iOS - Relaunch app on orientation change?

Question

On iOS, is it possible to relaunch an app automatically when the device orientation changes? Android has this feature (just make sure android:configChanges does not include orientation).

Answer 1

There are no methods available in iOS to restart your application, BUT you could manually reinstantiate initial root UIViewController when orientation changes.

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To reinstantiate root UIViewController you could use following static functions in your AppDelegate class:

static func getWindow() -> UIWindow? {
    return UIApplication.shared.keyWindow
}

static func resetViewController() {
    let window = getWindow()

    let controller = ...  /// Instantiate your inital `UIViewController`

    window?.rootViewController = controller
    window?.makeKeyAndVisible()
}

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To listen for orientation change use following method in UIViewController :

override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
    super.viewWillTransition(to: size, with: coordinator)
    AppDelegate.resetViewController() /// "Restarts" application
}

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While this is a viable approach, I would highly discourage you from restarting your application when orientation change happens and just handle orientation changes how it supposed to be handled according to Apple.