ios - 避免在iOS Swift中创建多个ViewController实例

在AppDelegate中，无论何时收到VoIP调用(推送通知)，都会调用以下函数，从而创建“VideoCallViewController”的多个实例

我使用了deinit(在VideoCallViewController中)，如下所示，检查在创建“VideoCallViewController”的新实例之前是否先初始化了“VideoCallViewController”的前一个实例，令我惊讶的是没有调用print("Deinitializing VC)，实例在内存中。

如果AppDelegate中已经存在VideoCallViewController的实例，如何显示VideoCallViewController及其导航 Controller 。

在VideoCallViewController中

deinit {
  print("Deinitializing VC)
}

在AppDelegate中

func pushRegistry(_ registry: PKPushRegistry, didReceiveIncomingPushWith payload: PKPushPayload, forType type: PKPushType) {

    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    videoVC = storyboard.instantiateViewController(withIdentifier: "VideoCallViewController") as! VideoCallViewController

    self.window = UIWindow(frame: UIScreen.main.bounds)
    self.window?.rootViewController = videoVC
    self.window?.makeKeyAndVisible()

}

最佳答案

可能的解决方案:创建对可为空的窗口的单例保持引用，以负责视频通话流程。在通知上更改可见窗口。在通话结束时-返回到应用程序主窗口。

例如。 :

class VideoCallManager {
    //MARK: - Singleton
    static let sharedInstance = VideoCallManager()
    private init() {}

    private var videoCallWindow: UIWindow?

    func navigateToVideoCallViewController() {
        if let window = self.videoCallWindow, window.keyWindow {
             //VideoCallViewController is displayed at the moment.
             return
        }

        videoCallWindow = UIWindow.init(frame: UIScreen.mainScreen().bounds)
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        videoVC = storyboard.instantiateViewController(withIdentifier: "VideoCallViewController") as! VideoCallViewController

        self.videoCallWindow?.rootViewController = videoVC
        self.videoCallWindow?.makeKeyAndVisible()
    }

    func returnToWindowOfAppDelegate() {
        if let window = self.videoCallWindow, window.keyWindow {
            (UIApplication.sharedApplication().delegate as? AppDelegate)?.window?.makeKeyAndVisible()

            self.videoCallWindow = nil
        }
    }
}

您的方法将如下所示:

func pushRegistry(_ registry: PKPushRegistry, didReceiveIncomingPushWith payload: PKPushPayload, forType type: PKPushType) {
    VideoCallManager.sharedInstance.navigateToVideoCallViewController()
}