What cuases my memory leak here:
I have global variable:
@property (nonatomic, strong) NSArray *productArray;
I have function implementation that query data from core data:
- (NSArray *)fetchallProductWithTag:(NSString *)tag
{
NSPredicate *predicate =
[NSPredicate predicateWithFormat:@"tags.name contains [cd] %@", tag];
NSSet *itemsSet = [self.managedObjectContext
fetchObjectsForEntityName:TABLE_NAME_PRODUCT
withPredicate:predicate
columns:nil unique:NO];
return itemsSet.allObjects;
}
Here is the implementation of fetchObjectsForEntityName:withPredicate:columns: from a category class:
- (NSSet *)fetchObjectsForEntityName:(NSString *)entityName
withPredicate:(NSPredicate *)predicate
columns:(NSArray *)columns
unique:(BOOL)unique
{
NSEntityDescription *entity = [NSEntityDescription
entityForName:entityName inManagedObjectContext:self];
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:entityName];
[request setEntity:entity];
[request setPredicate:predicate];
[request setReturnsDistinctResults:unique];
if( columns.count > 0)
[request setPropertiesToFetch:columns];
if( columns.count > 0 || unique )
[request setResultType:NSDictionaryResultType];
NSError *error = nil;
NSArray *results = [self executeFetchRequest:request error:&error];
if (error != nil)
{
[NSException raise:NSGenericException
format:@"Error fetching in %@; error:%@",
entityName, error.localizedDescription];
}
if( results.count > 0 )
{
return [NSSet setWithArray:results];
}
return nil;
}
In my view controller I have this function call:
self.productArray = [myClass fetchAllProductWithTag:@"All"];
Then somewhere in viewcontroller class code I reset the value of productArray:
self.productArray = [myClass fetchAllProductWithTag:@"Favorites"];
Then the leak happens.
It turned out that the line causing the leak was try-catch statement. I had something like this:
Product *product = nil;
@try
{
product = [self.productArray objectAtIndex:index];
}
@catch (NSException *exception)
{
return;
}
I didn't want to check if the index was out of bound. So I put it in a try-catch and return if an exception occur.
So, I tried to remove the try-catch and had something like this:
Product *product = nil;
if( index < self.productArray.count )
product = [self.productArray objectAtIndex:index]
else
return;
Finally, the leak was gone.
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