ios - 检查 UICollectionViewCell 子类中的变量是否为 nil

Question

我有这个 UICollectionViewcell

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! PostCell

    if let CurrentPost = posts[indexPath.row] as? Post {
        if(CurrentPost.PostImage == nil) {
            print(CurrentPost.PostText)
        }
    }

    return cell
}

class PostCell: UICollectionViewCell {
    override init(frame: CGRect) {
        super.init(frame: frame)
        designCell()
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    let postImage: UIImageView = {
        let v = UIImageView()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.contentMode = .scaleAspectFill
        return v
    }()

    func designCell() {
        addSubview(postImage)

        if (postImage.image == nil) {
            print("ss")
        }

        cellConstraints()
    }
}

现在我想做的是检查 posts[indexPath.row] PostImage 是否为 nil。如果它是 nil 那么在 PostCell 我想打印“ss”，否则我想将 postImage 的图像设置为 PostImage。

Answer 1

在你的手机里:

func passImage(imageToSet: UIImage?){
    if let image = imageToSet{
        //Do whatever you want
    }else{
        print("ss")
    }
}

在你的VC中

if let CurrentPost = posts[indexPath.row] as? Post{
    cell.passImage(imageToSet: CurrentPost.PostImage)
}