android AsyncTask with activity lifecycle

Question

Am using AsyncTask in order to download images within my activity

the flow goes like this:

protected void onPreExecute() {
        \\begin animation
}

protected IUpiResponse doInBackground(String... params) {
         \\ download the image
}

protected void onPostExecute(IUpiResponse upiResponse) {
         \\stop the animation
}

till here everything fine, the problem start if i go to background while the asynctask is working sometimes I get an exception nullpointer in the animation stops, because the views no longer valid (i guess),

I can check before the stop animation if the activity is in foreground but i prefer to avoid this approach, what else i can do ?

Answer 1

I prefer to avoid the asyncTask approach and to download the images in a simple thread, which also saves them to persistence layer such as file system, and then sends an Intent ,

Note: if the activity in the background the Intent ( if you register and unregister your receiver in onResume and onPause as advised ) will not be received so to avoid such cases inside onResume you can check if there is update waiting for you