How to get push notification when app is not running/app is terminated

Question

I have tried "Setting up a GCM Client App on iOS" from Google developers. My app has an android version and the server sends push notifications successfully to Android. In ios, I can retrieve the message to didRecieveRemoteNotification function.It looks like below when printed,

aps: {
    alert =     {
        body = tyyy;
        title = "2 is going out at 03/24/2016 15:02:48";
    };
    badge = 2;
    sound = default;
}

It receives this message when the app is in foreground and background. Nothing is shown in system tray when app is background.

When app is terminated and server is sending push notifications, I receive nothing, no activity shown.

My code is as below.

AppDelegate.swift

import UIKit

 @UIApplicationMain



class AppDelegate: UIResponder, UIApplicationDelegate, GGLInstanceIDDelegate,  GCMReceiverDelegate {

var window: UIWindow?

var connectedToGCM = false
var subscribedToTopic = false
var gcmSenderID: String?
var registrationToken = "AIzaSy-.....-11bSP6v72UvyKY"
var registrationOptions = [String: AnyObject]()

let registrationKey = "onRegistrationCompleted"
let messageKey = "onMessageReceived"
let subscriptionTopic = "/topics/global"


func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

    NSUserDefaults.standardUserDefaults().setBool(true, forKey: "APP_RUNNING")


    // Override point for customization after application launch.

    // [START_EXCLUDE]
    // Configure the Google context: parses the GoogleService-Info.plist, and initializes
    // the services that have entries in the file
    var configureError:NSError?
    GGLContext.sharedInstance().configureWithError(&configureError)
    assert(configureError == nil, "Error configuring Google services: \(configureError)")
    gcmSenderID = GGLContext.sharedInstance().configuration.gcmSenderID
    // [END_EXCLUDE]
    // Register for remote notifications
    if #available(iOS 8.0, *) {
        let settings: UIUserNotificationSettings =
        UIUserNotificationSettings(forTypes: [.Alert, .Badge, .Sound], categories: nil)
        application.registerUserNotificationSettings(settings)
        application.registerForRemoteNotifications()
    } else {
        // Fallback
        let types: UIRemoteNotificationType = [.Alert, .Badge, .Sound]
        application.registerForRemoteNotificationTypes(types)
    }

    // [END register_for_remote_notifications]
    // [START start_gcm_service]
    let gcmConfig = GCMConfig.defaultConfig()
    gcmConfig.receiverDelegate = self
    GCMService.sharedInstance().startWithConfig(gcmConfig)
    // [END start_gcm_service]

    application.registerUserNotificationSettings(UIUserNotificationSettings(forTypes: [.Alert, .Badge, .Sound],categories: nil))

    if let options = launchOptions {
        if let notification = options[UIApplicationLaunchOptionsLocalNotificationKey] as? UILocalNotification {
            if let userInfo = notification.userInfo {

                // do something neat here
            }
        }
    }

    return true
}

func subscribeToTopic() {
    // If the app has a registration token and is connected to GCM, proceed to subscribe to the
    // topic
    if(registrationToken != "" && connectedToGCM) {
        GCMPubSub.sharedInstance().subscribeWithToken(self.registrationToken, topic: subscriptionTopic,
            options: nil, handler: {(error:NSError?) -> Void in
                if let error = error {
                    // Treat the "already subscribed" error more gently
                    if error.code == 3001 {
                        print("Already subscribed to \(self.subscriptionTopic)")
                    } else {
                        print("Subscription failed: \(error.localizedDescription)");
                    }
                } else {
                    self.subscribedToTopic = true;
                    NSLog("Subscribed to \(self.subscriptionTopic)");
                }
        })
    }
}

func application( application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken
    deviceToken: NSData ) {

