以前的版本并没有真正工作的部分> 1。所以我的解决方案在这里找到了https://codentrick.com/create-a-tag-flow-layout-with-uicollectionview/。对于懒惰的人:

override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
    let attributesForElementsInRect = super.layoutAttributesForElements(in: rect)
    var newAttributesForElementsInRect = [UICollectionViewLayoutAttributes]()
    // use a value to keep track of left margin
    var leftMargin: CGFloat = 0.0;
    for attributes in attributesForElementsInRect! {
        let refAttributes = attributes 
        // assign value if next row
        if (refAttributes.frame.origin.x == self.sectionInset.left) {
            leftMargin = self.sectionInset.left
        } else {
            // set x position of attributes to current margin
            var newLeftAlignedFrame = refAttributes.frame
            newLeftAlignedFrame.origin.x = leftMargin
            refAttributes.frame = newLeftAlignedFrame
        }
        // calculate new value for current margin
        leftMargin += refAttributes.frame.size.width + 10
        newAttributesForElementsInRect.append(refAttributes)
    }

    return newAttributesForElementsInRect
}

我使用monotouch，所以名称和代码会有点不同，但你可以通过确保集合视图的宽度等于(x *单元格宽度)+ (x-1) * MinimumSpacing与x =每行单元格的数量来做到这一点。

只需要根据MinimumInteritemSpacing和Cell的宽度执行以下步骤

1)我们根据单元格大小+当前插入+最小间距计算每行项目的数量

float currentTotalWidth = CollectionView.Frame.Width - Layout.SectionInset.Left - Layout.SectionInset.Right (Layout = flowlayout)
int amountOfCellsPerRow = (currentTotalWidth + MinimumSpacing) / (cell width + MinimumSpacing)

2)现在你有了所有信息来计算集合视图的预期宽度

float totalWidth =(amountOfCellsPerRow * cell width) + (amountOfCellsPerRow-1) * MinimumSpacing

3)所以当前宽度与预期宽度之差为

float difference = currentTotalWidth - totalWidth;

4)现在调整insets(在本例中，我们将其添加到右侧，因此集合视图的左侧位置保持不变

Layout.SectionInset.Right = Layout.SectionInset.Right + difference;

Swift 5 UIKit编程

 //Create UICollectionView
lazy var collectionView: UICollectionView = {
    
    let layout = UICollectionViewFlowLayout()
    layout.scrollDirection = .horizontal
    
    //CollectionCellView width autoSize
    layout.estimatedItemSize = UICollectionViewFlowLayout.automaticSize
    
    let collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
    collectionView.translatesAutoresizingMaskIntoConstraints = false
    
    collectionView.register(CustomCollectionViewCell.self, forCellWithReuseIdentifier: cellId)
    collectionView.backgroundColor = .clear
    collectionView.delegate = self
    collectionView.dataSource = self
    collectionView.alwaysBounceHorizontal = true

//Add Spacing in each cell
    layout.minimumInteritemSpacing = 15
    layout.minimumLineSpacing = 15
    
    return collectionView
}()

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
}

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。

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