发布NSUserDefaults在iOS键盘扩展和包含应用之间进行更改吗？

Question

I thought I have tried everything and read every possible articles in this forum. But nothing seems to work. Here is some code snippet and some settings:

On Extension side:

let thisDefaults = NSUserDefaults(suiteName: "group.request.com")
thisDefaults?.setObject("Hello", forKey: "prevWord")
thisDefaults?.setObject("World", forKey: "word")
let success = thisDefaults?.Synchronize()

NSNotificationCenter.defaultCenter().postNotificationName("ExtensionRequestChanges", object: nil)

On Containingg app side:

NSNotificationCenter.defaultCenter().addObserver(self, selector:                Selector("DidReceiveRequest:", name: "ExtensionRequestChanges", 
object: nil)

func DidReceiveRequest(notification: NSNotification) {
      // Read defaults
      let thisDefaults = NSUserDefaults(suiteName: "group.request.com")
      let word = thisDefaults?.stringForKey("word")
      let prevWord = thisDefaults?.stringForKey("prevWord")
      ...
}

On the project settings:

. registered "group.request.com" app group to both the extension and containing app
. set "RequestOpenAccess" in NSExtensionAttributes to YES

But my DidReceiveRequest function never seemed to get called! Why???

Please help.

Answer 1

NSNotificationCenter only works in the process it's running in. Your keyboard extension and container app are separate processes. To post interprocess notifications, you should investigate the CFNotificationCenterGetDarwinNotifyCenter API call, which returns a Core Foundation notification center that can post notifications between processes, or other forms of interprocess communication.