I know a way to do this. Subclass the EditText and implement:
@Override
public boolean onKeyPreIme(int keyCode, KeyEvent event) {
if (event.getKeyCode() == KeyEvent.KEYCODE_BACK) {
// Do your thing.
return true; // So it is not propagated.
}
return super.dispatchKeyEvent(event);
}
Here is a link on how to use your custom views (for when you subclass EditText):
http://developer.android.com/guide/topics/ui/custom-components.html