App lifecycle for iOS devs

Article
10/14/2015

[This article is for Windows 8.x and Windows Phone 8.x developers writing Windows Runtime apps. If you’re developing for Windows 10, see the latest documentation]

Both iOS and Windows Store apps have a specific set of methods and events that are called or triggered as an app starts up and shuts down. Here's a comparison.

Although there isn't an exact 1:1 correlation between methods or when they are called during an app's lifecycle, the following methods and events will help you get an idea of what exist to help you launch your app. You should also read up on the Application lifecycle and Running code in the background.

Events associated with an app starting and ending

iOS Event	Windows 8 App Event equivalent
application:didFinishLaunchingWithOptions	Application.OnLaunched (or sometimes Application.OnActivated). On Windows Phone, OnLaunched is called each time the user launches the app from Start tile or app list, even when the app is currently suspended in memory. On Windows, launching a suspended app from Start tile or app list doesn’t call this method.
applicationDidBecomeActive	Application.OnLaunched (or Application.Start, but you rarely need to call this method specifically).
*applicationWillEnterForeground: (UIApplication )application**	Application.OnResuming
*applicationDidEnterBackground: (UIApplication )application**	Application.OnSuspending
*applicationWillEnterBackground:(UIApplication )application**	Application.OnSuspending
*applicationWillResignActive:(UIApplication )application**	Application.OnSuspending
*applicationWillTerminate:(UIApplication )application**	No direct equivalent event is available. Application.UnhandledException may be useful depending on the specific scenario.
*applicationDidReceiveMemoryWarning:(UIApplication )application**	No direct equivalent event is available. Application.UnhandledException may be useful depending on the specific scenario.

Events associated with a view, window or page opening and closing

iOS Event	Windows 8 App Event equivalent
initWithNibName	Page.Page constructor
loadView	FrameworkElement.Loaded event
ViewDidLoad	FrameworkElement.Loaded event
ViewWillAppear: (BOOL)animated	Page.OnNavigatedTo
ViewDidAppear: (BOOL)animated	Page.OnNavigatedTo
ViewWillDisappear: (BOOL)animated	Page.OnNavigatingFrom
ViewDidDisappear: (BOOL)animated	Page.OnNavigatedFrom
ViewDidUnload	FrameworkElement.Unloaded event
didRotateFromInterfaceOrientation	orientationchanged event