swift - iOS/swift : How to add one extension to multiple controllers?

Question

在一个名为 Extensions 的文件中，我尝试向 2 个 View Controller 添加一个扩展，这样我就不必将整个代码写两次。

import UIKit
extension TempConvertViewController {
// code
}

我需要为 LocationViewController 使用完全相同的代码。

如有任何帮助，我们将不胜感激!

编辑:谢谢大家的回应。

我想要实现的是在 2 个 Controller 中重用相同的键盘/ View 代码，因为它们都包含文本字段。我扩展 TempConvertViewController 的原因是因为我有一个变量 (activeTextField)，如果我在 UIViewController 中实现它，它将无法识别。

如果我将代码放在一个函数中，keyboardDidShow() 和 keyboardWillHide() 函数将不会在 Controller 本身中被识别。我收到错误消息:使用未解析的标识符“keyboardDidShow(notification:)”，使用未解析的标识符“keyboardWillHide(notification:)”请参阅下面代码的第二部分

这里是TempConvertViewController的扩展

extension TempConvertViewController: UITextFieldDelegate {

    @objc func keyboardDidShow(notification: Notification) {
        let notificationInfo: NSDictionary = notification.userInfo! as NSDictionary
        let keyboardSize = (notificationInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
        let yKeyboard = view.frame.size.height - keyboardSize.height
        let yTextFieldEditing: CGFloat! = activeTextField?.frame.origin.y

        if view.frame.origin.y >= 0 {

            //checking if textField is covered by keyboard
            if yTextFieldEditing > yKeyboard - 60 {
                UIView.animate(withDuration: 0.25, delay: 0.0, options: UIViewAnimationOptions.curveEaseIn, animations:{self.view.frame = CGRect(x: 0, y: self.view.frame.origin.y -
                    (yTextFieldEditing! - (yKeyboard - 60)), width: self.view.bounds.width, height: self.view.bounds.height)}, completion: nil)
            }
        }
    }

    @objc func keyboardWillHide(notification: Notification) {
        UIView.animate(withDuration: 0.25, delay: 0.0, options: UIViewAnimationOptions.curveEaseIn, animations: { self.view.frame = CGRect(x: 0, y:0, width: self.view.bounds.width, height: self.view.bounds.height)}, completion: nil)
    }
    func textFieldDidBeginEditing(_ textField: UITextField) {
        activeTextField = textField
    }

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        self.view.endEditing(true)
    }
}

TempConvertViewController:

override func viewDidLoad() {
        super.viewDidLoad()

        // Subscribe to Notifications
        let center: NotificationCenter = NotificationCenter.default;
        center.addObserver(self, selector: #selector(keyboardDidShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        center.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }

如果我设法将所有内容都包含在一个函数中，例如keyboardViewManagement()，我不能像这样为另一个 View Controller (LocationChangeViewController) 使用新的扩展:

extension LocationChangeViewController: UITextFieldDelegate {

// calling the function
func keyboardViewManagement()

}

再次感谢大家!

Answer 1

利用协议(protocol)的力量，毕竟我们很快

protocol Extendable: class {
    var editingTextField: UITextField? { get }
    func someFunc()
}

extension Extendable where Self: UIViewController {
    func someFunc() {
        // yor implementation
    }
}

class ViewController: UIViewController {
    var editingTextField: UITextField? {
        return activeTextField
    }
}