Question

我想根据标签的高度动态设置单元格的高度。

我创建了单元格：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *simpleTableIdentifier = @"ORDStepsCell";

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];

UILabel *stepsLabel;
UILabel *stepsNumberLabel;
UIImageView *bulletImageView;
UIImageView *cellBackgroungImage;

if (cell == nil) {
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:simpleTableIdentifier];

    CGRect stepsLabelFrame = CGRectMake(20, 0, 253, 21);
    CGRect bulletImageViewFrame = CGRectMake(281, 25, 29, 29);;
    CGRect stepsNumberLabelFrame = CGRectMake(3, 3, 21, 21);
    CGRect cellBackgroungImageFrame = CGRectMake(0, 0, 320, 80);

    cellBackgroungImage = [[UIImageView alloc] initWithFrame:cellBackgroungImageFrame];
    cellBackgroungImage.image = [UIImage imageNamed:@"list-item"];

    stepsLabel = [[UILabel alloc] initWithFrame:stepsLabelFrame];
    stepsLabel.textAlignment = UITextAlignmentRight;
    stepsLabel.tag = 0;

    bulletImageView = [[UIImageView alloc] initWithFrame:bulletImageViewFrame];
    bulletImageView.image = [UIImage imageNamed:@"step-bullet"];

    stepsNumberLabel = [[UILabel alloc] initWithFrame:stepsNumberLabelFrame];
    stepsNumberLabel.textAlignment = UITextAlignmentCenter;
    stepsNumberLabel.textColor = [UIColor whiteColor];
    stepsNumberLabel.backgroundColor = [UIColor clearColor];
    stepsNumberLabel.font = [UIFont boldSystemFontOfSize:17.0];
    stepsNumberLabel.tag = 1;

    [cell.contentView addSubview:cellBackgroungImage];
    [cell.contentView addSubview:stepsLabel];
    [cell.contentView addSubview:bulletImageView];
    [bulletImageView addSubview:stepsNumberLabel];

} else {
    stepsLabel = (UILabel *)[cell viewWithTag:0];
    stepsNumberLabel = (UILabel *)[cell viewWithTag:1];
}

stepsLabel.text = [preperationSteps objectAtIndex:indexPath.row];
[stepsLabel setBackgroundColor:[UIColor redColor]];
[stepsLabel setNumberOfLines:0];
[stepsLabel sizeToFit];

NSLog(@"cellHeight = %f", cell.frame.size.height);

stepsLabel.frame = CGRectMake(20, (cell.frame.size.height - stepsLabel.frame.size.height) / 2, 253, stepsLabel.frame.size.height);

stepsNumberLabel.text = [NSString stringWithFormat:@"%d", indexPath.row + 1];

[cell setSelected:NO];
[cell setSelectionStyle:UITableViewCellEditingStyleNone];

return cell;

}

然后我计算了标签的高度：

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
UILabel *cellLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 253, 30)];
NSString *labelText = [preperationSteps objectAtIndex:indexPath.row];
cellLabel.text = labelText;
[cellLabel setNumberOfLines:0];

[cellLabel sizeToFit];

cellLabel.frame = CGRectMake(0, 0, 253, cellLabel.frame.size.height);
CGFloat cellLabelHeight = cellLabel.frame.size.height;
NSLog(@"cellLabelHeight = %f", cellLabelHeight + 20);
return cellLabelHeight + 20;
}

在日志中：

2013-03-08 17:37:18.161 Recipe[37547:c07] cellLabelHeight = 125.000000
2013-03-08 17:37:18.161 Recipe[37547:c07] cellLabelHeight = 62.000000
2013-03-08 17:37:18.161 Recipe[37547:c07] cellLabelHeight = 41.000000
2013-03-08 17:37:18.162 Recipe[37547:c07] cellLabelHeight = 41.000000
2013-03-08 17:37:18.162 Recipe[37547:c07] cellLabelHeight = 41.000000
2013-03-08 17:37:18.162 Recipe[37547:c07] cellLabelHeight = 41.000000
2013-03-08 17:37:18.163 Recipe[37547:c07] cellLabelHeight = 62.000000
2013-03-08 17:39:34.852 Recipe[37581:c07] cellHeight = 44.000000
2013-03-08 17:39:34.852 Recipe[37581:c07] cellHeight = 44.000000
2013-03-08 17:39:34.853 Recipe[37581:c07] cellHeight = 44.000000
2013-03-08 17:39:34.853 Recipe[37581:c07] cellHeight = 44.000000
2013-03-08 17:39:34.854 Recipe[37581:c07] cellHeight = 44.000000
2013-03-08 17:39:34.854 Recipe[37581:c07] cellHeight = 44.000000
2013-03-08 17:39:34.855 Recipe[37581:c07] cellHeight = 44.000000

正如您所看到的那样，即使从heightForRowAtIndexPath返回的值不同，单元格的高度也是固定的44。我知道在cellForRowAtIndexPath之前调用heightForRowAtIndexPath（可以在日志中看到），那么如何更改高度呢？

Answer 1

您在heightForRowAtIndexPath中提供的高度是显示的内容。将此代码粘贴到控制器中，看看实际显示的高度。

-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
    NSLog(@"%f", cell.frame.size.height);
}

您登录cellForRowAtIndexPath的高度只是单元格的默认高度。在调用cellForRowAtIndexPath之后分配高度。

Answer 2

我想根据标签的高度动态设置单元格的高度。

您可能想要这样，但是您没有在-tableView:cellForRowAtIndexPath:方法中的任何位置设置单元格高度。 -tableView:heightForRowAtIndexPath:没有为您设置单元格的高度 - 在前一种方法中配置单元格时需要这样做。后一种方法的原因是表格可以确定其自身的高度。每当它重新加载其数据时，它会向代表询问每一行的高度，并使用该信息来计算表的总高度。每次为给定行提供单元格时，仍然必须设置单元格高度。

Answer 3

为我解决问题的方法是使用sizeWithFont:constrainedToSize:lineBreakMode:和cellForRowAtIndexPath方法中的heightForRowAtIndexPath计算标签的文字长度，然后使用cellForRowAtIndexPath中的标签设置框架计算的大小。
如果它对任何人都有任何帮助，我会发布代码。

动态更改自定义单元格的高度不起作用

3 个答案: