Onpostexecute Called Before Doinbackground Completes - Async Task

i have method like this : public void extractFiles() { AsyncTask extractionTask = new AsyncTask() { @Override

Solution 1:

publicvoidextractFiles() {
     new TheTask().execute(params);
}
classTheTaskextendsAsyncTask<Void,Void,Void>
{ 
     .......
}

You should call super first in

  @Override
    protectedvoidonPreExecute() 
      super.onPreExecute();
   }

Asynctask must be loaded on UI Thread. Asynctask onPreExecute() is inovked on the ui thread when asynctask is loaded. After which doInBAckground() is runs in the background thread. The result of doInBackground() is a parameter to onPostExecute().

When an asynchronous task is executed, the task goes through 4 steps:

1. onPreExecute(), invoked on the UI thread before the task is executed. This step is normally used to setup the task, for instance by showing a progress bar in the user interface.

2. doInBackground(Params...), invoked on the background thread immediately after onPreExecute() finishes executing. This step is used to perform background computation that can take a long time. The parameters of the asynchronous task are passed to this step. The result of the computation must be returned by this step and will be passed back to the last step. This step can also use publishProgress(Progress...) to publish one or more units of progress. These values are published on the UI thread, in the onProgressUpdate(Progress...) step.

3. onProgressUpdate(Progress...), invoked on the UI thread after a call to publishProgress(Progress...). The timing of the execution is undefined. This method is used to display any form of progress in the user interface while the background computation is still executing. For instance, it can be used to animate a progress bar or show logs in a text field.

4. onPostExecute(Result), invoked on the UI thread after the background computation finishes. The result of the background computation is passed to this step as a parameter.

http://developer.android.com/reference/android/os/AsyncTask.html

Solution 2:

check your condition in doinbackground completely perform your operation or not if perform then return true,

zhelper.unzip(xapkFilePath, exportDirectoryFilepath);

Solution 3:

I solved a very similar problem by declaring both doInBackground and onPostExecute synchronized. (...) protected synchronized Boolean doInBackground(Void... params) {...} protected synchronized void onPostExecute(Boolean result) {...} (...) In my case, doInBackground() was entering first (as it should) but somehow onPostExecute() was called before doInBackground() "technically" completed (I couldnt figure out why - maybe my unzip library objects had its own threads and did not block the doInBackground() method). Synchronizing the methods solved the problem (not without performance consequences, of course)