        // [END receive_apns_token]
        // [START get_gcm_reg_token]
        // Create a config and set a delegate that implements the GGLInstaceIDDelegate protocol.
        let instanceIDConfig = GGLInstanceIDConfig.defaultConfig()
        instanceIDConfig.delegate = self
        // Start the GGLInstanceID shared instance with that config and request a registration
        // token to enable reception of notifications
        GGLInstanceID.sharedInstance().startWithConfig(instanceIDConfig)
        registrationOptions = [kGGLInstanceIDRegisterAPNSOption:deviceToken,
            kGGLInstanceIDAPNSServerTypeSandboxOption:true]
        GGLInstanceID.sharedInstance().tokenWithAuthorizedEntity(gcmSenderID,
            scope: kGGLInstanceIDScopeGCM, options: registrationOptions, handler: registrationHandler)
        // [END get_gcm_reg_token]


}

// [START receive_apns_token_error]
func application( application: UIApplication, didFailToRegisterForRemoteNotificationsWithError
    error: NSError ) {
        print("Registration for remote notification failed with error: \(error.localizedDescription)")
        // [END receive_apns_token_error]
        let userInfo = ["error": error.localizedDescription]
        NSNotificationCenter.defaultCenter().postNotificationName(
            registrationKey, object: nil, userInfo: userInfo)
}


// [START ack_message_reception]
func application( application: UIApplication,
    didReceiveRemoteNotification userInfo: [NSObject : AnyObject]) {
        print("Notification received: \(userInfo)")
        // This works only if the app started the GCM service
        GCMService.sharedInstance().appDidReceiveMessage(userInfo);
        // Handle the received message
        // [START_EXCLUDE]
        NSNotificationCenter.defaultCenter().postNotificationName("reloadTableEvent", object: nil)
        NSNotificationCenter.defaultCenter().postNotificationName(messageKey, object: nil,
            userInfo: userInfo)
        // [END_EXCLUDE]
}

func application( application: UIApplication,
    didReceiveRemoteNotification userInfo: [NSObject : AnyObject],
    fetchCompletionHandler handler: (UIBackgroundFetchResult) -> Void) {
        print("Notification received: \(userInfo)")
        // This works only if the app started the GCM service
        GCMService.sharedInstance().appDidReceiveMessage(userInfo);
        // Handle the received message
        // Invoke the completion handler passing the appropriate UIBackgroundFetchResult value
        // [START_EXCLUDE]
        NSNotificationCenter.defaultCenter().postNotificationName(messageKey, object: nil,
            userInfo: userInfo)
        handler(UIBackgroundFetchResult.NoData);
        // [END_EXCLUDE]
}
// [END ack_message_reception]

func registrationHandler(registrationToken: String!, error: NSError!) {
    if (registrationToken != nil) {
        self.registrationToken = registrationToken
        print("Registration Token: \(registrationToken)")
        NSUserDefaults.standardUserDefaults().setValue(registrationToken, forKey: "registrationToken")
        self.subscribeToTopic()
        let userInfo = ["registrationToken": registrationToken]
        NSNotificationCenter.defaultCenter().postNotificationName(
            self.registrationKey, object: nil, userInfo: userInfo)
    } else {
        print("Registration to GCM failed with error: \(error.localizedDescription)")
        let userInfo = ["error": error.localizedDescription]
        NSNotificationCenter.defaultCenter().postNotificationName(
            self.registrationKey, object: nil, userInfo: userInfo)
    }
}

// [START on_token_refresh]
func onTokenRefresh() {
    // A rotation of the registration tokens is happening, so the app needs to request a new token.
    print("The GCM registration token needs to be changed.")
    GGLInstanceID.sharedInstance().tokenWithAuthorizedEntity(gcmSenderID,
        scope: kGGLInstanceIDScopeGCM, options: registrationOptions, handler: registrationHandler)
}
// [END on_token_refresh]

// [START upstream_callbacks]
func willSendDataMessageWithID(messageID: String!, error: NSError!) {
    if (error != nil) {
        // Failed to send the message.
    } else {
        // Will send message, you can save the messageID to track the message
    }
}

func didSendDataMessageWithID(messageID: String!) {
    // Did successfully send message identified by messageID
}
// [END upstream_callbacks]

func didDeleteMessagesOnServer() {
    // Some messages sent to this device were deleted on the GCM server before reception, likely
    // because the TTL expired. The client should notify the app server of this, so that the app
    // server can resend those messages.
}

func applicationWillResignActive(application: UIApplication) {
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}

func applicationDidEnterBackground(application: UIApplication) {

    NSUserDefaults.standardUserDefaults().setBool(false, forKey: "APP_RUNNING")

    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.

