如何仅使用代码在 iOS 应用程序中显示 ViewController？

Question

我想在我的应用中显示 ViewController 而不使用故事板入口点。

我确保删除了默认故事板入口点并且故事板 ID 和名称是正确的。当运行模拟器上的应用程序时，我得到的一切仍然只是黑屏。

这是我的 AppDelegate.swift 文件。

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.


        window = UIWindow(frame: UIScreen.main.bounds)

        let sb = UIStoryboard(name: "Main", bundle: nil)
        let initialViewController = sb.instantiateViewController(withIdentifier: "VC")


        window?.rootViewController = initialViewController
        window?.makeKeyAndVisible()




        return true
    }

    // MARK: UISceneSession Lifecycle

    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        // Called when a new scene session is being created.
        // Use this method to select a configuration to create the new scene with.
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }

    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
        // Called when the user discards a scene session.
        // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
        // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
    }


}

感谢各种帮助。

Answer 1

它与应用程序委托的 SceneDelegate 有点不同。您使用 UIWindowScene 来构造您的 UIWindow.

    let sb = UIStoryboard(name: "Main", bundle: nil)
    let initialViewController = sb.instantiateViewController(withIdentifier: "VC")

    if let windowScene = scene as? UIWindowScene {
        let window = UIWindow(windowScene: windowScene)
        window.rootViewController = initialViewController
        self.window = window
        window.makeKeyAndVisible()
    }

Answer 2

如果您使用的是 Viewcontrollers 和 xcode 11.3.1 或更高版本，请在创建新项目后按照以下步骤操作。

从 info.plist 中删除应用程序场景清单
删除SceneDelegate.swift文件
从 AppDelegate 文件中删除 Swift UI 相关方法。
删除ContentView.swift文件
新建ViewController文件文件>新建>Cocoa 触摸 Class
在 AppDelegate 文件中设置 MainViewController。

添加这个

window = UIWindow(frame: UIScreen.main.bounds)
   window!.rootViewController = MainViewController()
   window!.makeKeyAndVisible()
   window?.rootViewController = UINavigationController(rootViewController: MainViewController())

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