ios - Swift 改变 Coredata 的值，而不是创建新的

Question

我是新人，不懂任何 objC，也没有快速的教程。

我正在做一周计划的应用程序，我有按钮，可以将我添加到每一天 -姓名 -代码名称 -任务01 。 。 -任务10

但如果我想用另一个按钮编辑特定的一天，我总是删除其余的日子。我创建了一个有很多零的新实体，只有一天充满了信息。这是我的贫民窟解决方案，但它工作不正常，它工作了几次，然后它说它有大约 512 个 searchResults.count 并开始滞后并且不工作...

请帮助我，如何更改特定属性的值而不创建新实体

这是我星期二编辑的代码(本周其余时间与星期一相同，但代码很长，所以这里只有星期一和星期二的代码):

func getAndPrintData () {

    let fetchRequest: NSFetchRequest<Workout> = Workout.fetchRequest()

    do {
        let searchResults = try getContext().fetch(fetchRequest)
        print ("num of results = \(searchResults.count)")
        for works in searchResults as [NSManagedObject] {


            if let moc = managedObjectContext {
                let workout = Workout(context: moc)

                workout.mondayNameCD = works.value(forKey: "mondayNameCD") as! String?
                workout.mondayCodeNameCD = works.value(forKey: "mondayCodeNameCD") as! String?
                workout.mondayTask01 = works.value(forKey: "mondayTaks01") as! String?
                workout.mondayTask02 = works.value(forKey: "mondayTaks02") as! String?
                workout.mondayTask03 = works.value(forKey: "mondayTaks03") as! String?
                workout.mondayTask04 = works.value(forKey: "mondayTaks04") as! String?
                workout.mondayTask05 = works.value(forKey: "mondayTaks05") as! String?
                workout.mondayTask06 = works.value(forKey: "mondayTaks06") as! String?
                workout.mondayTask07 = works.value(forKey: "mondayTaks07") as! String?
                workout.mondayTask08 = works.value(forKey: "mondayTaks08") as! String?
                workout.mondayTask09 = works.value(forKey: "mondayTaks09") as! String?
                workout.mondayTask10 = works.value(forKey: "mondayTaks10") as! String?
                workout.tuesdayNameCD = DayName.text!
                workout.tuesdayCodeNameCD = CodeNameTextField.text!
                workout.tuesdayFocusCD = IconImageTextField.text!
                workout.tuesdayTask01 = Task01TextField.text!
                workout.tuesdayTask02 = Task02TextField.text!
                workout.tuesdayTask03 = Task03TextField.text!
                workout.tuesdayTask04 = Task04TextField.text!
                workout.tuesdayTask05 = Task05TextField.text!
                workout.tuesdayTask06 = Task06TextField.text!
                workout.tuesdayTask07 = Task07TextField.text!
                workout.tuesdayTask08 = Task08TextField.text!
                workout.tuesdayTask09 = Task09TextField.text!
                workout.tuesdayTask10 = Task10TextField.text!
            }
        }
    } catch {
        print("Error with request: \(error)")
    }
    saveToCoreData() {
        self.navigationController!.popToRootViewController(animated: true)
    }
}

func saveToCoreData(completion: @escaping ()->Void){
    managedObjectContext!.perform {
        do {
            try self.managedObjectContext?.save()
            completion()
            print("Product saved to CoreData")
        } catch let error {
            print("Could not save Product to CoreData: \(error.localizedDescription)")
        }
    }
}

var managedObjectContext: NSManagedObjectContext? {
    return (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
}

func getContext () -> NSManagedObjectContext {
    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    return appDelegate.persistentContainer.viewContext
}

Answer 1

在 for 循环内，您已经有一个托管对象works。只需更新其上的值，而不是创建新的锻炼。