I wanted to download data in background even when app is not running. Is it possible?
I have tried using background fetch but it is not working.
Please refer to the code below:
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: #escaping (UIBackgroundFetchResult) -> Void) {
UIApplication.shared.applicationIconBadgeNumber = 9
}
It gets called when app is running but not when app is killed
Unfortunately background fetch works for max 3 min after the app is deactivated or in the background. Except for VOIP, Location, Audio..ect
What you can do is send a remote push notification "according to a certain event taking place in your backend server" to your App so the user interacts with it and gets your app to the foreground.
As soon as the app is loaded to the foreground you can add an observer with a selector function in viewWillAppear to start fetching the data you need.
NotificationCenter.default.addObserver(self, selector:#selector(applicationWillEnterForeground(_:)), name:NSNotification.Name.UIApplicationWillEnterForeground, object: nil)
Selector function:
func applicationWillEnterForeground(_ notification: NSNotification) {
print("Fetch data")
}
Then in viewWillDisappear remove the observer:
NotificationCenter.default.removeObserver(self)
Related
I'm trying to get a push notification sent from server when user has my application in background, or closed and the notification came from server.
User clicks the push notification bar and the application opens.
This works, but I'm not sure how to get the notification object to make it seen and count down badges.
I tried to add observer in my mainviewcontroller
NotificationCenter.default.addObserver(
self,
selector: #selector(applicationWillEnterForeground(_:)),
name: UIApplication.willEnterForegroundNotification,
object: nil)
I tried to add code to my AppDelegate
func applicationWillEnterForeground(_ application: UIApplication) {
print(">>>>applicationWillEnterForeground;AppDelegate")
}
This two blocks are responding, but I'm not sure how to access clicked notification object
I have tried
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: #escaping (UIBackgroundFetchResult) -> Void)
But after the push notification click, application is opening a webpage in safari, so no processing is happening in this method
if remove notification was received when app was active - it's handling good. if app was at background orinactive - nothing happend. notifications are getting from Firebase Cloud Messaging. xcode 11.3.1
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo [AnyHashable : Any], fetchCompletionHandler completionHandler: #escaping (UIBackgroundFetchResult) -> Void) {
if application.applicationState == .active {
Utils.handlePushNotification(userInfo: userInfo) // works good
}
if application.applicationState == .background {
UserDefaults.standard.set(true, forKey: "openedFromPush") // doesn't work
}
if application.applicationState == .inactive {
UserDefaults.standard.set(true, forKey: "openedFromPush") // doesn't work
}
}
Make sure you ticked Remote notifications background mode in your app target's Signing & Capabilities options:
Your method should call completionHandler(.newData) or completionHandler(.noData) when responding to a notification that arrived while the app was in the background.
The Apple documentation states:
If the user opens your app from the system-displayed alert, the system may call this method again when your app is about to enter the foreground so that you can update your user interface and display information pertaining to the notification.
When a remote notification arrives, the system displays the notification to the user and launches the app in the background (if needed) so that it can call this method. Launching your app in the background gives you time to process the notification and download any data associated with it, minimizing the amount of time that elapses between the arrival of the notification and displaying that data to the user.
As soon as you finish processing the notification, you must call the
block in the handler parameter or your app will be terminated. Your
app has up to 30 seconds of wall-clock time to process the
notification and call the specified completion handler block. In
practice, you should call the handler block as soon as you are done
processing the notification.
i have solved my issue by using this:
func userNotificationCenter(_ center: UNUserNotificationCenter,
didReceive response:UNNotificationResponse,
withCompletionHandler completionHandler: #escaping () -> Void) {
}
I know there has been a lot written about this topic but I just can't find the right answer.
Is there a way how to know when the user received remote notification and when the user clicked on one on iOS 8.
I would like to know this because when I receive it I want to save it and when user clicks on it I want to open some view.
I have found this answer https://stackoverflow.com/a/16393957/1241217 but the problem is when user is in the app and opens notification center and clicks on one, the app is not inactive and not in the background.
I also found this answer https://stackoverflow.com/a/12937568/1241217 but I know that this is ran only when the app is killed and started from new.
I also don't want to do this https://stackoverflow.com/a/32079458/1241217 since I need to detect when I received notification.
So is there a way how to know if the user only clicked on notification. As far as I understood it has to be done in didReceiveRemoteNotification but I don't know how to separate between them. And I need an answer for before iOS 10 because the app target is iOS 8.
MY SOLUTION:
So as I wrote in the comment of Shabbir Ahmad answer my solution was to remember date when the application did become active and the date when the notification was received. If the difference between this dates was a second or less I accepted that as the user clicked on the notification.
You have to implement UNUserNotificationCenterDelegate and its method
userNotificationCenter(_:willPresent:withCompletionHandler:) and userNotificationCenter(_:didReceive:withCompletionHandler:) which gets called when a user taps a notification. In willPresent: you have to call the completionHandler with an option that would indicate what should happen when a notification arrives while the app is in foreground.
Registering such a delegate is easy:
UNUserNotificationCenter.current().delegate = self
So e.g.:
func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: #escaping (UNNotificationPresentationOptions) -> Void) {
completionHandler(UNNotificationPresentationOptions.alert)
}
func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: #escaping () -> Void) {
let userInfo = response.notification.request.content.userInfo
if let userInfo = userInfo as? [String: Any] {
// TODO: implement your logic
// just don't forget to dispatch UI stuff on main thread
}
}
You can implement that delegate by AppDelegate, but also by any NSObject, I would go with the latter to keep AppDelegate as clean as possible.
