instance method of class for iphone

Question

i want to create some header file for future use but i have 1 problem

i have defined a method in lets say Rimage class called check1 now i want to call that from maiviewcont

so i did this in mainVC.h i defined a instance of Rimage class

#import <UIKit/UIKit.h>
@class Rimage;
@interface Rahul_imageplaceCordinatesViewController : UIViewController {

    Rimage *aRimage;
}
@property (nonatomic,copy) Rimage *aRimage;
@end

and in .m

[self.aRimage check1];
aRimage = [Rimage check1];

but both are not working

i went for both +(void)check1 and -(void)check1 in Rimage class

do you have the @synthesize in the .m file? – christophercotton Jul 15 '10 at 04:29 — christophercotton, Jul 15 '10 at 04:29

score 0 · Accepted Answer · edited May 23 '17 at 12:03

0

The two examples you give do very different things:

[self.aRimage check1];

invokes an check1 instance method on aRimage.

aRimage = [Rimage check1];

calls the check1 class method on the Rimage class, and assigns the result to aRimage.

In both cases, you will need to #import "Rimage.h in your .m file, else you'll get warnings like "aRimage may not respond to 'check1'".

EDIT

Your ".h" file is declaring a property named "aRimage", but that value will be nil until you assign something to it, by doing something like:

self.aRimage = [[[Rimage alloc] init] autorelease];

See this question for a good explanation of the difference between class methods and instance methods.

ps. and don't forget to do a [aRimage release] in your dealloc method

edited May 23 '17 at 12:03

Community

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answered Jul 15 '10 at 01:17

David Gelhar

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but why i am cant see any output i already initialize an instance in .h of VC do i need to alloc them in .m – ram Jul 15 '10 at 01:49
by instance method you mean -(void)check1 and by class method you mean +(void)check1 thats it??? – ram Jul 15 '10 at 01:50

instance method of class for iphone

1 Answers1