Flutterはjson要求を送信し、jsonデータを解析します.
Flutterはjson要求を送信し、jsonデータを解析します。
ここ数日Flutterを見て、機能は比較的に強くて、しかし関連する資料は比較的に少なくて、ネット上で基本的にjsonのデータを送信していないで、ただjsonのデータを解析します.特に必要な学生に記録して、穴を踏んで資料を探すのを避けます.テキストリンク:https://blog.csdn.net/weixin_44259356/article/details/104424424
getリクエスト、Json解析
gatリクエストを開始し、返されたjsonデータを解析し、ipアドレスを表示します.import 'dart:convert';
import 'dart:io';
import 'package:flutter/material.dart';
void main() {
runApp(new MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
home: new MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({
Key key}) : super(key: key);
@override
_MyHomePageState createState() => new _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
var _ipAddress = 'Unknown';
_getIPAddress() async {
var url = 'https://httpbin.org/ip';
var httpClient = new HttpClient();
String result;
try {
var request = await httpClient.getUrl(Uri.parse(url));
var response = await request.close();
if (response.statusCode == HttpStatus.OK) {
var json = await response.transform(utf8.decoder).join();
var data = jsonDecode(json);
result = data['origin'];
} else {
result =
'Error getting IP address:
Http status ${
response.statusCode}';
}
} catch (exception) {
result = 'Failed getting IP address';
}
// If the widget was removed from the tree while the message was in flight,
// we want to discard the reply rather than calling setState to update our
// non-existent appearance.
if (!mounted) return;
setState(() {
_ipAddress = result;
});
}
@override
Widget build(BuildContext context) {
var spacer = new SizedBox(height: 32.0);
return new Scaffold(
body: new Center(
child: new Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Text('Your current IP address is:'),
new Text('$_ipAddress.'),
spacer,
new RaisedButton(
onPressed: _getIPAddress,
child: new Text('Get IP address'),
),
],
),
),
);
}
}
post Jsonリクエストの開始
以上のコードは以下のように修正すればよい
要求ヘッダの変更
request.headers.add("Content-Type", "application/json");
jsonデータの追加
request.add(utf8.encode("\{\"from\"\: \"xxxx\"\,\}"));
urlの変更
上記urlをjsonリクエストを受け入れる任意のバックグラウンドインタフェースに変更すればよい.
リファレンスリンク
https://flutterchina.club/networking/
import 'dart:convert';
import 'dart:io';
import 'package:flutter/material.dart';
void main() {
runApp(new MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
home: new MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({
Key key}) : super(key: key);
@override
_MyHomePageState createState() => new _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
var _ipAddress = 'Unknown';
_getIPAddress() async {
var url = 'https://httpbin.org/ip';
var httpClient = new HttpClient();
String result;
try {
var request = await httpClient.getUrl(Uri.parse(url));
var response = await request.close();
if (response.statusCode == HttpStatus.OK) {
var json = await response.transform(utf8.decoder).join();
var data = jsonDecode(json);
result = data['origin'];
} else {
result =
'Error getting IP address:
Http status ${
response.statusCode}';
}
} catch (exception) {
result = 'Failed getting IP address';
}
// If the widget was removed from the tree while the message was in flight,
// we want to discard the reply rather than calling setState to update our
// non-existent appearance.
if (!mounted) return;
setState(() {
_ipAddress = result;
});
}
@override
Widget build(BuildContext context) {
var spacer = new SizedBox(height: 32.0);
return new Scaffold(
body: new Center(
child: new Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Text('Your current IP address is:'),
new Text('$_ipAddress.'),
spacer,
new RaisedButton(
onPressed: _getIPAddress,
child: new Text('Get IP address'),
),
],
),
),
);
}
}
以上のコードは以下のように修正すればよい
要求ヘッダの変更
request.headers.add("Content-Type", "application/json");
jsonデータの追加
request.add(utf8.encode("\{\"from\"\: \"xxxx\"\,\}"));
urlの変更
上記urlをjsonリクエストを受け入れる任意のバックグラウンドインタフェースに変更すればよい.