滚动UICollectionView时，UICollectionView单元格在跳动

Question

大家好，我是IOS开发中的新手，我有一个UICollection，可在其中使用SDWebImageCache加载图像。 问题是我的UICollectionview单元格在快速滚动时感觉像在抽搐或发抖。 下面我发布我的代码以使用SDWebImageCache加载图像

  [_homeCellImage sd_setImageWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@%@",[dictionary objectForKey:@"user_image"],[QPCommonClass cropImageWithWidth:500 andHeight:500]]] placeholderImage:[UIImage imageNamed:@"defaultIcon"]];
    [_qpQuestionImage sd_setImageWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@%@",[dictionary objectForKey:@"image"],[QPCommonClass cropImageWithWidth:1400 andHeight:1200]]] placeholderImage:[UIImage imageNamed:@"question"] options:0 completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL){
        [_qpHomeActivityIndicator setHidden:YES];
        [_qpHomeActivityIndicator stopAnimating];

    }];

_homeCellImage和_qpQuestionImage是UIImageViews

Answer 1

1. 确保将图像加载到后台线程中。
2. 加载图像后，请确保将其缓存。

现在，当您通过cellForItem设置图像时，可以直接从缓存中加载图像，它应该更加平滑。

Answer 2

尝试这样做

[_homeCellImage setShowActivityIndicatorView:YES];

[_homeCellImage setIndicatorStyle:UIActivityIndicatorViewStyleGray];

[_homeCellImage sd_setImageWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@%@",[dictionary objectForKey:@"user_image"],[QPCommonClass cropImageWithWidth:500 andHeight:500]]] placeholderImage:[UIImage imageNamed:@"defaultIcon"] options:SDWebImageRefreshCached];

[_qpQuestionImage setShowActivityIndicatorView:YES];

[_qpQuestionImage setIndicatorStyle:UIActivityIndicatorViewStyleGray];

[_qpQuestionImage sd_setImageWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@%@",[dictionary objectForKey:@"image"],[QPCommonClass cropImageWithWidth:1400 andHeight:1200]]] placeholderImage:[UIImage imageNamed:@"question"] options:SDWebImageRefreshCached];

Answer 3

您必须在出队后添加这两行。

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