Unable to access push notification when app is in background for iOS 10

Question

For iOS 8 and 9, when the application is in the background, when a push notification is received, I am able to store the information it in the app. But for iOS 10, I cannot retrieve the information when the app is in the background. But only if I open/click on the notification, userNotification centerDidReceiveNotificationResponse is invoked.

For iOS 8 & 9, this works fine.

-(void) application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo fetchCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler
{
    // iOS 10 will handle notifications through other methods

    if( SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO( @"10.0" ) )
    {
        NSLog( @"iOS version >= 10. Let NotificationCenter handle this one." );
        // set a member variable to tell the new delegate that this is background
        return;
    }
    NSLog( @"HANDLE PUSH, didReceiveRemoteNotification: %@", userInfo );

    // custom code to handle notification content

    if( [UIApplication sharedApplication].applicationState == UIApplicationStateInactive )
    {
        NSLog( @"INACTIVE" );
        completionHandler( UIBackgroundFetchResultNewData );
    }
    else if( [UIApplication sharedApplication].applicationState == UIApplicationStateBackground )
    {
        NSLog( @"BACKGROUND" );
        completionHandler( UIBackgroundFetchResultNewData );
    }
    else
    {
        NSLog( @"FOREGROUND" );
        completionHandler( UIBackgroundFetchResultNewData );
    }
}

For iOS 10 the method is not invoked,

- (void)userNotificationCenter:(UNUserNotificationCenter *)center
       willPresentNotification:(UNNotification *)notification
         withCompletionHandler:(void (^)(UNNotificationPresentationOptions options))completionHandler
{
    NSLog( @"Handle push from foreground" );
    // custom code to handle push while app is in the foreground
    NSLog(@"%@", notification.request.content.userInfo);
}

- (void)userNotificationCenter:(UNUserNotificationCenter *)center
didReceiveNotificationResponse:(UNNotificationResponse *)response
         withCompletionHandler:(void (^)())completionHandler
{
    NSLog( @"Handle push from background or closed" );
    // if you set a member variable in didReceiveRemoteNotification, you  will know if this is from closed or background
    NSLog(@"%@", response.notification.request.content.userInfo);
}

Answer 1

I hope you have follow Below Steps.

Step 1 : Import " UserNotifications " framework.

#import <UserNotifications/UserNotifications.h> 

Step 2 : And your AppDelegate confirming " UNUserNotificationCenterDelegate " delegate

@interface AppDelegate : UIResponder <UIApplicationDelegate,UNUserNotificationCenterDelegate>

Step 3 : For iOS10, You can ask for the permission like this

UNUserNotificationCenter *center = [UNUserNotificationCenter currentNotificationCenter];
center.delegate = self;
[center requestAuthorizationWithOptions:(UNAuthorizationOptionSound | UNAuthorizationOptionAlert | UNAuthorizationOptionBadge) completionHandler:^(BOOL granted, NSError * _Nullable error){
     if(!error){
         // Permission for notifications is granted. Do the other code
     }
 }];  

Now I think the problem you are having in your code in Handling delegate methods for UserNotifications .

//Called when a notification is delivered to a foreground app.
-(void)userNotificationCenter:(UNUserNotificationCenter *)center willPresentNotification:(UNNotification *)notification withCompletionHandler:(void (^)(UNNotificationPresentationOptions options))completionHandler{
    NSLog(@"User Info : %@",notification.request.content.userInfo);
    completionHandler(UNAuthorizationOptionSound | UNAuthorizationOptionAlert | UNAuthorizationOptionBadge);
}

//Called to let your app know which action was selected by the user for a given notification.
-(void)userNotificationCenter:(UNUserNotificationCenter *)center didReceiveNotificationResponse:(UNNotificationResponse *)response withCompletionHandler:(void(^)())completionHandler{
    NSLog(@"User Info : %@",response.notification.request.content.userInfo);
    completionHandler();
}

Your code is missing below line of codes

    completionHandler(UNAuthorizationOptionSound | UNAuthorizationOptionAlert | UNAuthorizationOptionBadge);

And

    completionHandler();

In willPresentNotification and didReceiveNotificationResponse respectively.