Tell about the lifecycle of a Vue controller.

The lifecycle of a UIViewController in iOS represents a sequence of events from its creation to destruction. Main stages:

1. Initialization:
   • init?(coder aDecoder: NSCoder): Initialization from Storyboard/Nib.
   • init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?): Initialization from a Nib file or programmatically without Nib.
   • loadView(): Loading or creating the controller's root view. If using Storyboard/Nib, it is called automatically. When creating the view programmatically, it should be overridden.
2. Loading the view:
   • viewDidLoad(): Called after the controller's view is loaded into memory. Suitable for initialization settings that do not require access to geometries (sizes).
3. View appearance:
   • viewWillAppear(_ animated: Bool): Called just before the view becomes visible. Suitable for updating data that may change between appearances.
   • viewDidAppear(_ animated: Bool): Called after the view becomes visible. Suitable for starting animations or other tasks that should only run after full display.
4. View disappearance:
   • viewWillDisappear(_ animated: Bool): Called just before the view is about to become invisible. Suitable for saving state or stopping activities.
   • viewDidDisappear(_ animated: Bool): Called after the view has become invisible. Suitable for releasing resources or stopping processes not needed in the background.
5. Layout changes:
   • viewWillLayoutSubviews(): Called before the view controller's views change their sizes.
   • viewDidLayoutSubviews(): Called after the views have changed their sizes. Suitable for final adjustments of element sizes and positions.
6. Trait collection changes:
   • traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?): Called when environment traits change, such as size class, screen density, light/dark mode, etc.
7. Memory cleanup (Deinitialization):
   • deinit: Called just before the controller object is deallocated from memory. Used for resource cleanup, unregistering notifications, etc.

Important points:

• Methods loadView, viewDidLoad, viewDidAppear, viewWillDisappear, viewDidDisappear, deinit are called once during the controller's lifecycle.
• Methods viewWillAppear and viewDidAppear can be called multiple times, e.g., during navigation forward and back.

Example sequence of calls when creating and presenting a controller:

// Initialization (if from Storyboard/Nib)
init?(coder aDecoder: NSCoder)

// Or initialization (if programmatically)
init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?)

// Loading the view
loadView()
viewDidLoad()

// View appears
viewWillAppear(true)
// ... view is now visible ...
viewDidAppear(true)

// View disappears (e.g., when transitioning to another VC)
viewWillDisappear(true)
// ... view is now hidden ...
viewDidDisappear(true)

// Memory cleanup (when there are no more strong references to the controller)
deinit