Re: Order of instantiation within a NIB

FROM : John C. Randolph
DATE : Mon Apr 11 22:48:32 2005

On Apr 11, 2005, at 10:36 AM, John Brownlow wrote:

> I have a main editor window which has several drawers. Each of 
> these drawers is quite complicated so I gave each one its own 
> controller to separate out the logic, although they are staying in 
> the same NIB because they are fundamentally connected.
>
> Just for my own personal ease I would rather instantiate these 
> controllers in the NIB so I can hook them up with IBOutlets etc. 
> But then the question becomes, how to initialize them.
>
> If I could rely on all the objects in the NIB being initialized 
> when they are created then they could initialize themselves, but I 
> suspect that is not how things work and so not all the objects they 
> need will be there when they are instantiated.
>
> The alternative is to put the initialization in the 
> mainEditorWindowController which loads the NIB, but that grates 
> because I feel the objects should self-initialize. What is good 
> practice here? Should I have a -NIBDidLoad method that the 
> windowController calls, or a notification, or what?


In your -init method, perform whatever initialization you like that 
does *not* depend on any of your outlets being in place.  If you need 
to perform initialization that does depend on the connections in the 
nib, then implement -awakeFromNib:

- (void)awakeFromNib

Prepares the receiver for service after it has been loaded from an 
Interface Builder archive, or nib file. An awakeFromNib message is 
sent to each object loaded from the archive, but only if it can 
respond to the message, and only after all the objects in the archive 
have been loaded and initialized. When an object receives an 
awakeFromNib message, it’s guaranteed to have all its outlet instance 
variables set.


-jcr


John C. Randolph <<email_removed>> (408) 974-8819
Sr. Cocoa Software Engineer,
Apple Worldwide Developer Relations
http://developer.apple.com/cocoa/index.html