Question

I’m using Android-Query for the first time and I understand that it (takes care of the asynchronous tasks for you?) and simplifies/reduces code writing. Correct me if I’m wrong about the asynchronous tasks.

Also, if I am wrong, please help me write the method below so it is on another thread; I cant get it to work either way I do it.

I’m getting the following NPE:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.andaero.app/com.andaero.app.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
at android.app.ActivityThread.access$600(ActivityThread.java:123)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4424)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:787)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:554)at dalvik.system.NativeStart.main(Native Method)
--->Caused by: java.lang.NullPointerException
at com.andaero.app.utili.AsyncJSON.async_list_array(AsyncJSON.java:24)
at com.andaero.app.MainActivity.onCreate(MainActivity.java:84)
at android.app.Activity.performCreate(Activity.java:4465)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)

Within my MainActivity:

import com.androidquery.AQuery;
import com.androidquery.callback.AjaxCallback;
import com.androidquery.callback.AjaxStatus;
 ...
 AQuery aq;
 String json = null;

public class MainActivity extends Activity implements AnimationLayout.Listener
{
 @Override
 public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        ...
        AsyncJSON.async_list_array();
    }
}

My AsyncJSON class:

 public class AsyncJSON
 {
    static AQuery aq = null;
    static JSONArray jArray;
    String json = null;

public static void async_list_array()
{

String url = "http://192.168.1.34/Andaero/php/regulatory_list.php";
aq.ajax(url, JSONArray.class, new AjaxCallback<JSONArray>()
{

    @Override
    public void callback(String url, JSONArray json, AjaxStatus status)
    {

    if (json != null)
    {

    // successful ajax call, show status code, json content
    //jsonListCallback(json);
    Toast.makeText(aq.getContext(), status.getCode() + ":" + json.toString(), Toast.LENGTH_LONG).show();

    } else
    {

    // ajax error, show error code
    Toast.makeText(aq.getContext(), "Error:" + status.getCode(), Toast.LENGTH_LONG).show();
    }
    }
});
}

I took this code directly from their example but I cant see what I have wrong.

Thnx for your help.

Answer 1

It looks like you never initialized aq, so it’s null.