简单试用CoreData - NSFetchedResultsController

首先创建一个NSFetchedResultsController

var fetchedResultsVC : NSFetchedResultsController!

var appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate

再创建一个空命令

let fetchRequest = NSFetchRequest(entityName: "Item")

创建数组排序，按照key值升序或者降序排列

let sortDesctiptor = NSSortDescriptor(key: "name", ascending: true)

fetchRequest.sortDescriptors = [sortDesctiptor]

创建NSFetchedResultsController

fetchedResultsVC = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: appDelegate.managedObjectContext, sectionNameKeyPath: nil, cacheName: nil)

添加NSFetchedResultsController的协议（NSFetchedResultsControllerDelegate）

fetchedResultsVC.delegate = self

执行

do {

try fetchedResultsVC.performFetch()

}catch let error{

print(error)

}

由于目前能力有限，还不清楚如何使得添加数据时保持section不划分，So，添加如下以免报错：

func numberOfSectionsInTableView(tableView: UITableView) -> Int {

return (fetchedResultsVC.sections?.count)!

}

NSFetchedResultsControllerDelegate遵循的方法

func controllerWillChangeContent(controller: NSFetchedResultsController) {

tableView!.beginUpdates()

}

func controller(controller: NSFetchedResultsController, didChangeObject anObject: AnyObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?) {

switch type {

case .Insert:

tableView!.insertRowsAtIndexPaths([newIndexPath!], withRowAnimation: .Fade)

case .Delete:

tableView!.deleteRowsAtIndexPaths([indexPath!], withRowAnimation: .Fade)

case .Update:

let cell = tableView!.cellForRowAtIndexPath(indexPath!)

let model = fetchedResultsVC.objectAtIndexPath(indexPath!) as? Item

cell!.textLabel?.text = model!.name

cell!.detailTextLabel?.text = "\(model!.score)"

case .Move:

tableView!.insertRowsAtIndexPaths([newIndexPath!], withRowAnimation: .Fade)

tableView!.deleteRowsAtIndexPaths([indexPath!], withRowAnimation: .Fade)

  }

}

func controllerDidChangeContent(controller: NSFetchedResultsController) {

tableView!.endUpdates()

}

完了。

但是在didChangeObject这个方法中case .Move:之前没有写的时候，添加数据时tableView没有刷新，但是添加了case .Move:和里面的方法以后数据就正常了，我也不知道是不是xcode抽风了。