从 dart 中的嵌套地图中获取数据

Question

我想在列表项内的地图所有者中访问 avatar_url。

JsonMap

Answer 1

试试这个

    import "package:http/http.dart" as http;

    Future<List<String>> getListOfAvatarUrl() async {
  http.Response response = http.get("your uri"));
  if(response.statusCode == 200) {
    List<Map<String, dynamic>> items = jsonDecode(response.body)["items"];
    List<Map<String,dynamic>> owners = items.map<Map<String, dynamic>>((Map<String, dynamic> item) {
      return item['owner'];
    }).toList();
    List<String> avatarUrls = owners.map((Map<String, dynamic> owner) {
      return owner["avatar_url"].toString();
    }).toList();
    return avatarUrls;
  } 
  return [];
}

构建方法内部

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: FutureBuilder<List<String>>(
          future: getListOfAvatarUrl(),
          builder:
              (BuildContext context, AsyncSnapshot<List<String>> snapshot) {
            if (snapshot.hasData) {
              return ListView.builder(
                  itemCount: snapshot.data!.length,
                  itemBuilder: (context, index) {
                    return Image.network(snapshot.data![index]);
                  });
            }
            return CircularProgressIndicator();
          },
        ));