试试这个语法:

NSAttributedString *attributedText =
    [[NSAttributedString alloc] initWithString:text 
                                    attributes:@{NSFontAttributeName: font}];

CGSize maximumLabelSize = CGSizeMake(label.frame.size.width, FLT_MAX);
CGSize expectedLabelSize = [label sizeThatFits:maximumLabelSize];
float heightUse = expectedLabelSize.height;

最好使用自动尺寸(Swift):

  tableView.estimatedRowHeight = 68.0
  tableView.rowHeight = UITableViewAutomaticDimension

注: 1. UITableViewCell原型应该正确设计(对于实例不要忘记设置UILabel。numberolines = 0 etc) 2. 删除hightforrowatindexpath方法

视频: https://youtu.be/Sz3XfCsSb6k

基于@bitsand，这是一个新方法，我刚刚添加到我的NSString+Extras类别:

- (CGRect) boundingRectWithFont:(UIFont *) font constrainedToSize:(CGSize) constraintSize lineBreakMode:(NSLineBreakMode) lineBreakMode;
{
    // set paragraph style
    NSMutableParagraphStyle *style = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
    [style setLineBreakMode:lineBreakMode];

    // make dictionary of attributes with paragraph style
    NSDictionary *sizeAttributes = @{NSFontAttributeName:font, NSParagraphStyleAttributeName: style};

    CGRect frame = [self boundingRectWithSize:constraintSize options:NSStringDrawingUsesLineFragmentOrigin attributes:sizeAttributes context:nil];

    /*
    // OLD
    CGSize stringSize = [self sizeWithFont:font
                              constrainedToSize:constraintSize
                                  lineBreakMode:lineBreakMode];
    // OLD
    */

    return frame;
}

我只是使用结果帧的大小。

试试这个语法:

NSAttributedString *attributedText =
    [[NSAttributedString alloc] initWithString:text 
                                    attributes:@{NSFontAttributeName: font}];

改用sizeWithAttributes:，它现在接受一个NSDictionary。传入key UITextAttributeFont和你的字体对象，如下所示:

CGRect rawRect = {};
rawRect.size = [string sizeWithAttributes: @{
    NSFontAttributeName: [UIFont systemFontOfSize:17.0f],
}];

// Values are fractional -- you should take the ceil to get equivalent values
CGSize adjustedSize = CGRectIntegral(rawRect).size;