如何使 UICollectionView 透明？

Question

我几乎（字面意思？）尝试了一切以使水平集合视图透明，该视图覆盖在 map 视图上。

这是我的收藏视图：

fileprivate let restaurantCollection : UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        layout.scrollDirection = .horizontal
        layout.minimumInteritemSpacing = 0
        layout.minimumLineSpacing = 0
        let restaurant = UICollectionView(frame: .zero, collectionViewLayout: layout)
        restaurant.decelerationRate = .fast
        restaurant.backgroundView = nil
        restaurant.layer.backgroundColor = UIColor.clear.cgColor
        restaurant.backgroundColor = .clear
        restaurant.translatesAutoresizingMaskIntoConstraints = false
        restaurant.register(MapCell.self, forCellWithReuseIdentifier: "Cell")
        return restaurant
    }()

如您所见，它具有清晰的背景、清晰的图层，并且背景视图为零。

并且单元格也是透明的：

func setupView() {
    contentView.backgroundColor = UIColor.clear.withAlphaComponent(0)

    contentView.addSubview(cellBackground)
    cellBackground.translatesAutoresizingMaskIntoConstraints = false
    cellBackground.topAnchor.constraint(equalTo: contentView.topAnchor).isActive = true
    cellBackground.leadingAnchor.constraint(equalTo: contentView.leadingAnchor).isActive = true
    cellBackground.trailingAnchor.constraint(equalTo: contentView.trailingAnchor).isActive = true
    cellBackground.bottomAnchor.constraint(equalTo: contentView.bottomAnchor).isActive = true
    }

我还向单元格“backgroundView”添加了一个视图，该单元格的所有边都固定为常数 0。 这也很清楚。

lazy var cellBackground : UIView = {
    let view = UIView(frame: CGRect(x: 10, y: 6, width: self.frame.width, height: 220))
    view.clipsToBounds = true
    view.backgroundColor = .clear
    view.layer.backgroundColor = UIColor.clear.cgColor
    return view
}()

经过所有这些努力，集合视图仍然具有白色背景

视图层次结构：这是仍然是白色的视图

Answer 1

您需要确保将backgroundColor设置为清除

    self.collectionView.backgroundColor = UIColor.clear
    self.collectionView.backgroundView = UIView.init(frame: CGRect.zero)

Answer 2

对于现代列表布局 CollectionViews：

UICollectionLayoutListConfiguration.backgroundColor = .clear
UICollectionViewListCell.backgroundConfiguration = .clear()