UITableViewCell自适应高度

//再画布重绘的时候，重置cell自适应高度；
-(void)layoutSubviews
{
[super layoutSubviews];
_cou_title.text = _dataModel.cou_title;
_cou_publish_date.text = [NSString stringWithFormat:@"发布日期：%@",_dataModel.cou_publish_date];
_cou_expiration_date.text = [NSString stringWithFormat:@"结束日期：%@",_dataModel.cou_expiration_date];
_cou_description.text = _dataModel.cou_description;

CGSize descriSize = [_dataModel.cou_description sizeWithFont:[UIFont systemFontOfSize:15.0] constrainedToSize:CGSizeMake(300, 200) lineBreakMode:NSLineBreakByCharWrapping];
_cou_description.frame = CGRectMake(_cou_description.frame.origin.x, _cou_description.frame.origin.y,_cou_description.frame.size.width, descriSize.height);

}