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
    }
}

试试下面的代码，确保每个项目之间的间距为5px:

- (UIEdgeInsets)collectionView:(UICollectionView *) collectionView 
                        layout:(UICollectionViewLayout *) collectionViewLayout 
        insetForSectionAtIndex:(NSInteger) section {

    return UIEdgeInsetsMake(0, 0, 0, 5); // top, left, bottom, right
}

- (CGFloat)collectionView:(UICollectionView *) collectionView
                   layout:(UICollectionViewLayout *) collectionViewLayout
  minimumInteritemSpacingForSectionAtIndex:(NSInteger) section {    
    return 5.0;
}

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
    }
}

我尝试了iago849的答案，它起作用了。

斯威夫特4

open override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
    guard let answer = super.layoutAttributesForElements(in: rect) else {
        return nil
    }
    let count = answer.count
    for i in 1..<count {
        let currentLayoutAttributes = answer[i]
        let prevLayoutAttributes = answer[i-1]
        let origin = prevLayoutAttributes.frame.maxX
        if (origin + CGFloat(spacing) + currentLayoutAttributes.frame.size.width) < self.collectionViewContentSize.width && currentLayoutAttributes.frame.origin.x > prevLayoutAttributes.frame.origin.x {
            var frame = currentLayoutAttributes.frame
            frame.origin.x = origin + CGFloat(spacing)
            currentLayoutAttributes.frame = frame
        }
    }
    return answer
}

这是github项目的链接。 https://github.com/vishalwaka/MultiTags

回答Swift 3.0, Xcode 8

1.确保你设置了集合视图委托

class DashboardViewController: UIViewController {
    @IBOutlet weak var dashboardCollectionView: UICollectionView!

    override func viewDidLoad() {
        super.viewDidLoad()
        dashboardCollectionView.delegate = self
    }
}

2.实现uicollectionviewdelegatflowlayout协议，而不是UICollectionViewDelegate。

extension DashboardViewController: UICollectionViewDelegateFlowLayout {
    fileprivate var sectionInsets: UIEdgeInsets {
        return .zero
    }

    fileprivate var itemsPerRow: CGFloat {
        return 2
    }

    fileprivate var interitemSpace: CGFloat {
        return 5.0
    }

    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        sizeForItemAt indexPath: IndexPath) -> CGSize {
        let sectionPadding = sectionInsets.left * (itemsPerRow + 1)
        let interitemPadding = max(0.0, itemsPerRow - 1) * interitemSpace
        let availableWidth = collectionView.bounds.width - sectionPadding - interitemPadding
        let widthPerItem = availableWidth / itemsPerRow

        return CGSize(width: widthPerItem, height: widthPerItem)
    }

    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        insetForSectionAt section: Int) -> UIEdgeInsets {
        return sectionInsets
    }

    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 0.0
    }

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

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;