Firebase - Push Notifications - Not quite working as expected - ios

Question

In order to try out Push Notifications with Firebase I have been following these three documents:
One, Two, Three and Four.
I have one question, but before asking; here is what I can see:
When my app is in the foreground and a notification is sent, only this function is called:
userNotificationCenter(_:willPresent:withCompletionHandler:)
If I tap on the notification, then this one is also so called:
userNotificationCenter(_:didReceive:withCompletionHandler:)
When my app is in the background and a notification is sent, nothing is called.
If I tap on the notification, then this one is called:
userNotificationCenter(_:didReceive:withCompletionHandler:)
As a result of this situation, whithout having to react (by tapping on the notification); I can have the app perform some useful action when a notification is arriving while in the foreground, using the userNotificationCenter(_:willPresent:withCompletionHandler:) function.
On the other hand while in the background, I can only have the app perform some useful action when a notification is arriving if the user taps on the notification.
Is there a way for me to also have the app perform some useful action even if the user has no reaction?
Here is the relevant code I have at this point:
import UIKit
import Firebase
import UserNotifications
import FirebaseInstanceID
import FirebaseMessaging
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate, MessagingDelegate {
var window: UIWindow?
func application(_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
window = UIWindow(frame: UIScreen.main.bounds)
UNUserNotificationCenter.current().delegate = self
let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
UNUserNotificationCenter.current().requestAuthorization(
options: authOptions,
completionHandler: {
granted, error in
if error != nil {print("Error: \(error!)")}
if granted {
DispatchQueue.main.async
{application.registerForRemoteNotifications()}
}
})
FirebaseApp.configure()
.......
return true
}
func application(_ application: UIApplication,
didReceiveRemoteNotification userInfo: [AnyHashable: Any]) {
print(#function)
if let messageID = userInfo[gcmMessageIDKey] {
print("Message ID: \(messageID)")
}
// Print full message.
print(userInfo)
}
func application(_ application: UIApplication,
didReceiveRemoteNotification userInfo: [AnyHashable: Any],
fetchCompletionHandler completionHandler: #escaping (UIBackgroundFetchResult) -> Void) {
print(#function)
if let messageID = userInfo[gcmMessageIDKey] {
print("Message ID: \(messageID)")
}
// Print full message.
print(userInfo)
completionHandler(UIBackgroundFetchResult.newData)
}
}
For information, I am using Xcode Version 10.1, iOS 12.1 and Swift 4.2.

Answer 1

swift 4.2, Xcode 10.0, IOS 12.0
import UIKit
import Firebase
import UserNotifications
import FirebaseInstanceID
import FirebaseMessaging
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate, MessagingDelegate {
var window: UIWindow?
func application(_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
window = UIWindow(frame: UIScreen.main.bounds)
if #available(iOS 10.0, *) {
let center = UNUserNotificationCenter.current()
center.requestAuthorization(options: [.badge, .alert , .sound]) { (granted, error) in
let type: UIUserNotificationType = [UIUserNotificationType.badge, UIUserNotificationType.alert, UIUserNotificationType.sound]
let setting = UIUserNotificationSettings(types: type, categories: nil)
UIApplication.shared.registerUserNotificationSettings(setting)
UIApplication.shared.registerForRemoteNotifications()
}
} else {
let type: UIUserNotificationType = [UIUserNotificationType.badge, UIUserNotificationType.alert, UIUserNotificationType.sound]
let setting = UIUserNotificationSettings(types: type, categories: nil)
UIApplication.shared.registerUserNotificationSettings(setting)
UIApplication.shared.registerForRemoteNotifications()
}
application.registerForRemoteNotifications()
if(FIRApp.defaultApp() == nil){
FIRApp.configure()
}
NotificationCenter.default.addObserver(self,
selector: #selector(self.tokenRefreshNotification(notification:)),
name: NSNotification.Name.firInstanceIDTokenRefresh,
object: nil)
return true
}
#available(iOS 10.0, *)
func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: #escaping () -> Void) {
let userInfo = response.notification.request.content.userInfo as? NSDictionary
_ = UIStoryboard(name: "Main", bundle: nil)
let appdelegate = UIApplication.shared.delegate as! AppDelegate
let aps = userInfo?["aps"] as! NSDictionary
}
#available(iOS 10.0, *)
func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: #escaping (UNNotificationPresentationOptions) -> Void) {
completionHandler([.alert, .badge, .sound])
}
}
func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
// Convert token to string
let deviceTokenString = deviceToken.reduce("", {$0 + String(format: "%02X", $1)})
print("Device Token", deviceTokenString)
FIRInstanceID.instanceID().setAPNSToken(deviceToken, type: FIRInstanceIDAPNSTokenType.unknown)
}
func application(_ application: UIApplication, didReceiveRemoteNotification data: [AnyHashable : Any]) {
let appdelegate = UIApplication.shared.delegate as! AppDelegate
let aps = data["aps"] as! NSDictionary
let state = UIApplication.shared.applicationState
if state == .background {
}
if state == .active {
}
}
//MARK: Notification Center Call
func callNotificationCenter(){
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "reloadData"), object: nil)
}
func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) {
}
// start firebase
#objc func tokenRefreshNotification(notification: NSNotification) {
let refreshedToken = FIRInstanceID.instanceID().token()
print(refreshedToken)
connectToFcm()
}
func connectToFcm() {
FIRMessaging.messaging().connect { (error) in
if (error != nil) {
print("Unable to connect with FCM. \(error?.localizedDescription ?? "")")
} else {
print("Connected to FCM")
}
}
}