如何在 XCode 中生成 iOS 13 SwiftUI 项目？

Posted 2023-02-24

【中文标题】如何在 XCode 中生成 iOS 13 SwiftUI 项目？

【英文标题】：How to generate iOS 13 SwiftUI project in XCode?

【发布时间】：2021-10-25 06:56:16

【问题描述】：

所以目前在 XCode 13 中，当我第一次创建项目时，xcode 会为 ios 14.0+ 生成项目结构。

我是 iOS 新手，我想创建一个针对 iOS 13.0+ 的项目。如何告诉 XCode 为 iOS 13.0+ 生成项目模板？

【问题讨论】：

他们不再提供“生命周期”。我认为可以通过此选项采用 Xcode 12 中的模板。

@Asperi Apple 真的让开发人员的生活变得艰难，哈哈。我想我必须在互联网上挖掘才能找到模板。感谢您的回复。

我认为从 developer.apple.com 下载 Xcode 12 并直接从中获取更快。

知道了。谢谢。

【参考方案1】：

将此添加到.swift 文件中

import UIKit
import SwiftUI

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate 
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool 
        // Override point for customization after application launch.
        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.
    


class SceneDelegate: UIResponder, UIWindowSceneDelegate 
    
    var window: UIWindow?
    
    
    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) 
        // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
        // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
        // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).
        
        // Create the SwiftUI view that provides the window contents.
        let contentView = ContentView()
        
        // Use a UIHostingController as window root view controller.
        if let windowScene = scene as? UIWindowScene 
            let window = UIWindow(windowScene: windowScene)
            window.rootViewController = UIHostingController(rootView: contentView)
            self.window = window
            window.makeKeyAndVisible()
        
    
    
    func sceneDidDisconnect(_ scene: UIScene) 
        // Called as the scene is being released by the system.
        // This occurs shortly after the scene enters the background, or when its session is discarded.
        // Release any resources associated with this scene that can be re-created the next time the scene connects.
        // The scene may re-connect later, as its session was not neccessarily discarded (see `application:didDiscardSceneSessions` instead).
    
    
    func sceneDidBecomeActive(_ scene: UIScene) 
        // Called when the scene has moved from an inactive state to an active state.
        // Use this method to restart any tasks that were paused (or not yet started) when the scene was inactive.            
    
    
    func sceneWillResignActive(_ scene: UIScene) 
        // Called when the scene will move from an active state to an inactive state.
        // This may occur due to temporary interruptions (ex. an incoming phone call).
        
    
    
    func sceneWillEnterForeground(_ scene: UIScene) 
        // Called as the scene transitions from the background to the foreground.
        // Use this method to undo the changes made on entering the background.
    
    
    func sceneDidEnterBackground(_ scene: UIScene) 
        // Called as the scene transitions from the foreground to the background.
        // Use this method to save data, release shared resources, and store enough scene-specific state information
        // to restore the scene back to its current state.
    
    
    

然后更改Info.plist中的Application Scene Manifest条目

确保您删除/注释掉 @main 并且应用以 ContentView 开头

【参考方案2】：

我已经通过以下方法创建了一个兼容 iOS 13 的 SwiftUI 项目。这对于 iOS 13 有一个块，对于 iOS 14+ 有另一个块

第 0 步：使用 XCode 创建 SwiftUI 项目

这将有一个主 swift 文件和一个 ContentView.swift。

// ContentView.swift

import SwiftUI

struct ContentView: View 
    var body: some View 
        Text("Hello")
    


struct ContentView_Previews: PreviewProvider 
    static var previews: some View 
        ContentView()
    

第1步：更新Info.plist如下。

第 2 步：使用以下代码更新主 swift 文件。

import UIKit
import SwiftUI

@main
struct MainApp 
    static func main() 
        if #available(iOS 14.0, *) 
            MyView.main()
         else 
            UIApplicationMain(
                CommandLine.argc,
                CommandLine.unsafeArgv,
                nil,
                NSStringFromClass(AppDelegate.self))
        
    


@available(iOS 14.0, *)
struct MyView: App 
    var body: some Scene 
        WindowGroup 
            ContentView() // Add another view with content Text("From iOS 14+") to test both block runs
        
    


class AppDelegate: UIResponder, UIApplicationDelegate 
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool 
        return true
    

    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration 
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    

    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) 
    



class SceneDelegate: UIResponder, UIWindowSceneDelegate 

    var window: UIWindow?


    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) 
        let contentView = ContentView() // Add another view with content Text("From iOS 13") to test both block runs

        if let windowScene = scene as? UIWindowScene 
            let window = UIWindow(windowScene: windowScene)
            window.rootViewController = UIHostingController(rootView: contentView)
            self.window = window
            window.makeKeyAndVisible()
        
    

    func sceneDidDisconnect(_ scene: UIScene) 
        //
    

    func sceneDidBecomeActive(_ scene: UIScene) 
        //
    

    func sceneWillResignActive(_ scene: UIScene) 
       //
    

    func sceneWillEnterForeground(_ scene: UIScene) 
       //
    

    func sceneDidEnterBackground(_ scene: UIScene) 
        //
    

第 3 步：测试

从XCode -> Preferences -> Components安装iOS 13模拟器 为 iOS 13 和 iOS 14 创建两个单独的视图文件，然后从主 swift 文件中调用它。 测试和验证后，只需使用单一视图文件即可。 对代码块使用if #available(iOS 14, *) 条件，对类或其他对象使用@available(iOS 15, *)。