Swift 3版本

简单地创建一个UICollectionViewFlowLayout子类并粘贴这个方法。

override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
        guard let answer = super.layoutAttributesForElements(in: rect) else { return nil }

        for i in 1..<answer.count {
            let currentAttributes = answer[i]
            let previousAttributes = answer[i - 1]

            let maximumSpacing: CGFloat = 8
            let origin = previousAttributes.frame.maxX

            if (origin + maximumSpacing + currentAttributes.frame.size.width < self.collectionViewContentSize.width && currentAttributes.frame.origin.x > previousAttributes.frame.origin.x) {
                var frame = currentAttributes.frame
                frame.origin.x = origin + maximumSpacing
                currentAttributes.frame = frame
            }
        }

        return answer
}

我在Swift 3单元格间距的解决方案，如Instagram:

lazy var collectionView: UICollectionView = {
    let layout = UICollectionViewFlowLayout()
    let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
    cv.backgroundColor = UIColor.rgb(red: 227, green: 227, blue: 227)
    cv.showsVerticalScrollIndicator = false
    layout.scrollDirection = .vertical
    layout.minimumLineSpacing = 1
    layout.minimumInteritemSpacing = 1
    return cv
}()

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {

    switch UIDevice.current.modelName {
    case "iPhone 4":
        return CGSize(width: 106, height: 106)
    case "iPhone 5":
        return CGSize(width: 106, height: 106)
    case "iPhone 6,7":
        return CGSize(width: 124, height: 124)
    case "iPhone Plus":
        return CGSize(width: 137, height: 137)
    default:
        return CGSize(width: frame.width / 3, height: frame.width / 3)
    }
}

如何编程检测设备: https://stackoverflow.com/a/26962452/6013170

使用水平流布局，我也得到了10点之间的单元格间距。为了移除间距，我需要将minimumlinespespaces和minimumInterItemSpacing设置为零。

UICollectionViewFlowLayout *flow = [[UICollectionViewFlowLayout alloc] init];
flow.itemSize = CGSizeMake(cellWidth, cellHeight);
flow.scrollDirection = UICollectionViewScrollDirectionHorizontal;
flow.minimumInteritemSpacing = 0;
flow.minimumLineSpacing = 0;

此外，如果所有单元格大小相同，直接在流布局上设置属性比使用委托方法更简单、更有效。

最流行的答案的Swift版本。单元格之间的空格将等于cellSpacing。

class CustomViewFlowLayout : UICollectionViewFlowLayout {

    let cellSpacing:CGFloat = 4

    override func layoutAttributesForElementsInRect(rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
        if let attributes = super.layoutAttributesForElementsInRect(rect) {
        for (index, attribute) in attributes.enumerate() {
                if index == 0 { continue }
                let prevLayoutAttributes = attributes[index - 1]
                let origin = CGRectGetMaxX(prevLayoutAttributes.frame)
                if(origin + cellSpacing + attribute.frame.size.width < self.collectionViewContentSize().width) {
                    attribute.frame.origin.x = origin + cellSpacing
                }
            }
            return attributes
        }
        return nil
    }
}

记住，它是最小行间距，而不是最小项间距或单元格间距。因为你的collectionView的滚动方向是水平的。

如果是垂直的，则需要为单元格之间的水平空间设置单元格空间或项间空间，为单元格之间的垂直空间设置行间距。

objective - c版本

- (CGFloat)collectionView:(UICollectionView *)collectionView
                       layout:(UICollectionViewLayout*)collectionViewLayout
    minimumLineSpacingForSectionAtIndex:(NSInteger)section
    {
        return 20;
    }

斯威夫特版本:

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
    return 20
}

如果你想在不影响实际单元格大小的情况下调整间距，这是最适合我的解决方案。#xcode 9 #tvOS11 #iOS11 #swift

在uicollectionviewdelegatflowlayout中，改变实现下一个方法，诀窍是你必须使用它们两个，文档并没有真正指向我去思考那个方向。: D

open func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
    return cellSpacing
}

public func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
    return cellSpacing
}