SizedBox(height: 24.0),
            loginButton,
            forgotLabel
          ],
        ),
      ),
    );
  }
}

login(uid, password) async {
  print(uid);
  print(password);
  var url = "http://192.147.111.104:5000/login"; // iOS
  final http.Response response = await http.post(
    url,
    headers: <String, String>{
      'Content-Type': 'application/json; charset=UTF-8',
    },
    body: jsonEncode(<String, String>{
      'uid': uid,
      'password': password,
    }),
  );
  print(response.body);
  SharedPreferences prefs = await SharedPreferences.getInstance();
  var parse = jsonDecode(response.body);

  await prefs.setString('token', parse["token"]);
}

我无法理解这里的问题，我引用了这个源代码作为发送post请求的代码片段，我搜索了类似的问题，但是找不到任何与我的问题相关的解决方案，有人能帮我解决这个问题吗？

Answer 1

TextFormField是表单中用来收集用户输入的小部件。

https://api.flutter.dev/flutter/material/TextFormField-class.html

作为参数传递给小部件的TextEditingController是如何访问用户输入的。

https://api.flutter.dev/flutter/widgets/TextEditingController-class.html

在您执行post请求的情况下，您将希望访问controller.text，而不是传递整个小部件。

class VeryBasicForm extends StatefulWidget {
  @override
  _VeryBasicFormState createState() => _VeryBasicFormState();
}

class _VeryBasicFormState extends State<VeryBasicForm> {
  final uidController = TextEditingController();
  final passwordController = TextEditingController();
  @override
  void initState(){
  // set initial value here
  uidController.text = 'abc123';
  passwordController.text = 'abc123';
    super.initState();
  }

  @override
  void dispose() {
    uidController.dispose();
    passwordController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        TextFormField(
          textAlign: TextAlign.center,
          controller: uidController,
          keyboardType: TextInputType.text,
          autofocus: false,
          decoration: InputDecoration(
            hintText: 'Unique ID',
            contentPadding: EdgeInsets.fromLTRB(20.0, 10.0, 20.0, 10.0),
            border: OutlineInputBorder(borderRadius: BorderRadius.circular(32.0)),
          ),
        ),
        TextFormField(
          textAlign: TextAlign.center,
          controller: passwordController,
          autofocus: false,
          obscureText: true,
          decoration: InputDecoration(
            hintText: 'Password',
            contentPadding: EdgeInsets.fromLTRB(20.0, 10.0, 20.0, 10.0),
            border: OutlineInputBorder(borderRadius: BorderRadius.circular(32.0)),
          ),
        ),
        Padding(
          padding: EdgeInsets.symmetric(vertical: 16.0),
          child: RaisedButton(
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(24),
            ),
            onPressed: () async {
              // pass in the String values from inputs using the controllers
              await login(uidController.text, passwordController.text);
              SharedPreferences prefs = await SharedPreferences.getInstance();
              String token = prefs.getString("token");
              print(token);
              if (token != null) {
                Navigator.popAndPushNamed(context, LandingScreen.id);
              }
            },
            padding: EdgeInsets.all(12),
            color: Colors.lightBlueAccent,
            child: Text('Log In', style: TextStyle(color: Colors.white)),
          ),
        );
      ],
    );
  }
}

Answer 2

您正在将一个TextFormField小部件传递给我认为您想成为文本的东西。先定义一个控制器，

final myPasswordController = TextEditingController();
final myUIDController = TextEditingController();

然后在您的函数中使用它，如

final password = TextFormField(
  textAlign: TextAlign.center,
  controller: myPassWordController,
  autofocus: false,
  obscureText: true,
  decoration: InputDecoration(
    hintText: 'Password',
    contentPadding: EdgeInsets.fromLTRB(20.0, 10.0, 20.0, 10.0),
    border: OutlineInputBorder(borderRadius: BorderRadius.circular(32.0)),
  ),
);

final uid = TextFormField(
  textAlign: TextAlign.center,
  controller: myUIDController,
  keyboardType: TextInputType.text,
  autofocus: false,
  decoration: InputDecoration(
    hintText: 'Unique ID',
    contentPadding: EdgeInsets.fromLTRB(20.0, 10.0, 20.0, 10.0),
    border: OutlineInputBorder(borderRadius: BorderRadius.circular(32.0)),
  ),
);

然后在你被压抑；

         await login(myPasswordController.text, myPasswordController.text);