Getting null pointer exception on getting Async Task JSON using Android

Question

I'm getting a NullPointerException when I try to request a JSON with AsyncTask. I'm using loopj and AsyncTask

Here's my code:

 String str = null;   
    public class MainActivity extends Activity {
       @Override
       protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        new TheTask().execute();
       }

       class TheTask extends AsyncTask<Void, Void, String> {
         @Override
         protected String doInBackground(Void... params)  {

          try{
            AsyncHttpClient client = new AsyncHttpClient();
            client.addHeader("Authorization", "Token token=Wa5sfwP3ku7c15qkZTsd**");
            client.get("http://*********.com/api/v1/***", new AsyncHttpResponseHandler() {
                @Override
                public void onSuccess(String response) {
                    str = response;
                   Log.v("==========RESULT==========", response); 
                }
             });
          } catch(Exception e){
             Log.v("========== ERROR ==========", e.toString());
          }
          return str;   
        }

        @Override
        protected void onPostExecute(String result) {
          TextView txt = (TextView) findViewById(R.id.textView1);
          txt.setText("Result: " + result);   
        }
       }
    }

@Raghunandan updated my question. Is the onPostExecute means that the async is finished? — AllenC
– AllenC, Commented Mar 30, 2014 at 7:21
@Emmanuel java.lang.NullPointerException: println needs a message — AllenC
– AllenC, Commented Mar 30, 2014 at 7:22

agamov · Accepted Answer · 2014-03-30 07:30:46Z

3

You are doing it wrong. In your doInBackground() method you should use synchronous methods, and you are using asynchronous:

 client.get("http://*********.com/api/v1/***", new AsyncHttpResponseHandler() {
                @Override
                public void onSuccess(String response) {
                    str = response;
                   Log.v("==========RESULT==========", response); 
                }

That's why your doInBackground() returns null, and you are trying to deal with null in onPostExecute()

You should use methods from class SyncHttpClient from Loopj-Async library.

answered Mar 30, 2014 at 7:30

agamov

4,4371 gold badge30 silver badges31 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Getting null pointer exception on getting Async Task JSON using Android

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related