Question

I have few questions to ask about the following class

#import <Cocoa/Cocoa.h>

@interface SomeObject {
    NSString *title;
}

@property (retain) NSString *title;

@end




   implementation SomeObject

    @synthesize title;

    -(id)init {
        if (self=[super init])
        {
            self.title=[NSString stringWithFormat:@"allyouneed"];
        }

        return self;
    }

-(void)testMethod{
self.title=[[NSString alloc] init] ;
}

    -(void)dealloc {
        self.title=nil;

        [super dealloc];
    }

1. In the .h file do we need to declare the title and sub when we add the property. is it not enough to add the @property (retain) NSString *title; line.

2.Do i need to autorelease both assignment to title in the init and testMethod. if So why?

Can some one explain these things to me.

Answer 1

1-
You don’t need to declare the iVar in the header. You might also use

@synthesize myVar = _myVar;

if you want to go for a different iVar name

2-
Declaring a property “retain” means that every time you assign the property with a new object, it automatically releases the previous object and retain the new one.

Therefore, if you use a convenience method like stringwithFormat, the property will retain that object for you.

If you want to use alloc-init, for me the best way to do is:

NSString *str = [NSString alloc] init];
self.title = str;
[str release];

Besides, it is right to assign nil to the property in the dealloc because the property will release the object it has, and it calls retain on nil which doesn’t do anything