CODEWITHSUNDEEP
iosobjective-cuitableviewautomatic-ref-counting
Pham Hoan
Pham Hoan

Reputation: 2127

UITableViewCell Identifier without ARC floods memory

I'm working on an old project that runs without ARC. It has a lot of bugs and the code looks ugly and i'm rewriting it.

Take a quick look at my code

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [self.table dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil)
    {
        cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
    }

    cell = [self createCellWithInfo:[self.search objectAtIndex:indexPath.row]];
    return cell;
}

-(UITableViewCell *)createCellWithInfo:(NSDictionary *)info{

    UITableViewCell * cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@“Cell”] autorelease];
    //set image for cell
    //set text for cell.textlabel
    //set text for cell.detailTextLabel
    //create an UIButton and add to cell.content view
    return cell;
}

the point is at this line of code [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@“Cell”] autorelease]

if I use @"Cell" here, then the memory will rise up when I'm scrolling up and down continously on the table. After about 15 seconds of scrolling, my iphone 5c becomes lag.

if I set it to nil, everything is fine.

Can anybody explain this please ? I'm not familliar with non-ARC.

Thanks.

Upvotes: 0

Views: 451

Answers (2)

Mike Pollard
Mike Pollard

Reputation: 10195

UITableViewCell *cell = [self.table dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil){
    cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}

alone takes care of cell initialisation, you don't need the other line.

Upvotes: 0

Clafou
Clafou

Reputation: 15400

Inside the if block you are creating the cell without calling autorelease, which leaks memory without ARC.

And after the if block you are recreating it anyway (whether or not it was recycled), with autorelease this time, where all you should really be doing is reset its relevant properties so that you can successfully reuse a recycled cell (or configure a new cell).

Try replacing your code as follows:

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [self.table dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil)
    {
        cell = [[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
    }

    [self updateCell:cell withInfo:[self.search objectAtIndex:indexPath.row]];
    return cell;
}

-(void)updateCell:(UITableViewCell *)cell withInfo:(NSDictionary *)info{
    //set image for cell
    //set text for cell.textlabel
    //set text for cell.detailTextLabel
    //create an UIButton and add to cell.content view
}

Upvotes: 5

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