键盘的监听事件，获取键盘变动的坐标

func addCustomKeyboardEvent() {

        NSNotificationCenter.defaultCenter().removeObserver(self)

        NSNotificationCenter.defaultCenter().addObserver(self, selector:
#selector(WebCommentController.keyboardWillChange(_:)), name:
UIKeyboardWillChangeFrameNotification, object:
nil)

        NSNotificationCenter.defaultCenter().addObserver(self, selector:
#selector(WebCommentController.keyboardWillShow), name:
UIKeyboardWillShowNotification, object:
nil)

        NSNotificationCenter.defaultCenter().addObserver(self, selector:
#selector(WebCommentController.keyboardDidHide), name:
UIKeyboardDidHideNotification, object:
nil)

        

    }

func keyboardWillChange(sender:
NSNotification) {

        

        let userInfo:
NSDictionary = sender.userInfo!

        

        let duration = userInfo[UIKeyboardAnimationDurationUserInfoKey]!.doubleValue

        let keyboardFrame = userInfo[UIKeyboardFrameEndUserInfoKey]!.CGRectValue

}