This is a well worn post... but it is still missing an actual solution to the problem (as is pointed out in the various comments).
The original question is about detecting when the app was launched
/ opened from a push notification, e.g. a user taps on the
notification. None of the answers actually cover this case.
The reason can be seen in the call flow when a notification arrives, application:didReceiveRemoteNotification...
gets called when the notification is received AND again when the notification is tapped by the user. Because of this, you can't tell by just looking at UIApplicationState wether the user tapped it.
Additionally, you no longer need to handle the situation of a 'cold start' of the app in application:didFinishLaunchingWithOptions... as application:didReceiveRemoteNotification... is called again after launching in iOS 9+ (maybe 8 as well).
So, how can you tell if the user tap started the chain of events? My solution is to mark the time at which the app begins to come out of the background or cold start and then check that time in application:didReceiveRemoteNotification.... If it is less than 0.1s, then you can be pretty sure the tap triggered the startup.
Swift 2.x
class AppDelegate: UIResponder, UIApplicationDelegate {
var wakeTime : NSDate = NSDate() // when did our application wake up most recently?
func applicationWillEnterForeground(application: UIApplication) {
// time stamp the entering of foreground so we can tell how we got here
wakeTime = NSDate()
}
func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject], fetchCompletionHandler completionHandler: (UIBackgroundFetchResult) -> Void) {
// ensure the userInfo dictionary has the data you expect
if let type = userInfo["type"] as? String where type == "status" {
// IF the wakeTime is less than 1/10 of a second, then we got here by tapping a notification
if application.applicationState != UIApplicationState.Background && NSDate().timeIntervalSinceDate(wakeTime) < 0.1 {
// User Tap on notification Started the App
}
else {
// DO stuff here if you ONLY want it to happen when the push arrives
}
completionHandler(.NewData)
}
else {
completionHandler(.NoData)
}
}
}
Swift 3
class AppDelegate: UIResponder, UIApplicationDelegate {
var wakeTime : Date = Date() // when did our application wake up most recently?
func applicationWillEnterForeground(_ application: UIApplication) {
// time stamp the entering of foreground so we can tell how we got here
wakeTime = Date()
}
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
// ensure the userInfo dictionary has the data you expect
if let type = userInfo["type"] as? String, type == "status" {
// IF the wakeTime is less than 1/10 of a second, then we got here by tapping a notification
if application.applicationState != UIApplicationState.background && Date().timeIntervalSince(wakeTime) < 0.1 {
// User Tap on notification Started the App
}
else {
// DO stuff here if you ONLY want it to happen when the push arrives
}
completionHandler(.newData)
}
else {
completionHandler(.noData)
}
}
}
I have tested this for both cases (app in background, app not running) on iOS 9+ and it works like a charm. 0.1s is pretty conservative too, the actual value is ~0.002s so 0.01 is fine as well.
