ios - UICollectionViewFlowLayout 的行和列

Question

给定一个具有流式布局的 UICollectionView，计算 Collection View 的列数(垂直方向)或行数(水平方向)的最简单方法是什么？

Answer 1

我的做法(假设所有元素具有相同的大小):

- (void) countRowsAndColumns
{
    NSArray *layouts = [collectionViewLayout layoutAttributesForElementsInRect:self.collectionView.bounds];
    NSMutableSet *columns = [NSMutableSet set];
    NSMutableSet *rows = [NSMutableSet set];
    for (UICollectionViewLayoutAttributes *layout in layouts)
    {
        if (layout.representedElementCategory != UICollectionElementCategoryCell) continue;
        CGFloat x = layout.frame.origin.x;
        [columns addObject:@(x)];
        CGFloat y = layout.frame.origin.y;
        [rows addObject:@(y)];
    }
    _columnCount = columns.count;
    _rowCount = rows.count;
}