如何在 Swift 3 中编写键盘通知 [英] How to write Keyboard notifications in Swift 3

问题描述

我正在尝试将此代码更新为 swift 3:

I'm trying to update this code to swift 3:

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

NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name: UIKeyboardWillHideNotification, object: nil)`

到目前为止，我刚刚尝试了编译器给出的自动更正.结果是这样的代码:

So far, I've just tried the auto corrections given by the compiler. This results in code like this:

let notificationCenter = NotificationCenter.default()
notificationCenter.addObserver(self, selector: Selector(("keyboardWillShow:")), name: NSNotification.Name.UIKeyboardWillShow, object: nil)

notificationCenter.addObserver(self, selector: Selector(("keyboardWillHide:")), name: NSNotification.Name.UIKeyboardWillHide, object: nil)`

不幸的是，这并没有让我走多远，导致了额外的错误.

Unfortunately, that doesn't take me far, resulting in additional errors.

请问有人解决了吗?

请注意，我只是在尝试如何编写通知.我还没有(还)试图修复通知功能..谢谢

Please note that I'm just trying how to write the notifications. I'm not (yet) trying to fix the notification functions.. Thanks

推荐答案

Swift 4

override func viewDidLoad() {
    super.viewDidLoad()   
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}

func keyboardWillShow(notification: NSNotification) {
     print("keyboardWillShow")
}

func keyboardWillHide(notification: NSNotification){
     print("keyboardWillHide")
}

deinit {
     NotificationCenter.default.removeObserver(self)
}

您还可以在这些方法中使用以下代码获取键盘信息.

You can also get keyboard info using below code inside these methods.

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange), name: .UIKeyboardWillChangeFrame, object: nil) .      

@objc func keyboardWillChange(notification: NSNotification) {
     let duration = notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double
     let curve = notification.userInfo![UIKeyboardAnimationCurveUserInfoKey] as! UInt
     let curFrame = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
     let targetFrame = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
     let deltaY = targetFrame.origin.y - curFrame.origin.y
 }

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