ios - 访问 NSManagedObject 数据

Question

我正在使用核心数据。有两个ViewController ，在我的SecondViewController我正在使用fetchData()方法如下所示，获取我存储在 FirstViewController 中的数据.

 func fetchData() {
            var person = [NSManagedObject]()
            let appDel = UIApplication.sharedApplication().delegate as! AppDelegate
            let managedContext = appDel.managedObjectContext

            let fetchRequest = NSFetchRequest(entityName: "People")

            do{
                let results = try managedContext.executeFetchRequest(fetchRequest)
                person = results as! [NSManagedObject]
            } catch let error as NSError {
                print("Could not fetch data \(error)")
            }

            print(person)
    }

通过打印counters我已经验证有 2 data: <fault>我了解到我的数据实际上在那里，但它是一种节省内存的技术。

对于我的核心数据，我有一个名为 People 的实体具有属性 firstName , lastName和address .

我的问题是如何使用 NSManagedObject提取 person 中的所有数据？ (2 个对象具有 3 个属性)

Answer 1

试试这个代码

      func fetchData() {

           var peoples  = [People]() // Where People = your NSManaged Class
           var fetchRequest = NSFetchRequest(entityName: "People")
           let appDel = UIApplication.sharedApplication().delegate as! AppDelegate
           let context = appDel.managedObjectContext

           do
           {    
             peoples = try context.executeFetchRequest(fetchRequest) as! [People]
           } 
           catch let error as NSError
           {
             print("Could not fetch data \(error)")
           }
           // Then you can use your propertys.
           for people in peoples {
             print("FirstName: \(people.firstName)  LastName: \(people.lastName)   Address: \(people.address)")   
           }

     }

最好从 fetchData 方法返回对象数组并在 secondViewController 中使用它。