请求 JSON

final TextView mTxtDisplay = (TextView) findViewById(R.id.txtDisplay);
ImageView mImageView;
String url = "http://ip.jsontest.com/";

final 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) {
        // ...
    }
});

requestQueue.add(jsObjRequest);