UITableView自我调整单元格滚动问题，细胞高度差异很大

  func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell{

    let json = JSON(data: activityTableView.onlineFeedsData)[indexPath.row] // new
    if(json["topic"]["reply_count"].int > 0){
        if let cell: FeedQuestionAnswerTableViewCell = tableView.dequeueReusableCellWithIdentifier(kCellIdentifier_reply) as? FeedQuestionAnswerTableViewCell{

            cell.selectionStyle = .None
            cell.tag = indexPath.row
            cell.relatedTableView = self.activityTableView
            cell.configureFeedWithReplyCell(cell, indexPath: indexPath, rect: view.frame,key: "activityTableView")
            // Make sure the constraints have been added to this cell, since it may have just been created from scratch
            cell.layer.shouldRasterize = true
            cell.layer.rasterizationScale = UIScreen.mainScreen().scale

            return cell
        }
    }else{
        if let cell: FeedQuestionTableViewCell = tableView.dequeueReusableCellWithIdentifier(kCellIdentifier) as? FeedQuestionTableViewCell{

            cell.selectionStyle = .None
            cell.tag = indexPath.row
            cell.relatedTableView = self.activityTableView
            cell.configureFeedCell(cell, indexPath: indexPath, rect: view.frame)
            // Make sure the constraints have been added to this cell, since it may have just been created from scratch

            cell.layer.shouldRasterize = true
            cell.layer.rasterizationScale = UIScreen.mainScreen().scale
            return cell
        }
    }


    return UITableViewCell()
}
  func tableView(tableView: UITableView, cellFo