Question

我正在尝试运行此代码，但由于person.emp_id作为int变量而出错，有人可以帮忙吗？我曾尝试制作字符串，但仍然遇到相同的错误，我也尝试在int中进行解析 error: The argument type '(int) → dynamic' can't be assigned to the parameter type '(String) → void'

import 'package:flutter/material.dart';
import 'dart:async';
import 'package:http/http.dart' as http;
import 'dart:convert';

void main() {
    runApp(MaterialApp(
        home: MyGetHttpData(),
    ));
}


class MyGetHttpData extends StatefulWidget {
    @override
    MyGetHttpDataState createState() => MyGetHttpDataState();
}


class MyGetHttpDataState extends State<MyGetHttpData> {
    final String url = "https://raw.githubusercontent.com/uc-ach/flutter/master/test.json";
    List data;


    Future<String> getJSONData() async {
    var response = await http.get(
      Uri.encodeFull(url),
      headers: {"Accept": "application/json"});


      print(response.body);


setState(() {

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

  data = dataConvertedToJSON;
});

return "Successfull";
}

@override
Widget build(BuildContext context) {
return Scaffold(
  appBar: AppBar(
    title: Text("Inside Sales User List"),
  ),

  body: ListView.builder(
      itemCount: data == null ? 0 : data.length,
      itemBuilder: (BuildContext context, int index) {
        return Container(
          child: Center(
              child: Column(

                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: <Widget>[
                  Card(
                    child: Container(
                      child: ListTile(
                          title: Text(

                            data[index]['name'],

                            style: TextStyle(
                                fontSize: 22.0, color: Colors.lightBlueAccent),
                          ),
                          onTap: () {
                            Navigator.push(
                              context,
                              MaterialPageRoute(builder: (context) => new SecondRoute(person: new Person(data[index]['name'],data[index]['post'],data[index]['emp_id']))),
                            );
                          },
                      ),

                      padding: const EdgeInsets.all(15.0),
                    ),
                  )
                ],
              )),
        );
      }),
);
}
@override
void initState() {
super.initState();


this.getJSONData();
}
}
class Person {
    final String name;
    final String post;
    int empId;
    Person(this.name, this.post, this.empId);
}
class SecondRoute extends StatelessWidget {
    final Person person;
   SecondRoute({Key key, @required this.person}) : super(key: key);
   @override
   Widget build(BuildContext context) {
   return Scaffold(
   appBar: AppBar(
    title: Text("Details for " +person.name),
   ),
  body: Padding(
    padding: EdgeInsets.all(16.0),

      child: Column( children: <Widget>[
  Text("Name: " +person.name, style: TextStyle(
      fontSize: 20.0),),
    Text("Emp Id: " +person.empId, style: TextStyle(
        fontSize: 20.0),)
      ],),
  ),
);
}
}

Answer 1

只需将代码更改为

Text("Emp Id: " + person.empId.toString(), style: TextStyle(fontSize: 20.0),)

“ person.empId”是一个int值，您正在将其分配给“文本”窗口小部件，该窗口小部件始终期望使用String值。

Answer 2

当您在MaterialPageRoute上创建新的Person对象时，您是从json获取数据的，它作为String出现，但是您的Person的id定义为int。将字符串转换为int应该可以解决您的问题：

MaterialPageRoute(builder: (context) => new SecondRoute(
  person: new Person(
    data[index]['name'],
    data[index]['post'],
    int.parse(data[index]['emp_id'])
  )
)),

错误：无法将参数类型int分配给参数类型字符串

2 个答案: