The custom input view to display when the receiver becomes the first responder.
- iOS 3.2+
- tvOS 9.0+
The value of this read-only property is
nil. A responder object that requires a custom view to gather input from the user should redeclare this property as read-write and use it to manage its custom input view. When the receiver becomes the first responder, the responder infrastructure presents the specified input view automatically. Similarly, when the receiver resigns its first responder status, the responder infrastructure automatically dismisses the specified input view.