Detect changes on NSUserDefaults with suiteName

Question

I created appGroups and did set up a NSUserDefaults using that group. I have a observer for which is not triggered when the value is changed.

let defaults = NSUserDefaults(suiteName: "group.daniesy.text")!            
defaults.addObserver(self, forKeyPath: "temp", options: NSKeyValueObservingOptions.New, context: nil)
defaults.setBool(!defaults.boolForKey("temp"), forKey: "temp")
defaults.synchronize()

override func observeValueForKeyPath(keyPath: String, ofObject object: AnyObject, change: [NSObject : AnyObject], context: UnsafeMutablePointer<Void>) {
    println("changed")
}

However if i ignore the appGroup and use NSUserDefaults.standardUserDefaults() it works as expected. Any idea why it's not working?

yes, weird... observer for forKeyPath it's not working with suiteName; the only solution is to observer "globally" all the NSUserDefault: NSNotificationCenter.defaultCenter().addObserver(self, selector: "defaultsChanged_selector", name: NSUserDefaultsDidChangeNotification, object: nil) — TonyMkenu, Oct 28 '14 at 10:10
Would this work when changing nsuser defaults externally? Like from a widget or other app? — Dănuț Mihai Florian, Oct 28 '14 at 13:40
It's working, you can check this example also - http://www.glimsoft.com/06/28/ios-8-today-extension-tutorial/ (PS Hello Cluj! :D ) — TonyMkenu, Oct 28 '14 at 14:30
The sharing of data works indeed, i need the observer to work. Hello Bucuresti :D :)) — Dănuț Mihai Florian, Oct 28 '14 at 14:33
I have tested the above code (Today Extension) and the observer it's working properly (at least for the moment iOS 8.1) — TonyMkenu, Oct 28 '14 at 14:35
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/63797/discussion-between-tonymkenu-and-dnu-mihai-florian). — TonyMkenu, Oct 28 '14 at 14:56
As of the release of iOS 10 and macOS 10.12, the Foundation release notes mention... Key-Value Observing and NSUserDefaults - In previous releases, KVO could only be used on the instance of NSUserDefaults returned by the +standardUserDefaults method.... These limitations have both been corrected. — bergdesign, Oct 06 '16 at 02:47

score 4 · Answer 1 · edited Jun 20 '20 at 09:12

Foundation Release Notes for macOS 10.12 and iOS 10

https://developer.apple.com/library/archive/releasenotes/Miscellaneous/RN-Foundation-OSX10.12/index.html

Key-Value Observing and NSUserDefaults

In previous releases, KVO could only be used on the instance of NSUserDefaults returned by the +standardUserDefaults method. Additionally, changes from other processes (such as defaults(1), extensions, or other apps in an app group) were ignored by KVO. These limitations have both been corrected. Changes from other processes will be delivered asynchronously on the main queue, and ignore NSKeyValueObservingOptionPrior.

score 2 · Answer 2 · edited Apr 28 '16 at 20:24

Try adding suitename instead of initializing. Set up an App Group if you want to share the data

let defaults = NSUserDefaults.standardUserDefaults()
defaults.addSuiteNamed("group.daniesy.text")
defaults.addObserver(self, forKeyPath: "temp", options: NSKeyValueObservingOptions.New, context: nil)
defaults.setBool(!defaults.boolForKey("temp"), forKey: "temp")
defaults.synchronize()

override func observeValueForKeyPath(keyPath: String, ofObject object: AnyObject, change: [NSObject : AnyObject], context: UnsafeMutablePointer<Void>) {
    println("changed")
}

Detect changes on NSUserDefaults with suiteName

2 Answers2

Foundation Release Notes for macOS 10.12 and iOS 10

Key-Value Observing and NSUserDefaults