CODEWITHSUNDEEP
iphoneobjective-ciosxcode
Vlad Z.
Vlad Z.

Reputation: 3451

UITableViewController scrolling lag with large amount of images

I have following code of cellForRowAtIndexPathmethod:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"champion cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    UIImage *cellIcon = [UIImage imageNamed:[arrayOfChampionPictures objectAtIndex:indexPath.row]];
    [[cell imageView] setImage:cellIcon];

    cell.imageView.frame = CGRectMake(0.0f, 0.0f, 70.0f, 70.0f);

    cell.imageView.layer.cornerRadius = 7;
    [cell.imageView.layer setMasksToBounds:YES];

    cell.textLabel.text = [arrayOfChampionNames objectAtIndex:indexPath.row];

    return cell;
}

Where arrayOfChampionNames is local database stored in NSMutableArray that contains pictures names. It's about 103 cells with images in my UITableView. It lags at first scroll from beginning to end, after that it's scrolling smoothly. There's no lags on simulator.

Possible solutions I came up with, but i don't know how to realise them

Upvotes: 1

Views: 1214

Answers (2)

Benjamin Mayo
Benjamin Mayo

Reputation: 6679

I'll tell you where the lag is coming from - corner radius. Pre compute the images rounded corners. Doing them dynamically kills scrolling performance.

Upvotes: 2

Mick MacCallum
Mick MacCallum

Reputation: 130183

You forgot something:

static NSString *CellIdentifier = @"champion cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

if (cell == nil) {
       cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}

This way you'll actually utilize the reusable identifier that you created.

Upvotes: 0

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