斯威夫特4:

label.lineBreakMode = .byWordWrapping

label.numberOfLines = 0

label.translatesAutoresizingMaskIntoConstraints = false

label.preferredMaxLayoutWidth = superview.bounds.size.width - 10 

textLabel.lineBreakMode = UILineBreakModeWordWrap;
textLabel.numberOfLines = 0;

上面的解决方案对我的情况不起作用。我是这样做的:

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    // ...

    CGSize size = [str sizeWithFont:[UIFont fontWithName:@"Georgia-Bold" size:18.0] constrainedToSize:CGSizeMake(240.0, 480.0) lineBreakMode:UILineBreakModeWordWrap];
    return size.height + 20;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil)
    {
        // ...
        cell.textLabel.lineBreakMode = UILineBreakModeWordWrap;
        cell.textLabel.numberOfLines = 0;
        cell.textLabel.font = [UIFont fontWithName:@"Georgia-Bold" size:18.0];
    }

    // ...

    UILabel *textLabel = [cell textLabel];
    CGSize size = [text sizeWithFont:[UIFont fontWithName:@"Georgia-Bold" size:18.0]
                                        constrainedToSize:CGSizeMake(240.0, 480.0)
                                            lineBreakMode:UILineBreakModeWordWrap];

    cell.textLabel.frame = CGRectMake(0, 0, size.width + 20, size.height + 20);

    //...
}

你应该试试这个:

-(CGFloat)dynamicLblHeight:(UILabel *)lbl
{
    CGFloat lblWidth = lbl.frame.size.width;
    CGRect lblTextSize = [lbl.text boundingRectWithSize:CGSizeMake(lblWidth, MAXFLOAT)
                                               options:NSStringDrawingUsesLineFragmentOrigin
                                            attributes:@{NSFontAttributeName:lbl.font}
                                               context:nil];
    return lblTextSize.size.height;
}

UILabel *helpLabel = [[UILabel alloc] init];
NSAttributedString *attrString = [[NSAttributedString alloc] initWithString:label];
helpLabel.attributedText = attrString;
// helpLabel.text = label;

helpLabel.textAlignment = NSTextAlignmentCenter;
helpLabel.lineBreakMode = NSLineBreakByWordWrapping;
helpLabel.numberOfLines = 0;

出于某些原因，它在iOS 6中不为我工作，不知道为什么。尝试了带和不带带属性的文本。任何建议。

在IB中，将行数设置为0(允许无限行)

当使用IB在文本框中输入时，使用“alt-return”插入一个返回值并转到下一行(或者您可以复制已经被行隔开的文本)。

使用它在UILabel中有多行文本:

textLabel.lineBreakMode = NSLineBreakByWordWrapping;
textLabel.numberOfLines = 0;

迅速:

textLabel.lineBreakMode = .byWordWrapping
textLabel.numberOfLines = 0