iOS13外部屏幕镜像，出现“不应调用setScreen”错误

Question

我正在尝试将自定义视图控制器呈现给iOS 13中的外部连接屏幕。我遵循了本教程：

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

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[C0行中，我在Xcode 11.4.1控制台中收到错误：

[Assert] 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：]。调用-[UIWindow setWindowScene：]。

自定义视图控制器未显示在外部显示器中。

我应该改变什么？我想同时处理iOS 13.x和以前的设备。

Answer 1

[在iOS 13设备中，不要设置externalWindow!.screen = screen，而应在screen对象上设置windowScene。在此之前，您应该从externalWindow的连接场景中找出匹配的windowScene。修改后的方法如下：

UIApplication

注意：我们建议将

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
    var sceneHasBeenSet = false
    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) {
                    // Set windowScene here, no need to set screen
                    externalWindow!.windowScene = windowScene
                    sceneHasBeenSet = true
                }
            }
        }
    }
    if false == sceneHasBeenSet {
        // Set screen the traditional way
        externalWindow!.screen = screen
    }
    externalWindow!.isHidden = false

}

设置为不推荐使用isHidden。