iOS UICollectionView 一行三个计算 高度

- (void)updateData:(NSMutableArray<SearchCategoriesCellModel *> *)listArr isNormal:(BOOL)isNormal isMoreAlert:(BOOL)isMoreAlert{
    self.listArr = listArr;
    self.isNormal = isNormal;///更换cell
    
    ///取余结果：3 一行3个
    NSUInteger result = listArr.count % 3;
    NSUInteger row = 0;///多少行
    if (result == 0) {
        row = listArr.count/3;///行数计算
    }else{
        row = listArr.count/3 + 1;
    }
    
    ///列表高度
    CGFloat listHeight = 0;
    
    if (isMoreAlert) {//高度高一些
        [self.listBgView mas_updateConstraints:^(MASConstraintMaker *make) {
            if (@available(iOS 11.0, *)) {
                make.top.equalTo(self.mas_safeAreaLayoutGuideTop).offset(50);
            } else {
                make.top.equalTo(self).offset(50);
            }
        }];
        
        if (row * 55 + 20 > 420) {
            self.listView.showsVerticalScrollIndicator = YES;
        }
        listHeight = row * 55 + 20 > 420 ? 420 : row * 55 + 20;
    }else{
        listHeight = row * 55 + 20 > 265 ? 265 : row * 55 + 20 ;
        if (row * 55 + 20 > 265) {
            self.listView.showsVerticalScrollIndicator = YES;
        }
    }
    
    [self.listView mas_updateConstraints:^(MASConstraintMaker *make) {
        make.height.mas_equalTo(listHeight);
    }];
    [self.listView reloadData];
}