Re: Sending a msg. to a class
Re: Sending a msg. to a class
- Subject: Re: Sending a msg. to a class
- From: Glen Simmons <email@hidden>
- Date: Thu, 25 Oct 2007 17:33:16 -0500
Ah. Definitely a terminology problem. He referred to sending a
message to classes, which got me going the wrong direction. Yes, I'd
definitely recommend that z at least read the intro to ObjC pdf.
Glen
On Oct 25, 2007, at 4:27 PM, Murat Konar wrote:
Clearly, "z" has a situation where he declared a bunch of variables
SomeClass* pawn1;
SomeClass* pawn2;
.
.
.
SomeClass* pawn16;
and wants to iterate over them.
Unfortunately, "z" also thinks that Obj-C has some way to
dynamically construct "references by name" to these objects (you
can do this in JavaScript, for example).
I'm unaware of any scheme to get this JavaScript like idiom to work
in Obj-C, certainly none that are as simple as just stuffing all
those pawns in an array to begin with and iterating over that.
"z", you should probably spend some time with some of the
introductory Objective-C docs out there.
_murat
On Oct 25, 2007, at 1:52 PM, Shawn Erickson wrote:
On 10/25/07, Glen Simmons <email@hidden> wrote:
On Oct 25, 2007, at 2:35 PM, z wrote:
I'll appreciate someone to help me understand the problem and
suggest solution.
I'm trying to send a msg. to Pawn1 thru Pawn16 classes, but it
doesn't work from inside the loop.
Thanks.
- (IBAction)resetAll: (id)sender {
// [toPawn1 showYourself]; //--- This works
fine.
// .......
// [toPawn16 showYourself];
/ but the following generates a warning: 'NSMutableString' may not
respond to '-showYourself'
for (i = 1; i <= 16; ++i) {
NSMutableString *str = [NSMutableString
stringWithFormat: @"toPawn
%i", i];
[ [str className] showYourself];
[str release];
}
}
1. You're not sending the showYourself method to the class, but to
the object that is returned from the -className message, which is an
NSString instance. That's why you're getting the warning. To get a
class object from an NSString, you need to use NSClassFromString
function.
2. You shouldn't release str, since you didn't alloc, retain or copy
it. See the docs on memory management.
NSString* className = [NSString stringWithFormat:@"toPawn%i", i];
Class theClass = NSClassFromString(className);
[theClass showYourself];
However it looks like showYourself is an instance method give what
little information has been posted so far... so I don't think the
above would do what he wants in the end.
-Shawn
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