ios - UITableView “received memory warning” 消息

Question

我正在使用 iPod touch5 测试我的应用程序并收到内存警告，

我正在使用自己的 UITableViewCell ，如何改进我的代码？非常感谢。

单元格:

- (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;
}

表格 View :

- (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

内存警告本身不是问题。根据我对setImageWithURLRequest:的理解，它使用默认的 NSURLCache 来缓存图像，每当收到内存警告时，系统就会释​​放缓存。您的内存不应以这种方式增加超过分配的限制。

顺便说一下，一个改进是分配 UIActivityIndicatorView在细胞内。在您当前的代码中，每次重新使用单元格时都会重新分配它...