Request JSON

https://developer.android.com/training/volley/request.html

Request JSON
Volley provides the following classes for JSON requests:

JsonArrayRequest—A request for retrieving a JSONArray response body at a given URL.
JsonObjectRequest—A request for retrieving a JSONObject response body at a given URL, allowing for an optional JSONObject to be passed in as part of the request body.
Both classes are based on the common base class JsonRequest. You use them following the same basic pattern you use for other types of requests. For example, this snippet fetches a JSON feed and displays it as text in the UI:

TextView mTxtDisplay;
ImageView mImageView;
mTxtDisplay = (TextView) findViewById(R.id.txtDisplay);
String url = "http://my-json-feed";

JsonObjectRequest jsObjRequest = new JsonObjectRequest
        (Request.Method.GET, url, null, new Response.Listener<JSONObject>() {

    @Override
    public void onResponse(JSONObject response) {
        mTxtDisplay.setText("Response: " + response.toString());
    }
}, new Response.ErrorListener() {

    @Override
    public void onErrorResponse(VolleyError error) {
        // TODO Auto-generated method stub

    }
});

// Access the RequestQueue through your singleton class.
MySingleton.getInstance(this).addToRequestQueue(jsObjRequest);

For an example of implementing a custom JSON request based on Gson, see the next lesson, Implementing a Custom Request.