Flutter进阶—网络与本地异步加载资源

@H_696_4@通过网络加载JSON文件的实例

import 'dart:convert';
import 'package:Flutter/material.dart';
import 'package:Flutter/http.dart' as http;
void _networkLoading() {
  // 将给定标头的http GET请求发送到给定的URL，并注册回调，参数为http响应
  http.get('https://domokit.github.io/examples/stocks/data/stock_data_2.json').then((http.Response responsE) {
    // 响应的主体作为字符串返回
    String netdata = response.body;
    // JsonDecoder类解析JSON字符串并构建相应的对象
    JsonDecoder decoder = new JsonDecoder();
    // 将给定的JSON字符串输入转换为其对应的对象
    List<List<String>> json = decoder.convert(netdata);
    // 输出给定的JSON数据
    print(json[0][1]); }); }

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@H_696_4@通过异步加载本地Json资源，需要先在pubspec.yaml文件添加资源文件，然后再通过异步加载资源文件，以下为实例

name: menus_demo
description: A new Flutter project.
dependencies:
  Flutter:
    sdk: Flutter
Flutter:
  uses-material-design: true
  assets:
    - assets/config.json

import 'dart:convert';
import 'dart:async' show Future;
import 'package:Flutter/material.dart';
import 'package:Flutter/services.dart' show rootBundle;
Future<String> loadAsset() async {
  return await rootBundle.loadString('assets/config.json');
}
void _loadJson() {
  loadAsset().then((value){
    JsonDecoder decoder = new JsonDecoder();
    List<List<String>> json = decoder.convert(value);
    print('姓名：'+json[0][0]+'，年龄：'+json[0][1]); }); }

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