iOS 不规则collectionview cell创建 可分组 可自定义

1、根据业务需要 弄了一个不规则cell 排版
主要是cell的size 的设定
方法一：继承UICollectionViewFlowLayout 做的操作

// 分组 section 设定size  可根据需要自动调整cell 的size
- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect{
   NSArray *array = [super layoutAttributesForElementsInRect:rect];
   
   for (int i = 1; i < array.count; i++){
       UICollectionViewLayoutAttributes * attribute = array[i];
       UICollectionViewLayoutAttributes * attribute2 = array[i-1];

       if (attribute.indexPath.section == attribute2.indexPath.section && attribute.frame.origin.x != 0) {
           NSInteger maximumSpacing = 10;
           NSInteger origin = CGRectGetMaxX(attribute2.frame);
           
           if (origin + maximumSpacing + attribute.frame.size.width <= self.collectionView.frame.size.width - 10) {
               CGRect frame = attribute.frame;
               frame.origin.x = origin + maximumSpacing;
               attribute.frame = frame;
           } else {
               CGRect frame = attribute.frame;
               frame.origin.x = maximumSpacing;
               frame.origin.y = CGRectGetMaxY(attribute2.frame) + maximumSpacing;
               attribute.frame = frame;

           }   
       }
   }
   return array;
}

- (BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds{
   return YES;
}

正常添加一个collectionView
主要需要实现自定义cell 根据文本内容设定size

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    NSString *txt = self.tags[indexPath.row];
    CGSize size = [txt boundingRectWithSize:CGSizeMake(MAXFLOAT, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:13]} context:nil].size;
    return CGSizeMake(size.width + 15, 25);
}

代码：地址