Question

这是我添加观察者的功能

func subscribeToKeyboardNotifications() {
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
}

但是.UIKeyboardWillShow给我一个错误

'UIKeyboardWillShow'已重命名为   'UIResponder.keyboardWillShowNotification'

将“ UIKeyboardWillShow”替换为   'UIResponder.keyboardWillShowNotification'

但是当我更换它

func subscribeToKeyboardNotifications() {
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIResponder.keyboardWillShowNotification, object: nil)
}

我收到此错误

表达式类型不明确，没有更多上下文

Answer 1

不带点

NotificationCenter.default.addObserver(self, 
selector: #selector(keyboardWillShow), 
name: UIResponder.keyboardWillShowNotification, object: nil)

Answer 2

let notificationCenter = NotificationCenter.default

notificationCenter.addObserver(forName: UIResponder.keyboardWillShowNotification, object: nil, queue: nil) { (notification) in
                self.keyboardWillShow(notification: notification)
            }
notificationCenter.addObserver(forName: UIResponder.keyboardWillHideNotification, object: nil, queue: nil) { (notification) in
                self.keyboardWillHide(notification: notification)
            }

Answer 3

只需导入模块UIKit，因为UIResponder是UIKit而不是Foundation模块的一部分

SWIFT 5代码

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        addObservers()
    }

    public func addObservers() {
        NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
    }

    @objc func handleKeyboardWillShow(_: Notification) {
        // Here handle keyboard
    }
}

Answer 4

我已经使用了它，并且工作得很好

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShowOrHide(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil);

我想在键盘显示时更改视图的框架

4 个答案: