How to get JsonArray from a class who AsyncTask

Question

I\'m trying to create a class to retrieve a JsonArray from a url. This class extends AsyncTask to avoid creating multiple AsyncTasks on interfaces.

The class works fin

Answer 1

You need to use a callback. Simply add the following…

variable:

private Callback callback;

inner-interface:

public interface Callback{
    public void call(JSONArray array);
}

constructor:

public QueryJsonArray(Callback callback) {
    this.callback = callback;
}

Additionally, change your class declaration to:

public class QueryJsonArray extends AsyncTask<Void, Void, JSONArray>

and change the return type of doInBackground to JSONArray.

At the end of doInBackground, add:

return jsonRetorno;

Finally, add the following method with contents:

public void onPostExecute(JSONArray array) {
    callback.call(array);
}

---

Now, to execute the task, just do:

QueryJsonArray obj = new QueryJsonArray(new Callback() {
    public void call(JSONArray array) {
        //TODO: here you can handle the array
    }
});
JSONArray jArray = obj.execute(myUrl);

---

As a side note, you could greatly simplify all of this using a third party library, such as droidQuery, which would condense all of the above code to:

$.ajax(new AjaxOptions().url(myUrl).success(new Function() {
    public void invoke($ d, Object… args) {
        JSONArray array = (JSONArray) args[0];
        //TODO handle the json array.
    }
});