iOS save last used view controller to user defaults

[abcdefg12345]

im trying to save and restore last used view controller when the app is opened, however there is the issue that im using a diffrent swift file for each view controller and im not sure how to save it to user defaults.

this is how i switch between controllers

let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
            let newViewController = storyBoard.instantiateViewController(withIdentifier: "Sample1") as! SampleFile1
            self.present(newViewController, animated: true, completion: nil)

I can save the string objects easily but the last part where it says (withIdentifier: "Sample1") as! SampleFile1, how do i save this SampleFile1 and retrieve it?

 

[firewood]

Try creating a Dictionary with the ID as key and the class reference as the value. Fill it with all your controllers. Then do a lookup in that Dictionary.

 

[abcdefg12345]

Try creating a Dictionary with the ID as key and the class reference as the value. Fill it with all your controllers. Then do a lookup in that Dictionary.

i got it working like that:

save at the end of viewdidload in every class:

let storyBoard = self.storyboard?.value(forKey: "name") //get storyboard id
        let newViewController = self.restorationIdentifier //get identifier of view controller
        UserDefaults.standard.set(storyBoard, forKey: "storyBoard") // save to user defaults
        UserDefaults.standard.set(newViewController, forKey: "newViewController")

then in AppDelegate:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

//define variable strings
var storyBoard = ""
        var newViewController = ""
        if let storyBoardLoad = UserDefaults.standard.string(forKey: "storyBoard") {
            storyBoard = storyBoardLoad // restore and set variables
        }
        if let newViewControllerLoad = UserDefaults.standard.string(forKey: "newViewController") {
            newViewController = newViewControllerLoad
        }
       
        if !(storyBoard == "") && !(newViewController == "") { // check that the string is not empty then set main view controller
            let storyboard : UIStoryboard = UIStoryboard(name: storyBoard, bundle: nil)
           
            let vc : UIViewController = storyboard.instantiateViewController(withIdentifier: newViewController)
            self.window?.rootViewController = vc 
        }
       
        return true
}

 

[PhoneyDeveloper]

For completeness sake Apple has built-in functionality to save/restore app state. I personally haven't had great luck using this but for simple apps this may work well for you.

View Controller Programming Guide for iOS: Preserving and Restoring ...

Strategies for Implementing Specific App Features - Apple Developer

State Restoration Tutorial: Getting Started - Ray Wenderlich

There are many more links. Search for: iOS save/restore app state

 

[albebaubles]

i got it working like that:

save at the end of viewdidload in every class:

let storyBoard = self.storyboard?.value(forKey: "name") //get storyboard id
        let newViewController = self.restorationIdentifier //get identifier of view controller
        UserDefaults.standard.set(storyBoard, forKey: "storyBoard") // save to user defaults
        UserDefaults.standard.set(newViewController, forKey: "newViewController")

then in AppDelegate:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

//define variable strings
var storyBoard = ""
        var newViewController = ""
        if let storyBoardLoad = UserDefaults.standard.string(forKey: "storyBoard") {
            storyBoard = storyBoardLoad // restore and set variables
        }
        if let newViewControllerLoad = UserDefaults.standard.string(forKey: "newViewController") {
            newViewController = newViewControllerLoad
        }
      
        if !(storyBoard == "") && !(newViewController == "") { // check that the string is not empty then set main view controller
            let storyboard : UIStoryboard = UIStoryboard(name: storyBoard, bundle: nil)
          
            let vc : UIViewController = storyboard.instantiateViewController(withIdentifier: newViewController)
            self.window?.rootViewController = vc
        }
      
        return true
}

whoa, arent you only saving the 'id' of the view controller in user defaults? Is that what you intended or were you specifically asking how to serialize the entire VC to user defaults?