viewDidLoad in iPhone

What 开发者_Go百科is ViewDidLoad() method for?

This function is executed, when the view controller loaded your view sucessfully - and you can do there your custom initializations as well.

If you are new to iPhone development, take a look at the apple reference: http://developer.apple.com/library/ios/#documentation/uikit/reference/UIViewController_Class/Reference/Reference.html

I have seen too many times -viewDidLoad used to setup the view controller's title, navigationItem, tabBarItem or any of the properties of these, such as the right/leftBarButtonItems on navigationItem. This is is not advised, because these properties may be needed before the view is loaded.

As an example, a tab bar controller needs each view controller's tabBarItem but won't load the view to the unselected tabs; So -viewDidLoad won't be called before the tabBarItem is needed.

It's called when the view loaded. Is it really that complicated??