设置UILabel的行间距

UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(10, 100, 300, 20)];
label.backgroundColor = [UIColor lightGrayColor];
[label setNumberOfLines:0];
label.font = [UIFont systemFontOfSize:25.0f];
[self.view addSubview:label];

NSString *labelText = @"我很喜欢梁咏琪的歌曲，我在上高一的时候就经常听她的歌，现在听到她的歌，我好像回到了那个时候\n我很喜欢梁咏琪的歌曲，我在上高一的时候就经常听她的歌，现在听到她的歌，我好像回到了那个时候";

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:labelText];
NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];

[paragraphStyle setLineSpacing:10];//调整行间距
[paragraphStyle setParagraphSpacing:40];//调整段落间距

[attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, labelText.length)];
label.attributedText = attributedString;
[label sizeToFit];