private func addNotificationObserver() {
NSNotificationCenter.defaultCenter().addObserver(self, selector:#selector(Class.keyboardWillShow(_:)), name:UIKeyboardWillShowNotification, object:nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector:#selector(Class.keyboardWillHidden(_:)), name:UIKeyboardWillHideNotification, object:nil)
}
@objc private funckeyboardWillShow(notify:NSNotification) {
print("show+++")
}
@objcprivatefunckeyboardWillHidden(notify:NSNotification) {
print("hidden+++")
}