Working with App Lifecycle

import UIKit

@main
class AppDelegate: UIResponder, UIApplicationDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        print("App launched")
        return true
    }

    func applicationDidEnterBackground(_ application: UIApplication) {
        print("App entered background")
    }

    func applicationWillEnterForeground(_ application: UIApplication) {
        print("App will enter foreground")
    }

    func applicationDidBecomeActive(_ application: UIApplication) {
        print("App became active")
    }

    func applicationWillResignActive(_ application: UIApplication) {
        print("App will resign active")
    }
}

import UIKit

@main
class AppDelegate: UIResponder, UIApplicationDelegate {

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Setup code here
        return true
    }

    func applicationDidBecomeActive(_ application: UIApplication) {
        // App is now active
    }

    func applicationWillResignActive(_ application: UIApplication) {
        // App is about to become inactive
    }

    func applicationDidEnterBackground(_ application: UIApplication) {
        // App is now in background
    }

    func applicationWillEnterForeground(_ application: UIApplication) {
        // App is about to enter foreground
    }

    func applicationDidReceiveMemoryWarning(_ application: UIApplication) {
        // Handle memory warning
    }

    func applicationWillTerminate(_ application: UIApplication) {
        // App is about to terminate
    }
}

import UIKit

class SceneDelegate: UIResponder, UIWindowSceneDelegate {
    var window: UIWindow?

    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        // Configure the window and root view controller
        guard let windowScene = (scene as? UIWindowScene) else { return }
        
        window = UIWindow(windowScene: windowScene)
        let rootViewController = UIViewController()
        rootViewController.view.backgroundColor = .systemBackground
        window?.rootViewController = rootViewController
        window?.makeKeyAndVisible()
    }

    func sceneDidDisconnect(_ scene: UIScene) {
        // Called when the scene disconnects from the session
    }

    func sceneDidBecomeActive(_ scene: UIScene) {
        // Called when the scene becomes active
    }

    func sceneWillResignActive(_ scene: UIScene) {
        // Called when the scene will resign active
    }

    func sceneWillEnterForeground(_ scene: UIScene) {
        // Called when the scene will enter foreground
    }

    func sceneDidEnterBackground(_ scene: UIScene) {
        // Called when the scene enters background
    }
}

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    // Custom initialization code
    print("App launched successfully")
    return true
}

import UIKit

@main
class AppDelegate: UIResponder, UIApplicationDelegate {
    func applicationWillTerminate(_ application: UIApplication) {
        // Save data to disk or clean up resources
        print("App is about to terminate")
    }
}

import BackgroundTasks

func scheduleBackgroundTask() {
    let request = BGProcessingTaskRequest(identifier: "com.example.background")
    request.earliestBeginDate = Date().addingTimeInterval(300) // 5 minutes
    do {
        try BGTaskScheduler.shared.submit(request)
    } catch {
        print("Failed to schedule background task: \(error)")
    }
}

func handleBackgroundTask(_ task: BGTask) {
    task.expirationHandler = {
        task.cancel()
    }

    // Perform background work here
    DispatchQueue.global().async {
        // Simulate work
        sleep(2)
        task.finish()
    }
}

import UIKit

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

    func application(_ application: UIApplication, performFetchWithCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
        // Fetch data in background
        fetchData { success in
            if success {
                completionHandler(.newData)
            } else {
                completionHandler(.noData)
            }
        }
    }

    func fetchData(completion: @escaping (Bool) -> Void) {
        // Simulate network request
        DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
            completion(true)
        }
    }
}

let config = URLSessionConfiguration.background(
    identifier: "com.example.backgroundSession"
)
let session = URLSession(configuration: config, delegate: self, delegateQueue: nil)

func urlSession(
    _ session: URLSession,
    didCompleteWithError error: Error?
) {
    if let error = error {
        print("Background session error: \(error)")
    } else {
        print("Background session completed successfully")
    }
}

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

class MyViewController: UIViewController, UIStateRestoring {
    @IBOutlet weak var textField: UITextField!
    
    override func encodeRestorableState(with coder: NSCoder) {
        super.encodeRestorableState(with: coder)
        coder.encode(textField.text, forKey: "textFieldText")
    }
    
    override func decodeRestorableState(with coder: NSCoder) {
        super.decodeRestorableState(with: coder)
        textField.text = coder.decodeObject(forKey: "textFieldText") as? String
    }
}

class MyViewController: UIViewController {
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Clean up cached data or images
        if isViewLoaded {
            // Clear any cached resources
            cachedImages = nil
        }
    }
}