用NSAttributedString画下划线

UILabel *lable = [[UILabel alloc] initWithFrame:CGRectMake(20, 60, 100, 30)];

    [self.view addSubview:lable];

    lable.backgroundColor = [UIColor redColor];

    lable.textAlignment = NSTextAlignmentCenter;

    NSString *oldPrice = @"￥ 999999";

    NSUInteger length = [oldPrice length];

    [self.view addSubview:lable];

    

    NSMutableAttributedString *attri = [[NSMutableAttributedString alloc] initWithString:oldPrice];

    [attri addAttribute:NSStrikethroughStyleAttributeName value:@(NSUnderlinePatternSolid | NSUnderlineStyleSingle) range:NSMakeRange(0, length)];

    [attri addAttribute:NSStrikethroughColorAttributeName value:[UIColor yellowColor] range:NSMakeRange(0, length)];

    [lable setAttributedText:attri];