在新的iOS 14应用程序中使用BGTaskScheduler应用程序接口。没有AppDelegate的情况下如何注册任务？

Question

我正在使用BGTaskScheduler应用程序接口在我的iOS 14应用程序中注册后台任务，该应用程序将新应用程序用作@Main而不是AppDelegate。我认为我们应该使用下面的scenePhase来模仿AppDelegate中didFinishLaunching的前面的功能，但是下面的代码导致了崩溃：*** Assertion failure in -[BGTaskScheduler _unsafe_registerForTaskWithIdentifier:usingQueue:launchHandler:], BGTaskScheduler.m:185 2020-12-01 12:53:40.645091-0500 newFitnessApp[13487:1952133] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'All launch handlers must be registered before application finishes launching'如何实现BGTaskScheduler？

@main
struct newFitnessAppApp: App {
    
    @Environment(\.scenePhase) var scenePhase
    
    //Launch Count (for requesting reviews and to show tutorial)
    //var launchCount = UserDefaults.standard.integer(forKey: TrackerConstants.launchCountKey)
    //var testMode = true
    //@Environment(\.scenePhase) private var phase
    let trackerDataStore = TrackerDataStore(workoutLoader: HealthKitWorkoutLoader())
    
    var body: some Scene {
        WindowGroup {
            AppRootView().environmentObject(trackerDataStore)
        }
        .onChange(of: scenePhase) { newScenePhase in
            switch newScenePhase {
            case .active:
                print("App is active")
                registerBackgroundTasks()

Answer 1

尝试在init中完成此操作

@main
struct newFitnessAppApp: App {

   init() {
      registerBackgroundTasks()
   }

// ... other code
}

或者在委托回调https://stackoverflow.com/a/62538373/12299030中使用AppDelegate适配器执行此操作