使UICollectionViewFlowLayout不使单元格在同一行居中

class CustomFlowLayout: UICollectionViewFlowLayout {
    override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
        let attributes = super.layoutAttributesForElements(in: rect)
        
        // 遍历所有单元格的布局属性
        for attribute in attributes ?? [] {
            // 判断是否需要调整布局
            if attribute.representedElementKind == nil {
                // 修改单元格的frame属性，向左偏移100个点
                attribute.frame.origin.x -= 100
            }
        }
        
        return attributes
    }
}

// 在UICollectionView的代理方法中设置CustomFlowLayout为布局对象
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    return CGSize(width: 100, height: 100)
}

let collectionView = UICollectionView(frame: CGRect.zero, collectionViewLayout: CustomFlowLayout())