基于启动 storyboard 加载屏幕偏离中心？

Question

I have 2 storyboards: Onboarding and Main. Everything works great as far as execution goes. The issue is that I have loading screen at the start of Main.storyboard that looks different depending on which storyboard launches.

Scenario 1: New user launches the app, it goes through Onboarding.storyboard then Main.storyboard launches and the loading screen looks as it should like this: Correct Screen

Scenario 2: User launches the app for the second time, therefore Onboarding.storyboard is not launched: Loading screen is off centre like this: Wrong Screen

Long story short: If there is no Onboarding.storyboard, it doesn't look right. The issue is only shown on iPad landscape; portrait looks fine.

All of my loading screen code is inside my first view controller of Main.Storyboard so I'm guessing that the issue is the order in which the code is called?

Onboarding.Storyboard only has 1 view controller Main.Storyboard goes: TabBarController -> NavController -> FirstVC

I placed my SceneDelegate code below along with the loading screen code of FirstVC.

In case you want to dig in deeper, I'm using RevealingSplashView available on github. Since I don't think that's the issue I didn't get into that further.

SceneDelegate:

    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {

    guard let windowScene = (scene as? UIWindowScene) else { return }

    window = UIWindow(frame: windowScene.coordinateSpace.bounds)
    window?.windowScene = windowScene

    let onboardingStoryboard = UIStoryboard(name: "Onboarding", bundle: nil)
    let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
    var vc: UIViewController

    if UserDefaults.standard.value(forKey: "firstTimer") == nil {
        vc = onboardingStoryboard.instantiateInitialViewController()!
    } else {
        vc = mainStoryboard.instantiateInitialViewController()!
    }

    self.window?.rootViewController = vc
    self.window?.makeKeyAndVisible()
}

FirstVC relevant code:

class firstVC: UIViewController {

    var revealingSplashView : RevealingSplashView!

override func viewDidLoad() {
    super.viewDidLoad()

    showLoadingScreen()
}

func showLoadingScreen() {

       revealingSplashView = RevealingSplashView(iconImage: UIImage(named: "Icon")!, iconInitialSize: CGSize(width: 150, height: 150), backgroundImage: UIImage(named: "loadBackground")!)
       revealingSplashView.animationType = .heartBeat
       revealingSplashView.startAnimation()

       view.addSubview(revealingSplashView)
}

Answer 1

Check to see that your layout constraints are the same in both of your storyboards. I'd recommend just setting them to center horizontal and center vertical on both of them.

In your scene delegate callback, why are you calling instantiateInitialViewController() twice per storyboard?

In my iOS 12 project, I used storyboards to kick things off. In app delegate didFinishLaunching, I would override and set the window if and only if it was a new user. So my "Main" storyboard would kick in most of the time.

Same technique could be applied here. Check out the Info.plist values you need to set for UIScene storyboard to work. You can override the window if you want to show the first time onboarding, otherwise let the system instantiate your main storyboard.

Answer 2

Further testing revealed that if I return SceneDelegate to its "factory default" state, therefore launching Main.storyboard, I had no issues.

To fix the issue I simply changed my SceneDelegate to:

    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {

    guard let windowScene = (scene as? UIWindowScene) else { return }

    if UserDefaults.standard.value(forKey: "firstTimer") == nil {

        window = UIWindow(frame: windowScene.coordinateSpace.bounds)
        window?.windowScene = windowScene

        let onboardingStoryboard = UIStoryboard(name: "Onboarding", bundle: nil)
        var vc: UIViewController

        vc = onboardingStoryboard.instantiateInitialViewController()!

        self.window?.rootViewController = vc
        self.window?.makeKeyAndVisible()
    }

}