ios - 多次调用 deleteRowsAtIndexPaths

Question

关于这个问题有几个问题。我已经尝试了所有建议的答案，但还没有任何效果。所以我有这个 func用户收到的拒绝报价。我可以拒绝报价并删除单元格行，但是当只剩下一个单元格时，我得到 fatal error: Index out of range


func declineButtonTapped(sender: AnyObject) {
    self.view.userInteractionEnabled = false
    let buttonRow = sender.tag  // this is the tag from my custom cell button
    let offer = offers[buttonRow]  // I get the error here 
    let loadingNotification = MBProgressHUD.showHUDAddedTo(self.view, animated: true)
    loadingNotification.mode = MBProgressHUDMode.Indeterminate
    loadingNotification.labelText = "declining offer...."
    let myUrl = NSURL(string: "\(ipAddress)/api/v1.0/offers.php")
    let request = NSMutableURLRequest(URL: myUrl!)
    request.HTTPMethod = "POST"
    let postString = "id=\(offer.id!)&action=decline&offer_id=\(offer.offer_id!)"
    request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true) 
    let task = NSURLSession.sharedSession().dataTaskWithRequest(request)
        { data, response, error in

            if error != nil {

                let messageToDisplay = error                    
                self.view.userInteractionEnabled = true

                return

            }


            do{
                let json = try NSJSONSerialization.JSONObjectWithData(data!, options: .MutableContainers) as? NSDictionary

                if let parseJSON = json{

                    let resultValue = parseJSON["status"] as? String

                       if resultValue == "Success"{


                          dispatch_async(dispatch_get_main_queue()) {

                            print("before count is \(self.offers.count)") // before the error the count is 2 here
                            self.offers.removeAtIndex(buttonRow) //update my model
                            self.tableView.deleteRowsAtIndexPaths([NSIndexPath(forRow: buttonRow, inSection: 0)], withRowAnimation: UITableViewRowAnimation.Fade)
                            print("after count is \(self.offers.count)") //then the count is 1 here      
                            MBProgressHUD.hideAllHUDsForView(self.view, animated: true)

                            self.view.userInteractionEnabled = true

                        }


                     }else{

                        //no success    
                }
             }


         } catch{

      }

  }

    task.resume()

}

内部cellForRowAtIndexPath我为按钮分配标签值

offerCell.declineButton.tag = indexPath.row
offerCell.declineButton.addTarget(self, action: #selector(OpenDealsDetailsViewController.declineButtonTapped(_:)), forControlEvents: UIControlEvents.TouchUpInside)

******更新*****

我想我发现了错误。当我打印 print("button row is\(buttonRow)")号码没有更新。所以它第一次调用正确的行但第二次它保留它在 declineButtonTapped 时的 indexPath.row。第一次被调用

button row is0
before count is 2
after count is 1
button row is1 // this of course should be 0 as there is only one cell left
fatal error: Index out of range

如果我尝试做

self.offers.removeAtIndex(buttonRow)                                
self.tableView.deleteRowsAtIndexPaths([NSIndexPath(forRow: buttonRow, inSection:   0)], withRowAnimation: UITableViewRowAnimation.Fade)
self.tableView.reloadData()

我收到以下错误:

Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (1) must be equal to the number of rows contained in that section before the update (1), plus or minus the number of rows inserted or deleted from that section (0 inserted, 1 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).

Answer 1

您要么不应该使用标签，要么在每次更改后完全重新加载表格 View 。或者，您可以迭代可见单元格并更新其标记值。

如果您总是并且只删除表中的最后一行，那就没问题了。一旦删除较早的行，该行之后的所有行现在都具有不正确的标记值。因此，当您转到最后一行时，该标记中实际上并不存在该行，并且任何其他无效行将导致您从服务器中删除错误的项目。

更好的方法是向单元格传递一个类的实例，该类可以执行删除操作并回调 View Controller 并提供更新的详细信息。然后 View Controller 可以更新其数据源和 TableView 。通过这种方式，您可以将表索引路径与要对数据执行的操作分开。