在单元格之间以及边距和单元格 UICollectionView 之间创建相等的空间

Question

我有一个 UICollectionView。在某些设备上，细胞紧贴设备的边缘，而中心有很大的间隙。我尝试过更改插图和最小间距，但两者都不起作用。我在情节提要中创建了这个，所以我没有与格式相关的代码。如何使单元格之间的空间等于外部单元格和边缘之间的空间，以便中间没有巨大的间隙？谢谢。

图像的边缘是设备的精确边缘

Answer 1

假设您使用UICollectionViewFlowLayout 并且您的单元格具有固定大小：

自定义单元格代码：（我添加了一些阴影和圆角，忽略它）

import UIKit

class CollectionViewCell: UICollectionViewCell {
    override init(frame: CGRect) {
        super.init(frame: frame)


        layer.shadowColor = UIColor.lightGray.cgColor
        layer.shadowOffset = CGSize(width: 0, height: 2.0)
        layer.shadowRadius = 5.0
        layer.shadowOpacity = 1.0
        layer.masksToBounds = false
        layer.shadowPath = UIBezierPath(roundedRect: bounds, cornerRadius: contentView.layer.cornerRadius).cgPath
        layer.backgroundColor = UIColor.clear.cgColor

        contentView.layer.masksToBounds = true
        layer.cornerRadius = 10
    }

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

查看控制器代码：

import UIKit

private let reuseIdentifier = "Cell"

class CollectionViewController: UICollectionViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        /// Class registration
        collectionView.register(CollectionViewCell.self, forCellWithReuseIdentifier: reuseIdentifier)
        /// Expected cell size
        let cellSize = CGSize(width: 120, height: 110)

        /// Number of columns you need
        let numColumns: CGFloat = 2
        /// Interitem space calculation
        let interitemSpace = ( UIScreen.main.bounds.width - numColumns * cellSize.width ) / (numColumns + 1)

        /// Setting content insets for side margins
        collectionView.contentInset = UIEdgeInsets(top: 10, left: interitemSpace, bottom: 10, right: interitemSpace)

        /// Telling the layout which cell size it has
        (self.collectionView.collectionViewLayout as! UICollectionViewFlowLayout).itemSize = cellSize
    }

    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 10
    }

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath)
        cell.backgroundColor = .white
        return cell
    }
}

结果如下：