ios - 从扩展中获取 ViewController 的实例

Question

我想从扩展访问ViewController，然后重写库中的函数，该函数应该更改变量或从特定的 ViewController(在本例中为“ViewController”)调用方法。

我该怎么做？还是有更推荐的选择？

(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ViewController 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.
        }
    }

发布通知

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

---

协议(protocol)

在 ViewController B 中创建协议(protocol)和弱变量

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

weak var delegate: ProtocolB?

当您从 A 呈现/推送 ViewController B 时

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

将协议(protocol)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)