flutter 读取json

效果图

项目目录里新建一个load_json目录，里面再新建一个person.json文件。

[
  {
    "name" : "Suye",
    "age" : "27",
    "height" : "170",
    "gender" : "male",
    "hair_color" : "black"
  },
  {
    "name" : "Surina",
    "age" : "26",
    "height" : "160",
    "gender" : "female",
    "hair_color" : "brown"
  },
  {
    "name" : "Terigele",
    "age" : "25",
    "height" : "174",
    "gender" : "male",
    "hair_color" : "black"
  }
]

之后在pubspec.yaml里配置引入资源。

这个配置文件比较坑，需要注意缩进格式，多一个或少一个空格就会出错。

之后就是写主函数了。

import 'dart:convert';

import 'package:flutter/material.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: Colors.teal,
      ),
      home: new MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State {
  List data;
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text(widget.title),
      ),
      body: new Center(
        child: FutureBuilder(
          future: DefaultAssetBundle.
          of(context).
          loadString('load_json/person.json'),
          builder: (context,snapshot){
            // ignore: deprecated_member_use
            var mydata = JSON.decode(snapshot.data.toString());

            return ListView.builder(
              itemBuilder: (BuildContext context,int index){
                return Card(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.stretch,
                    children: [
                      Text("Name:" + mydata[index]["name"]),
                      Text("Age:" + mydata[index]["age"]),
                      Text("Height:" + mydata[index]["height"]),
                      Text("Hair:" + mydata[index]["hair_color"]),
                      Text("Gender:" + mydata[index]["gender"]),
                    ],
                  ),
                );
              },
              itemCount: mydata == null ? 0 : mydata.length,
            );
          },
        ),
      ),
    );
  }
}

读取json文件需要用到Future，异步操作都会用到，相当于web里的promise。（个人理解，水平有限、轻点喷~有高手路过，请帮忙纠正）

读取后需要解析，需要引入convert库，然后用 JSON.decode(snpashot.data.toSpring())