Question

我在我的集合视图中使用以下代码：cellForItemAtIndexPath

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *identifier = @"Cell";

    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];

    UIImageView *recipeImageView = (UIImageView *)[cell viewWithTag:100];
    recipeImageView.image = nil;
    if ([ImageArray count] >0){

            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^(void) {
                NSData *data0 = [NSData dataWithContentsOfURL: [NSURL URLWithString:[ImageArray objectAtIndex:indexPath.row]]];
                UIImage *image = [UIImage imageWithData: data0];

                dispatch_sync(dispatch_get_main_queue(), ^(void) {
                    recipeImageView.image = image;
                });
            });

    }

    [spinnerShow stopAnimating];

    cell.layer.shouldRasterize = YES;
    cell.layer.rasterizationScale = [UIScreen mainScreen].scale;

    return cell;
}

问题是，如果我滚动集合视图，图像会闪烁。为什么会这样？当我滚动图像时，如何防止图像闪烁？

Answer 1

我认为根本原因是加载以下2行图像的成本：

NSData *data0 = [NSData dataWithContentsOfURL: [NSURL URLWithString:[ImageArray objectAtIndex:indexPath.row]]];
UIImage *image = [UIImage imageWithData: data0];

我的解决方案是使用AFNetworking加载图片处理，请参考链接：https://github.com/AFNetworking/AFNetworking

安装AFNetworking后，您只需：

if ([ImageArray count] >0){
    [recipeImageView setImageWithURL:[NSURL URLWithString:[ImageArray objectAtIndex:indexPath.row]] placeholderImage:nil];
}

希望你喜欢这个！

滚动时CollectionView图像闪烁

1 个答案: