Using iOS App Extensions with

About iOS App Extensions in Mobile SDK Apps

An iOS app extension is a separate target in your project. It lives in its own folder and is added to your app bundle as a separate binary unit. However, the app extension can access the same resources and libraries as your main app. Apple offers many extension types, as described in App Extensions articles at developer.apple.com.

Project Settings

1. In your Mobile SDK app, create an extension target as described in the Apple developer documentation. How you handle this step and the type of extension is between you and iOS.
2. After you’ve created the target, select the top-level node of your Mobile SDK workspace in the Xcode Project Navigator. This step opens your project in the Project Editor.
3. In both app and extension targets, sign in to the same developer team.
4. Click General, and then specify a unique bundle identifier for the app target. Here’s how it looks in Xcode 12.4:
5. Repeat the bundle identifier step for the extension target. This identifier must also be unique.
6. In your app configuration, select your Mobile SDK app target and then click Capabilities.
7. Turn on App Groups and Keychain Sharing in your app target.
8. Under App Groups, select or create an app group. Use a unique label that identifies your app, such as “group.myapp.shared”.
9. Under Keychain Sharing, select or create a keychain group. Use a unique label that identifies your app, such as “com.myapp.MyApp”.
10. Repeat the App Groups and Keychain Sharing steps for your extension target. The two values in the extension target must exactly match the corresponding values in the application target.

App Group Settings

When you incorporate an iOS app extension into a forceios app, you add code that tells Mobile SDK that you’re working in an app group. You add these lines in two places: the AppDelegate class in your main app, and the view controller or scene delegate class in your app extension.

Mobile SDK provides a utility class, SFSDKDatasharingHelper, that stores the necessary properties. Values you set for these properties in the main app and the app extension must be identical.

1@implementation NSUserDefaults (SFAdditions)
2
3+ (NSUserDefaults *)msdkUserDefaults {
4    NSUserDefaults *sharedDefaults = nil;
5    if ([SFSDKDatasharingHelper sharedInstance].appGroupEnabled) {
6        sharedDefaults = [[NSUserDefaults alloc] 
7            initWithSuiteName:[SFSDKDatasharingHelper sharedInstance].appGroupName];
8    } else {
9        sharedDefaults = [NSUserDefaults standardUserDefaults];
10    }
11    return sharedDefaults;
12}
13
14@end

AppDelegate Code Changes

The following steps apply to the init method of your main app’s AppDelegate class.

1. At the top of the init method, set appGroupName and appGroupEnabled on the SFSDKDatasharingHelper shared instance.
   1...
   2- (id)init
   3{
   4    self = [super init];
   5    if (self) {
   6     // Insert these two lines, using your app group name 
   7        [SFSDKDatasharingHelper sharedInstance].appGroupName = 
   8            @"<your app group name>"; 
   9        [SFSDKDatasharingHelper sharedInstance].appGroupEnabled = YES; 
   10...

2. After the user has successfully logged in, store a value reflecting the login status in an object that the extension code can access. You can infer the status by reading the currentUser property of the SFUserAccountManager object. To safely and consistently update the login status, set this property in the callback method of the registerBlockForCurrentUserChangeNotifications call in the init method. The following example uses the Mobile SDK NSUserDefaults (SFAdditions) category to store the Boolean value under a key named userLoggedIn.
   1[SFSDKAuthHelper registerBlockForCurrentUserChangeNotifications:^{
   2    __strong typeof (weakSelf) strongSelf = weakSelf;
   3    BOOL loggedIn = [SFUserAccountManager.sharedInstance currentUser] != nil;
   4    [[NSUserDefaults msdkUserDefaults] setBool:loggedIn forKey:@"userLoggedIn"];
   5    [strongSelf resetViewState:^{
   6        [strongSelf setupRootViewController];
   7    }];
   8}];

App Extension Code Changes

At runtime, your iOS app extension operates as a second app, so you have to “bootstrap” it as well. You apply the same appGroupName and appGroupEnabled changes as you did in the main app’s AppDelegate class.

App extensions can’t perform authentication tasks such as user logins. However, before making calls to a Mobile SDK manager such as MobileSyncSDKManager, you must verify that a user has logged in. You do this verification by checking the value stored by the main app in the NSUserDefaults dictionary.

1. In your app extension’s initialization entry point, set and enable the app group.
   1[SFSDKDatasharingHelper sharedInstance].appGroupName = @"<your app group name>"; 
   2[SFSDKDatasharingHelper sharedInstance].appGroupEnabled = YES;

2. Verify that the userLoggedIn value indicates success. Continue with other Mobile SDK calls only if userLoggedIn equals YES.

If the app determines that a user has successfully logged in, the app extension can apply that user’s shared credentials to Salesforce API calls.