reloadData UICollectionView上的内存泄漏

Question

I'm working on my first project with iOS and should be considered a beginner with both Objective-C and xcode.

I'm building an app which displays sets of items in which the amount can vary from 1-200 items. I'm retrieving the items from RSS feeds and parse the XML. I've been able to show the items in a UITableView without problems and it's working the way I want it to.

The app is for both the iPhone and iPad (testing on 6.1) and my goal is to show the items in a UICollectionView on the iPad and in a UITableView on iPhone. I've been able to show the items in the collectionview but when I call the reloadData method the app crashes with the following error:

"Thread 1: EXC_BAD_ACCESS (code=1, address=0,50c1ecd9)"

In my search for the answer I read that turning on zombies could help me locate the problem, it's giving me this error:

[CollectionCell release]: message sent to deallocated instance 0xc177470

# Address Category Event Type RefCt Timestamp Size Responsible Library Responsible Caller 1507 0x16941940 CollectionCell Release 1 00:21.272.192 0 UIKit -[UICollectionView reloadData] 1508 0x16941940 CollectionCell Release 0 00:21.275.833 0 Foundation -[NSAutoreleasePool drain] 1509 0x16941940 CollectionCell Zombie -1 00:21.279.332 0 Foundation -[NSAutoreleasePool drain]

CollectionCell is my custom UICollectionViewCell class.

I'll provide both the code for the UITableView and UICollectionView which I think is most relevant to the source of the problem:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

static NSString *CellIdentifier = @"NewsCell_iPhone";
UITableViewCell *cell = nil;
cell = (NewsCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];

if (cell == nil) {
    NSArray *nib = nil;
    nib = [[NSBundle mainBundle] loadNibNamed:@"NewsCell_iPhone" owner:self options:nil];
    cell = [nib objectAtIndex:0];
} 

UICollectionView:

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {

static NSString *CellIdentifier = @"CollectionCell";
UICollectionViewCell *cell = (CollectionCell *)[collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];

if (cell == nil) {
    NSLog(@"Test");
    NSArray *nib = nil;
    nib = [[NSBundle mainBundle] loadNibNamed:@"CollectionCell_iPad" owner:self options:nil];
    cell = [nib objectAtIndex:0];
}

NewsCell (UITableViewCell)

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self) {
    // Initialization code
}
return self;
}

CollectionCell (UICollectionViewCell)

- (id)initWithFrame:(CGRect)frame {

self = [super initWithFrame:frame];

if (self) {
    // Initialization code
    NSArray *arrayOfViews = [[NSBundle mainBundle] loadNibNamed:@"CollectionCell" owner:self options:nil];

    if ([arrayOfViews count] < 1) {
        return nil;
    }

    if (![[arrayOfViews objectAtIndex:0] isKindOfClass:[UICollectionViewCell class]]) {
        return nil;
    }

    self = [arrayOfViews objectAtIndex:0];
}
return self;
}

I hope I've included what's necesarry to solve this problem, I'm open to any advice to improve my code.

Answer 1

Seeing your code, and your comment that ARC is off, the memory leak is most likely happening because you're allocating space for your objects, but never releasing it.

If you're fairly new to programming, specifically dynamic memory management, I would suggest turning ARC on so you don't have to worry about releasing objects.

Also, follow your tutorial, if it has ARC on, turn it on, if it's off, turn it off. This is because if it's on in the tutorial, it won't implement dealloc methods, which server the purpose of freeing up memory.