Flutter 颤振-如何将JSON加载到futurebuilder中
我正在尝试创建一个非常简单的flatter应用程序,它将加载一篇文章中的所有数据和参数,并创建一个包含详细信息的滚动列表。 目前我没有收到任何错误,但是加载循环永远旋转,即使JSON已成功返回,任何帮助或想法都将不胜感激。 以下是我目前掌握的情况:Flutter 颤振-如何将JSON加载到futurebuilder中,flutter,Flutter,我正在尝试创建一个非常简单的flatter应用程序,它将加载一篇文章中的所有数据和参数,并创建一个包含详细信息的滚动列表。 目前我没有收到任何错误,但是加载循环永远旋转,即使JSON已成功返回,任何帮助或想法都将不胜感激。 以下是我目前掌握的情况: import 'dart:async'; import 'dart:convert'; import 'package:flutter/foundation.dart'; import 'package:flutter/material.dart';
import 'dart:async';
import 'dart:convert';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
Future<List<Post>> fetchPosts(http.Client client) async {
var url = "contacts.json";
var client = new http.Client();
var request = new http.Request('POST', Uri.parse(url));
var body = {'type': 'getContacts'};
request.bodyFields = body;
var data = http.post(url, body: {"type": "getContacts"})
.then((response) {
print(response.body);
return compute(parsePosts, response.body);
});
}
// A function that will convert a response body into a List<Photo>
List<Post> parsePosts(String responseBody) {
final parsed = json.decode(responseBody).cast<Map<String, dynamic>>();
return parsed.map<Post>((json) => Post.fromJson(json)).toList();
}
class Post {
final String First;
final String Last;
final String Email;
final String Phone;
final String Photo;
final String Full;
Post({this.Full, this.First, this.Last, this.Photo, this.Email, this.Phone});
factory Post.fromJson(Map<String, dynamic> json) {
return new Post(
Full: json['Full'] as String,
First: json['First'] as String,
Last: json['Last'] as String,
Photo: json['Photo'] as String,
Email: json['Email'] as String,
Phone: json['Phone'] as String,
);
}
}
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
final appTitle = 'CONTACTS';
return MaterialApp(
title: appTitle,
home: MyHomePage(title: appTitle),
);
}
}
class MyHomePage extends StatelessWidget {
final String title;
MyHomePage({Key key, this.title}) : super(key: key);
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(title),
),
body: FutureBuilder<List<Post>>(
future: fetchPosts(http.Client()),
builder: (context, snapshot) {
if (snapshot.hasError) print(snapshot.error);
return snapshot.hasData
? PhotosList(photos: snapshot.data)
: Center(child: CircularProgressIndicator());
},
),
);
}
}
class PhotosList extends StatelessWidget {
final List<Post> photos;
PhotosList({Key key, this.photos}) : super(key: key);
@override
Widget build(BuildContext context) {
return ListView.builder(
itemCount: photos == null ? 0 : photos.length,
itemBuilder: (BuildContext context, i) {
return new ListTile(
title: new Text(photos[i].Last + " " + photos[i].First),
subtitle: new Text(photos[i].Phone),
leading: new CircleAvatar(
backgroundImage:
new NetworkImage(photos[i].Photo),
)
);
}
);
}
}
因为您使用的是
Future
和async
,所以可以使用wait
进行异步操作。
所以你的fetchPosts
应该是这样的
Future<List<Post>> fetchPosts(http.Client client) async {
var url = "contacts.json";
var client = new http.Client();
var request = new http.Request('POST', Uri.parse(url));
var body = {'type': 'getContacts'};
request.bodyFields = body;
var data = await http.post(url, body: {"type": "getContacts"});
print(data.body);
return await compute(parsePosts, data.body);
}
Future fetchPosts(http.Client)异步{
var url=“contacts.json”;
var client=newhttp.client();
var request=newhttp.request('POST',Uri.parse(url));
var body={'type':'getContacts'};
request.bodyFields=body;
var data=wait http.post(url,主体:{“type”:“getContacts”});
打印(data.body);
返回等待计算(parsePosts、data.body);
}
因为您使用的是Future
和async
,所以可以使用wait
进行异步操作。
所以你的fetchPosts
应该是这样的
Future<List<Post>> fetchPosts(http.Client client) async {
var url = "contacts.json";
var client = new http.Client();
var request = new http.Request('POST', Uri.parse(url));
var body = {'type': 'getContacts'};
request.bodyFields = body;
var data = await http.post(url, body: {"type": "getContacts"});
print(data.body);
return await compute(parsePosts, data.body);
}
Future fetchPosts(http.Client)异步{
var url=“contacts.json”;
var client=newhttp.client();
var request=newhttp.request('POST',Uri.parse(url));
var body={'type':'getContacts'};
request.bodyFields=body;
var data=wait http.post(url,主体:{“type”:“getContacts”});
打印(data.body);
返回等待计算(parsePosts、data.body);
}
您也可以参考这篇文章。它非常有用
你也可以参考这篇文章。它非常有用
谢谢!错过等待它是什么导致它不承认它是完整的。谢谢!错过等待它是什么导致它不承认它是完整的。请添加更多的链接到您的答案。解释链接中的内容,以防将来无法使用。谢谢,请添加更多链接到您的答案。解释链接中的内容,以防将来无法使用。非常感谢。