P.S.: Of course, this assumes that you have been granted permissions by the user (UNUserNotificationCenter.current().requestAuthorization(options:completionHandler:)) and you are registered to accept notifications (UIApplication.shared.registerForRemoteNotifications()).
Read more in Scheduling and Handling Local Notifications, section Responding to the Delivery of Notifications - while the section is about local notifications, it is exactly the same for the remote ones (they are handled both by the same delegate).
when you click on notification in background mode before ios 10 and when you are in foreground,in both cases your below method will call,
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any],
fetchCompletionHandler completionHandler: #escaping (UIBackgroundFetchResult) -> Void)
So you can differentiate the behaviour,
First of all you assign a boolean variable in AppDelegate class like this:
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
var isUserTapOnNotification = false
after that make true isUserTapOnNotification in
func applicationWillEnterForeground(_ application: UIApplication) {
isUserTapOnNotification = tue
}
because when you tap on notification bar, your app will came in foreground and applicationWillEnterForeground will call first,
after that your didReceiveRemoteNotification will call:
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any],
fetchCompletionHandler completionHandler: #escaping (UIBackgroundFetchResult) -> Void) {
if #available(iOS 10.0, *) {
//do nothing
}else { //<ios 10
if isUserTapOnNotification == true {//when app is in background and user tap on notification bar
//do action whatever you want
} else { //when user is in foreground and notification came,
//before ios10,notification bar not display in foreground mode,So you can show popup by using userInfo
}
}
after that applicationDidBecomeActive will call and you reset isUserTapOnNotification to false like this:
func applicationDidBecomeActive(_ application: UIApplication) {
isUserTapOnNotification = false
}
I hope this answer will help you.
Scenarios:
1) Silent or Normal payload when App's in Foreground:
Nothing happens
2) Silent payload when App's in Background:
Nothing happens
3) Normal payload when App's in Background:
If User click the notification to open the App.
triggers the application:didReceiveRemoteNotification:fetchCompletionHandler
If user open the App clicking the App icon:
Nothing happens
These are the payloads I'm using for the APNs:
Normal payload: .
{
"aps":{
"alert":"andre test",
"badge":0,
"sound":"default",
"content-available":1
},
"acme-syncalarm":"true"
}
Silent payload: .
{
"aps":{
"content-available":1
},
"acme-syncalarm":"true"
}
I've implemented the Remote Push Notification using this code:
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: #escaping (UIBackgroundFetchResult) -> Void) {
print("Receeeeeeeeived: \(userInfo)")
UIApplication.shared.applicationIconBadgeNumber = 11
completionHandler(.newData)
}
I also implemented this to check if the App is recovering from a kill state (as I've read in some Questions too), but the code never enters the print(rn)line.
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
if let rn = launchOptions?[UIApplicationLaunchOptionsKey.remoteNotification] {
print(rn)
}
}
EDIT 1 -
I have also enabled Remote Notifications in background mode for the App.
What do I have to do to cover the "Nothing Happens" Scenarios? 1 , 2 and 3.2 ?
Some notes:
"If user open the App clicking the App icon: Nothing happens" <-- That's expected, because you didn't interact with any notification directly. Imagine if you had 5 notifications arrived. How would you know which notification you should process...
normal payload won't have any key named content-available. So that again is a silent notification. Can you first see my answer here?
Some suggestions:
Make sure you've enabled Remote Notifications in background mode. Like this:
Additionally See here. iOS 11 initial releases were buggy for silent notifications. Make sure you have the latest version for your testing, otherwise it won't work. If you have an iOS 10 device, then first try testing with that...
Make sure you have Background App refresh and notifications available on your device. To see how to do it, refer to my linked answer.
Are you creating the payload yourself or you're using FireBase? If you're using Firebase then some of the keys change...and you must adjust accordingly.
make sure you've set some object as the delegate of UNUserNotificationCenterDelegate e.g.:
UNUserNotificationCenter.current().delegate = delegateObject
func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: #escaping (UNNotificationPresentationOptions) -> Void) {
let content = notification.request.content
// Process notification content
completionHandler([.alert, .sound, .badge]) // Display notification as regular alert and play sound
}
Code copied from here.
If you don't do such then you won't be showing any notification when the app is in the foreground. This should resolve the issue of when app is in foreground and you've received a normal remote notification.
App remote notification work well when app is foreground or background state but not works when App is killed manually,
Added background fetch in plist.
Tried with:
NSLog("Do something")
under this method still not able to receive in swift :
func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: #escaping () -> Void)
and
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any], fetchCompletionHandler completionHandler: #escaping (UIBackgroundFetchResult) -> Void)
When you kill the app manually, the remoteNotifications cannot be handled before the app is launched again.
When a remote notification is present, and you open the app by tapping on that notification, the app launches in the usual manner with the
didFinishLaunchingWithOptions
method being called in the app delegate. But in this case, your notification data would be passed in the 'Options' parameter. You can then check for this parameter and perform the required tasks
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool
{
if (launchOptions != nil)
{
let dictionary:NSDictionary = launchOptions?[UIApplicationLaunchOptionsRemoteNotificationKey] as! NSDictionary
self.setNotification(dictionary)
}
return true
}
You cannot handle a push notifications while app is not running. You only can handle when a user open the app form notification.
There is good article about that: How to handle remote notification with background mode enabled