从扩展中获取 ViewController 的实例

Question

我想从 extension[=21] ViewController access =] 然后覆盖库中的函数，该函数应更改变量或从特定 ViewController（在本例中为 "ViewController"）调用方法。

我该怎么做？或者有更推荐的选择吗？

（提示：我不想实例化一个新的 VC）

import PopupDialog class ViewController: UIViewController { //e.g. variable and method to access from extension var score: Int = 0; func startGame(){ ... } } extension PopupDialog{ open override func viewWillDisappear(_ animated: Bool) { //change variables //maybe also invoke methods } }

Answer 1

您可以使用 Notification 或 Protocol 在 ViewControllers

之间进行通信

通知示例：

创建一个扩展以使用通知名称：

extension Notification.Name {
    static let ScoreUpdateNotification = Notification.Name("ScoreUpdateNotification")
}

在 First ViewController 的 DidLoad

中添加 Observer 方法

NotificationCenter.default.addObserver(self, selector: #selector(triggerThisMethod), name: Notification.Name.ScoreUpdateNotification, object: nil)

@objc func triggerThisMethod(_ notification: NSNotification) {
        // When the notification arrives, this method will be called
        if let object = notification.object {
            // If there is Object passed with notification you will get it here.
        }
    }

到Post通知

let objectToPass = 23
NotificationCenter.default.post(name: .ScoreUpdateNotification, object: objectToPass)

协议

在 ViewController B

中创建协议和弱变量

protocol ProtocolB: class {
    func didUpdateScore(_ score: Int)
}

weak var delegate: ProtocolB?

当你 Present/Push ViewController B 来自 A

let viewControllerB = // ...
viewControllerB.delegate = self
//present viewControllerB

将协议方法添加到 ViewController A

extension ViewController: ProtocolA {
    func didUpdateScore(_ score: Int) {
        // Do things
    }
}

触发方法调用：

delegate?.didUpdateScore(25)

从扩展中获取 ViewController 的实例

Get Instance of ViewController from within extension

extension-methods

viewcontroller

ios

swift

通知示例：

协议