In an iOS app, is there any method to get notified either user changed the date or time setting.
Actually in an app we want to know the time difference between the two app sessions. It can be done by saving the time when user closed the app and when user restart again. But what if user change the time setting in between.
Can we get noticed at the starting of the game whether user changed the time/date setting.
Any suggestions would be of great help.
UIApplicationSignificantTimeChangeNotification is what you're looking for. But there's another case where date may change, for example when user changes time zone. In this case you need to observe NSSystemTimeZoneDidChangeNotification.
I believe that this is what applicationSignificantTimeChange: (on the app delegate) and the UIApplicationSignificantTimeChangeNotification notification is used for (though the case where the user manually changes their time is not listed as an example)
Related
I Did lots of BG tasks in the past, But Trying to get data when app is killed (Even when user is giving Always permission) seems not to work.
I wonder if there is a solution for that.
To make things clear, I am not talking at the moment when app change from Active or Background even to suspended mode. I'm talking about if the user is using the app and set permissions but then kills the app and after that i need every hour to get data from the user and send data to them.
Is there a way to do that?
Can a Today widget help me with that? Does a Today widget "lives" all the time and i can get that from it 24/7?
Whet is working is CLLocation manager. This is working even when the app is killed. But only when the user is changing a location.
I need that to work when the user is in the same place also.
Non of the other methods work. Not BGTask (I need every hour on the hour and not when apple decide to do things), Nor Silent Push Notification for some reason (Regular ones work, but i Don't want to bother the user with a push every hour just for getting and sending data).
Sorry there is no code to show as this is a very general question. But i think that is very important one to many people and can't find an answer for that.
I created a scene to present weekly goals. I count up a variable each second a user is using my App and save it to the UserDefaults. How can I reset(Set to 0) each Monday at 6PM in order to reset the 'weekly' goal automatically in the background whether the App is terminated or not? I would also include a Usernotification. Can I even execute code within the Usernotification? I'm using SWIFT.
Thanks for any help!
If the app is not running, it isn't running, and nothing can guarantee that it will do something at a certain time except sending a Push Notification from your server at that time.
However, it would be better to revise your goals. Keep in mind that if the user sees your app at all, the user is using your app. So you can always detect the situation and change whatever needs to be changed whenever the user foregrounds/launches the app. The effect will be exactly the same.
It may work.
When users begin any event (e.g., open your app, sign in, or click a button), get the current date and save the date to a variable. Then put some code to compare the date in the variable with a current time in each Viewcontroller. When the current date is different from the date in the variable, (a) update the variable with the current date and (b) activate the codes that we want to execute using "if" statement. It works for me.
May be I am asking a stupid question here.
I recently noticed an UIApplication delegate method
- (void)applicationSignificantTimeChange:(UIApplication *)application {
}
I was wondering what will be its actual use? Do we need to handle this. Can anyone explain a scenario that can happen in an iOS application and we need to do some coding here.
My App is really sensitive to system time, that is the reason I am asking this question. After seeing this API , I have a feeling that I am missing something here to handle.
I am just curious to know... :)
Thanks,
Ramesh Chandran A
Per the documentation on iOS, this method is called:
Examples of significant time changes include the arrival of midnight,
an update of the time by a carrier, and the change to daylight savings
time. The delegate can implement this method to adjust any object of
the app that displays time or is sensitive to time changes. Prior to
calling this method, the app also posts a
UIApplicationSignificantTimeChange notification to give interested
objects a chance to respond to the change. If your app is currently
suspended, this message is queued until your app returns to the
foreground, at which point it is delivered. If multiple time changes
occur, only the most recent one is delivered.
Examples of when this should be used include:
If your app has repeating scheduled events, such as a local notification that now is past, and your app should reschedule the next notification (like daily reminders).
If your app displays data in time ago that needs to be correct, even if the user sets a bad time (for example a medical app that shows your current glucose reading or similar). If a glucose monitor showed an old glucose value as the users current glucose value for instance, the user could make the wrong decision and get hurt.
How you respond to this event depends on your application. You could for instance, read UTC from a server to see if the phone's UTC is correct within some margin, and take appropriate action, such as warning the user, or updating an internal offset between actual UTC and phone UTC.
Hope that helps.
-applicationSignificantTimeChange: is roughly equivalent to the UIApplicationSignificantTimeChangeNotification notification.
I have a custom date picker control that highlights the today date. Subscribing to this notification allows it to change its highlight at midnight, or if the user messes with the time setting manually.
In my app I'm registering a NSSystemClockDidChangeNotification notification in AppDelegate method application:application didFinishLaunchingWithOptions:options.
Posted whenever the system clock is changed. This can be initiated by
a call to settimeofday() or the user changing values in the Date and
Time Preference panel. The notification object is null. This
notification does not contain a userInfo dictionary.
Month ago it was working fine, but these days every time I suspend my app, lock my iPhone and leave it 2 minutes to pass, when opening the app, the selector method is called, which is weird to me. I didn't change the system or time, I just let the device idle.
Can anyone help me understand this? I just want to execute some code when the user manually change the system time, just in that case (tried with UIApplicationSignificantTimeChangeNotification but that doesn't help).
Like that: Getting iOS system uptime, that doesn't pause when asleep
But remember, this solution will fail sometimes because of out-of-sync when system tries to update time from NTP server when the Internet connection is not reachable.
This answer is a bit late but this is what the apple support team replied when I ask a similar question:
Part of the question I asked:
Could it be possible for the OS posted [this notification] if the
time/timezone has not changed in the device?
The answer I got from them:
Absolutely [1]. It's common for a notification like this to be posted
redundantly. In some cases it's triggered by a state change you can't
see. For example — and I haven't tested this theory, so it's just an
example of how this sort of thing can come about — this notification
might be posted if the system's giant list of time zone info has
changed. So, the time zone state has changed, but it's not something
that affects your app.
But in other cases, a notification might be truly redundant (-: iOS
is a complex system and in some cases this complex machinery generates
redundant notifications, and there's no need to filter them out
because…
Your app should respond to such notifications be refetching the info
it cares about and updating its state based on that. If this update
is expensive, keep your own copy of the previous state, compare the
current system state to that, and only do the update if the stuff you
care about has actually changed.
I need a piece of code for Xcode (obj-c) that runs every day at 00:00.
The reason for this is because my server updates data each new day and I would like my app to synchronize with the update.
I was thinking about doing a timer that runs every minute and checks the time (from internet, not the phones time), but it seems like there could be an more efficient way.
Help or pointers really appreciated!
Thanks
Use the calendar app on your mac. Set up a recurring event every day at 0:00. At the point where you pick the type of alert, you can select an option to open a file (as opposed to a pop-up, etc.). Pick your app as the file to be opened.
When the app becomes active, register a local notification (UILocalNotification) to trigger at midnight.
Then, you can perform the updates at the app delegate's -application:didReceiveLocalNotification:
You can then cancel the notification when the application goes to background by calling the UIApplication's method -cancelLocalNotification:
I don't think it's even required to use notification here. Notification is usually on best effort basis and doesn't guarantee the delivery. This can be done in few simple steps.
Save the lastUpdated time in your iOS app. Probably in NSUserDefaults or if you're using local database you can store it there as well.
Everytime user launches the application check how much time has elapsed since last update.
If it's more than 24 hours then make an API call to your server and check if there's any new updates available (which you can determine probably from server timestamp). Get the latest data (possibly only the delta difference in stead of everything).
Update the lastUpdated time in your iOS app.