UITableViewCell中的动态内容视图？

Question

我正在尝试在我的UITableViewCell中放置一个用故事板创建的评论。该视图的大小取决于要显示的注释数和每个注释主体的大小。视图在我的cellForRowAtIndexPath:方法中设置，并调用此函数：

-(void)setupWithComments:(NSArray*)comments count:(int)count {
    int commentsToDisplay = comments.count;

    if (commentsToDisplay == 0) {
        return;
    }

    CGFloat yValue = 0;
    for (int i = commentsToDisplay - 1; i >= 0 ; i--) {
        PComment *comment = [comments objectAtIndex:i];

        UIView *containerBlock = [[UIView alloc] init];

        UILabel *timeAgoLabel = [[UILabel alloc] init];
        timeAgoLabel.text = [PUtilities timeAgo:comment.createdAt];
        timeAgoLabel.font = [UIFont systemFontOfSize:12.0];
        timeAgoLabel.textAlignment = NSTextAlignmentRight;
        timeAgoLabel.textColor = [UIColor whiteColor];
        [containerBlock addSubview:timeAgoLabel];

        [timeAgoLabel makeConstraints:^(MASConstraintMaker *make) {
            make.bottom.equalTo(containerBlock.bottom).with.offset(-10);
            make.right.equalTo(containerBlock.right).with.offset(-10);
        }];

        NSAttributedString *commentString = [PUtilities attributeSubstrings:@[comment.formattedBody, comment.creator.username]
                                                             withAttributes:@[CommentBodyAttributes, UsernameAttributes]
                                                             inFormatString:[NSString stringWithFormat:@"%@  %@", comment.creator.username, comment.formattedBody]];

        CGRect commentSize = [comment.attributedBody boundingRectWithSize:CGSizeMake(270, 9999)
                                                         options:(NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading)
                                                         context:nil];

        UILabel *commentLabel = [[UILabel alloc] init];
        commentLabel.numberOfLines = 0;
        commentLabel.lineBreakMode = NSLineBreakByWordWrapping;
        commentLabel.attributedText = commentString;
        commentLabel.tag = (i + 1);

        [containerBlock addSubview:commentLabel];

        [commentLabel makeConstraints:^(MASConstraintMaker *make) {
            make.left.equalTo(containerBlock.left).with.offset(25);
            make.top.equalTo(containerBlock.top).with.offset(10);
            make.right.equalTo(containerBlock.right).with.offset(-25);
        }];

        CGFloat height = CGRectGetHeight(commentSize) + 20;
        containerBlock.frame = CGRectMake(0, yValue, 320, height);
        yValue += height;

        [PUtilities logFrame:containerBlock.frame];

        [self addSubview:containerBlock];
    }
}

挑战在于使表格视图单元格的大小正确。默认情况下，它们应该是帧的大​​小，减去状态栏（548）。我试图用这种方法获得细胞的正确高度：

-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    NSDictionary *CommentBodyAttributes = @{
                                            NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue" size:12.0],
                                            NSForegroundColorAttributeName: [UIColor whiteColor]
                                            };

    PVideo *video = [self.videos objectAtIndex:indexPath.section];

    if (video.mostRecentComments.count != 0) {

        __block CGFloat height = 0;
        [video.mostRecentComments enumerateObjectsUsingBlock:^(PComment *comment, NSUInteger index, BOOL *stop) {
            NSAttributedString *commentString = [PUtilities attributeSubstrings:@[comment.formattedBody, comment.creator.username]
                                                                 withAttributes:@[CommentBodyAttributes, CommentBodyAttributes]
                                                                 inFormatString:[NSString stringWithFormat:@"%@  %@", comment.creator.username, [comment formattedBody]]];

            CGRect commentSize = [commentString boundingRectWithSize:CGSizeMake(270, 9999)
                                                             options:(NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading)
                                                             context:nil];
            height += CGRectGetHeight(commentSize) + 20;
        }];

        NSLog(@"%f", height + 457);

        return 457 + height;
    }else {
        return kVideoCellHeight;
    }
}

但它从来没有适当的大小，导致评论被切断，或底部的空间过多。我刚刚遗漏的代码中是否有明显的错误？