原理

很简单就是通过修改文本属性attributedString。

代码

直接上代码了。拉拉拉拉

-（void）test{
    NSMutableAttributedString *attributedString =    
 [[NSMutableAttributedString alloc] initWithString:self.contentLabel.text];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];  
  [paragraphStyle setLineSpacing:3];


//调整行间距       
[attributedString addAttribute:NSParagraphStyleAttributeName 
                         value:paragraphStyle 
                         range:NSMakeRange(0, [self.contentLabel.text length])];
    self.contentLabel.attributedText = attributedString;
}

还有另一种方式更加简单

    UILabel *label = [[UILabel alloc]init];
    
    [label setValue:@(30) forKey:@"lineSpacing"];