iOS 改变字符串局部颜色

NSString *textStr = [NSString stringWithFormat:@"%@：%@",@"今天天气好吗？".@"不好，外面都没有太阳"];

NSString *nameStr = [NSString stringWithFormat:@"%@：",@"今天天气好吗？"];

 NSString*messageStr = [NSStringstringWithFormat:@"%@",@"不好，外面都没有太阳"];

 NSMutableAttributedString *attrs = [[NSMutableAttributedString alloc] initWithString:textStr];

  attrsaddAttribute:NSForegroundColorAttributeName value:[NIMKit sharedKit].config.nickColor range:[textStr rangeOfString:nameStr]];

   [attrsaddAttribute:NSForegroundColorAttributeName value:[UIColor whiteColor] range:[textStr rangeOfString:messageStr]];

     self.nameLabel.attributedText= attrs;