SwiftUI应用生命周期iOS14在哪里放置AppDelegate代码？

Question

现在AppDelegate和SceneDelegate已从SwiftUI中删除了，我应该将以前使用的代码放在exSceneDelegate和AppDelegate的Firebase配置中？

所以我的AppDelegate中目前有以下代码：

我现在应该在哪里放置这段代码？

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.
    
    FirebaseConfiguration.shared.setLoggerLevel(.min)
    FirebaseApp.configure()
    return true
}

Answer 1

这是SwiftUI生命周期的解决方案。经过Xcode 12b / iOS 14的测试

import SwiftUI
import UIKit

// no changes in your AppDelegate class
class AppDelegate: NSObject, UIApplicationDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
        print(">> your code here !!")
        return true
    }
}

@main
struct Testing_SwiftUI2App: App {

    // inject into SwiftUI life-cycle via adaptor !!!
    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate

    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

Answer 2

在您的 {"params":"endpoint":"import","action":"main","authenticationToken":"myToken", "authenticationKey":"<myKey>","dataMain":[]},"tokenUsage":"requestsReadToday":"0","requestsWriteToday":"25","requestsReadInLastMinute":"1","requestsWriteInLastMinute":"0"},"tokenLimits":{"limitReadRequestsPerMinute":60,"limitReadRequestsPerDay":3000,"limitWriteRequestsPerMinute":60,"limitWriteRequestsPerDay":3000},"requestAction":"main","endpoint":"import","success":true,"customersImported":[{"CustomerID":"548745","PestRoutesCustomerID":"10109","Action":"Updated"}],"processingTime":"587 milliseconds","count":0} 中覆盖初始化程序似乎也可行：

App

Answer 3

您完全不应在应用程序委托中放入这种代码，否则您最终将面临Massive App Delegate。相反，您应该考虑将代码重构为更有意义的部分，然后将正确的部分放在正确的位置。对于这种情况，您唯一需要做的就是确保一旦应用准备好并且仅执行一次，代码便会执行这些功能。因此init方法可能很棒：

@main
struct MyApp: App {
    init() {
        setupFirebase()
    }

    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

private extension MyApp {
    func setupFirebase() {
        FirebaseConfiguration.shared.setLoggerLevel(.min)
        FirebaseApp.configure()
    }
}

---

AppDelegate吗？

您可以拥有自己的自定义类，并将其分配为delegate。但是请注意，它不适用于分配前发生的事件。例如：

class CustomDelegate: NSObject, UIApplicationDelegate {
    static let Shared = CustomDelegate()
}

后来：

UIApplication.shared.delegate = CustomDelegate.Shared

观察通知

实际上，大多数AppDelegate方法都在观察可以手动观察而不是定义新类的通知。例如：

NotificationCenter.default.addObserver(
    self,
    selector: #selector(<#T##@objc method#>),
    name: UIApplication.didBecomeActiveNotification,
    object: nil
)

---

本地AppDelegate包装器

您可以将应用程序委托直接注入到@main结构中：

@UIApplicationDelegateAdaptor(CustomDelegate.self) var appDelegate

注意：使用AppDelegate

请记住，添加AppDelegate意味着您正在终止默认的多平台支持，并且必须手动检查平台。

Answer 4

您还可以将新的ScenePhase用于AppDelegate和SceneDelegate所具有的某些代码。喜欢去后台或变得活跃。来自

struct PodcastScene: Scene {
    @Environment(\.scenePhase) private var phase

    var body: some Scene {
        WindowGroup {
            TabView {
                LibraryView()
                DiscoverView()
                SearchView()
            }
        }
        .onChange(of: phase) { newPhase in
            switch newPhase {
            case .active:
                // App became active
            case .inactive:
                // App became inactive
            case .background:
                // App is running in the background
            @unknown default:
                // Fallback for future cases
            }
        }
    }
}

示例功劳：https://wwdcbysundell.com/2020/building-entire-apps-with-swiftui/

Answer 5

请注意，以下方法将停止跨平台支持，因此仅在计划仅针对iOS进行构建时才应使用。

在Xcode 12-beta中创建SwiftUI应用时，您仍然可以拥有AppDelegate和SceneDelegate。

您只需要确保在创建应用时为生命周期选择了正确的选项。

确保为生命周期选择 UIKit App Delegate ，您将获得一个AppDelegate和一个SceneDelegate

Answer 6

我看到很多将 init 用作 didFinishLaunching 的解决方案。但是，在 didFinishLaunching 结构的 init 之后调用 App。

相反，我们可以创建一个块来在调用 didFinishLaunching 时通知我们。这允许在 SwiftUI 世界中（而不是在 AppDelegate 中）保留更多代码。

class AppDelegate: NSObject, UIApplicationDelegate {

  var didFinishLaunching: ((AppDelegate) -> Void)?

  func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions
      launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil
  ) -> Bool {
    didFinishLaunching?(self)
    return true
  }
}

@main
struct MyApp: App {
  @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate

  @ObservedObject private var applicationModel = ApplicationModel()

  // `init` gets called BEFORE `didFinishLaunchingWithOptions`
  init() {

    // Subscribe to get a `didFinishLaunching` call
    appDelegate.didFinishLaunching = { [weak applicationObject] appDelegate in

      // Setup any application code...
      applicationModel?.setup()
    }
  }

  var body: some Scene {
    return WindowGroup {
      if applicationObject.isUserLoggedIn {
        LoggedInView()
      } else {
        LoggedOutView()
      }
    }
  }
}