Swift3.0 键盘高度监听获取

方法:通过通知监听键盘的动态

1.键盘的动态有四种:

 public static let UIKeyboardWillShow: NSNotification.Name

    public static let UIKeyboardDidShow: NSNotification.Name

    public static let UIKeyboardWillHide: NSNotification.Name

    public static let UIKeyboardDidHide: NSNotification.Name

2.下面监听下弹出之前,和回收之前的事件

//键盘弹起
    @objc private func willShow(nottification:NSNotification){

        let info:NSDictionary = nottification.userInfo as NSDictionary!
//        print(info)
       //通过输出看到下面的信息

         /*
Optional([AnyHashable("UIKeyboardCenterBeginUserInfoKey"): NSPoint: {207, 849},

AnyHashable("UIKeyboardIsLocalUserInfoKey"): 1,

AnyHashable("UIKeyboardCenterEndUserInfoKey"): NSPoint: {207, 623},

AnyHashable("UIKeyboardBoundsUserInfoKey"): NSRect: {{0, 0}, {414, 226}},

AnyHashable("UIKeyboardFrameEndUserInfoKey"): NSRect: {{0, 510}, {414, 226}},

AnyHashable("UIKeyboardAnimationCurveUserInfoKey"): 7,

AnyHashable("UIKeyboardFrameBeginUserInfoKey"): NSRect: {{0, 736}, {414, 226}},
            
AnyHashable("UIKeyboardAnimationDurationUserInfoKey"): 0.25])
 */

        //取出键盘的高度
        let keyValue = info.object(forKey: "UIKeyboardFrameEndUserInfoKey")
        let keyRect = (keyValue as AnyObject).cgRectValue
        let height = keyRect?.size.height
        print(height!)

    }

    //键盘收起
    @objc private func willHide(nottification:NSNotification){

    }