Question

我正在尝试从Viewcontroller内部恢复模式SceneDelegate。

但是，此代码不允许模态视图控制器显示，并导致以下错误： "Unbalanced calls to begin/end appearance transitions for...".

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {

    if let userActivity = connectionOptions.userActivities.first ?? session.stateRestorationActivity {
        // Restoring Data and Modal VC:

        let storyboard = UIStoryboard(name: "Main", bundle: .main)
        let splitController =  storyboard.instantiateViewController(withIdentifier: "splitVC") 
        if let navigationController = window?.rootViewController as? UINavigationController {
             splitController.modalPresentationStyle = .fullScreen
             self.window?.makeKeyAndVisible()
             navigationController.present(splitController, animated: false, completion: nil)
        }
    } else {
        print("No User Activity")
        // Loads Initial VC
    }

}

有关如何解决此问题并从Viewcontroller呈现模态SceneDelegate的任何想法

Answer 1

当您尝试在呈现一个新UIViewController的动画完成之前加载它时，就会发生这种情况。您应该只在主线程上异步调用演示文稿：

DispatchQueue.main.async { navigationController.present(splitController, animated: false, completion: nil) }

模态视图控制器状态恢复SceneDelegate

1 个答案: