如何从 List<Marker> 获取信息并构建标记

Question

这是我的功能：

Future <List <Markers>> getMarker() async {
String myUrl = "http://10.25.84.36:5000/api/markers";
var response = await http.get(myUrl,
    headers: {
      'Accept': 'application/json',

    });

var jsonData = json.decode(response.body);

List<Markers> markers =[];

var u;

for( u in jsonData){

  u.forEach((v) { Markers marker = Markers(v["id"],v["lag"],v["log"]);

  markers.add(marker); });


}

print(markers.length);
print(markers);
return markers;

}

它返回一个 Future 的实例，我想使用这些信息来创建标记，我该怎么做？

Answer 1

class Markers {
  int id;
  int lag;
  String log;

  Markers({this.id, this.lag, this.log});

  Markers.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    lag = json['lag'];
    log = json['log'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['id'] = this.id;
    data['lag'] = this.lag;
    data['log'] = this.log;
    return data;
  }
}

 Future <List<Markers>> getMarker() async {
    String myUrl = "http://10.25.84.36:5000/api/markers";
    var response = await http.get(myUrl,
        headers: {
          'Accept': 'application/json',

        });

    var jsonData = json.decode(response.body);

    List<Markers> markers = [];

    // assuming you have the following json: [{"id": 1, "lag": 100, "log": "bla"}, {"id": 2, "lag": 110, "log": "bla2 "}, {" id ": 3," lag ": 90," log ":" bla "}]

      jsonData.forEach((v) => markers.add(Markers.fromJson(v)));


    print(markers.length);
    markers.forEach((v) => print(v.toJson()));
    return markers;
}

forEach 对列表中的每个元素运行一个函数。 在这种情况下，地图 {id: x, lag: y, log: z}