How to determine the active textfield

Question

How to determine which text field is active ? (which one have the focus on it).

I found this code in objective-C but don't know how if it is still working and how to translate it in swift

NSResponder *firstResponder = [[NSApp keyWindow] firstResponder];
    if ([firstResponder isKindOfClass:[NSText class]] && [(id)firstResponder delegate] == mySearchField) {
    NSLog(@"Yup.");
}

Answer 1

Here you go:

var responder = window.firstResponder
if responder.isKind(of: NSText.self) {
    let fieldEditor = responder as! NSText
    responder = fieldEditor.delegate as! NSResponder
}

At the end is responder the focused control. If the focused control is a NSTextField then the first responder is the field editor, a NSTextView inside the text field. The delegate of the field editor is the control.