ios - swift - NSMangedObjectContext 不刷新数据

Question

我有两个 View Controller ，第一个用于显示存储在 CoreData 中的对象列表，第二个用于创建新对象。

创建新对象后，我返回对象列表，但新创建的对象不存在。重新启动应用程序后，将显示新对象。这是我的代码:

ListOfProjectsViewController:

var projects:[ProjectItem] = []

lazy var managedObjectContext = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext

    override func viewDidAppear(animated: Bool) {
        loadProjects()
    }

    func loadProjects() {

        do {
            let results = try managedObjectContext.executeFetchRequest(fetchRequest)
            projects = results as! [ProjectItem]

            tableView.reloadData()
        } catch let error as NSError {
            print("Could not fetch \(error), \(error.userInfo)")
        }

    }

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

        if segue.identifier == "CreateNewProjectSegue" {
            let vc = segue.destinationViewController as! CreateNewProjectViewController
            vc.project = NSEntityDescription.insertNewObjectForEntityForName("ProjectItem", inManagedObjectContext: managedObjectContext) as? ProjectItem
        }
    }

创建新项目:

let managedObjectContext = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext
var project:ProjectItem?

@IBAction func saveAndCloseBtnPressed(sender: AnyObject) {
        project?.title = projectTitleField.text
        project?.number = projectNmField.text
        project?.comments = projectCommentsTextView.text

        try! project?.managedObjectContext?.save()

        do {
            try self.managedObjectContext.save()
        } catch {
            fatalError("Failure to save context: \(error)")
        }

        self.navigationController?.popViewControllerAnimated(true)

    }

我做错了什么？

Answer 1

managedObjectContext.executeFetchRequest(fetchRequest) 返回一个静态数组，因此它不会在基础数据更改时更新。

您应该改用 NSFetchedResultsController，这样您就可以在发生变化时收到更新通知。