Push notification not getting in back ground state through GCM in ios - ios

Question

I have integrated push notification through GCM everything is working fine. But I am not getting notification message and sound. And the function didReceiveNotification: called in app delegate. And also not getting in background state.

Answer 1

Before making any comment or downvote consider following things.
I assume you have configured App Identifier in Developer portal, if not visit Apple Developer center
You have generated required provisional Profile & Certificate from Apple Developer Portal. If not visit App Distribution Guide
Make sure you have configured your bundle identifier correctly as defined in Apple Developer portal.
Following answer guides to configure APNS using your custom backend to send Push Notifications not for FireBase/GCM. To configure it using Firebase or GCM(As Firebase Cloud Messaging (FCM) is the new version of GCM) follow Google documentation
If all the above things are configured correctly then follow below steps:
Step 1: Register for APNS with Appropriate settings in didFinishLaunchingWithOptions inside AppDelegate file
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Override point for customization after application launch.
let notificationTypes: UIUserNotificationType = [UIUserNotificationType.Alert, UIUserNotificationType.Badge, UIUserNotificationType.Sound]
let pushNotificationSettings = UIUserNotificationSettings(forTypes: notificationTypes, categories: nil)
application.registerUserNotificationSettings(pushNotificationSettings)
application.registerForRemoteNotifications()
return true
}
Step 2: Add delegate methods to handle success or failure for APNS registration by adding following delegate methods
func application(application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: NSData) {
// Convert binary Device Token to a String (and remove the <,> and white space charaters).
var deviceTokenStr = deviceToken.description.stringByReplacingOccurrencesOfString(">", withString: "", options: nil, range: nil)
deviceTokenStr = deviceTokenStr.stringByReplacingOccurrencesOfString("<", withString: "", options: nil, range: nil)
deviceTokenStr = deviceTokenStr.stringByReplacingOccurrencesOfString(" ", withString: "", options: nil, range: nil)
print(deviceTokenStr);
// *** Store device token in your backend server to send Push Notification ***
}
func application(application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: NSError) {
print(error)
}
Step 3: Now you have configured your APNS on device end, You can fire Push Notification from your server/backend, When Push Notification is received following method will be called when your app is in Foreground. Implement it into AppDelegate.
func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject]) {
print(userInfo)
}
To handle Push Notification while your application is in background (but not killed by removing from multitask) you need to take care of following things.
Make sure you have enabled Background Modes in Project Navigation->Targets->Capabilities->Turn on Background Modes and select Remote Notifications.
Now implement following method to handle Push Notification while in background. Make sure you handle UIBackgroundFetchResult properly.
func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject], fetchCompletionHandler completionHandler: (UIBackgroundFetchResult) -> Void) {
}
Note: If func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject], fetchCompletionHandler completionHandler: (UIBackgroundFetchResult) -> Void) method is implemented func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject]) method will not be called.
Read more about APNS in Apple Documentation.

Answer 2

Usually, iOS apps can receive push notifications via APNS not GCM and could not get any data when app is in background state. If iOS app gets push notification via APNS and it is in background state, the push notifications just shown in notification center & top of the screen with app's icon. If you see the notification, there's no problem with the server.
And there's no data arrived when app is in the background state, you should make your server api for the notifications data when the app is back on foreground state.