做电商类的app时，会经常遇到打折的时候，而网上打折价格的lable的删除线千篇一律，其实IOS本自带的就有删除闲的功能，Demo如下
UILabel *numberPrice=[[UILabel alloc]init];
numberPrice.text=@"199.0元";
numberPrice.textColor=[UIColor grayColor];
NSUInteger length = [numberPrice.text length];
//添加删除线
NSMutableAttributedString *attri = [[NSMutableAttributedString alloc] initWithString:numberPrice.text];
[attri addAttribute:NSStrikethroughStyleAttributeName value:@(NSUnderlinePatternSolid | NSUnderlineStyleSingle) range:NSMakeRange(2, length-2)];
[attri addAttribute:NSStrikethroughColorAttributeName value:[UIColor grayColor] range:NSMakeRange(2, length-2)];
[numberPrice setAttributedText:attri];
