Swift and CoreData / Data Storage

Swift and CoreData / Data Storage

I'm just learning Objective-C / Cocoa Touch and Core Data. So, what are the new possibilities to implement data storage in iOS App Projects that are written in pure Swift? I really like the language, but as far as I know all core data methods are written in Objective-C. So will the core data classes/methods converted to Swift-Code automatically or will we have to mix up Objective-C Code for Core data and Swift-Code for everything else?

Answer by Ben Gottlieb for Swift and CoreData / Data Storage

All Objective-C frameworks are swift-ready. Swift-friendly headers are automatically generated (on-demand, it appears), and you can access anything from Swift that you can from ObjC.

Answer by IascCHEN for Swift and CoreData / Data Storage

I had tested use swift to access coredata, please visit the demo code : https://github.com/iascchen/SwiftCoreDataSimpleDemo .

Answer by MGM for Swift and CoreData / Data Storage

This is how I implemented core data.

A couple of really important notes:

• You have to add this to your NSManagedObject class:

  @objc(MyObject)

• You have to add the entity name to your default configuration class in the .xcdatamodel (picture included)

• You can't simply make an NSManagedObject.

  var myObject : MyObject = MyObject()  

You have to do this:

let appDelegate: AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate  let context: NSManagedObjectContext = appDelegate.managedObjectContext  let entityName: String = "MyObject"  let myEntityDescription = NSEntityDescription.entityForName(entityName, inManagedObjectContext: context)  var myObject = MyObject(entity: myEntityDescription, insertIntoManagedObjectContext: context)  

Here is my NSManagedObject. I included two fetch methods as well as a class method for object construction. You may notice that I am taking advantage of the new enum system so that I can easily access my entity names and entity attributes

import UIKit  import CoreData    enum MyObjectPropertyList {       case name      func description() -> String {          switch self {          case .name:              return "name"          }      }  }    @objc(MyObject)  class MyObject: NSManagedObject {        @NSManaged var name: String        //      //// CREATE CLASS OBJECT      //        class func createMyObject (propertyName:MyObjectPropertyList, value:String, context: NSManagedObjectContext) -> MyObject? {          if !value.isEmpty {              let propertyType = propertyName.description()                let entityName = "MyObject"              let request : NSFetchRequest = NSFetchRequest(entityName: entityName)              request.returnsObjectsAsFaults = false              request.predicate = NSPredicate(format: "\(propertyType) = %@", value)              var error: NSError? = nil              var matches: NSArray = context.executeFetchRequest(request, error: &error)                if (matches.count > 1) {                  // handle error                  return matches[0] as? MyObject              } else if matches.count ==  0 {                  let entityDescription = NSEntityDescription.entityForName(entityName, inManagedObjectContext: context)                  var myObject : MyObject = MyObject(entity: entityDescription, insertIntoManagedObjectContext: context)                  myObject.name = value                  return myObject              }              else {                  println(matches[0])                  return matches[0] as? MyObject              }          }          return nil      }  }        //      //// FETCH REQUESTS      //        func myGeneralFetchRequest (entity : CoreDataEntities,                                property : MyObjectPropertyList,                                 context : NSManagedObjectContext) -> AnyObject[]?{            let entityName = entity.description()          let propertyName = property.description()            let request :NSFetchRequest = NSFetchRequest(entityName: entityName)          request.returnsObjectsAsFaults = false          let sortDescriptor : NSSortDescriptor = NSSortDescriptor(key: propertyName, ascending: true)          request.sortDescriptors = [sortDescriptor]          var error: NSError? = nil          var matches: NSArray = context.executeFetchRequest(request, error: &error)            if matches.count > 0 {              return matches          }          else {              return nil          }      }        func myNameFetchRequest (entity : CoreDataEntities,                             property : MyObjectPropertyList,                                value : String,                              context : NSManagedObjectContext) -> AnyObject[]? {            let entityName = entity.description()          let propertyName = property.description()            let request :NSFetchRequest = NSFetchRequest(entityName: entityName)          request.returnsObjectsAsFaults = false          request.predicate = NSPredicate(format: "\(propertyName) = %@", value)          let sortDescriptor :NSSortDescriptor = NSSortDescriptor(key: propertyName, ascending: true)          request.sortDescriptors = [sortDescriptor]          var error: NSError? = nil          var matches: NSArray = context.executeFetchRequest(request, error: &error)            if matches.count > 0 {              return matches          }          else {              return nil          }      }        //      //// PRINT FETCH REQUEST      //        func printFetchedArrayList (myarray:AnyObject[]) {          if myarray.count > 0 {              println("Has \(myarray.count) object")              for myobject : AnyObject in myarray {                  var anObject = myobject as MyObject                  var thename = anObject.name                  println(thename)              }          }          else {              println("empty fetch")          }      }  

