NSFetchedResultsController调用didChangeObject而不是update [英] NSFetchedResultsController calls didChangeObject delete instead of update

问题描述

这是代码，我通过Magical Record保存模型：

  MagicalRecord.saveWithBlock（{（localContext） - > ; void in 
 var localNotification = CDNotification.MR_findFirstByAttribute（notificationID，withValue：notification.notificationID，inContext：localContext）as CDNotification 
 localNotification.readNumber = NSNumber（bool：true）
} 
  

在调用以上代码后调用Delete而不是update：

func controller（controller：NSFetchedResultsController，didChangeObject object：AnyObject，atIndexPath indexPath：NSIndexPath，forChangeType type：NSFetchedResultsChangeType，newIndexPath：NSIndexPath）{
switch type {
case NSFetchedResultsChangeType.Insert：
self.tableView.insertRowsAtIndexPaths（[newIndexPath]，withRowAnimation：.Fade）
case NSFetchedResultsChangeType.Update：
如果let cell = self.tableView.cellForRowAtIndexPath （indexPath）{
self.configureCell（cell as TableViewCell，atIndexPath：indexPath，withNotification：object as CDNotification）
}
self.tableView.reloadRowsAtIndexPaths（[indexPath]，withRowAnimation：.Fade）
case NSFetchedResultsChangeType.Move：
self.tableView.deleteRowsAtIndexPaths（[indexPath]，withRowAnimation：.Fade）
self.tableView.insertRowsAtIndexPaths（[newIndexPath]，withRowAnimation：.Fade）
case NSFetchedResultsChangeType.Delete：
self.tableView.deleteRowsAtIndexPaths（[indexPath]，withRowAnimation：.Fade）
默认值：
return
}
}


这只会发生在我为fetch请求设置谓词时，例如：

  fetchRequest.predicate = NSPredicate（format：user == john）
  

解决方案

这里发生的是，而不是你期望的 NSFetchedResultsChangeUpdate 更改事件， NSFetchedResultsChangeDelete 后跟 NSFetchedResultsChangeInsert 。您还可以看到与源和目标具有相同indexPath的 NSFetchedResultsChangeMove 。这是 iOS 9的几个测试版中的已知问题 22380191 和其他人。

This is the code, I save the model via Magical Record:

MagicalRecord.saveWithBlock({ (localContext) -> Void in
                    var localNotification = CDNotification.MR_findFirstByAttribute("notificationID", withValue: notification.notificationID, inContext: localContext) as CDNotification
                    localNotification.readNumber = NSNumber(bool: true)
                })

Delete is called instead of update after the code above is called:

func controller(controller: NSFetchedResultsController, didChangeObject object: AnyObject, atIndexPath indexPath: NSIndexPath, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath) {
    switch type {
    case NSFetchedResultsChangeType.Insert:
        self.tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Fade)
    case NSFetchedResultsChangeType.Update:
        if let cell = self.tableView.cellForRowAtIndexPath(indexPath){
            self.configureCell(cell as TableViewCell, atIndexPath: indexPath, withNotification: object as CDNotification)
        }
        self.tableView.reloadRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
    case NSFetchedResultsChangeType.Move:
        self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
        self.tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Fade)
    case NSFetchedResultsChangeType.Delete:
        self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
    default:
        return
    }
}

This only happens if I set the predicate for fetch request, in example:

fetchRequest.predicate = NSPredicate(format:"user == john")

解决方案

What is happening here is that instead of the NSFetchedResultsChangeUpdate change event you expect, you are getting a NSFetchedResultsChangeDelete followed by NSFetchedResultsChangeInsert. You may also see a NSFetchedResultsChangeMove with the same indexPath as source and destination. This is a known issue in several beta versions of iOS 9 22380191 and others.

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