Android/Java：有没有办法在监听器触发后调用方法的返回？

Question

I'm using Volley to get a JSONObject from an HTTP Api.

My problem is that I want my method to wait for the Response Listener getting the result, otherwise my method is returning a null object.
I tried using synchronize wait and notify to achieve it, but it doesn't seem to work, the activity freezes after the isFinished.wait() and the listener doesn't trigger. Can you tell me what's wrong in my code?

public JSONObject query(String url) throws InterruptedException {
    finished=false;
    Req = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
        @Override
        public void onResponse(JSONObject response) {
            synchronized (isFinished){
                Retour = response;
                finished = true;
                isFinished.notifyAll();
            }
        }
    },
    new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            synchronized (isFinished){
                Retour = null;
                finished = true;
                isFinished.notifyAll();
            }
        }
    });
    Queue.add(Req);
    synchronized (isFinished) {
        while (!finished) {
            isFinished.wait();
        }
        return Retour;
    }
}

Answer 1

I solved it by changing the design, so the method doesn't return anything, but calls back a Consumer interface that then retrieve the Result into a class field Data :

Consumer<JSONObject> cons = a -> Data=a;

The original code became:

public void query(String url,Consumer<JSONObject> cons) {
    Req = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
        @Override
        public void onResponse(JSONObject response) {
            Retour = response;
            callb.accept(Retour);
        }
    },
    new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            Retour = null;
            callb.accept(null);
        }
    });
    Queue.add(Req);
}