替代 iOS 已弃用的 UIApplicationExitsOnSuspend

Question

I have an app that I do NOT want to run in the background. There is nothing my app can do in background mode, and allowing it to only adds annoying UI complications. I want the app to terminate when it is removed from the foreground.

UIApplicationExitsOnSuspend was Apple's method of allowing this before, and it worked perfectly for my use case. However, it is now deprecated and they are rejecting apps with that Info.plist value.

The only alternative I've been able to find is exit(0) in an app delegate method, but Apple strongly discourages this, and it appears as a crash.

Is there any other viable alternative? I simply do not want my app to run in the background, all it does is drain a user's battery unnecessarily.

Answer 1

As an alternative to UIApplicationExitsOnSuspend I check the elapsed time in background an reset my navigation if needed:

• I keep the last time the app did enter in background ( NSUserDefaults in applicationDidEnterBackground )
• When the application did become active again I check the saved time (in applicationDidBecomeActive ) against a given time threshold.
• I reset my navigation if my threshold is overrun (this allow me to resync my app or re-ask for login after some times, but allowing a quick phone call for exemple)

Since it's an old app here is the objective-c:

appdelegate.m:

- (void)applicationDidEnterBackground:(UIApplication *)application {
    NSLog(@"APPLIFE : going to sleep ... ");
    [[NSUserDefaults standardUserDefaults] setObject: [NSDate date] forKey:@"last-background-time"];
}

- (void)applicationDidBecomeActive:(UIApplication *)application {

    NSLog(@"APPLIFE : ... back to front");
    NSDate * bgTime = [[NSUserDefaults standardUserDefaults] objectForKey:@"last-background-time"];

    NSTimeInterval secondsSinceLastRun = fabs([bgTime timeIntervalSinceNow]);
    double threshold = 60 * 60 * 24; //in seconds.   

    if (secondsSinceLastRun > threshold) {
        NSLog(@"APPLIFE : Too old, reboot app");
        //[navigationController popToRoot] or whatever you want
    }
}

Answer 2

For SwiftUI, Add this to the App struct:

@UIApplicationDelegateAdaptor(AppDelegate.self) var delegate

then add these two classes:

class AppDelegate: UIResponder, UIApplicationDelegate {

func application(
    _ application: UIApplication,
    configurationForConnecting connectingSceneSession: UISceneSession,
    options: UIScene.ConnectionOptions
  ) -> UISceneConfiguration {
    let sceneConfig = UISceneConfiguration(name: nil, sessionRole: connectingSceneSession.role)
    sceneConfig.delegateClass = SceneDelegate.self // 👈🏻
    return sceneConfig
  }

}

class SceneDelegate: NSObject, UIWindowSceneDelegate {

func sceneWillResignActive(_ scene: UIScene) { // This will force the app to start fresh each time after two seconds (so the close animation looks clean) do { sleep(2) } exit(0) } }