Life of viewcontroller#objective c#ios#novice
life of view controllers
life of view controller
- init: ViewController loaded, no interface element (IBOutlet) available yet (all nil)
- viewDidLoad: the nib/storyboard has been loaded and all objects are available. The user sees nothing yet not sure of the Geometry of the Device
- viewWillAppear: the view is about to be displayed
- viewDidAppear: the view is on screen
- viewWillDisappear: the view is about to go away
- viewDidDisappear: the view just was taken off the window
- viewDidUnload: NEVER CALLED in iOS6/7
- didReceiveMemoryWarning: You don’t know if, when and how often this is called. Prior to iOS6 it might unload the view, after iOS6 it just purges an offscreen cache or does nothing
- dealloc: the viewController is about to get destroyed
usage of view controller
viewDidLoad: Add Observers for non-view things. Override this method to perform additional initialization on views that were loaded from nib files. Called when you create the class and load from xib.
viewWillAppear: Adjust Geometry of the Device add Observers for UI effects. good for hiding/showing fields or any operations that you want to happen every time before the view is visible Called after the view appears - great place to start an animations or the loading of external data from an API.
viewDidAppear: start an animations or the loading of external data from an API. Add observers for external data UI effects.
viewWillDisappear: remove observers for UI effects
viewDidDisappear: remove observers for external data UI effects
dealloc remove Observers for non-view things.