Question

我有一个使用UIKeyboardWillShow＆amp;在几个不同的控制器中隐藏通知。我决定尝试整合将键盘视图移动到基于协议的扩展所需的逻辑。

这是我的协议

public protocol KeyboardType : class {
    func keyboardWillShow(_ sender: Notification)
    func keyboardWillHide(_ sender: Notification)
}

接下来，我为我的新协议添加了一个扩展，以便我需要做的就是实现我的“KeyboardType协议，我将获得访问必要的功能，以便用键盘移动我的视图：

这是我的扩展程序

public extension KeyboardType where Self: UIViewController {

    func addObservers() { 
        NotificationCenter.default.addObserver(self, selector: #selector(Self.keyboardWillShow(_:)), name:NSNotification.Name.UIKeyboardWillShow, object: self.view.window)
        NotificationCenter.default.addObserver(self, selector: #selector(Self.keyboardWillHide(_:)), name:NSNotification.Name.UIKeyboardWillHide, object: self.view.window)
    }

    func removeObservers() {
        NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: self.view.window)
        NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: self.view.window)

    }

    func keyboardWillHide(_ sender: Notification) {
        let userInfo: [AnyHashable : Any] = (sender as NSNotification).userInfo!
        let keyboardSize: CGSize = (userInfo[UIKeyboardFrameBeginUserInfoKey]! as AnyObject).cgRectValue.size
        self.view.frame.origin.y += keyboardSize.height
    }

    func keyboardWillShow(_ sender: Notification) {
        let userInfo: [AnyHashable : Any] = sender.userInfo!

        let keyboardSize: CGSize = (userInfo[UIKeyboardFrameBeginUserInfoKey]! as AnyObject).cgRectValue.size
        let offset: CGSize = (userInfo[UIKeyboardFrameEndUserInfoKey]! as AnyObject).cgRectValue.size

        if keyboardSize.height == offset.height {
            if self.view.frame.origin.y == 0 {
                UIView.animate(withDuration: 0.1, animations: { () -> Void in
                    self.view.frame.origin.y -= keyboardSize.height
                })
            }
        } else {
            UIView.animate(withDuration: 0.1, animations: { () -> Void in
                self.view.frame.origin.y += keyboardSize.height - offset.height
            })
        }
    }

}

问题

问题是编译器要求我将@objc添加到我的keyboardWillShow和keyboardWillHide方法中。当我允许Xcode添加关键字时，编译器立即要求我删除@objc关键字。

'#selector'的参数是指实例方法'keyboardWillShow' 没有暴露于Objective-C

我的问题

在这种情况下，如何将keyboardWillShow暴露给Objective-C？

或

有没有更好的方法来完成同样的任务？

Answer 1

你试过这个吗？：

@objc public protocol KeyboardType {
    func keyboardWillShow(_ sender: Notification)
    func keyboardWillHide(_ sender: Notification)
}

您还需要导入UIKit

Answer 2

我会采用不同的方法扩展UIViewController，如下所示：

protocol KeyboardController {
    func keyboardWillShow(_ sender: Notification)
    func keyboardWillHide(_ sender: Notification)
}

extension UIViewController: KeyboardController {
    func addObservers() {
        NotificationCenter.default.addObserver(self,
                                               selector: #selector(keyboardWillShow(_:)),
                                               name:.UIKeyboardWillShow,
                                               object: view.window)
        NotificationCenter.default.addObserver(self,
                                               selector: #selector(keyboardWillHide(_:)),
                                               name:.UIKeyboardWillHide,
                                               object: view.window)
    }

    func removeObservers() {
        NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow, object: view.window)
        NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillHide, object: view.window)
    }

    func keyboardWillHide(_ notification: Notification) {
        print("---> keyboardWillHide")

        guard let userInfo = notification.userInfo else { return }
        let keyboardSize = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size
        print("keyboardSize", keyboardSize)

    }

    func keyboardWillShow(_ notification: Notification) {
        print("---> keyboardWillShow")
        guard

            let userInfo = notification.userInfo,
            let keyboardSize = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size,
            let offset = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue.size
        else { return }

        if keyboardSize.height == offset.height {
            if self.view.frame.origin.y == 0 {
                UIView.animate(withDuration: 0.1, animations: { () -> Void in
                    self.view.frame.origin.y -= keyboardSize.height
                })
            }
        } else {
            UIView.animate(withDuration: 0.1, animations: { () -> Void in
                self.view.frame.origin.y += keyboardSize.height - offset.height
            })
        }
    }

}

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        addObservers()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

另一个选项和我最喜欢的选项是子类UIViewController：

class KeyboardViewController: UIViewController {

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        addObservers()
    }
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        removeObservers()
    }

    func addObservers() {
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(_:)), name: .UIKeyboardWillShow, object: view.window)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(_:)), name: .UIKeyboardWillHide, object: view.window)
    }

    func removeObservers() {
        NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow, object: view.window)
        NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillHide, object: view.window)
    }

    func keyboardWillHide(_ notification: Notification) {
        print("---> keyboardWillHide")
        if let keyboardHeight = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size.height {
            print("keyboardHeight", keyboardHeight)
            view.frame.origin.y += keyboardHeight
        }
    }

    func keyboardWillShow(_ notification: Notification) {
        print("---> keyboardWillShow")
        if let userInfo = notification.userInfo,
            let keyboardHeight = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size.height,
            let offsetHeight = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue.size.height {
            print("userInfo", userInfo)
            print("keyboardHeight", keyboardHeight)
            print("offsetHeight", offsetHeight)
            if keyboardHeight == offsetHeight {
                if self.view.frame.origin.y == 0 {
                    UIView.animate(withDuration: 0.1, animations: { () -> Void in
                        self.view.frame.origin.y -= keyboardHeight
                    })
                }
            } else {
                UIView.animate(withDuration: 0.1, animations: { () -> Void in
                    self.view.frame.origin.y += keyboardHeight - offsetHeight
                })
            }
        }
    }
}

class ViewController:  KeyboardViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
       super.didReceiveMemoryWarning()
       // Dispose of any resources that can be recreated.
    }
}

在扩展方法中向Objective-C公开实例方法

我的问题

2 个答案: