CODEWITHSUNDEEP
iosmemory-leaksnsmutabledictionary
Suchi
Suchi

Reputation: 10039

iOS - unable to remove memory leak

In my TaggingScreen.m init function, I do -

tags = [myTagMgr getMyTags];

In my getMyTags method, I do the following -

NSMutableDictionary *myTags = [NSMutableDictionary new];
....
return myTags;

I get a memory leak for myTags in this method. Where should I release the memory? "tags" is a property which is used throughout the TaggingScreen class. So if I do an autorelease, I get an exception saying "message sent to deallocated instance" when I try to access tags in other methods of the class.

EDIT:

- (NSMutableDictionary *)getMyTags
{

NSMutableDictionary *myTags=[NSMutableDictionary new];
NSFetchRequest *fetchRequest = [[[NSFetchRequest alloc] init]autorelease];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Tag" 
                                inManagedObjectContext:localObjectContext];
[fetchRequest setEntity:entity];

NSError *error = nil;
NSArray *fetchedArrayObjects = [localObjectContext executeFetchRequest:fetchRequest error:&error];

if (fetchedArrayObjects ==nil) {
    return nil;
}   
if ([fetchedArrayObjects count]==0) {
    return nil;
}   

Tag *aMessage; 
for (int i=0; i<[fetchedArrayObjects count];i++) 
{
    aMessage= (Tag *)[fetchedArrayObjects objectAtIndex:(NSUInteger)i];

    [myTags setValue:[aMessage isSet] forKey:[aMessage tagName]];
    }
return myTags;
}

Upvotes: 0

Views: 260

Answers (4)

yuji
yuji

Reputation: 16725

Vignesh and Vin's solutions are correct, but based on what you've said, the best thing to do would be to change tags into a strong property:

@property (nonatomic, strong) NSMutableDictionary *tags;

Unless you're in a situation where a retain loop might arise (say, a delegate object), you should use strong so your properties aren't deallocated from under you.

In addition, unless you're using ARC, you'll want to autorelease myTags:

return [myTags autorelease];

Oh, and if you're not using ARC, you'll want to make sure to release tags in dealloc.

Upvotes: 1

Lorenzo B
Lorenzo B

Reputation: 33428

if you do it in init method you can do the following:

tags = [[myTagMgr getMyTags] retain];

instead in your getMyTags method

return [myTags autorelease];

In this manner you have +1 for your NSDictionary and you can access it with self.tags within your controller.

where

@property (nonatomic, retain) NSDictionary* tags;

Remember to release it in dealloc

- (void)dealloc
{
   [tags release]; tags = nil;
   [super dealloc];
}

P.S. I'm assuming you don't use ARC.

Upvotes: 1

Vignesh
Vignesh

Reputation: 10251

You should autorelease in the method. If you need it you will have to retain it where you call it.

tags = [[myTagMgr getMyTags] retain];

Upvotes: 0

Vin
Vin

Reputation: 10548

try :

return [myTags autorelease];

Upvotes: 0

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