每次调用ViewdidLoad

Question

Why every time I change UIViewController embed in UINavigationController using show push in storyboard ViewDidLoad is called?

It hasn't to be called only once or I have to check programmatically if it is already loaded?

Another relative question:

In the following best practices found here in StackOverflow that user are talking about init method, but if my ViewController are loaded by storyboard where I have to initialise my properties?

Best practices

Remember not to do view controller initialisation in viewDidLoad. This is a common mistake. For stuff that should only happen once when the view controller is loaded, do it in one of the controller's init methods.

Answer 1

viewDidLoad is called first time when the viewController's view is loaded, (either by accessing the view controller's view or by presenting a view controller via modal presentation or via a push presentation). Once the view controller is loaded, viewDidLoad will not get called again. If you want to use init method, you need to use initWithCoder for the things that are from storyboard.