Java socket.io wait for callback

Question

My Activity code:

public String getValue(JSONObject data) {
    String value;
    socket.emit("request", data, new Ack() {
        @Override
        public void call(Object... args) {
            value = (String) args[1]; // how to wait for this value?
        });

    return value;
}

How do I wait for the value that came from the socket.io callback?

score 0 · Answer 1 · answered May 20 '20 at 19:29

Try this

public class  getvalue extends AsyncTask<JSONObject,Void,String>{


          @Override
          protected String doInBackground(JSONObject... jsonObjects) {
              String value;
              socket.emit("request", jsonObjects, new Ack() {
                  @Override
                  public void call(Object... args) {
                      value = (String) args[1]; // how to wait for this value?
                  }
          });
          return value;
      }
          protected void onPostExecute(String result) {
              //result is the final String;
          }
      }

And after that go to Activity that you want to use this function in and try this :

 getvalue a=new getvalue();
            getvalue.execute(data);

Here is some useful link https://developer.android.com/reference/android/os/AsyncTask

AsyncTask Android example hopefully to work

thanks for the help but as you can see I need to wait for the socket emit callback which is asynchronous. So, it's not gonna work. — Footniko, May 20 '20 at 20:51

score 0 · Answer 2 · answered Dec 19 '22 at 12:06

For anyone who's still facing for the same issue, use CompletableFuture

public String request(JSONObject... objects) {
    CompletableFuture<String> future = new CompletableFuture<>();
    socket.emit("request", objects, (Ack) callback -> {
        future.complete(args[1].toString());
    });
    return future.join();
}

However, note that if answer wasn't provided, your code will be blocked until the answer would be provided by the server, however this is the question itself, so here you are

Java socket.io wait for callback

2 Answers2