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@dougdiego
Last active May 2, 2024 22:47
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Migrate NSUserDefaults to App Groups - Swift
func migrateUserDefaultsToAppGroups() {
// User Defaults - Old
let userDefaults = NSUserDefaults.standardUserDefaults()
// App Groups Default - New
let groupDefaults = NSUserDefaults(suiteName: "group.myGroup")
// Key to track if we migrated
let didMigrateToAppGroups = "DidMigrateToAppGroups"
if let groupDefaults = groupDefaults {
if !groupDefaults.boolForKey(didMigrateToAppGroups) {
for key in userDefaults.dictionaryRepresentation().keys {
groupDefaults.setObject(userDefaults.dictionaryRepresentation()[key], forKey: key)
}
groupDefaults.setBool(true, forKey: didMigrateToAppGroups)
groupDefaults.synchronize()
print("Successfully migrated defaults")
} else {
print("No need to migrate defaults")
}
} else {
print("Unable to create NSUserDefaults with given app group")
}
}
@PedroCavaleiro
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An updated version of your code to Swift 4

func migrateUserDefaultsToAppGroups() {
        
        // User Defaults - Old
        let userDefaults = UserDefaults.standard
        
        // App Groups Default - New
        let groupDefaults = UserDefaults(suiteName: "group.myGroup")
        
        // Key to track if we migrated
        let didMigrateToAppGroups = "DidMigrateToAppGroups"
        
        if let groupDefaults = groupDefaults {
            if !groupDefaults.bool(forKey: didMigrateToAppGroups) {
                for key in userDefaults.dictionaryRepresentation().keys {
                    groupDefaults.set(userDefaults.dictionaryRepresentation()[key], forKey: key)
                }
                groupDefaults.set(true, forKey: didMigrateToAppGroups)
                groupDefaults.synchronize()
                print("Successfully migrated defaults")
            } else {
                print("No need to migrate defaults")
            }
        } else {
            print("Unable to create NSUserDefaults with given app group")
        }
        
    }

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ghost commented Feb 24, 2020

thx so much!

@shaundon
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This is super helpful, thank you!

@MatyasKriz
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I don't really understand why would you call userDefaults.dictionaryRepresentation() twice when you can just do

for (key, value) in standardDefaults.dictionaryRepresentation() {
    groupDefaults.set(value, forKey: key)
}

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