save uiimageview to coredata as binary data swift (5) - core-data

Question

I am trying to save a imageview as a image to binary data in core data. My code is not working. It has a compile error. In View controller it is not regisitering cdHandler. All i want to do is save the the imaveview as binary data in a core data model.I have 2 classes a app delegate and a view controller.
CLASS VIEW CONTROLLER
import UIKit
import CoreData
class ViewController: UIViewController {
var canVasView = UIImageView()
#objc func hhh() {
let photo = self.canVasView.image
let data = photo!.pngData()
if cdHandler.saveObject(pic: data!){
}
}
}
APP DELEGATE
import UIKit
import CoreData
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
lazy var persistentContainer: NSPersistentContainer = {
/*
The persistent container for the application. This implementation
creates and returns a container, having loaded the store for the
application to it. This property is optional since there are legitimate
error conditions that could cause the creation of the store to fail.
*/
let container = NSPersistentContainer(name: "Model")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
// Replace this implementation with code to handle the error appropriately.
// fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
/*
Typical reasons for an error here include:
* The parent directory does not exist, cannot be created, or disallows writing.
* The persistent store is not accessible, due to permissions or data protection when the device is locked.
* The device is out of space.
* The store could not be migrated to the current model version.
Check the error message to determine what the actual problem was.
*/
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
class cdHandler: NSObject {
private class func getContext() -> NSManagedObjectContext {
let appdeleagetzz = UIApplication.shared.delegate as! AppDelegate
return appdeleagetzz.persistentContainer.viewContext
}
class func saveObject(pic: Data, userName: String) -> Bool {
let context = getContext()
let entity = NSEntityDescription.entity(forEntityName: "User", in: context)
let managedObject = NSManagedObject(entity: entity!, insertInto: context)
managedObject.setValue(pic, forKey:"pic")
managedObject.setValue(userName, forKey:"userName")
do {
try context.save()
return true
} catch {
return false
}
}
class func deletObject(user: User) -> Bool {
let context = getContext()
context.delete(user)
do {
try context.save()
return true
} catch {
return false
}
}
class func fetchObject() -> [User]? {
do {
let context = getContext()
return try context.fetch(User.fetchRequest())
} catch {
return [User]()
}
}
}
}

Answer 1

The error message, *Value of type 'AppDelegate' has no member named 'persistentContainer', explains the problem. Indeed, when I look at the code for your AppDelegate class, I can confirm that it has no member named 'persistentContainer'. (If I am reading it correctly, the last two lines in the file are closing curly brackets. The first one closes your cdHandler nested class, and the second one closes your AppDelegate class.)
Do the following exercise. In Xcode, click in the menu: File > New Project and select iOS, Application and Single View App. Name your new project Junk. Switch on the Core Data checkbox. Click button Create. After it is done, look at the AppDelegate.swift which Xcode created, and in the AppDelegate class, you see it contains 8 functions (func). The 7th one is lazy var persistentContainer. Aha! The compiler is telling you that you probably should not have deleted those 8 functions, persistentContainer in particular.
You should copy that persistentContainer func from that Junk project into your AppDelegate class in your real project. Or, to head off future trouble, consider copying most of the other 7 funcs also. As you can see, most of them don't do anything except provide comments with explanations that are useful for beginners. After you are done copying, close the Junk project. (I overwrite my Junk project with a new Junk project several times in a typical week, especially when answering StackOverflow questions.)
That should fix this particular error and answer this question. Onward to the next issue. :)
Response to comment that you still get the error with cdHandler
Having nothing else to go on, I presume that the error that you are referring to is the compiler error still in your screenshot. In other words, you are saying that adding the persistentContainer definition did not make it any better.
Well, it works for me. Please replace all of the code in your AppDelegate.swift class with the following, build and run it…
import UIKit
import CoreData
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
AppDelegate.cdHandler.testGetContext()
return true
}
lazy var persistentContainer: NSPersistentContainer = {
/*
The persistent container for the application. This implementation
creates and returns a container, having loaded the store for the
application to it. This property is optional since there are legitimate
error conditions that could cause the creation of the store to fail.
*/
let container = NSPersistentContainer(name: "Junk")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
// Replace this implementation with code to handle the error appropriately.
// fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
/*
Typical reasons for an error here include:
* The parent directory does not exist, cannot be created, or disallows writing.
* The persistent store is not accessible, due to permissions or data protection when the device is locked.
* The device is out of space.
* The store could not be migrated to the current model version.
Check the error message to determine what the actual problem was.
*/
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
class cdHandler: NSObject {
private class func getContext() -> NSManagedObjectContext {
let appdeleagetzz = UIApplication.shared.delegate as! AppDelegate
return appdeleagetzz.persistentContainer.viewContext
}
class func testGetContext() {
let context = getContext()
print("getContext() succeeded, got \(context)")
}
class func saveObject(pic: Data, userName: String) -> Bool {
let context = getContext()
let entity = NSEntityDescription.entity(forEntityName: "User", in: context)
let managedObject = NSManagedObject(entity: entity!, insertInto: context)
managedObject.setValue(pic, forKey:"pic")
managedObject.setValue(userName, forKey:"userName")
do {
try context.save()
return true
} catch {
return false
}
}
class func deletObject(user: NSManagedObject) -> Bool {
let context = getContext()
context.delete(user)
do {
try context.save()
return true
} catch {
return false
}
}
}
}
You see that compiles with no errors. Also, it runs and the AppDelegate.cdhandler.getContext() method works. As you can see, in AppDelegate.application(application:didFinishLaunchingWithOptions:), I have added a call to a new method which I defined later,AppDelegate.cdHandler.testGetContext()`. It works perfectly.
Are you getting a different error now? If so, you need to specify whether it is a Build or Run error. In either case, copy and paste the text of the error into your question, and tell us where it occurs.