iOS 给NSString文字中间或底部添加横线

给NSString类型的文字添加横线一种是添加到文字底部，一种是添加到文字中间

1.文字底部添加横线

NSMutableAttributedString *forgetTitle = [[NSMutableAttributedString alloc] initWithString:@"忘记密码"];
    NSRange titleRange = {0,[forgetTitle length]};
    [forgetTitle addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleSingle] range:titleRange];
    [self.forgetPsdButton setAttributedTitle:forgetTitle
                          forState:UIControlStateNormal];

2.文字中间添加横线

self.oldPriceLabel.text = @"4500";
    self.oldPriceLabel.textColor = [UIColor lightGrayColor];
    NSMutableAttributedString *newPrice = [[NSMutableAttributedString alloc] initWithString:[NSString stringWithFormat:@"$%@",self.oldPriceLabel.text]];
    [newPrice addAttribute:NSStrikethroughStyleAttributeName value:@(NSUnderlinePatternSolid | NSUnderlineStyleSingle) range:NSMakeRange(0, newPrice.length)];
    self.oldPriceLabel.attributedText = newPrice;

文字中间添加删除线时有时候会无效果 原因可能是富文本不支持中文字符 解决方法如下

富文本支持中文 NSBaselineOffsetAttributeName : @(NSUnderlineStyleSingle)

[newPrice setAttributes:@{NSStrikethroughStyleAttributeName: @(NSUnderlineStyleSingle), NSBaselineOffsetAttributeName : @(NSUnderlineStyleSingle)} range:NSMakeRange(0,newPrice.length)];