How to find out what UITextField caused a UIKeyboardWillShowNotification?

Question

I am trying to use a customized keyboard in my application, but I am hitting problems when trying to restrict it to one particular UITextField.

I based my code on this X

Answer 1

Couldn't get any of the above to work. Had to do it manually:

if ([companyName isFirstResponder]) {
    // ...............
}
else if ([notes isFirstResponder]) {
    //.............
    }
}