對UITableView的一部分使用NSFetchedResultsController

Question

我在UISplitViewController中有一個UITableViewController。這tableViewController收到兩件事情：

1. 發票
2. Customer對象的數組

所以我在做什麼是填充在UITableView中的第一部分（或Section 0）發票的詳細信息。

對於第二部分，我使用NSFetchedResultsController來獲取具有invoice == nil的客戶的所有屬性，並在表視圖的第二部分中顯示該屬性。

所以基本上只使用NSFetchedResultsController而不是UITableViewController而不是整個東西。

現在，一切工作正常。但是，當我點擊第2部分的行時，我提供用戶將property添加到新發票。當我這樣做，我得到這個錯誤：

CoreData: error: Serious application error. An exception was caught from the delegate of NSFetchedResultsController during a call to -controllerDidChangeContent:. Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (2) 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, 0 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out). with userInfo (null) 

不知道爲什麼會這樣。我明白fetchedResultsController期望Section 0，但我確定它被手動強制只使用Section 1。

的代碼以供參考是：

func controller(controller: NSFetchedResultsController, didChangeObject anObject: AnyObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?) { 
    switch (type) { 
    case .Insert: 
     if let indexPath = newIndexPath { 
      let editedNewIndexPath = NSIndexPath(forRow: indexPath.row, inSection: 1) 
      tableView.insertRowsAtIndexPaths([editedNewIndexPath], withRowAnimation: .Fade) 
     } 
     break; 
    case .Delete: 
     if let indexPath = indexPath { 
      let editedCurrentIndexPath = NSIndexPath(forRow: indexPath.row, inSection: 1) 
      tableView.deleteRowsAtIndexPaths([editedCurrentIndexPath], withRowAnimation: .Fade) 
     } 
     break; 
    case .Update: 
     if let indexPath = indexPath { 
      let editedCurrentIndexPath = NSIndexPath(forRow: indexPath.row, inSection: 1) 
      if let cell = tableView.cellForRowAtIndexPath(editedCurrentIndexPath){ 
       configureCell(cell, atIndexPath: editedCurrentIndexPath) 
       //tableView.selectRowAtIndexPath(indexPath, animated: true, scrollPosition: .None) 
      } 
     } 
     break; 
    case .Move: 
     if let indexPath = indexPath { 
      let editedCurrentIndexPath = NSIndexPath(forRow: indexPath.row, inSection: 1) 
      tableView.deleteRowsAtIndexPaths([editedCurrentIndexPath], withRowAnimation: .Fade) 
     } 

     if let newIndexPath = newIndexPath { 
      let editedNewIndexPath = NSIndexPath(forRow: newIndexPath.row, inSection: 1) 
      tableView.insertRowsAtIndexPaths([editedNewIndexPath], withRowAnimation: .Fade) 
     } 
     break; 
    } 
} 

// MARK: - Table view data source 

override func numberOfSectionsInTableView(tableView: UITableView) -> Int { 
    return 2 
} 

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int { 
    if section == 0{ 
     if let ivData = self.invoices{ 
      print("Section0 - \(ivData.count)") 
      return ivData.count 
     } 
    } 
    else if section == 1{ 
     if let sections = fetchedResultsController.sections { 
      let sectionInfo = sections[0] 
      print("Section1 - \(sectionInfo.numberOfObjects)") 
      if sectionInfo.numberOfObjects > 0{ 
       return sectionInfo.numberOfObjects 
      } 
      else{ 
       return 1 
      } 
     } 
    } 
    return 0 
} 

的代碼保存新的發票是：

do{ 
        self.invoices!.append(billRecord as! InvoiceInfo) 
        try billRecord.managedObjectContext?.save() 
        try self.customer!.managedObjectContext?.save() 
        try record.managedObjectContext?.save() 
        //self.lookUpLotsWithoutBills() 
        self.tableView.reloadData() 

       } 
       catch{ 
        self.invoices!.removeObject(ivRecord) 
        let alertController = UIAlertController(title: "Unexpected Error", message: "Your data could not be updated. Please try again later.", preferredStyle: .Alert) 
        alertController.addAction(UIAlertAction(title: "Done", style: .Cancel, handler: nil)) 
        self.presentViewController(alertController, animated: true, completion: nil) 
       } 

出了什麼問題嗎？

Answer 1

看起來您的FRC工作正常，但您的代碼並未告知表格視圖有關將新發票行添加到第0部分的問題。它不完全清楚爲什麼，但我會猜測因爲FRC在添加發票之後但在調用表上的重新加載數據之前觸發更新。在那個時候，第0節的行數是錯誤的，你還沒有告訴表。