通过可变字符串在UILabel上面加横线

 NSString *oldPrice = @"¥ 12345";
 NSUInteger length = [oldPrice length];

 NSMutableAttributedString *attri = [[NSMutableAttributedString alloc] initWithString:oldPrice];
 [attri addAttribute:NSStrikethroughStyleAttributeName value:@(NSUnderlinePatternSolid | NSUnderlineStyleSingle) range:NSMakeRange(2, length-2)];
 [attri addAttribute:NSStrikethroughColorAttributeName value:UIColorFromRGB(0x999999, 1) range:NSMakeRange(2, length-2)];
 [oldPriceLabel setAttributedText:attri];

 主要是通过addAttribute:方法添加

   NSUInteger length = [stringPrice length];

    NSMutableAttributedString *attri = 

[[NSMutableAttributedString alloc] initWithString:stringPrice];

    [attri addAttribute:NSStrikethroughStyleAttributeName

value:@(NSUnderlinePatternSolid | NSUnderlineStyleSingle) 

range:NSMakeRange(0, length)];

    [attri addAttribute:NSStrikethroughColorAttributeName 

value:[UIColor grayColor] range:NSMakeRange(0, length)];

    [lbPrice setAttributedText:attri];