How do I get a reference to the app delegate in Swift?
SwiftSwift Problem Overview
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.
Swift Solutions
Solution 1 - Swift
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 & 5, this is done as follows:
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let aVariable = appDelegate.someVariable
Solution 2 - Swift
Swift 4.2
In Swift, easy to access in your VC's
extension UIViewController {
var appDelegate: AppDelegate {
return UIApplication.shared.delegate as! AppDelegate
}
}
Solution 3 - Swift
Convenience Constructors
> Add in AppDelegate Class at the end of code
Swift 5.5
func appDelegate() -> AppDelegate {
return UIApplication.shared.delegate as! AppDelegate
}
To use AppDelegate reference anywhere in code?
> For example: Call AppDelegate Method named setRoot > > appDelegate().setRoot()
Solution 4 - Swift
This could be used for OS X
let appDelegate = NSApplication.sharedApplication().delegate as AppDelegate
var managedObjectContext = appDelegate.managedObjectContext?
Solution 5 - Swift
It's pretty much the same as in Objective-C
let del = UIApplication.sharedApplication().delegate
Solution 6 - Swift
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
Solution 7 - Swift
Appart from what is told here, in my case I missed import UIKit:
import UIKit
Solution 8 - Swift
SWIFT < 3
Create a method in AppDelegate Class for ex
func sharedInstance() -> 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() -> AppDelegate{
return UIApplication.shared.delegate as! AppDelegate
}
Solution 9 - Swift
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.
}
Solution 10 - Swift
-
Make sure you
import UIKit -
let appDelegate = UIApplication.sharedApplication().delegate! as! AppDelegate
Solution 11 - Swift
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
Solution 12 - Swift
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"
Solution 13 - Swift
extension AppDelegate {
// MARK: - App Delegate Ref
class func delegate() -> AppDelegate {
return UIApplication.shared.delegate as! AppDelegate
}
}
Solution 14 - Swift
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 !!!
Solution 15 - Swift
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
Solution 16 - Swift
In Swift 3.0 you can get the appdelegate reference by
let appDelegate = UIApplication.shared.delegate as! AppDelegate
Solution 17 - Swift
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
}
}
Solution 18 - Swift
In the Xcode 6.2, this also works
let appDelegate = UIApplication.sharedApplication().delegate! as AppDelegate
let aVariable = appDelegate.someVariable