    GCMService.sharedInstance().disconnect()
    // [START_EXCLUDE]
    self.connectedToGCM = false
    // [END_EXCLUDE]
}

func applicationWillEnterForeground(application: UIApplication) {

    NSUserDefaults.standardUserDefaults().setBool(true, forKey: "APP_RUNNING")

    // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
}

func applicationDidBecomeActive(application: UIApplication) {

    NSUserDefaults.standardUserDefaults().setBool(true, forKey: "APP_RUNNING")

    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.

    // Connect to the GCM server to receive non-APNS notifications
    GCMService.sharedInstance().connectWithHandler({(error:NSError?) -> Void in
        if let error = error {
            print("Could not connect to GCM: \(error.localizedDescription)")
        } else {
            self.connectedToGCM = true
            print("Connected to GCM")
            // [START_EXCLUDE]
            self.subscribeToTopic()
            // [END_EXCLUDE]
        }
    })
}

func applicationWillTerminate(application: UIApplication) {

    NSUserDefaults.standardUserDefaults().setBool(false, forKey: "APP_RUNNING")

    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}

func application(application: UIApplication, didReceiveLocalNotification notification: UILocalNotification) {
    if let userInfo = notification.userInfo {
        NSNotificationCenter.defaultCenter().postNotificationName(
            "LoadEventViewController", object: nil, userInfo: userInfo)
    }
}




}

ViewController, popping local notification

func scheduleLocal(message: String) {
    let settings = UIApplication.sharedApplication().currentUserNotificationSettings()

    if settings!.types == .None {
        let ac = UIAlertController(title: "Can't schedule", message: "Either we don't have permission to schedule notifications, or we haven't asked yet.", preferredStyle: .Alert)
        ac.addAction(UIAlertAction(title: "OK", style: .Default, handler: nil))
        presentViewController(ac, animated: true, completion: nil)
        return
    }

    // create a corresponding local notification
    let notification = UILocalNotification()
    notification.alertBody = message // text that will be displayed in the notification
    notification.alertAction = "open" // text that is displayed after "slide to..." on the lock screen - defaults to "slide to view"
    notification.fireDate = NSDate(timeIntervalSinceNow: 0) // todo item due date (when notification will be fired)
    notification.soundName = UILocalNotificationDefaultSoundName // play default sound
    notification.userInfo = ["UUID": 1, ] // assign a unique identifier to the notification so that we can retrieve it later
    notification.category = "TODO_CATEGORY"
    UIApplication.sharedApplication().scheduleLocalNotification(notification)
}

I have 2 questions,

1. Is it possible to receive and show push notification even when app is in terminated state? If so, how?
2. Have I done something wrong in the code?

Solution

This is your push notification JSON?

aps: { "content-available" = 1; }

If yes, then you are sending a silent push. Silent push means that the user get's no visual notification, just the app delegate callback of your app is called. Remove the content-available tag and pass a message text instead.

If the App is in the foreground iOS does not show a push notification, but just calls the delegate. Then you can show an Alert View or something else you prefer.

Or you can show this: https://github.com/avielg/AGPushNote

Regarding the state "terminated by user", here the Apple doc (for silent push):

Apple documentation

Use this method to process incoming remote notifications for your app. Unlike the application:didReceiveRemoteNotification: method, which is called only when your app is running in the foreground, the system calls this method when your app is running in the foreground or background. In addition, if you enabled the remote notifications background mode, the system launches your app (or wakes it from the suspended state) and puts it in the background state when a remote notification arrives. However, the system does not automatically launch your app if the user has force-quit it. In that situation, the user must relaunch your app or restart the device before the system attempts to launch your app automatically again.