title: download json using Ion library
body: <p>I'am working with ion for download image in my custom list, and it's work perfect! Now I want to use this lib for json. So I tried it, but it's not work.</p>
  
  <p>Anybody know why this sample code return NULL? Or how do it simple?</p>
  
  <pre><code>import android.support.v7.app.ActionBarActivity;
  import android.os.Bundle;
  
  import com.google.gson.JsonObject;
  import com.koushikdutta.async.future.FutureCallback;
  import com.koushikdutta.ion.Ion;
  
  
  public class MainActivity extends ActionBarActivity {
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
  
          Ion.with(this)
                  .load("http://api.androidhive.info/volley/person_object.json")
                  .asJsonObject()
                  .setCallback(new FutureCallback&lt;JsonObject&gt;() {
                      @Override
                      public void onCompleted(Exception e, JsonObject result) {
                          // do stuff with the result or error
                          System.out.println(result);
                      }
                  });
      }
  
  }
  </code></pre>