Android Back Button and Progress Dialog

Question

I have an AsyncTask that shows a progressDialog whilst working (it calls runOnUiThread from within doInBackground to show the progress dialog).

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Answer 1

Treating back button like a cancellation is not the correct way.
Cancellation also occurs when a user touches the screen outside of the dialog box. You want to differentiate those two actions, no?

Correct approach would be to extend the ProgressDialog class and override the onBackPressed method.

private class SubProgressDialog extends ProgressDialog {
    public SubProgressDialog(Context context) {
        super(context);
    }
    @Override
    public void onBackPressed() {
        /** dismiss the progress bar and clean up here **/
    }
}


public void displayProgressBar(){
    progressBar = new SubProgressDialog(this);
    progressBar.setProgressStyle(ProgressDialog.STYLE_SPINNER);
    progressBar.setCancelable(false);
    progressBar.setMessage(getString(R.string.authorizing));        
    progressBar.show();   
    new Thread(new Runnable() {
      public void run() {
      }
       }).start();     

}

Notice the setCancelable(false), again emphasizing that back button is different than a simple cancellation.
Also this will effecitvely ignore any other touch inputs from the user.