how to fetch data from Core Data as soon as it is added to database

Question

I am making a simple task app using core data where in the main view controller I show list of task and there is bar button which takes me to a new view controller where I add new task to list the problem is

let fetchReq: NSFetchRequest<MoneyOut> = MoneyOut.fetchRequest()
    do{
        myArr = try container.viewContext.fetch(fetchReq)
    }catch{
        print(error)
    }
    OperationQueue.main.addOperation {
        print(self.myArr)
        self.myTableView.reloadData()
    }

this works fine in main view controller but when I add a new task to list and come back to this main view controller my list is not updated I am using the code in view did load I know if I use this code in view will appear it will work just fine but the problem is i don't want to fetch all the data again when I have already fetched all data except the new data I just added is there a way we can do this

Answer 1

now I know the answer, well one of the method is to use Notification Center, as soon as core data context get saved you call

NotificationCenter.default.addObserver(self, selector: #selector(yourfunc), name: NSNotification.Name.NSManagedObjectContextDidSave, object: nil)

in place of yourfunc you write what you want to do, one of the thing you can do is fetch the data again and reload your table.