SwiftUI app life cycle

gistfile1.txt

import SwiftUI

@main
struct testSwitUIApp: App {
    let persistenceController = PersistenceController.shared
    
    @Environment (\.scenePhase) private var scenePhase
    
    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
    
    init() {
        print("init app........")
    }

    var body: some Scene {
        WindowGroup {
            ContentView()
                .environment(\.managedObjectContext, persistenceController.container.viewContext)
        }
        
        .onChange(of: scenePhase) { phase in
            if phase == .background {
                print("phase: .background")
            }
            
            if phase == .active {
                print("phase: .active")
                appDelegate.doSmth()
            }
            
            if phase == .inactive {
                print("phase: .inactive")
            }
        }
    }
}

class AppDelegate: NSObject, UIApplicationDelegate {
    
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
        return true
    }
    
    func doSmth() {}
}