说明：我正在尝试在ListView中显示json文件中的值。我制作了一个类来读取json文件并从密钥中获取值。这可以正常工作，但是我无法将键值带入ListView。我使用名为“ EmployeeInfo”的单独类获取键值，并使用称为“ jsonContent”的方法读取json文件的内容。到目前为止，我可以实例化类，执行方法并将类变量打印到控制台上。但是，我无法将此类变量值加载到ListView标题中。
我无法在此代码中加载变量，但能够通过：print（jsonrd.EmployeeJson [“ Name”]
打印import 'package:flutter/material.dart';
import 'package:emas_app/Dependant.dart' as Dep;
import 'dart:convert';
void main() => runApp(new Fourth());
class Fourth extends StatefulWidget {
@override
MemberInfoState createState() => new MemberInfoState();
}
class MemberInfoState extends State<Fourth>{
List data;
@override
Widget build(BuildContext context) {
var jsonrd = new Dep.EmployeeInfo(); // Go to the house and open the door
jsonrd.jsonContent(); // E
return new Scaffold(
body: new Container(
child: new Center(
child:new FutureBuilder(
future: DefaultAssetBundle
.of(context)
.loadString('assets/MemberInfo.json'),
builder: (context,snapshot){
var mydata = JSON.decode(snapshot.data.toString());
print("mydata: " + mydata.toString());
var jsondata = new Dep.EmployeeInfo();
jsondata.jsonContent();
final name = jsondata.EmployeeJSON["Name"].toString();
return new ListView.builder(
itemBuilder:(BuildContext context,int index){
return new Card(
child:new Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
new ListTile(
title: new Text("Name " ),
subtitle: new Text(name),
),
new ListTile(
title: new Text("Identification " ),
subtitle: new Text( mydata[index]["Employee"]["Identification"]),
),
new ListTile(
title: new Text("Company " ),
subtitle: new Text( mydata[index]["Employee"]["Company"]),
),
new ListTile(
title: new Text("Date Of Birth " ),
subtitle: new Text( mydata[index]["Employee"]["DateOfBirth"]),
),
const Divider(
color: Colors.white,
height: 50.0,
),
new MaterialButton(
color: Colors.indigo,
height:50.0,
minWidth: 50.0,
textColor: Colors.white,
child: new Text("More"),
onPressed: () => print(jsonrd.EmployeeJSON["Name"])
),
],
),
);
},
itemCount: mydata == null ? 0 : mydata.length,
);
},
),
//
//
),
),
);
}
}
呼叫Json（代码）：
导入“ package：flutter / material.dart”；
import 'dart:async';
import 'dart:convert';
import 'package:http/http.dart' as http;
final String url = "http://crm.emastpa.com.my/MemberInfo.json";
List depData;
class EmployeeInfo {
// String jsonContent;
List data;
String Employee;
String empname;
String empdep;
Map <String, dynamic> EmployeeJSON = new Map<String, dynamic>();
void jsonContent() {
Future<String> getData() async {
var res = await http.get(
Uri.encodeFull("http://crm.emastpa.com.my/MemberInfo.json"),
headers: {"Accept": "application/json"});
var resBody = json.decode(res.body);
this.data = resBody;
this.EmployeeJSON = resBody[0]["Employee"];
Employee = resBody[0]["Employee"]["Name"];
depData = resBody[0]["Dependents"];
this.empname = this.EmployeeJSON["Name"];
this.empdep= depData[0]["Dependents"];
return "Success!";
}
getData();
}
}
输出 正在执行热装... I / flutter（24432）：mydata：空 在1,696毫秒内重新加载了549个库中的8个。 I / flutter（24432）：mydata：空 I / flutter（24432）：mydata：空 I / flutter（24432）：mydata：空 I / flutter（24432）：mydata：空 与设备的连接断开。
答案 0 :(得分：2)
哇，您的代码真的很困难。您正在build方法中执行一个future，而不仅仅是在FutureBuilder中期待它的结果。
我已经进行了深刻的修改，仍然保留了您想要做的事情的精神。
但是您应该真正创建一个返回雇员列表的Future，而不是在FutureBuilder中处理html响应。
import 'package:flutter/material.dart';
import 'dart:convert';
import 'dart:async';
import 'package:http/http.dart' as http;
final String url = "http://crm.emastpa.com.my/MemberInfo.json";
class EmployeeInfo {
String Employee;
String empname;
String empdep;
Map<String, dynamic> EmployeeJSON = new Map<String, dynamic>();
}
Future<String> jsonContent() async {
var res = await http.get(
Uri.encodeFull("http://crm.emastpa.com.my/MemberInfo.json"),
headers: {"Accept": "application/json"});
return res.body;
}
void main() => runApp(new Fourth());
class Fourth extends StatefulWidget {
@override
MemberInfoState createState() => new MemberInfoState();
}
class MemberInfoState extends State<Fourth> {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: new Scaffold(
body: new Container(
child: new Center(
child: new FutureBuilder<String>(
future: jsonContent(),
builder: (context, snapshot) {
if (snapshot?.hasData) {
var mydata = json.decode(snapshot.data);
final name = mydata[0]["Employee"]["Name"];
return new ListView.builder(
itemBuilder: (BuildContext context, int index) {
return new Card(
child: new Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
new ListTile(
title: new Text("Name "),
subtitle: new Text(name),
),
new ListTile(
title: new Text("Identification "),
subtitle: new Text(
mydata[index]["Employee"]["Identification"]),
),
new ListTile(
title: new Text("Company "),
subtitle: new Text(
mydata[index]["Employee"]["Company"]),
),
new ListTile(
title: new Text("Date Of Birth "),
subtitle: new Text(
mydata[index]["Employee"]["DateOfBirth"]),
),
const Divider(
color: Colors.white,
height: 50.0,
),
new MaterialButton(
color: Colors.indigo,
height: 50.0,
minWidth: 50.0,
textColor: Colors.white,
child: new Text("More"),
),
],
),
);
},
itemCount: mydata == null ? 0 : mydata.length,
);
} else {
return CircularProgressIndicator();
}
},
),
),
),
),
);
}
}