Swift CollectionView 随机图像为 null

Question

您好，我的 UICollectionView 有问题。首先，我有一个来自服务器的图像列表，其中包含 url 图像。

但是当 url 为 null 时，单元格显示随机图像。我想要当 url 为 null 时，只是不显示图像。

我正在使用 SDWebImage 向 UIImageView 显示图像。

func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return listData.count
}

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("CollectionViewCell", forIndexPath: indexPath) as! MyCollectionListViewCell
        if let url = self.listData[indexPath.row]["photo"] as? String {
            let urlPhoto = NSURL(string:url!)
            cell.imageView.sd_setImageWithURL(urlPhoto, placeholderImage:img)
            cell.imageView.contentMode = UIViewContentMode.ScaleAspectFill
            cell.imageView.layer.masksToBounds = true
            cell.imageView.clipsToBounds = true
         }
}

Answer 1

由于 UICollectionViewCell 将被重用，只需将单元格的图像设置为 nil:

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("CollectionViewCell", forIndexPath: indexPath) as! MyCollectionListViewCell
        if let url = self.listData[indexPath.row]["photo"] as? String {
            let urlPhoto = NSURL(string:url!)
            cell.imageView.sd_setImageWithURL(urlPhoto, placeholderImage:img)
            cell.imageView.contentMode = UIViewContentMode.ScaleAspectFill
            cell.imageView.layer.masksToBounds = true
            cell.imageView.clipsToBounds = true
         } else {
            cell.imageView.image = nil
         }
}