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
}()

在头文件中定义UICollectionViewDelegateFlowLayout协议。

实现UICollectionViewDelegateFlowLayout协议的如下方法:

- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
{
    return UIEdgeInsetsMake(5, 5, 5, 5);
}

点击这里查看苹果文档的UIEdgeInsetMake方法。

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

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
    }
}

如果你在创建一个水平集合视图，那么为了在单元格之间留出空间，你需要设置属性minimumlinespcing。