On 2011 Sep 23, at 15:57, Quincey Morris wrote:
> a. What do you mean by "unnecessary"? Your choices for an outlet are pretty
> much ivar or property. Are you suggesting the property is "unnecessary"
> because it could be an ivar instead?
Yes. After studying this some more I see that, in older code, I did not
declare outlets as properties. Instead, I put the IBOutlet directive on the
ivar,
@interface MyWinCon : NSWindowController
{
IBOutlet FooView *m_fooView ;
}
and then if I wanted other objects to be able to access these, instead of
declaring a property I would declare and implement a getter
- (FooView*)fooView {
return m_fooView ;
}
> b. @dynamic isn't magic. It says the methods are provided by something else
> (other than user-written implementations or @synthesized implementations).
> What's the something else you're thinking of here?
The "something" is that I thought the IBOutlet tells the compiler to access
instance variables directly. After reading Greg Parker's responses and the
links, I see that the executable actually is different if an outlet is
@synthesize vs. @dynamic. If you use @synthesize, it really does synthesize
setters and getters, and these really are used during nib loading. If you use
@dynamic, setters and getters are not synthesized, and nib loading accesses
instance variables directly using, for instance, object_setInstanceVariable().
So now I understand that if an outlet is declared as an @property, as Xcode has
been doing in recent versions, it needs to be implemented, for example by
@synthesize. Using @dynamic would be wrong because it allows me to write code
that invokes, e.g., -[MyWinCon fooView], which would cause a "method not found
for selector" runtime exception.
Actually, the old way still seems more straightforward, but anyhow I see how it
works now.
Thank y'all.
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