iOS 当UILabel多行时，改变文本的行间距

 UILabel *MessageDetailLabel=[[UILabelalloc]initWithFrame:CGRectMake(0, 100, 320, 100)];

    MessageDetailLabel.text=@"测试史蒂夫哈绥芬河市冯绍峰健身房健身房健身房健身房健身房和健身房健身房就是倒海翻江是建会封建社会封建社会说到底冯绍当";

    MessageDetailLabel.numberOfLines=3;

    NSMutableAttributedString *attributedString = [[NSMutableAttributedStringalloc] initWithString:MessageDetailLabel.text];

    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStylealloc] init];

    [paragraphStyle setLineSpacing:3];//调整行间距

    [attributedString addAttribute:NSParagraphStyleAttributeNamevalue:paragraphStyle range:NSMakeRange(0, [MessageDetailLabel.textlength])];

     MessageDetailLabel.attributedText = attributedString;

     MessageDetailLabel.textColor=[UIColorcolorWithHexString:@"#343434"];

     MessageDetailLabel.font=[UIFontsystemFontOfSize:13];

    [self.ViewaddSubview:MessageDetailLabel];