arrays - 如何将地图列表中的项目显示到列表视图中
问题描述
我不知道如何从系统主题或视频请求中显示主题 ID 的值。
我从一个 http 请求获取源到这个 url:https ://public.free.beeceptor.com/api
以下是回应。
{
"body": {
"System Topics": [
{
"Topic ID": "2",
"Title": "Tres",
"Description": "Dos"
},
{
"Topic ID": "3",
"Title": "Pls Work",
"Description": "nfewtrwe"
},
{
"Topic ID": "4",
"Title": "Juice",
"Description": "Bar"
}
],
"Video Requests": [
{
"Topic ID": "1",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What's you first christmas like?",
"Description": "Please tell me about your Christmas?"
},
{
"Topic ID": "4",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": ""
},
{
"Topic ID": "5",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": ""
},
{
"Topic ID": "6",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": ""
},
{
"Topic ID": "7",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": ""
},
{
"Topic ID": "8",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": ""
},
{
"Topic ID": "9",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": "From james"
},
{
"Topic ID": "10",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": "From james"
}
]
}
}
我想像这样将值显示到列表视图中,但直接来自 https 流。
Container(
width: 338,
height: 500.0,
child: ListView.builder(
itemCount: data == null ? 0 : data.length,
itemBuilder: (context, i) {
return Container(
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.circular(20.0),
),
height: 74.0,
margin: const EdgeInsets.only(bottom: 10.0),
width: MediaQuery.of(context).size.width,
child: Row(
children: <Widget>[
Container(
child: Text(data[i]["System Topics"]["Topic ID"]),
height: 74.0,
width: 73.0,
decoration: BoxDecoration(
color: Colors.orange,
borderRadius: BorderRadius.only(
topLeft: const Radius.circular(20.0),
bottomLeft: const Radius.circular(20.0)),
),
),
Container(
height: 74.0,
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.only(
topRight: const Radius.circular(20.0),
bottomRight: const Radius.circular(20.0)),
),
width: 265.0,
child: Center(
child: Text(
data[i],
style:
TextStyle(fontSize: 24.0, color: maincolor),
)),
)
],
),
);
},
),
),
我已经解析了 JSON,但是当我尝试将它用作这样的对象时:
文本(问题[i].body.systemTopics.topicid)
它不让我。但是,如果我这样做: questions[i].body.systemTopics 那么它不会抛出错误
解决方案
编辑:更新了使用提供的序列化器 OP 并使用有状态小部件的答案。
请注意,在下面的代码中,数据是不变的,但您已经对其进行了调整以处理异步 http 请求,因为我想在此处的 dartpad 中显示答案。
import 'package:flutter/material.dart';
import 'dart:convert';
final Color darkBlue = Color.fromARGB(255, 18, 32, 47);
void main() {
runApp(MainWidget());
}
class MainWidget extends StatelessWidget {
@override
Widget build(context) {
return MaterialApp(home: Scaffold(body: Questions()));
}
}
class Questions extends StatefulWidget {
@override
_QuestionsPageState createState() => _QuestionsPageState();
}
class _QuestionsPageState extends State<Questions> {
QuestionModel data;
var users;
String url =
'https://90d53c1e-1ca3-4d5e-982e-0ff81a3ba7f5.mock.pstmn.io/profile/questions';
requestQuestionsAPI() {
// final response = await http.get(Uri.encodeFull(url), headers: {"Accept": "application/json"});
setState(() {
//data = json.decode(response.body);
// Isntead of http fecth a constant data
data = questionModelFromJson('''{
"body": {
"System Topics": [
{"Topic ID": "2", "Title": "Tres", "Description": "Dos"},
{"Topic ID": "3", "Title": "Pls Work", "Description": "nfewtrwe"},
{"Topic ID": "4", "Title": "Juice", "Description": "Bar"}
],
"Video Requests": [
{
"Topic ID": "1",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What's you first christmas like?",
"Description": "Please tell me about your Christmas?"
