swift获取键盘高度

NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillAppear:", name: UIKeyboardWillShowNotification, object: nil)

NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillDisappear:", name:UIKeyboardWillHideNotification, object: nil)

func keyboardWillAppear(notification: NSNotification) {

        // 获取键盘信息
        let keyboardinfo = notification.userInfo![UIKeyboardFrameBeginUserInfoKey]

        let keyboardheight:CGFloat = (keyboardinfo?.CGRectValue.size.height)!

        print("键盘弹起")

        print(keyboardheight)

    }

    func keyboardWillDisappear(notification:NSNotification){

        print("键盘落下")
    }