The frame is not guaranteed to be the same in viewDidLoad as it will be when the view is eventually displayed. UIKit adjusts the frame of your view controller’s view prior to displaying it, based on the context in which will appear. The size is determined based on interface orientation and the dimensions of any … Read more
From Apple documentation: awakeFromNib: The nib-loading infrastructure sends an awakeFromNib message to each object recreated from a nib archive, but only after all the objects in the archive have been loaded and initialized. When an object receives an awakeFromNib message, it is guaranteed to have all its outlet and action connections already established. See: Nib … Read more
The Activity class has onCreate and onResume methods that are pretty analagous to viewDidLoad and viewDidAppear. Activity.onResume EDIT To add to this, since some have mentioned in the comments that the view tree is not yet fully available during these callbacks, there is the ViewTreeObserver that you can listen to if you need first access … Read more
viewDidLoad is called when the class is loaded however no ui elements have been initialised and therefore any attempt to reference them will be overwritten or unavaliable during the initialisation process which happens between the viewDidLoad and viewDidAppear calls. Once all ui element have been initalised and drawn viewDidAppear is called. viewDidLoad – Called after … Read more
If you are overriding the method you should still call the method in the super. Even if the super class is not doing anything with it today, Apple might one day change the implementation and your code will mysteriously stop working. If you really don’t need to do anything in that method, leave it out … Read more
Depending on what kind of actions you need to perform, there are several techniques: -(id)initWithFrame:(CGRect)frame – UIView’s designated initializer; always sent to a UIView to initialize it, unless the view is loaded from a nib; -(id)initWithCoder:(NSCoder *)coder – always sent to initialize a UIView whenever the view is loaded from a nib; -(void)awakeFromNib – sent … Read more
viewDidLoad is things you have to do once. viewWillAppear gets called every time the view appears. You should do things that you only have to do once in viewDidLoad – like setting your UILabel texts. However, you may want to modify a specific part of the view every time the user gets to view it, … Read more