i'm trying to get the new BackgroundTask framework to work in my app. I'm testing on a real device running iOS 13.4.
Everything works as expected (minimal setup, like is described here: https://developer.apple.com/documentation/backgroundtasks/bgtaskscheduler )
Unfortunately the task gets only called if the app is still in the background. If applicationWillTerminate() is called (e.g. when the user closes the app from the multitasking manager), the task will not get executed.
I have not found anything on this topic in the docs. Also i think this behaviour was different with the now deprecated Background Modes (see also: iOS - Background Services when app is terminated )
Can anyone clarify/confirm/correct on this?
Thanks in advance!
Related
I'm building a Flutter app and need to call a function every day (to schedule some notifications). I came across the flutter_background_fetch package, which seems to be a perfect solution for Android, since the main limitation of the minimum 15 minute interval is not a problem.
However, I am supremely confused about how well the package works for iOS. According to the README, "When your app is terminated, iOS no longer fires events". However, I've also seen posts on Stackoverflow that claim that iOS Background App Refresh periodically relaunches your app to run background fetches (and posts that say it is unreliable or doesn't work at all).
So does flutter_background_fetch work on iOS when the app is terminated (eg. double tap home and swipe up)?
Edit: Also exploring flutter_workmanager, which seems promising.
There is no perfect Dart solution for iOS to schedule background task as android when app terminate, in android we can use Alarm Manager
But you can try native side implementation with BGTaskScheduler
https://github.com/fluttercommunity/flutter_workmanager
application:handleEventsForBackgroundURLSession:completionHandler: doesn't run when the uploads are finished in the background. When all the upload/download tasks are completed in the background then iOS should wake up the app and call the above method. But it doesn't.
I have tested this by terminating the app from 'xcode stop' button and also terminated from an exception.
I have followed Background Transfer consideration.
I have tested this on Apple developer guide: Background example and it is not working.
I have also tested this on AppCoda: Background example and it is not working
Both of the examples which are given in 2 and 3 points are not working on iOS 9.0 and xCode 7.0. Before upgrading to iOS9.0, I had tested this on iOS7.0 and xcode 5.0 where it ran perfectly.
I am assuming that it would work on the real device.
What am I missing here? Can anybody confirm whether handleEventsForBackgroundURLSession works in iOS9.0 simulator or am I doing anything wrong? Since it doesn't work for the examples given in 2 and 3 so I guess maybe I am testing it wrong.
#ZayinKrige answered this in a comment:
background download events don't fire on a simulator. You can only test this on a real device
And to expand a bit, here's a guide for testing background session code:
https://forums.developer.apple.com/message/42353#42353
In my case, the cause of this was that I was using uploadTask(withStreamedRequest:...), which is not compatible with background URL sessions. I switched to use uploadTask(with:request, fromFile:...) instead and everything started working.
I'm writing a WatchKit app which needs to make a query to our Parse server. Because this is a network call, I follow the following procedure:
I make a call from WatchKit to the iOS app using openParentApplication:reply:
Inside of handleWatchKitExtensionRequest:userInfo:reply:, I start a background task with a UIBackgroundTaskIdentifier to ensure the iOS app isn't terminated immediately
I set up my PFQuery and call findObjectsInBackgroundWithBlock:
In the block I pass to the PFQuery, I reply the relevant information to the watch
I wrote this app maybe a month ago before the Apple Watch was out, and it ran just fine in the Watch simulator. Yesterday I received my Apple Watch and I was able to get the app running on the watch, but it doesn't quite work - I managed to figure out that when the iOS app is actively running in the foreground on the iPhone, then everything is great; but if the app is not active (e.g. backgrounded or terminated), then findObjectsInBackgroundWithBlock: never actually calls the block, and execution seems to just stop.
Does anyone have any ideas of what might be going on? My initial thought was that the iOS app is getting suspended/killed before it can complete the query, but I was pretty sure the background task would prevent that.
PS. If anyone stumbles upon this question because they were looking for how to get a WatchKit app running on an actual watch, I found this post extremely helpful in getting it working.
Turned out that I had several problems related to openParentApplication:reply:, and they all seem to have been resolved by using the technique from this post:
http://www.fiveminutewatchkit.com/blog/2015/3/11/one-weird-trick-to-fix-openparentapplicationreply
I had started a background task for my own app, but I didn't use the "bogus workaround" background task described in this post, because it wasn't necessary for me in the simulator. On the watch, though, it apparently was.
I am really stuck on this problem and I need your help! I'm doing an iPhone app.When iPhone swap between app and Facebook redirection in safari , iPhone shutdown the app for memory saving.
What I am doing is I am providing fb sharing in background from my app.
When I am doing fb sharing its shares successfully in background and comes back to my app successfully.At that time my app is not crashing. But when I go to safari and type Facebook and open fb site to check my shared post , in background my app is crashing.
This issue is coming in iPhone with iOS 7, I am not facing this issue in iOS 8.Check this post : Prevent IOS to shutdown an app when it app switch to facebook for login and permission request but this solution doesn't work for me as I am using pod to install fb and doing background share.
Though it's too late to answer this but I believe it may be helpful for others.
In App Programming Guide for iOS under "Being a Responsible Background App" section it was said that
your background running app would be terminated if it doesn't follow one of the given requirements.
You can familiarize with the full documentation. I'll quote 2 of them which exactly fit your problem:
Being a Responsible Background App
The foreground app always has precedence over background apps when it comes to the use of
system
resources and hardware. Apps running in the background need to be
prepared for this discrepancy and adjust their behavior when running
in the background. Specifically, apps moving to the background should
follow these guidelines:
Do not make any OpenGL ES calls from your code. You must not create an EAGLContext object or issue any OpenGL ES drawing commands
of any kind while running in the background. Using these calls causes
your app to be killed immediately. Apps must also ensure that any
previously submitted commands have completed before moving to the
background. For information about how to handle OpenGL ES when moving
to and from the background, see Implementing a Multitasking-aware
OpenGL ES Application in OpenGL ES Programming Guide.
Do minimal work while running in the background. The execution time given to background apps is more constrained than the amount of
time given to the foreground app. Apps that spend too much time
executing in the background can be throttled back by the system or
terminated.
To sum up, maybe your app is doing one of the above-given tasks when it's moved to the background after Facebook sharing.
This question already has answers here:
Will iOS region monitoring call didEnterRegion on my app if my app is in a terminated state?
(2 answers)
Closed 8 years ago.
I'm creating a location aware application. I was able to create geofences already,
when I test it in my iPhone, I noticed that the calllback methods -didEnterRegion and -didExitRegion are being called when the application is running in foreground and background. But when I killed the application (meaning the application state is "not running") the said method call backs are not being called.
So, what am I missing here? Is there any configuration that I need to do? Any thought guys? Thank you!
This is correct behaviour depending on how you 'killed' the app. If you stopped the app by swiping up from the multi-tasking view (double tap home) then iOS 7 interprets this as meaning you do not want the app to operate at all - either in the foreground or background. If the app is 'killed' as a result of being in the background when the device needs more memory then it will continue to operate in background mode.
Refer to this answer - Region monitoring in ios 7
In order to test you can stop your application using Xcode, simulate a low-memory situation while your app is suspended or call exit() for testing purposes.