How can I parse json data from websocket server in flutter? - json

Question

The WebSocket server is supposed to shoot json data as soon as it goes up, and I want to create a StreamBuilder that updates the data as it shoots me FutureBuilder has received async and wait http.get, and how do I make a Stream for my stream builder?
Here is the futurebuilder when I receive information from http server!(for all information, no realtime)
I want to receive information like this by streambuilder from websocket server for realtime!
class BallInformationWidget extends StatefulWidget {
#override
BallInformationWidgetState createState() => BallInformationWidgetState();
}
class BallInformationWidgetState extends State<BallInformationWidget> {
#override
Widget build(BuildContext context) {
return FutureBuilder<List<BallInformation>>(
future: getHttpBallInfo(urlPrefix),
builder: (context, snapshot) {
print('http data : ${snapshot.data}');
print('http length : ${snapshot.data.length}\n');
print('http type : ${snapshot.data[0].id.runtimeType}\n');
BallInformation ballInfo = snapshot.data[0]; // 공하나 객체 선언 후에 for 문?
return Padding(
padding: const EdgeInsets.symmetric(vertical: 5.0),
child: Text(snapshot.hasData ? '${ballInfo.id}' : 'Loading...'),
);
},
);
}
}
class BallInformation {
int id;
double speed;
String result;
Map trajectoryParameter;
BallInformation(this.id, this.speed, this.result, this.trajectoryParameter);
BallInformation.fromJson(Map<String, dynamic> data) {
this.id = data['id'];
this.speed = data['speed'];
this.result = data['result'];
this.trajectoryParameter = data['trajectory_parameter'];
}
}
Future<List<BallInformation>> getHttpBallInfo(String url) async {
http.Response response = await http.get(url);
String responseBody = response.body;
var dataS = json.decode(responseBody);
List<BallInformation> ballInformation = [];
// If I receive json(only one information
ballInformation.add(BallInformation.fromJson(dataS));
// If I receive json(List, more than 1 information)
// for (var data in dataS){
// ballInformation.add(BallInformation.fromJson(data));
// }
return ballInformation;
}

Answer 1

The standart method for this is json.decode(snapshot.data). This will return a map of your json data in the request.