I need to be notified exactly at midnight.(I will execute a piece of code but that's besides the point).
How would I set this up in RxSwift? Is there a built in feature that I missed, or is this actually just a standard case of PublishSubject,
and deciding when (midnight happens) to call next() on it is out of scope of RxSwift?
The short answer is that you can't do this in a way that will be allowed on the app store. The closest you can come will be a scheduled local notification that fires at midnight, but that will display a message to the user, and only invoke your app if the user acknowledges the notification.
Related
target:
Now, I have a mission that is use the queue to manage the mutiple of notifications. So no matter how many notifications app received in a short time when app is active, app can play the notification UI(firstly show the notification UI, then dismiss it) at a fixed frequency. For example, play the notification UI every 2 seconds. But I have no idea about how to control the frequency of the task in the queue,Thank you!
What you describe is a rather complex task, and would involve learning about several technologies.
I'm not sure if queues are appropriate. A simple array and a timer might be better.
Set up an array in your app delegate to hold notifications that need to be displayed. When you receive a notification, add it to your array.
Then set up a timer that runs when the app is active. When the timer fires, pull a notification off the front of the array and display it.
Explaining how to do each of those things is beyond the scope of a SO post. You need to do some research on your own, write some code, and post specific questions if you get stuck.
I need to notify user when a certain condition is met but that condition might or might not meet in months. I need to run condition check in background (even when app terminates) so that I could detect condition is met (even if it happens after 3 months). If condition is met then I need to send notification only to a single user (not all users).
I am not sure what is the best way of doing it. Local Notification or Push Notification? I can not schedule a local notification in advance because I don’t know when it will meet the condition. I think Push notification is not needed because I am sending only one notification to only one user in several days/months.
I also need to constantly run this check in background. I know it can be run infinitely in background by using location update (significant monitoring or background navigation). But my condition checking code doesn’t actually require location updates. As far as I understand, Apple allows only location update or network related task in background (for few minutes). That's why I am thinking of putting my code in background location update code.
In my opinion , I should use local notification and put my code in background location update code so that I could check constantly if certain condition is met. This background check will schedule local notification and show it to the user who is using that device. I don’t think it is possible to schedule a push notification by code running in background.
In summary, I have following 3 questions
Should I put my code in background location update? If not, what is the right approach of running my code infinitely in background without location update?
Will Apple reject application if I put my code in background location update while location update code doesn’t actually send/receive current location?
What kind of notification should I use in this kind of situation where I send notification to a single user after months? Would you use Local Notification? or Push Notification.
Please reply. Any help is truly appreciated.
Thanks in advance.
This is a bit of a tricky problem unfortunately.
Apple won't allow you to create long-running operations in the background. As you mentioned, you can add code in the background with location updates or audio, but neither of those are very good solutions since (1) Apple will likely reject you from the app store and (2) the user will probably close the app if they notice a big locations banner at the top of their phone (or a weird background audio signal), and closing the app will kill your operation. For any truly long-running tasks it's probably best to set up a server and run a cron job or equivalent long-running operation. It's the only way you can know that the task will continue running.
Sorry, I was just answering one at a time, but as I mentioned above, yes, they'll probably reject your code for that. As a rule of thumb: if you think the Apple-created code you're using wasn't meant for what you're using it for, Apple will probably reject your app.
It sounds like you should use a remote notification. If you do use a remote notification, you'll probably want some sort of backend anyway. You could use a local notification to notify a user after a few months, but you would need to know the exact time to send it up front, which it doesn't sound like you would.
In summary: Try to build a simple BE. Maybe use Firebase Functions or something, and also build an APNS system to send pushes. In the app, tell the server to start processing the information and send the push back when it's done. The situation sounds like a perfect use case for server-side logic.
Hope that helps!
I'm trying to code an app that reminds me to hit a certain diet goal (drink 8 glasses of water, eat two fruits, take vitamins etc)
The problem is if I code these as reminders using local notifications, I don't get to execute code. So I can't adjust the reminders every hour relative to my goal. For example don't show the reminder if I already hit the goal. Or say stop the reminder past dinner time and start again in the morning.
If I code these as NSTimer the problem is they don't run in the background.
I suppose I can move all the logic to a server and use push notification instead. But this is huge amount of work for what I would consider a very simple self reminder app.
What is the right approach?
if I code these as reminders using local notifications, I don't get to execute code
I use a pill-taking app, and it does use local notifications. The local notification does let the app execute code, if the user taps / swipes (whatever) the notification. The app then puts up a dialog where I enter what actually happened (I took the pill, I skipped it, etc.).
The app simply assumes that if the user doesn't respond and tell it what happened, then nothing happened (i.e. the user missed the pill). How does it know that? Well, as with any local notification-based timer app, the app must maintain an internal list of pending events. It strikes a pending event from the list when it knows the outcome. That way, if the app is not running and then it is running, it can look back over its list and note that there are past pending events, thus proving that the user failed to respond to a reminder.
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.