Android: how to disable controls during progress bar is active

I show my infinte progress bar in the action bar "as usual":

requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
...
setProgressBarIndeterminateVisibility(true);
...
setProgressBarIndeterminateVisibility(false);

and the real work is done in a background thread (AsyncTask)

The problem: all controls on the UI are enabled, so the user can continue to modify the underlying data before the long lasting process is finished.

Simply disabling all controls is not possible because when disabling an EditText, also the keyboard is closed automatically by Android.

Any ideas how to prevent user input during the background work?

Thanks,

Chris