android - AsyncTask onPostExecute never gets called

Question

I am not sure what I am doing wrong but onPostExecute never gets called.

• Created a base class called BaseActivity.java
• From my original Activity I extended this class.
• Placed PostToOpenFeint class inside BaseActivity

• Called it from the UI thread from the main activity my doing:

  new PostToOpenFeint.execute();
  

The onPreExecute(), doInBackground(..) gets triggered, but for some reason the onPostExecute never gets called.

Thank you in Advance!

Dave

 private class PostToOpenFeint extends AsyncTask<Void, Void, Void> {
  /*
   * (non-Javadoc)
   * 
   * @see android.os.AsyncTask#doInBackground(Params[])
   */
  @Override
  protected Void doInBackground(Void... params) {
   // does all the work here
   return null;
  }


  /*
   * (non-Javadoc)
   * 
   * @see android.os.AsyncTask#onPostExecute(java.lang.Object)
   */
  @Override
  protected void onPostExecute(Void result) {
   // TODO Auto-generated method stub
   super.onPostExecute(result);
   Toast.makeText(MainScreen.this, "Done syncing", Toast.LENGTH_LONG).show();
  }

  /*
   * (non-Javadoc)
   * 
   * @see android.os.AsyncTask#onPreExecute()
   */
  @Override
  protected void onPreExecute() {
   // TODO Auto-generated method stub
   super.onPreExecute();
   Toast.makeText(MainScreen.this, "About to sync all your scores", Toast.LENGTH_LONG).show();
  }

---

Looking into it more, this is what I was able to observe. For example if I place this call:

 new PostToOpenFeint.execute();

right after onCreate of the Activity, then everything works fine. If I place this call say inside a button listener.

settingsButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
   new PostToOpenFeint.execute();
}
});

The onPostExecute() never gets called, not sure what I am doing wrong. The restriction I read was to call this from UI Thread and I am calling it from UI thread.

question from:https://stackoverflow.com/questions/4494720/asynctask-onpostexecute-never-gets-called

Answer 1

I had a similiar problem just now. I was extending AsyncTask<Integer,Integer,Integer> and my onPostExecute method looked like:

protected void onPostExecute(int result)

This seemed OK to me, but then again I'm more of a .NET guy than a Java guy. I changed it to:

protected void onPostExecute(Integer result)

because for some reason Java thinks there is a difference between int and Integer?

I think that your problem is that you're declaring the return type as void in your:

extends<Void,Void,Void>

That means no params, no progress and no result. If you want to execute something when it's done, I think you need to give it some kind of value like and integer or a boolean.

If you change your extends to:

<Void,Void,Integer>

Now your passing no params, not publishing any progress, but are returning a value. Change your onPostExecute method to accept an Integer:

protected void onPostExecute(Integer result)

Then change the return in your doInBackground method to something like:

return 1;

Then it should execute for you.