How do I get a reference to the app delegate in Swift

Question

How do I get a reference to the app delegate in Swift   Ultimately  I want to use the reference to access the managed object context

User · Answer

Here is the Swift 5 version  let delegate   UIApplication shared delegate as  AppDelegate  And to access the managed object context      if let delegate   UIApplication shared delegate as  AppDelegate            let moc   delegate managedObjectContext                     your code here                 or  using guard      guard let delegate   UIApplication shared delegate as  AppDelegate  else           return            let moc   delegate managedObjectContext                 your code here

User · Answer

As of iOS 12 2 and Swift 5 0  AppDelegate is not a recognized symbol  UIApplicationDelegate is  Any answers referring to AppDelegate are therefore no longer correct  The following answer is correct and avoids force-unwrapping  which some developers consider a code smell   import UIKit  extension UIViewController     var appDelegate  UIApplicationDelegate       guard let appDelegate   UIApplication shared delegate else         fatalError  Could not determine appDelegate              return appDelegate

User · Answer

The other solution is correct in that it will get you a reference to the application s delegate  but this will not allow you to access any methods or variables added by your subclass of UIApplication  like your managed object context  To resolve this  simply downcast to  AppDelegate  or what ever your UIApplication subclass happens to be called  In Swift 3  4  amp  5  this is done as follows   let appDelegate   UIApplication shared delegate as  AppDelegate let aVariable   appDelegate someVariable

User · Answer

This could be used for OS X  let appDelegate   NSApplication sharedApplication   delegate as AppDelegate var managedObjectContext   appDelegate managedObjectContext

User · Answer

In the Xcode 6 2  this also works   let appDelegate   UIApplication sharedApplication   delegate  as AppDelegate  let aVariable   appDelegate someVariable

User · Answer

Appart from what is told here  in my case I missed import UIKit   import UIKit

User · Answer

it is very simple  App delegate instance  let app   UIApplication shared delegate as  AppDelegate   you can call a method with one line syntax  app callingMethod     you can access a variable with this code  app yourVariable    Assigning a value

User · Answer

Here s an extension for UIApplicationDelegate that avoids hardcoding the AppDelegate class name   extension UIApplicationDelegate        static var shared  Self               return UIApplication shared delegate  as  Self             use like this  let appDelegate   MyAppDelegate shared    will be of type MyAppDelegate

User · Answer

I use this in Swift 2 3   1 in AppDelegate class  static let sharedInstance  AppDelegate   UIApplication sharedApplication   delegate as  AppDelegate   2 Call AppDelegate with  let appDelegate   AppDelegate sharedInstance

User · Answer

extension AppDelegate           MARK  - App Delegate Ref     class func delegate   - gt  AppDelegate           return UIApplication shared delegate as  AppDelegate

User · Answer

Convenience Constructors     Add in AppDelegate Class at the end of code   Swift 5  func appDelegate   - gt  AppDelegate       return UIApplication shared delegate as  AppDelegate     To use AppDelegate reference in your class        Call AppDelegate Method      appDelegate   setRoot

User · Answer

Try simply this   Swift 4     Call the method  UIApplication shared delegate as  AppDelegate   whateverWillOccur     where in your AppDelegate      MARK  - Whatever func whateverWillOccur             Your code here

User · Answer

Make sure you import UIKit let appDelegate   UIApplication sharedApplication   delegate  as  AppDelegate

User · Answer

In my case  I was missing import UIKit on top of my NSManagedObject subclass  After importing it  I could remove that error as UIApplication is the part of UIKit  Hope it helps others

User · Answer

Swift 4 2  In Swift  easy to access in your VC s  extension UIViewController       var appDelegate  AppDelegate       return UIApplication shared delegate as  AppDelegate

User · Answer

It s pretty much the same as in Objective-C  let del   UIApplication sharedApplication   delegate

User · Answer

SWIFT  lt  3  Create a method in AppDelegate Class for ex  func sharedInstance   - gt  AppDelegate          return UIApplication sharedApplication   delegate as  AppDelegate         and call it some where else for ex  let appDelegate   AppDelegate   AppDelegate   sharedInstance     SWIFT     3 0  func sharedInstance   - gt  AppDelegate      return UIApplication shared delegate as  AppDelegate

User · Answer

In Swift 3 0 you can get the appdelegate reference by  let appDelegate   UIApplication shared delegate as  AppDelegate

[swift] How do I get a reference to the app delegate in Swift?

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