iOS13外部屏幕镜像，出现错误:不应调用setScreen [英] iOS13 external screen mirroring, getting error: setScreen should not be called

问题描述

我正在尝试向iOS 13中的外部连接屏幕呈现自定义视图控制器.我遵循了本教程:

I am trying to present a custom view controller to external connected screen in iOS 13. I followed this tutorial:

http://www.spazstik-software.com/blog/article/how-to-display-custom-content-on-a-external-screen-from-a-ios-device a>

我有以下代码:

/// A private method used to setup a external screen with a window
/// loaded with a ExternalScreenViewController
///
/// - parameter screen: A UIScreen object to connect the
/// ExternalScreenViewController too
private func setupExternalScreen(screen: UIScreen) {
  guard externalWindow == nil,
    let vc = self.storyboard?.instantiateViewControllerWithIdentifier("ExternalScreen") as? ExternalScreenViewController else {
      return
  }

  externalWindow = UIWindow(frame: screen.bounds)
  externalWindow!.rootViewController = vc
  externalWindow!.screen = screen
  externalWindow!.hidden = false
}

在 externalWindow！.screen = screen 行中，我在Xcode 11.4.1控制台中遇到错误:

In the line externalWindow!.screen = screen I am getting an error in the Xcode 11.4.1 console:

[声明] UIKit客户端中的错误:-如果客户端采用UIScene生命周期，则不应调用-[UIWindow setScreen:].呼叫-[UIWindow setWindowScene:].

自定义视图控制器未显示在外部显示器中.

The custom view controller does not show up in the external display.

我应该改变什么?我想同时处理iOS 13.x和以前的设备.

What should I change? I want to handle both iOS 13.x and prior devices.

推荐答案

在iOS 13设备中，应在上设置 windowScene ，而不是设置 screen externalWindow 对象.在此之前，您应该从 UIApplication 的连接场景中找到匹配的 windowScene .修改后的方法如下:

In iOS 13 devices, instead of setting screen, you should set windowScene on the externalWindow object. Before that, you should find out matching windowScene from UIApplication's connected scenes. The revised method is as follows:

private func setupExternalScreen(screen: UIScreen, shouldRecurse: Bool = true) {
    // For iOS13 find matching UIWindowScene
    var matchingWindowScene: UIWindowScene? = nil
    if #available(iOS 13.0, *) {
        let scenes = UIApplication.shared.connectedScenes
        for aScene in scenes {
            if let windowScene = aScene as? UIWindowScene {
                // Look for UIWindowScene that has matching screen
                if (windowScene.screen == screen) {
                    matchingWindowScene = windowScene
                    break
                }
            }
        }
        if matchingWindowScene == nil {
            // UIWindowScene has not been created by iOS rendered yet
            // Lets recall self after delay of two seconds
            if true == shouldRecurse {
                DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 2) {
                    self.setupExternalScreen(screen:screen, shouldRecurse: false)
                }
            }
            // Dont proceed furthure in iOS13
            return
        }
    }

    guard externalWindow == nil, let vc = self.storyboard?.instantiateViewControllerWithIdentifier("ExternalScreen") as? ExternalScreenViewController else {
      return
    }

    externalWindow = UIWindow(frame: screen.bounds)
    externalWindow!.rootViewController = vc
    if #available(iOS 13.0, *) {
        // Set windowScene here, no need to set screen
        externalWindow!.windowScene = matchingWindowScene
    } else {
        // Set screen the traditional way
        externalWindow!.screen = screen
    }
    externalWindow!.isHidden = false

}

注意:我们应该将 isHidden 设置为不建议使用 hidden .

Note: we should set isHidden as hidden is deprecated.

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