subclassed UIButton and compiler warnings

[pollyp]

Hi,

I'm a objective-C newbie trying to wring the last few compiler warnings out of my code. I've got one case that's got me stumped, and the mighty google does not seem to be able to help me.

I've got a button class that's subclassed from UIButton. (I've since learned that's problematic, and I should have created a whole new class. But I'd like to avoid rewriting this piece if I can.) Anyway, inside my class I'm doing things like calling setTitle:forState:, which generates the following compiler warning:

warning: 'UIButton' may not respond to '+setTitle:forState:'

I've changed my code to invoke this message on self, self cast to UIButton *, and super -- but I always get this warning. The code runs fine. I'm also perplexed about why the compiler thinks setTitle:forState: is a class method; of course it is an instance method.

So, what am I missing here?

Thanks in advance,

Polly

[justill45]

Originally Posted by pollyp

Hi,

I'm a objective-C newbie trying to wring the last few compiler warnings out of my code. I've got one case that's got me stumped, and the mighty google does not seem to be able to help me.

I've got a button class that's subclassed from UIButton. (I've since learned that's problematic, and I should have created a whole new class. But I'd like to avoid rewriting this piece if I can.) Anyway, inside my class I'm doing things like calling setTitle:forState:, which generates the following compiler warning:

warning: 'UIButton' may not respond to '+setTitle:forState:'

I've changed my code to invoke this message on self, self cast to UIButton *, and super -- but I always get this warning. The code runs fine. I'm also perplexed about why the compiler thinks setTitle:forState: is a class method; of course it is an instance method.

So, what am I missing here?

Thanks in advance,

Polly

post the code please

[pollyp]

Sure thing. Here's my code:

#import "MySubclassedButton.h"

@implementation MySubclassedButton
+ (id)withFrame:(CGRect)frame withTitle:(NSString *)title
{
	if ( self = [super buttonWithType:UIButtonTypeRoundedRect]) {
		[ self setFrame:frame];
		[ self setTitleEdgeInsets: UIEdgeInsetsMake(0.0,10.0,0.0,10.0) ];
		[ self setTitle:title forState:UIControlStateNormal];
	}
    return self;
}
@end

The setFrame generates this compiler warning:
warning: 'MySubclassedButton' may not respond to '+setFrame:'

I get similar warnings for setTitleEdgeInsets and setTitle. If I cast to a UIButton object, I get this instead:
warning: 'UIButton' may not respond to '+setFrame:'

Here's the associated header file:

#import <Foundation/Foundation.h>

@interface MySubclassedButton : UIButton {
}

+ (id)withFrame:(CGRect)frame withTitle:(NSString *)title;
@end

I'm using version 3.1.4 of Xcode and I'm compiling for a 3.0 device target.

Thanks in advance for any light you can shed on this headscratcher.

Polly

[justill45]

Originally Posted by pollyp

Sure thing. Here's my code:

#import "MySubclassedButton.h"

@implementation MySubclassedButton
+ (id)withFrame:(CGRect)frame withTitle:(NSString *)title
{
	if ( self = [super buttonWithType:UIButtonTypeRoundedRect]) {
		[ self setFrame:frame];
		[ self setTitleEdgeInsets: UIEdgeInsetsMake(0.0,10.0,0.0,10.0) ];
		[ self setTitle:title forState:UIControlStateNormal];
	}
    return self;
}
@end

The setFrame generates this compiler warning:
warning: 'MySubclassedButton' may not respond to '+setFrame:'

I get similar warnings for setTitleEdgeInsets and setTitle. If I cast to a UIButton object, I get this instead:
warning: 'UIButton' may not respond to '+setFrame:'

Here's the associated header file:

#import <Foundation/Foundation.h>

@interface MySubclassedButton : UIButton {
}

+ (id)withFrame:(CGRect)frame withTitle:(NSString *)title;
@end

I'm using version 3.1.4 of Xcode and I'm compiling for a 3.0 device target.

Thanks in advance for any light you can shed on this headscratcher.

Polly

well, i just did a very basic test on changing it, i made and IBAction and i made and IBOUtlet named theButton. heres what i tried first and it worked fine by using th eoutlet i created.

-(IBAction)button:(id)sender {
	
	[theButton setTitle:@"Test" forState:UIControlStateNormal];
}

However, when i didnt use the Outlet and just did self i got the same exact error as you did , heres the code

-(IBAction)button:(id)sender {
	
	[self setTitle:@"hello" forState:UIControlStateNormal];
}

my advice, just make and out of the UIButton, adn connect it to the button, its pretty simple , very basic. Is there something you're trying to do where you cant use and IBOutlet???

[Toro Liu]

[quote=pollyp;135037]Sure thing. Here's my code:

#import "MySubclassedButton.h"

@implementation MySubclassedButton
+ (id)withFrame:(CGRect)frame withTitle:(NSString *)title
{
	if ( self = [super buttonWithType:UIButtonTypeRoundedRect]) {
		[ self setFrame:frame];
		[ self setTitleEdgeInsets: UIEdgeInsetsMake(0.0,10.0,0.0,10.0) ];
		[ self setTitle:title forState:UIControlStateNormal];
	}
    return self;
}
@end

Maybe the codes should be written as following:

+ (id)buttonWithFrame:(CGRect)frame withTitle:(NSString *)title
{
        UIButton *retBtn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
         [retBtn setFrame:frame];
         [retBtn ....];
         return retBtn;
}

[nobre84]

Within a class method ( +(id) with ... ) , any reference to self means the class object. So you are really calling +setFrame, +setTitle, etc.

Toro Liu way is appropriate. Just remember to autorelease the resulting object.

[pollyp]

[Slaps self on forehead]

D'oh! You're completely correct. Thanks for pointing out the right way to do this.

Polly