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393

answers:

2

Hi,

I'm trying to pass a CGRect:

SEL frameSel = NSSelectorFromString(@"setFrame:");
CGRect rect = CGRectMake(10, 10, 200, 100);
[object performSelector:frameSel withObject:rect ];

But this does not compile

I also tried:

SEL frameSel = NSSelectorFromString(@"setFrame:");
CGRect rect = CGRectMake(10, 10, 200, 100);
NSValue * value = [NSValue valueWithCGRect:rect];
[object performSelector:frameSel withObject:value ];

Actually, this does compile but when I debug, the frame is not setted correctly:

po object
<UILabel: 0x39220f0; frame = (0 0; 200 100); text = 'reflectionLabel'; clipsToBounds = YES; userInteractionEnabled = NO; layer = <CALayer: 0x3922240>>

But it should be frame = (10 10; 200 100)

How can I solve this problem?

Thank you in advance!

+1  A: 
CGRect rect = CGRectMake(10, 10, 200, 100);
[object performSelector:frameSel withObject:rect ];

But this does not compile

Correct, because rect is a structure, not a pointer to an object.

CGRect rect = CGRectMake(10, 10, 200, 100);
NSValue * value = [NSValue valueWithCGRect:rect];
[object performSelector:frameSel withObject:value ];

Actually, this does compile but when I debug, the frame is not setted correctly:

po object
<UILabel: 0x39220f0; frame = (0 0; 200 100); text = 'reflectionLabel'; clipsToBounds = YES; userInteractionEnabled = NO; layer = <CALayer: 0x3922240>>

Well, it's not garbage, so it would seem that it worked, even though the origin somehow remained zero. You may want to ask a separate question about that.

Anyway, why are you using performSelector:withObject:? You're not addressing it to a specific thread and you're not putting it on a delay; why not simply say object.frame = rect?

Peter Hosey
Object is of type NSObject *I cannot simply say object.frameI really need to use NSObject*>>> Well, it's not garbage, so it would seem that it worked, even though the origin somehow remained zero. You may want to ask a separate question about that.I really need an answer on that question.Thanks!!
Fabrizio Farinelli
If you know it has a `frame` property, cast it to `UIView *` and then use `object.frame = rect`. If you don't know it has a `frame` property, use KVC (http://developer.apple.com/iphone/library/documentation/Cocoa/Conceptual/KeyValueCoding/) to set the property, and catch the exception that will happen if it doesn't have one.
Peter Hosey
A: 

Object is of type NSObject * I cannot simply say object.frame I really need to use NSObject*

Well, it's not garbage, so it would seem that it worked, even though the origin somehow remained zero. You may want to ask a separate question about that.

I really need an answer on that question. Thanks

Fabrizio Farinelli
I think Peter meant you should raise another question.
Abizern