ios - MasterViewController更新时如何刷新DetailViewController

Question

我有一个应用程序，用户可以在其中更新和添加任务。但是当用户更新任务时，我需要更新 DetailViewController 中的详细信息

当用户更新任务并保存 MasterViewController 中的数据时，保存但 DetailViewController 中的数据保持不变


我该如何解决它，以便详细信息也得到更新

使用 添加和编辑任务添加项目 Controller

我尝试了以下方法，但如果它们都没有，都导致应用程序崩溃

 let vc = DetailViewController()
 let row = vc.view.layoutIfNeeded();

//Second method

let vc = MasterViewController() 
vc.performSegue(withIdentifier: "showDetail", sender: vc.self)

数据在 DetailViewController 中使用

  override func viewDidLoad() {
        super.viewDidLoad()
        table.delegate = self
        table.dataSource = self

        lblName.text = detail.name ?? ""
        lblCode.text = detail.code ?? ""     
    }

主视图 Controller

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "showDetail" {
   if let indexPath = tableView.indexPathForSelectedRow {
       let object = fetchedResultsController.object(at: indexPath)
       let controller = (segue.destination as! UINavigationController).topViewController as! DetailViewController
                controller.details = object;
                controller.navigationItem.leftBarButtonItem = splitViewController?.displayModeButtonItem
                controller.navigationItem.leftItemsSupplementBackButton = true
                detailViewController = controller
            }
    }
}

编辑 View Controller

func editEvents(_ sender: Any){
        let fetchRequest: NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "Proj")

        do {
            let test = try context.fetch(fetchRequest)

            var objectUpdate = test[0] as! Assesment;


            objectUpdate.name = txtname.text ?? ""
            objectUpdate.code = txtCode.text ?? "";

            do {
                try context.save()

            }
            catch {
                print(error)
            }
        }
        catch {
            print(error)
        }
    }

我想在 editEvent 函数完成执行后更新详细信息

无论如何我可以让它工作吗？

Answer 1

如果您正在使用 coreData .. 您可以详细实现 FRC .. 这样您每次在回调中都会获得刷新的数据...

在您的 MasterViewController定义一个变量

这是另一种解决方法

private var controller : DetailViewController? = nil

然后在你的 Segue 方法中使用这个 Controller

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "showDetail" {
   if let indexPath = tableView.indexPathForSelectedRow {
       let object = fetchedResultsController.object(at: indexPath)
       self.controller = (segue.destination as! UINavigationController).topViewController as! DetailViewController // here you set your instence variable controller
                controller.details = object;
                controller.navigationItem.leftBarButtonItem = splitViewController?.displayModeButtonItem
                controller.navigationItem.leftItemsSupplementBackButton = true
                detailViewController = controller
            }
    }
}


func editEvents(_ sender: Any){
        let fetchRequest: NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "Proj")

        do {
            let test = try context.fetch(fetchRequest)

            var objectUpdate = test[0] as! Assesment;


            objectUpdate.name = txtname.text ?? ""
            objectUpdate.code = txtCode.text ?? "";



            do {
                try context.save()
                if let detailsCotrollerExists = controller {
                 detailsCotrollerExists.updateDataWithObject(objectUpdate) // function you will write in detail class which takes object and refresh data there .. Either outlets or Table/Collection View reload
                }
            }
            catch {
                print(error)
            }
        }
        catch {
            print(error)
        }
    }

然后你在 DetailViewController 中写一个函数func updateDataWithObject(_ obj: Assesment)您将在详细类中编写函数，该类在该类中获取对象并刷新数据.. 导出或表/ Collection View 重新加载
在 DetailViewController 中写入函数

func updateDataWithObject(_ obj: Assesment) {
  // Refresh data
}