Swift -- UICollectionView中cell的排版布局

    override func layoutSubviews() {
    
    
        super.layoutSubviews()
        if let layout = rightCollectionView.collectionViewLayout as? UICollectionViewFlowLayout {
    
    
            layout.minimumLineSpacing = 15 //该属性：每横行cell之间的间距
            layout.minimumInteritemSpacing = 15 //该属性：每列cell之间的间距
            let row :CGFloat = 5 //每行5个cell
            let itemW = (rightCollectionView.w - (row+1)*layout.minimumLineSpacing)/row  //cell的宽
            let itemH = (rightCollectionView.h - (row+1)*layout.minimumInteritemSpacing)/row //cell的高
            layout.itemSize = CGSize(width: itemW, height: itemH)
            rightCollectionView.collectionViewLayout = layout
        }
    }