UICollectionViewFlowLayout 的行和列 [英] Rows and columns of UICollectionViewFlowLayout

问题描述

给定一个带有流布局的UICollectionView，计算集合视图的列数(垂直方向)或行数(水平方向)的最简单方法是什么?

Given a UICollectionView with flow layout, what's the simplest way to calculate the number of columns (vertical direction) or rows (horizontal direction) of the collection view?

推荐答案

我的hackish方式(假设所有元素具有相同的大小):

My hackish way of doing it (assumes all elements have the same size):

- (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;
}

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