Gracefully handle IOException inside AsyncTask?

Issue

How to gracefully display a Toast when an IOException occurs inside the doInBackground of an AsyncTask?

Solution

You can override either onPostExecute or onProgressUpdate to display messages on the UI thread.

To use onProgressDisplay declare the second type as String when you extend AsyncTask:

private class YourTask extends AsyncTask<ParamType, String, ReturnType> {

and override onProgressUpdate:

protected void onProgressUpdate(String... progress) {
     String errMsg = progress[0];
     Toast.makeText(getApplicationContext(), errMsg, Toast.LENGTH_SHORT).show();
}

then you can call the "progress" function when your exception occurs in doInBackground:

protected ReturnType doInBackground(ParamType... params) {
     try {
         // do stuff
     } catch (IOException e) {
        publishProgress("My Error Msg goes here");
     }
     return result;
 }

Answered By - Rob