我对这种json感到困惑。 因为我从未见过有人解释这种json数据。
我从链接中获取jsondata，并且json数据显示如下
{
"data": [
{
"jenis_komoditas": "Gabah IR 64 KP",
"harga": "5400",
"satuan": "Kg",
"persen": null,
"perubahan": "0",
"selisi": "0",
"image": "assets\/thumb\/gabah.png"
},
{
"jenis_komoditas": "Gabah IR 64 KG",
"harga": "6200",
"satuan": "Kg",
"persen": null,
"perubahan": "0",
"selisi": "0",
"image": "assets\/thumb\/gabah1.png"
}
]
}
出现错误。 有人可以帮助我如何从第一个json类型获取数据吗？
答案 0 :(得分：0)
您将以json数组的形式获取数据，因此您可以简单地从对象中迭代调用它。像这样
如果您通过数据变量获取数据：
final jsondata=json.decode(data);
for (var dataf in jsondata['data']){
print(dataf['jenis_komoditas']);
}
答案 1 :(得分：0)
您可以使用
解析完整的json字符串 Payload payload = payloadFromJson(jsonString);
print('${payload.data[0].jenisKomoditas}');
相关课程
// To parse this JSON data, do
//
// final payload = payloadFromJson(jsonString);
import 'dart:convert';
Payload payloadFromJson(String str) => Payload.fromJson(json.decode(str));
String payloadToJson(Payload data) => json.encode(data.toJson());
class Payload {
List<Datum> data;
Payload({
this.data,
});
factory Payload.fromJson(Map<String, dynamic> json) => Payload(
data: List<Datum>.from(json["data"].map((x) => Datum.fromJson(x))),
);
Map<String, dynamic> toJson() => {
"data": List<dynamic>.from(data.map((x) => x.toJson())),
};
}
class Datum {
String jenisKomoditas;
String harga;
String satuan;
dynamic persen;
String perubahan;
String selisi;
String image;
Datum({
this.jenisKomoditas,
this.harga,
this.satuan,
this.persen,
this.perubahan,
this.selisi,
this.image,
});
factory Datum.fromJson(Map<String, dynamic> json) => Datum(
jenisKomoditas: json["jenis_komoditas"],
harga: json["harga"],
satuan: json["satuan"],
persen: json["persen"],
perubahan: json["perubahan"],
selisi: json["selisi"],
image: json["image"],
);
Map<String, dynamic> toJson() => {
"jenis_komoditas": jenisKomoditas,
"harga": harga,
"satuan": satuan,
"persen": persen,
"perubahan": perubahan,
"selisi": selisi,
"image": image,
};
}
完整代码
import 'package:flutter/material.dart';
// To parse this JSON data, do
//
// final payload = payloadFromJson(jsonString);
import 'dart:convert';
Payload payloadFromJson(String str) => Payload.fromJson(json.decode(str));
String payloadToJson(Payload data) => json.encode(data.toJson());
class Payload {
List<Datum> data;
Payload({
this.data,
});
factory Payload.fromJson(Map<String, dynamic> json) => Payload(
data: List<Datum>.from(json["data"].map((x) => Datum.fromJson(x))),
);
Map<String, dynamic> toJson() => {
"data": List<dynamic>.from(data.map((x) => x.toJson())),
};
}
class Datum {
String jenisKomoditas;
String harga;
String satuan;
dynamic persen;
String perubahan;
String selisi;
String image;
Datum({
this.jenisKomoditas,
this.harga,
this.satuan,
this.persen,
this.perubahan,
this.selisi,
this.image,
});
factory Datum.fromJson(Map<String, dynamic> json) => Datum(
jenisKomoditas: json["jenis_komoditas"],
harga: json["harga"],
satuan: json["satuan"],
persen: json["persen"],
perubahan: json["perubahan"],
selisi: json["selisi"],
image: json["image"],
);
Map<String, dynamic> toJson() => {
"jenis_komoditas": jenisKomoditas,
"harga": harga,
"satuan": satuan,
"persen": persen,
"perubahan": perubahan,
"selisi": selisi,
"image": image,
};
}
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
String jsonString = '''
{
"data": [
{
"jenis_komoditas": "Gabah IR 64 KP",
"harga": "5400",
"satuan": "Kg",
"persen": null,
"perubahan": "0",
"selisi": "0",
"image": "assets\/thumb\/gabah.png"
},
{
"jenis_komoditas": "Gabah IR 64 KG",
"harga": "6200",
"satuan": "Kg",
"persen": null,
"perubahan": "0",
"selisi": "0",
"image": "assets\/thumb\/gabah1.png"
}
]
}
''';
void _incrementCounter() {
Payload payload = payloadFromJson(jsonString);
print('${payload.data[0].jenisKomoditas}');
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Invoke "debug painting" (press "p" in the console, choose the
// "Toggle Debug Paint" action from the Flutter Inspector in Android
// Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
// to see the wireframe for each widget.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.display1,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
输出
I/flutter (23421): Gabah IR 64 KP