Re: structs in Mutable containers
Re: structs in Mutable containers
- Subject: Re: structs in Mutable containers
- From: Roland King <email@hidden>
- Date: Tue, 16 Sep 2008 20:37:35 +0800
well can you manage the lifetime of the CGPoints well enough to use
valueWithPointer: which, if I read it correctly, doesn't free the
pointer when it's done? Or just write your own NSObject derivation you
can pass a CGPoint to, by value and have it copied, or as a pointer,
but which it owns and frees later for you?
On Sep 16, 2008, at 6:46 PM, Christian Giordano wrote:
I just realized valueWithPoint is not available on the iPhone SDK and,
I can't understand why, it can't be discussed here. Both things of
course suck! :)
Thanks a lot, chr
On Tue, Sep 16, 2008 at 11:24 AM, Graham Cox
<email@hidden> wrote:
On 16 Sep 2008, at 7:18 pm, Christian Giordano wrote:
... forKey:[[NSNumber alloc] initWithInt:BAND_RED]];
Not a really elegant solution but I can understand that those
containers require pointers.
Now I need to create a NSMutableArray of CGPoint, how can I make it
became a pointer?
... addObject:CGPointMake(x,y)];
returns indeed "error: incopatible type for argument 1 of
'addObject:'
Is there a more elegant way to use structs as key or as mutable
container's items?
[NSValue valueWithPoint:NSMakePoint( x, y )];
this wraps a NSPoint with an object that can be stored in a
dictionary.
CGPoints and NSPoints have the same structure so you can cast one to
t'other.
For keys, the usual approach if your keys are simply constants is
to define
them as literal strings:
// .h
extern NSString* BAND_RED;
// .m
NSString* BAND_RED = @"BAND_RED";
A literal string is directly usable as an object. If the key needs
to change
dynamically (rare) then strings are still a good bet, but the "wrap
in a
NSValue" approach is acceptable I guess.
hth,
Graham
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