I'm trying to get data from url with background fetch. My func tries to get data and if there is a new data, it sends local notification. Background fetch works after about 10 - 20 minutes when i minimize the app. But when i kill the app (double click home button and close app) it doesn't work. I waited about 1 hour but it didn't work. I am using background service in android and it is working successfully. Is there any way to get data from url and send local notification when app is closed? I am using Xcode 6 and swift 1.2
The Background Fetching will NOT happen in your app after the user has killed it in the multitasking UI. This is by design.
Take a look at Apple's documentation that mentions:
Apps that support background execution may be relaunched by the system
to handle incoming events. If an app is terminated for any reason
other than the user force quitting it, the system launches the app...
and
In most cases, the system does not relaunch apps after they are force
quit by the user. One exception is location apps, which in iOS 8 and
later are relaunched after being force quit by the user. In other
cases, though, the user must launch the app explicitly or reboot the
device before the app can be launched automatically into the
background by the system.
As you noticed in the documentation, there's only 1 exception when the app will be relaunched if it was force killed: by using location services. Unfortunately this does not apply to you.
Also, you cannot detect if the app was force killed by the user. Check this StackOverflow answer.
The Background Fetching will NOT Update in your app after the user has killed app from background. it is not Possible
Related
I need to notify the user about new features of my app as soon as the app update finishes and the app is not in the foreground (i.e., it is terminated or is in the background). How do I achieve this? This scenario will happen if the app was already installed and auto-updates were on.
I achieved this on Android using MY_PACKAGE_REPLACED broadcast receiver. I've read about NSNotificationName in NSNotificationCenter in iOS but couldn't find an equivalent to MY_PACKAGE_REPLACED.
You cannot do this with iOS without the app running in the background Period. Even if your app is running in the background after Appstore updates the app, your app gets killed and you don't have control over it until the user launches it for the first time.
Maybe you could try sending a silent push notification to the app to see if it responds and try to get the current app version.
I'm building an iOS app for iOS 8 & 9 and I am facing the problem that when the app goes to background the system is terminating it after just 2 or 3 minutes.
My testing is easy:
I kill all running apps from my iPhone.
I restart my iPhone (to ensure no other apps are taking memory).
I launch my app.
I do nothing inside my app.
I press the "Home" button, moving my app to background.
I wait doing nothing else for 2 or 3 minutes.
I open my app again and surprise, the system has terminated it and now it is restarting as a new launch.
Some comments:
The app does not use CoreLocation in background neither any other service.
I've profiled the app, trying to understand if it is consuming too much memory. When moving to background, it consumes around 25Mb of RAM memory. I'm attaching a screenshot below.
This behavior has been tested on iPhone 5, 5s, 6, 6+.
In iPhone 6s and 6s+ seems to take a bit more time to happen, but still happens.
My question is: Do you know why would this be happening? anything I might not be considering or just forgetting?
I don't want to force my app to run in background by using CoreLocation or something similar. And I'm ok if the system kills my app eventually. What I don't want is that everytime I move my app to background the system terminates it.
Any hint or help will be appreciated.
Thanks,
All applications are automatically killed by the system
According the Apple documentation:
App Termination
Apps must be prepared for termination to happen at any time and should not >wait to save user data or perform other critical tasks. System-initiated >termination is a normal part of an app’s life cycle. The system usually >terminates apps so that it can reclaim memory and make room for other apps >being launched by the user, but the system may also terminate apps that >are misbehaving or not responding to events in a timely manner.
Suspended apps receive no notification when they are terminated; the >system kills the process and reclaims the corresponding memory. If an app >is currently running in the background and not suspended, the system calls >the applicationWillTerminate: of its app delegate prior to termination. >The system does not call this method when the device reboots.
In addition to the system terminating your app, the user can terminate >your app explicitly using the multitasking UI. User-initiated termination >has the same effect as terminating a suspended app. The app’s process is >killed and no notification is sent to the app.
https://developer.apple.com/library/ios/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/TheAppLifeCycle/TheAppLifeCycle.html#//apple_ref/doc/uid/TP40007072-CH2-SW1
You can track position but you will certainly see a blue status bar to indicate that an application use GPS tracking.
Maybe you can try to "wake up" your app in background with silent notification...
If it is not necessary to keep your app alive, trust the system...
Some error in inside your code. Please select debug Navigator before run your app... Now you can able to find your error..
Or too much memory also it will terminated..
Apps which are running in the background drain battery life faster, It gives you a bad perception of the device, instead of the app, because the average consumer has no idea that it's an app draining battery.
