UILabel 设置行间距

　　UILabel *label1 = [[UILabel alloc]initWithFrame:frame];
    label1.numberOfLines = 0;
    [self.view addSubview:label1];
    NSString *testString = @"欢迎您加入*******************";
    NSMutableAttributedString * attributedString1 = [[NSMutableAttributedString alloc] initWithString:testString];
    NSMutableParagraphStyle * paragraphStyle1 = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle1 setLineSpacing:15];
    [attributedString1 addAttribute:NSParagraphStyleAttributeName value:paragraphStyle1 range:NSMakeRange(0, [testString length])];
    [label1 setAttributedText:attributedString1];