How to utilize AsyncTask for handling asynchronous RestRequests

Question

I want to access an online API through an android application. For this purpose I have written easy to access functions to send requests via the android Volley package. However the app immediately displays 0s when I try to assign a value, that I have recieved through sending a request, to a TextView. I realize that this probably is because the function handles the Object as "null" because the response has not yet arrived and that I need to use AsyncTasks to handle this properly but the Developer Guide from Android Studio didn't really help me too much because, to be absolutely 100% honest with you, I'm not a software engineer and I'm absolutely lost at this point.

Here's some code on how I access the API:

    org.json.JSONObject makeRequest(String URL, String method, String[] headers){
    int reqType;

    switch(method.toUpperCase()){
        case "GET":
            reqType = Request.Method.GET;
            break;
        case "DELETE":
            reqType = Request.Method.DELETE;
            break;
        default:
            return null;
    }
    Response.Listener<JSONObject> listener = new Response.Listener<JSONObject>(){
        @Override
        public void onResponse(JSONObject Response){
            result = Response;
        }
    };
    Response.ErrorListener err = new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            result = null;
        }
    };
    JsonObjectRequest req = new JsonObjectRequest(reqType, URL, null, listener, err){
        @Override
        public Map<String, String> getHeaders() throws AuthFailureError {
            Map<String, String>  params = new HashMap<String, String>();
            params.put(headers[0], headers[1]);

            return params;
        }
    };
    ;
    rQ_volley.add(req);

    return result;
}

And additionally some code on where I access the method above

    JSONArray koordTargetArr = rBuild.makeRequestArr("https://nominatim.openstreetmap.org/search?q="+target+"&format=json&polygon=1&addressdetails=1", "get",headersLonLat);
    if(koordTargetArr != null) {
        JSONObject koordTargetOBJ = koordTargetArr.getJSONObject(0);
        koordTarget = koordTargetOBJ.getString("lon").concat(",").concat(koordTargetOBJ.getString("lat"));
    }
    else return 0;

I would appreciate any help you could give me on things like where I implement the AsyncTask and how I build one. I have experience in the async library in Node.js if that helps at all.

EDIT: This is NOT a duplicate of How to use java.net.URLConnection to fire and handle HTTP requests I already know how to send HTTP Requests, I don't know how to use android AsyncTask, HTTP Requests are NOT the topic of this question.

Possible duplicate of [How to use java.net.URLConnection to fire and handle HTTP requests](https://stackoverflow.com/questions/2793150/how-to-use-java-net-urlconnection-to-fire-and-handle-http-requests) — Joel, Jun 22 '19 at 19:18
Don't think so since the link you attached talks about HTTP requests and my question asks about AsyncTasks from android. Please read the whole question before accusing it of being a duplicate — Sepx3, Jun 22 '19 at 19:45

score 0 · Accepted Answer · answered Jun 22 '19 at 19:48

0

Have you considered using Retrofit?

It will handle, construction and deserialization of all your network needs without needing to use AsyncTask + custom utilities functions.

answered Jun 22 '19 at 19:48

Joel

838
5
12

I have not heard of it yet, I will look into it, thank you for the hint – Sepx3 Jun 22 '19 at 19:49
Great, if it solves your issue make sure to accept the answer so others in the community can benefit. – Joel Jun 22 '19 at 19:50

How to utilize AsyncTask for handling asynchronous RestRequests

1 Answers1