Thus iOS won't allow your app to run in the background, more than a few seconds. But there are some exception, an app can request extension to this by declaring that its starting a Background Task.
for more info you can check below links:
http://blog.dkaminsky.info/2013/01/27/keep-your-ios-app-running-in-background-forever/
http://www.speirs.org/blog/2012/1/2/misconceptions-about-ios-multitasking.html
I'm trying to debug an issue with my iPhone app that seems to be getting terminated while running on the device (it never happens in the simulator). The app is for iOS 8 only.
Once app enters the background (via the user hitting the home button) I start Significant-Change Location service. When a location updates happens while the app is suspended the system should put the app in the background where I then send an update to my server with the location. That operation is wrapped in a proper beginBackgroundTaskWithExpirationHandler to allow me the time needed to make the network call.
It appears though my app is getting terminated by the system because sometimes when I resume the app from the suspended state it is no longer in the view last seen when minimizing but is back at the root controller as if starting from a fresh launch. It does not appear to be due to a crash as I do not see it in the crash log nor is New Relic reporting such. The app is suspended though, not terminated, probably because it is getting launched again into the background from a location update.
The question is, is there a way to know that my app was indeed terminated by the system, and if so, for what reason(memory, exceeding background execution time, etc.) and at what time. Is there a log kept somewhere containing this information?
I'm under the impression I can not use applicationWillTerminate because the docs say this is not called when an app is suspend.
You may check in Devices page. (Shortcut is Command + Shift + 2)
How can one test the scenario of Application Launch in background for handling Background NSURLSession's event?
Flow:
Application starts a upload/download task using Background URL
session.
User hits home button. App is in suspended or in background
state.
OS decides to Exit the application. I know, one can exit the app by double-tapping home button and swipe-up the particular app. But in that case OS will never re-launch the app in background for event handling.
Upload/download task needs some event handling. OS re-lauches App in background.
So the question is how do I make OS exit the app like it may normally do after some-time. The purpose is to test the code for this scenario. I tried using UIApplicationExitsOnSuspend but it does not work since then App can not be launched in Background.
It's not a perfect solution, but I was able to manually test the launch of an app due to a Background URLSession on a physical device as follows:
Connect device for debugging via USB
Disable Internet connectivity on device (i.e. disable WiFi/Cellular)
Start the app via Xcode
Issue a request using background URLSession. The request shouldn't fail, it will just be waiting around for an Internet connection until it times out, so use a reasonably long timeout to make testing easier.
Kill the app via Xcode (press stop button)
View the device logs via Windows > Devices and Simulators
Enable Internet connectivity on the device again without starting the app
The requests from the background URLSession should then complete and in the device logs (from step 6.) you should see any NSLog statements issued as a result of the app being launched via the application(_:handleEventsForBackgroundURLSession:completionHandler:) app delegate method.
They key point is that killing the app via Xcode, as opposed to killing it using device itself, does not prevent the app from being relaunched for background event handling.
A possible alternative to killing the app manually via Xcode might be to intentionally crash the app in code - this might be more suitable for automated testing.
You could write an app that has a button that allocates and intentionally leaks chunks of memory. If you get this thing to allocate enough RAM, the OS will start killing other apps to get their RAM back.
Hopefully this would exhibit the behavior you need.
In iOS7, will an app that has requested continuous location updates (not signification changes/ region monitoring) be relaunched after a reboot?
When I reboot my phone, the app is suspended, then terminated. When I restart my phone, the app stays in the terminated state until I manually start it.
I've tried adding a background fetch with minimum refresh intervals to relaunch the app, but that's never called either.
In the apple doc it explains that if I enable significant location changes, it will launch my app from a terminated state, but does not mention anything about continuous location updates.
Any recommendations on how to get my app to continue receiving updates after relaunch?
I don't think this is going to be possible because its no use if your app launches in the background anyway because the monitoring for location updates initial request HAS to be made while your app is in the foreground.
If this request is made while the app is in the background then it doesn't work. You somehow have to get your app into the foreground so you can start the process of getting updates again.
You could add significant location changes temporarily as an experiment so that your app gets woken up and then see if you can get location updates once your app has been launched into a background state but I'm 99% sure you won't be successful.
I have tested for many months, the only possible way for iOS to relaunch the app for new location updates after the app is terminated/suspended is using the locationManager method startMonitoringSignificantLocationChanges. If you use startUpdatingLocation, iOS will not relaunch the app for you and hence the app can not get the location update.
If you want to understand the details about the differences between getting location update in the background vs getting location update even when the app is kill/terminated/suspended, please see:-
A) Getting location update when the app is In the background, please see: Background Location Services not working in iOS 7
B) Getting location update when the app is suspended/terminated, please see: How to Get Location Updates for iOS 7 and 8 Even when the App is Suspended
I have written 2 very long article explaining the different between the 2 scenario. The source codes for the above 2 scenario are also available on the GitHub.