Sharing data between an iOS 8 share extension and

Question

Recently, I've been making a simple iOS 8 share extension to understand how the system works. As Apple states in its App Extension Programming Guide:

By default, your containing app and its extensions have no direct access to each other’s containers.

Which means the extension and the containing app do not share data. But in the same page Apple brings a solution:

If you want your containing app and its extensions to be able to share data, use Xcode or the Developer portal to enable app groups for the app and its extensions. Next, register the app group in the portal and specify the app group to use in the containing app.

Then it becomes possible to use NSUserDefaults to share data between the containing app and the extension. This is exactly what I would like to do. But for some reason, it does not work.

In the same page, Apple suggests the standard defaults:

var defaults = NSUserDefaults.standardUserDefaults()

In a WWDC presentation (217), they suggest a common package:

var defaults = NSUserDefaults(suiteName: kDefaultsPackage)

Also, I enabled App Groups for both the containing app target and the extension target, with the same App Group name:

But all this setup is for nothing. I cannot retrieve the data I stored in the containing app, from the extension. It is like two targets are using completely different NSUserDefaults storages.

So,

1. Is there a solution for this method?
2. How can I share simple data between the containing app and the share extension? The data is just user credentials for an API.

Answer 1

If you have

group.yourappgroup

use

var defaults = NSUserDefaults(suiteName: "yourappgroup")

This works for me

Answer 2

In my scenario I'm sharing data between the parent iOS app and WatchKit. I'm using Xcode 6.3.1, iOS Deployment Target 8.3

var defaults = NSUserDefaults(suiteName: "group.yourappgroup.example")

In your viewDidLoad make sure you synchronize:

    override func viewDidLoad() {
    super.viewDidLoad()

    defaults?.synchronize()

}

Example of a button sending text but of course you can pass whatever:

 @IBAction func btnSend(sender: UIButton) {
    var aNumber : Int = 0;
    aNumber = aNumber + 1

    //Pass anything with this line
    defaults?.setObject("\(aNumber)", forKey: "userKey")
    defaults?.synchronize()

}

Then on the other side make sure app group matches:

 var defaults = NSUserDefaults(suiteName: "group.yourappgroup.example")

Then synchronize and cal: (In this case "lblNumber" is an IBOutlet label)

defaults?.synchronize()
var tempVar = defaults!.stringForKey("userKey")!;
lblNumber.setText(tempVar);

Then if you wanted to set something on this side and sync it back then just do the same thing and synchronize and just make sure the stringForKey that you call on the other side is the same:

defaults?.setObject("sending sample text", forKey: "sampleKey")
defaults?.synchronize()

Hope this makes sense

Answer 3

You may share data by Following below steps:

1) Select your project -> Select Capabilities tab -> Enable App Groups -> Click on '+' -> paste your bundle Id after 'group.'

2) Select your Extension -> Select Capabilities tab -> Enable App Groups -> Click on '+' -> paste your bundle Id after 'group.'

3) Place below code in your main app for which data you want to share:

NSUserDefaults * appGroupData = [[NSUserDefaults alloc]initWithSuiteName:@"group.com.appname"];
NSData * data = [NSKeyedArchiver archivedDataWithRootObject:[self allData]]; // Get my array which I need to share
[appGroupData setObject:data forKey:@"Data"];
[appGroupData synchronize];

4) You may get object in extension:

NSUserDefaults * appGroupData = [[NSUserDefaults alloc] initWithSuiteName:@"group.com.appname"];
NSData * data = [appGroupData dataForKey:@"Data"];
NSArray * arrReceivedData = [NSKeyedUnarchiver unarchiveObjectWithData:data];

Answer 4

So apparently it works, only when the group name is used as the suite name for NSUserDefaults.

The documentation says NSUserDefaults.standartUserDefaults() should also work but it does not, and this is probably a bug.

Answer 5

You should use NSUserDefaults like this:

Save data:

objc

NSUserDefaults *shared = [[NSUserDefaults alloc] initWithSuiteName:@"group.yougroup"];
[shared setObject:object forKey:@"yourkey"];
[shared synchronize];

swift

let defaults = UserDefaults(suiteName: "group.yourgroup")
defaults?.set(5.9, forKey: "yourKey")

Read data:

objc

NSUserDefaults *shared = [[NSUserDefaults alloc] initWithSuiteName:@"group.yougroup"];
id value = [shared valueForKey:@"yourkey"];
NSLog(@"%@",value);

swift

let defaults = UserDefaults(suiteName: "group.yourgroup")
let x = defaults?.double(forKey: "yourKey")
print(x)

This will work fine!

Answer 6

I translated in swift foogry's answer and it works!!

Save data:

let shared = NSUserDefaults(suiteName: "nameOfCreatedGroup")
shared("Saved String 1", forKey: "Key1")
shared("Saved String 2", forKey: "Key2")

Read data:

let shared = NSUserDefaults(suiteName: "nameOfCreatedGroup")!
valueToRead1 = shared("Key1") as? String
valueToRead2 = shared("Key2") as? String
println(valueToRead1)   // Saved String 1
println(valueToRead2)   // Saved String 2