Synchronization with JSONObjectRequest (Android)

Question

I am making an Android app and I need to make a JSONObjectRequest to get a parameter (logo) from a package.json in a github repository.

This is the method where I make the JSON request

public void askLogoPath(String url) {

    JsonObjectRequest req = new JsonObjectRequest(url,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    try {
                        if (response.has("logo"))
                           Global.getInstance().setLogo(response.getString("logo"));
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }

                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            error.printStackTrace();
        }
    });

    // Adding request to request queue
    QueueController.getInstance().addToRequestQueue(req);

}

I have defined a variable (logo) in Global class that follows Singleton pattern, so I can access it everywhere in my program. After making this request, I want to set a variable with the value of logo.

This is the piece of code where I call the previous function.

if (full_name != null) {
        String url = "https://raw.githubusercontent.com/" + full_name + "/master/";
        this.askLogoPath(url + "package.json");
        this.setLogoPath(Global.getInstance().getLogo());
}

I have noticed that the onResponse part is the last one to be executed, so when I do setLogoPath(Global.getInstance.getLogo()) logo is still null, so I can't set logoPath in the previous line. I would like to wait until this is executed, so it won't be null.

Is there any way to make it synchronous so I can do this?

Thank you very much

Answer 1

It was solved by adding a callback. When the JSON request receives a response, it calls the onSuccess() method of the callback function, and in the main function the rest of the code is inside this onSuccess() method.