Detect if application: didReceiveRemoteNotificatio

问题:

application: didReceiveRemoteNotification: fetchCompletionHandler:

is different from

application: didReceiveRemoteNotification:

How? from the docs:

Unlike the application:didReceiveRemoteNotification: method, which is called only when your app is running, the system calls this method regardless of the state of your app. If your app is suspended or not running, the system wakes up or launches your app and puts it into the background running state before calling the method. If the user opens your app from the system-displayed alert, the system calls this method again so that you know which notification the user selected.

My struggle is: I want to know if the method was called by the user tapping an a system-displayed alert from the Notification Center or from a silent push notification that wakes up the device. Currently, as far as I can see, there is no obvious way to differentiate.

- (BOOL)application: didFinishLaunchingWithOptions:

Tracking the launchOptions in the above method is not a solution because it's only called if the app is suspended/not running in background. If it's running in the background it doesn't get called.

回答1:

The Apple docs are a bit confusing

application: didReceiveRemoteNotification: fetchCompletionHandler:  

is used if your application supports the remote-notification background mode (ie you're doing BackgroundFetch.)

application: didReceiveRemoteNotification:  

is called when the OS receives a RemoteNotification and the app is running (in the background/suspended or in the foreground.)
You can check the UIApplicationState to see if the app was brought to foreground by the user (tapping on notification) or was already running when notification comes in.

- (void) application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo {
      UIApplicationState state = [application applicationState];
        // user tapped notification while app was in background
    if (state == UIApplicationStateInactive || state == UIApplicationStateBackground) {
         // go to screen relevant to Notification content
    } else {
         // App is in UIApplicationStateActive (running in foreground)
         // perhaps show an UIAlertView
    }
}

回答2:

You could check the UIApplication's applicationState to distinguish silent calls from calls made with the application being actively used by the user:

typedef enum : NSInteger {
   UIApplicationStateActive,
   UIApplicationStateInactive,
   UIApplicationStateBackground
} UIApplicationState;

Or keep your own flag set on the delegate's applicationDidEnterBackground:.

回答3:

Application State is not reliable because if you have control center or Apple's notification center open over your app, application: didReceiveRemoteNotification: fetchCompletionHandler: will get called and the application state will be Inactive.

I'm having the same issue trying to respond to a click on the notification while the app is in the background and there doesn't seem to be a reliable way to solely identify this.

回答4:

When application: didReceiveRemoteNotification:fetchCompletionHandler: method is called app state is UIApplicationStateInactive if user taps on alert (in this case you would like to prepare some UI) and is UIApplicationStateBackground when app is silently woken (in this case you just load some data).

回答5:

I'm not sure if I understand your question.

Do you want to differentiate between a silent push notification background fetch and a noisy push notification? You can simply check whether the push notification dictionary contains the "content-available" key: [[userInfo objectForKey:@"aps"] objectForKey:@"content-available"] If it does, then it should be a silent push. If not, it was a normal push.

Do you want to know if that background fetch method is called when the application receives a notification and it is in suspended/not running? If so, you can do the following:

• Download and import LumberJacks into your app. Look through the directions and learn how to set it up such that you can save logs to the disk.

• Put this in any method you want to see whether/when that method is invoked:

  • DDLogDebug(@"%@ - %@",NSStringFromSelector(_cmd),NSStringFromClass([self class]));

  This will print the class and the method to the log file.

• Examine the log file after sending yourself a push notification to your background-fetch enabled app, and see if any of the methods get called by looking at your log file.

If you have set up your app correctly for background fetch, the method application: didReceiveRemoteNotification: fetchCompletionHandler: will be called even when the app is backgrounded/not running if you receive a push notification (silent push or not).

回答6:

In case of swift

func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject]) {

    let state : UIApplicationState = application.applicationState
    if (state == .Inactive || state == .Background) {
        // go to screen relevant to Notification content
    } else {
        // App is in UIApplicationStateActive (running in foreground)
    }
}

回答7:

For Swift: In application(_:didFinishLaunchingWithOptions:) parse the application options. If they exist, you know the app was launched from them tapping.

  if let remoteNotif = launchOptions?[UIApplicationLaunchOptionsKey.remoteNotification] as? [String: Any] {
        print("Remote notfi is \(remoteNotif)")
        if let notification = remoteNotif["aps"] as? [AnyHashable : Any] {
        /// - parse notification
      }
  }

Otherwise, you can handle the tap in, and you know that the app is open/background/inactiveapplication(_:didReceiveRemoteNotification:fetchCompletionHandler:)

回答8:

In iOS 10.0+ you can use the method

- (void)userNotificationCenter:(UNUserNotificationCenter *)center didReceiveNotificationResponse:(UNNotificationResponse *)response withCompletionHandler:(void (^)(void))completionHandler;

to detect when user taps on a system-displayed alert from the NotificationCenter.

If you implement the method above

• - (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo fetchCompletionHandler:(void (^)(UIBackgroundFetchResult result))completionHandler; will be called only when a notification is received
• - (void)userNotificationCenter:(UNUserNotificationCenter *)center didReceiveNotificationResponse:(UNNotificationResponse *)response withCompletionHandler:(void (^)(void))completionHandler; will be called when user taps on notification