Returns a Boolean value indicating whether the receiver is willing to relinquish first-responder status.
- iOS 10.0+
- tvOS 10.0+
YES if the receiver can resign first-responder status,
This method returns
YES by default. You can override this method in your custom responders and return a different value if needed. For example, a text field containing invalid content might want to return
NO to ensure that the user corrects that content first.