Add UIApplication lifecycle notification support

[ajayjapan]

Hi,

I noticed that several UIApplication lifecycle notifications are currently unavailable in Skip. These are commonly used in shared code to respond to app lifecycle changes (for example, refreshing state when the app returns to the foreground or cleaning up when backgrounding).

Notifications Requested

• UIApplication.willEnterForegroundNotification
• UIApplication.didFinishLaunchingNotification
• UIApplication.didBecomeActiveNotification
• UIApplication.willResignActiveNotification

Current Workaround

I have defined a custom extension in my Skip project and I am manually posting from the corresponding MainActivity lifecycle methods:

extension UIApplication {
  static let willEnterForegroundNotification = Notification.Name("UIApplicationWillEnterForegroundNotification")
}

override fun onResume() {
    super.onResume()
    NotificationCenter.default.post(Notification(name = UIApplication.willEnterForegroundNotification))
}

I imagine the Android lifecycle callbacks map fairly cleanly to these notifications, so it might be possible to expose them in Skip at some point to better align with iOS behavior and simplify shared lifecycle handling.

Of course, I completely understand if this isn’t a current priority — just wanted to share the suggestion in case it’s helpful.

Thanks again!

[marcprux]

The way we handle this is in the AppDelegate that is part of the template project. For example, MyAppDelegate.onResume is called from the iOS onChange(of: .active) and the Android onResume().

You can add your own notification mechanism from your AppDelegate. Agreed, though, that it would probably be nice to just be able to use standard notifications for this.

[aabewhite]

We support SwiftUI's scenePhase too:

https://developer.apple.com/documentation/swiftui/scenephase