UITableView “received memory warning” message

Question

I'm testing my app with iPod touch5 and received memory warning,

I am using my own UITableViewCell , how can I improve my code? Thank you very much.

Cell:

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

    self.frame = CGRectMake(0.0, 0.0, 320.0, 255.0);


    self.shot_imageView = [[UIImageView alloc] initWithFrame:CGRectMake(10.0, 0.0, 300.0, 225.0)];
    [self addSubview:self.shot_imageView];

    UIImageView *viewsImageView = [[UIImageView alloc] initWithFrame:CGRectMake(15.0, 231.0, 13.0, 13.0)];
    viewsImageView.image = [UIImage imageNamed:@"eye"];
    [self addSubview:viewsImageView];

    self.viewsLabel = [[UILabel alloc] initWithFrame:CGRectMake(33.0, 230.0, 65.0, 15.0)];
    [self addSubview:self.viewsLabel];

    UIImageView *likesImageView = [[UIImageView alloc] initWithFrame:CGRectMake(150.0, 233.0, 10.0, 10.0)];
    [self addSubview:likesImageView];

    self.likesLabel = [[UILabel alloc] initWithFrame:CGRectMake(165.0, 230.0, 45.0, 15.0)];
    [self addSubview:self.likesLabel];


    UIImageView *commentsImageView = [[UIImageView alloc] initWithFrame:CGRectMake(270.0, 233.0, 10.0, 10.0)];
    [self addSubview:commentsImageView];

    self.commentsLabel = [[UILabel alloc] initWithFrame:CGRectMake(285.0, 230.0, 35.0, 15.0)];
    [self addSubview:self.commentsLabel];
}

return self;
}

TableView:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSUInteger section = [indexPath section];

static NSString *CellIdentifier = @"Cell";
Shots *shot =  [self.dataSource objectAtIndex:section];
//NSString *url = shot.image_url;
MyTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if ( cell == nil )
{
    cell = [[MyTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}

//[cell.shot_imageView setImageWithURL:[NSURL URLWithString:shot.image_url] placeholderImage:[UIImage imageNamed:@"placeholder"]];
UIActivityIndicatorView *activityIndicatorView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
activityIndicatorView.center = cell.shot_imageView.center;
[activityIndicatorView startAnimating];
[cell.shot_imageView addSubview:activityIndicatorView];
__weak typeof(cell) weakCell = cell;
[cell.shot_imageView setImageWithURLRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:shot.image_url]]
                            placeholderImage:[UIImage imageNamed:@"placeholder"]
                                     success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) {
                                         [activityIndicatorView stopAnimating];
                                         [activityIndicatorView removeFromSuperview];
                                         weakCell.shot_imageView.image = image;
                                     }
                                     failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) {
                                         [activityIndicatorView stopAnimating];
                                         [activityIndicatorView removeFromSuperview];
                                         [weakCell.shot_imageView setImage:[UIImage imageNamed:@"placeholder"]];
                                     }];

cell.likesLabel.text = [NSString stringWithFormat:@"%@",shot.likes_count];
cell.viewsLabel.text = [NSString stringWithFormat:@"%@",shot.views_count];
cell.commentsLabel.text = [NSString stringWithFormat:@"%@",shot.comments_count];
cell.selectionStyle = UITableViewCellSelectionStyleNone;

return cell;

}

Answer 1

Memory Warning is not an issue by itself. According to my understanding on setImageWithURLRequest:, it uses the default NSURLCache to cache images and the cache will be freed by the system whenever a memory warning is received. You memory should never increase over the assigned limit this way.

By the way, an improvement would be to alloc the UIActivityIndicatorView inside the cell. In your current code, you reallocate it each time a cell is reused...