},
{
"Topic ID": "4",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": ""
},
{
"Topic ID": "5",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": ""
},
{
"Topic ID": "6",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": ""
},
{
"Topic ID": "7",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": ""
},
{
"Topic ID": "8",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": ""
},
{
"Topic ID": "9",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": "From james"
},
{
"Topic ID": "10",
"From Name": "New User",
"From Email": "dawdw@gmail.com",
"Title": "What is your name?",
"Description": "From james"
}
]
}
}''');
});
}
_questions() {
requestQuestionsAPI();
}
void initState() {
super.initState();
_questions();
}
dispose() {
super.dispose();
}
@override
Widget build(BuildContext context) {
return MyNewWidget(questionModel: data);
}
}
class MyNewWidget extends StatefulWidget {
final QuestionModel questionModel;
MyNewWidget({this.questionModel});
@override
_MyNewWidgetState createState() => _MyNewWidgetState();
}
class _MyNewWidgetState extends State<MyNewWidget> {
@override
Widget build(BuildContext context) {
print(widget.questionModel);
return MyList(
bodyElement: widget.questionModel.body,
);
}
}
class MyList extends StatelessWidget {
final Body bodyElement;
MyList({this.bodyElement});
@override
Widget build(BuildContext context) {
return Column(children: [
Text(
'Sytem Topics',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 25,
fontStyle: FontStyle.italic),
),
Divider(),
Expanded(
child: ListView.builder(
shrinkWrap: true,
itemCount: bodyElement.systemTopics.length,
itemBuilder: (context, index) {
return MyListElement(
id: bodyElement.systemTopics[index].topicId,
description: bodyElement.systemTopics[index].description,
);
}),
),
Text(
'Video Requests',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 25,
fontStyle: FontStyle.italic),
),
Divider(),
Expanded(
child: ListView.builder(
shrinkWrap: true,
itemCount: bodyElement.videoRequests.length,
itemBuilder: (context, index) {
return MyListElement(
id: bodyElement.videoRequests[index].topicId,
description: bodyElement.videoRequests[index].description,
);
}),
)
]);
}
}
class MyListElement extends StatelessWidget {
final String id;
final String description;
MyListElement({this.id, this.description});
@override
Widget build(BuildContext context) {
print('id is $id');
return Container(
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.circular(20.0),
),
height: 74.0,
margin: const EdgeInsets.only(bottom: 10.0),
child: Row(
children: <Widget>[
Container(
alignment: Alignment.center,
child: Text(id),
height: 74.0,
width: 73.0,
decoration: BoxDecoration(
color: Colors.orange,
borderRadius: BorderRadius.only(
topLeft: const Radius.circular(20.0),
bottomLeft: const Radius.circular(20.0)),
),
),
Container(
height: 74.0,
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.only(
topRight: const Radius.circular(20.0),
bottomRight: const Radius.circular(20.0)),
),
width: 265.0,
child: Center(
child: Text(
description,
style: TextStyle(fontSize: 24.0, color: Colors.red),
)),
)
],
),
);
}
}
/// Serializers
QuestionModel questionModelFromJson(String str) =>
QuestionModel.fromJson(json.decode(str));
String questionModelToJson(QuestionModel data) => json.encode(data.toJson());
class QuestionModel {
Body body;
QuestionModel({
this.body,
});
factory QuestionModel.fromJson(Map<String, dynamic> json) => QuestionModel(
body: Body.fromJson(json["body"]),
);
Map<String, dynamic> toJson() => {
"body": body.toJson(),
};
}
class Body {
List<SystemTopic> systemTopics;
List<VideoRequest> videoRequests;
Body({
this.systemTopics,
this.videoRequests,
});
factory Body.fromJson(Map<String, dynamic> json) => Body(
systemTopics: List<SystemTopic>.from(
json["System Topics"].map((x) => SystemTopic.fromJson(x))),
videoRequests: List<VideoRequest>.from(
json["Video Requests"].map((x) => VideoRequest.fromJson(x))),
);
Map<String, dynamic> toJson() => {
"System Topics":
List<dynamic>.from(systemTopics.map((x) => x.toJson())),
"Video Requests":
List<dynamic>.from(videoRequests.map((x) => x.toJson())),
};
}
class SystemTopic {
String topicId;
String title;
String description;
SystemTopic({
this.topicId,
this.title,
this.description,
});
factory SystemTopic.fromJson(Map<String, dynamic> json) => SystemTopic(
topicId: json["Topic ID"],
title: json["Title"],
description: json["Description"],
);
Map<String, dynamic> toJson() => {
"Topic ID": topicId,
"Title": title,
"Description": description,
};
}
class VideoRequest {
String topicId;
String fromName;
String fromEmail;
String title;
String description;
VideoRequest({
this.topicId,
this.fromName,
this.fromEmail,
this.title,
this.description,
});
factory VideoRequest.fromJson(Map<String, dynamic> json) => VideoRequest(
topicId: json["Topic ID"],
fromName: json["From Name"],
fromEmail: json["From Email"],
title: json["Title"],
description: json["Description"],
);
Map<String, dynamic> toJson() => {
"Topic ID": topicId,
"From Name": fromName,
"From Email": fromEmail,
"Title": title,
"Description": description,
};
}
对应的输出如下图所示。
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