我试图通过使用 GCD 为 Collection 视图加载单元格来解决性能问题。我的单元格加载代码如下：
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView
cellForItemAtIndexPath:(NSIndexPath *)indexPath{
UICollectionViewCell *slideCell =
[collectionView dequeueReusableCellWithReuseIdentifier:slideCellIdentifier
forIndexPath:indexPath];
slideCell.backgroundColor = [UIColor lightGrayColor];
slideCell.selectedBackgroundView = [[UIView alloc]initWithFrame:slideCell.bounds];
slideCell.selectedBackgroundView.backgroundColor = [UIColor redColor];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
@autoreleasepool {
SlideHeader *slideHeader = [self.fetchedResultsController objectAtIndexPath:indexPath];
UIImageView *imageView = [[UIImageView alloc] init];
imageView.contentMode = UIViewContentModeScaleAspectFill;
imageView.clipsToBounds = YES;
imageView.frame = CGRectMake(2, 2, slideCell.bounds.size.width-4, slideCell.bounds.size.height -4);
if (slideHeader.frontCoverImage) {
NSData *frontCoverImage = slideHeader.frontCoverImage;
imageView.image = [UIImage imageWithData:frontCoverImage];
}
dispatch_async(dispatch_get_main_queue(), ^{
NSArray *visibleCells = [self.collectionView visibleCells];
if ([visibleCells containsObject:slideCell]) {
[slideCell.contentView addSubview:imageView];
if (slideHeader.slideTitle.length > 0) {
UILabel *titleLabel = [[UILabel alloc]initWithFrame:CGRectMake(slideCell.bounds.origin.x, slideCell.bounds.size.height - 30, slideCell.bounds.size.width, 30)];
titleLabel.text = slideHeader.slideTitle;
titleLabel.backgroundColor = [UIColor lightTextColor];
titleLabel.font = [UIFont boldSystemFontOfSize:18];
titleLabel.textColor = [UIColor blackColor];
titleLabel.textAlignment = UITextAlignmentCenter;
titleLabel.userInteractionEnabled = NO;
[slideCell.contentView addSubview:titleLabel];
}
}
});
}
});
return slideCell;
}
我正在使用 ARC 并内置 6.1。我相信 arc 会为我释放 GCD 内存，但我最终遇到了一个问题：
以下是内存使用的屏幕截图：
当我继续上下滚动收藏视图时，内存上升了。我花了很长时间才释放内存，当内存使用率足够高时，这会导致程序崩溃。
我尝试像在我的代码中一样在 GCD 块中添加 autorealse，但这无助于更快地释放内存。
我能问我能做些什么来解决这个问题吗？谢谢你。