Here is my view controller

import UIKit  import CoreData    enum CoreDataEntities {      case MyObject      func description() -> String {          switch self {          case .MyObject:              return "MyObject"          }      }  }    class ViewController: UIViewController {        //      //// MOC      //        var managedObjectContext : NSManagedObjectContext = NSManagedObjectContext()        //      //// Text Field      //        @IBOutlet var myTextField : UITextField        //      //// BUTTONS      //        @IBAction func saveButtonPress(sender : UIButton) {          makeEntityAction()      }        @IBAction func fetchButtonPress(sender : UIButton) {          fetchObjectAction()      }        //      //// ACTIONS      //        func makeEntityAction () {          println("-- Make action --")            let value:String = self.myTextField.text          var myObject : MyObject = MyObject.createMyObject(MyObjectPropertyList.name, value : value, context: self.managedObjectContext)!          saveContext(self.managedObjectContext)      }        func fetchObjectAction () {          println("-- Fetch action --")            if let myTotalarray = myGeneralFetchRequest(CoreDataEntities.MyObject, MyObjectPropertyList.name, self.managedObjectContext) {              printFetchedArrayList(myTotalarray)          }          if let mySinglearray: AnyObject[] = myNameFetchRequest(CoreDataEntities.MyObject, MyObjectPropertyList.name, "Bill", self.managedObjectContext) {              println("(--  --)")              printFetchedArrayList(mySinglearray)          }        }        //      //// LOAD & SAVE      //        func loadContext () {          let appDelegate: AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate          let context: NSManagedObjectContext = appDelegate.managedObjectContext          self.managedObjectContext = context      }        func saveContext (context: NSManagedObjectContext) {          var error: NSError? = nil          context.save(&error)      }        //      //// LOAD      //        func myLoad () {          loadContext ()          println("Loaded Context")      }        //      //// Life Cycle      //        override func viewDidLoad() {          super.viewDidLoad()          myLoad ()      }    }  

Answer by mcintst for Swift and CoreData / Data Storage

XCode 6 Beta 4 now lets you choose either Objective C or Swift when you generate NSManagedObject subclasses from your data model.

Answer by mike.kz for Swift and CoreData / Data Storage

If you wanna have a play around with Swift and CoreData, I've written a framework thats an Active Record style assistant to CoreData.

SuperRecord Swift Framework

(note: not a shameless plug :) i actually thought this would be useful for the user).

Answer by GK100 for Swift and CoreData / Data Storage

Here is another approach to adding CoreData to your Swift app. This approach hides the CoreData implementation details from the rest of the app. In the app, you use queries/updates like these:

Query("Order").sort("date").fetch()  

or:

let newClient = Query("Client").create() as? Client  

See Gist: https://gist.github.com/gk11/438c3f2883c5d7c0b0d8

Answer by Vignesh Kumar for Swift and CoreData / Data Storage

I have created the easy tutorial for the Swift to access CoreData. please follow the tutorial with sample project.

Table of Contents

• What is CoreData?
• Create Project with CoreData.
• Create Entities and Attributes in Model Layer.
• User Object life cycle : Create, Fetch, Update, Delete datas.
• Download Sample Project

https://github.com/vigneshuvi/CoreData .

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