swift UITableViewCell拷贝

func tableView(tableView: UITableView,performAction action: Selector,forRowAtIndexPath indexPath: NSIndexPath,withSender sender: AnyObject?) {
        if action == Selector("copy:") {
            if let cell = tableView.cellForRowAtIndexPath(indexPath) as? JokeViewCell {
                UIPasteboard.generalPasteboard().string = cell.contentLabel.text
            }
        }
    }

    func tableView(tableView: UITableView,canPerformAction action: Selector,forRowAtIndexPath indexPath: NSIndexPath,withSender sender: AnyObject?) -> Bool {
        return action == Selector("copy:")
    }

    func tableView(tableView: UITableView,shouldShowMenuForRowAtIndexPath indexPath: NSIndexPath) -> Bool {
        return true
    }