static void aOnChange(final TextView tv, fO r) {
  androidUI(r {
    tv.addTextChangedListener(new TextWatcher {
     public void afterTextChanged(Editable s) { pcallF(r); }
     public void beforeTextChanged(CharSequence s, int start,
       int count, int after) {}
     public void onTextChanged(CharSequence s, int start,
       int before, int count) {}
    });
  });
}