问题：

新建工程，选择最低支持iOS13报错：

'main()' is only available in iOS 14.0 or newer

'Scene' is only available in iOS 14.0 or newer

'WindowGroup' is only available in iOS 14.0 or newer

解决：

注释掉上面代码，重新创建一个AppDelegate作为入口：

import Foundation
import SwiftUI@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {var window: UIWindow?func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {// 创建一个UIHostingController来托管你的ContentViewlet contentView = ContentView()// 设置windowlet window = UIWindow(frame: UIScreen.main.bounds)window.backgroundColor = .whitewindow.rootViewController = UIHostingController(rootView: contentView)self.window = windowwindow.makeKeyAndVisible()return true}
}

info.plist中移除Application Scene Manifest

然后，重新运行就没问题了