富文本的使用（让字符串特定字符颜色不同和在字符串上划横线）

+ (NSMutableAttributedString *) transCurrentStr:(NSString *)currentString;
{
    NSMutableAttributedString *str = [[NSMutableAttributedString alloc] initWithString:currentString];
    [str addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:15] range:NSMakeRange(0,str.length)];
    //设置固定范围字体颜色不同
    [str addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(1,str.length)];
    //在字符串中间划横线
    [str addAttribute:NSStrikethroughStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleThick] range:NSMakeRange(0, str.length)];
// 调整行间距
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setLineSpacing:6];
    [str addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [str length])];

return str;}