Why doesn't the app work 6 seconds after launch?

Hi everybody,

There is one strange problem in my application. When the application is launched on the phone for the first time, it does not work for the first six seconds. After that everything works fine. The app also works fine when re-launched on the phone and when launched on the simulator.

The application itself is small and not complicated, all data is stored on the device. It uses a Tab Bar Controller with three tabs. Another strange feature is that if I click on the icons in these first six seconds, then nothing works right away, but then all the commands are executed. Those, it looks like the application has accepted the commands, but it takes a long time to execute them.

Has anyone faced such a problem? What could be causing this?

Any ideas are appreciated.



Swift 5.2, Xcode 11.6, macOS Catalina 10.5.6


When the application is launched on the phone for the first time

Do you mean first time after download ?
Could you show the code for sceneDelegate and appDelegate ?
| Do you mean first time after download ?

Yes, first time after download.

In these two files I have not changed anything in the code

Code Block
import UIKit
@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.
    }
}



Code Block
import UIKit
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).
        guard let _ = (scene as? UIWindowScene) else { return }
    }
    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.
    }
}


So it is not caused by this code.

Have you defined a launchscreen storyboard ? Usually, the delay is "masked" by the display of this storyboard, which can last several seconds, the time for the phone to perform some configuration.

Do you see your launch screen ? Does the delay occurs after launchscreen disappear ?
the delay occurs after the launch screen have been finishing. Moreover, on the previous version, in which there is no launch screen, the delay also occurs.
Why doesn't the app work 6 seconds after launch?
 
 
Q