I have enabled background mode for location services in my app, but when I send the app to the background, it seems that the location services are switched off after a few seconds (the arrow of location services in the device's status bar disappears). I'm not programmatically stopping the location manager, and I'm using standard location service with its best accuracy.
What can I be missing?
Thanks in advance
For iOS 7 and above, When the app is on the background and not executing code. Normally, the system will move app from background mode to suspended mode automatically without any notification. When you app is in suspended mode, you can not do anything (no location update).
In order to keep the app active in the background for iOS 7 and above, you will have to know when to restart the locationManager.
I have a blog post with a detail explanation and also a complete solution uploaded to Github on how to keep the app active in the background, please check this post for more details:- Background Location Services not working in iOS 7
Related
Do background mode functions like Background fetch and Location update work if the app is terminated? Or it only works if the app enters background?
Thanks
Yes, it works (most of the time), if you set up everything correctly and have the permissions. Your app need's to be launched at least 1 time, so it can subscribe to the updates.
For background fetch, set UIApplication.shared.setMinimumBackgroundFetchInterval(3600) at the didFinishLaunching method, implement the performFetchWithCompletionHandler method, and enable the Background Fetch in the Background Modes.
Pay attention to do it as quickly as possible, and call the completionHandler as soon as possible.
Read more on Updating Your App with Background App Refresh here
For notification updates, you must also set the allowsBackgroundLocationUpdates property of your CLLocationManager object to true, and enable the Location updates in the Background Modes.
Read more on Handling Location Events in the Background here
Background fetch works like, it allows the app to download the contents when it is background. If the app is terminated and gets some trigger to download content, it will actually wake up by doing silent-launch of the app in the background and download the contents. Please see the Apple description on this below.
Each of the preceding modes lets the system know that your app should
be woken up or launched at appropriate times to respond to relevant
events. For example, an app that begins playing music and then moves
to the background still needs execution time to fill the audio output
buffers. Enabling the Audio mode tells the system frameworks that they
should continue to make the necessary callbacks to the app at
appropriate intervals. If the app does not select this mode, any audio
being played or recorded by the app stops when the app moves to the
background.
Here, preceding modes refer to Background fetch, Audio and AirPlay, Location updates and other Background modes of the app.
Please refer Apple document on Background Execution. See Declaring Your App’s Supported Background Tasks for more info on different background modes.
Location update works differently. There are multiple Apple services available to fetch location.
Significant Location service: It works in all modes. Foreground, Background and even in terminated mode.
Standard Location service: It works only in FG and BG mode. It does not work when the app is in terminated mode.
On more details on Location in BG, please refer Handling Location Events in the Background document.
Hope it helps.
Background fetch and Location update work if the app is terminated? Or it only works if the app enters background?
It depends on which type of location service you have used in the project. Refer below analysis of all types of location services.
Standard location service: If you implemented standard location service then it will work only for background and foreground
state.
Significant location updates: If you implemented significant location updates then it will work for background, foreground and
terminate state as well.
Region Monitoring: If you implemented significant location updates then it will work for background, foreground and
terminate state as well.
Visits Location Service: If you implemented Visits Location Service then it will work for background, foreground and
terminate state as well.
Please refer below references.
Apple official doc
Raywenderlich article
I am using Skobbler sdk in my application for navigation. I need to continuously send data of navigation to other device. But the navigation in background works for only 15 minutes after that it stops navigating in background. I have also tried enabling the following key value pairs in plist :
Required Background modes-
1. App registers for location updates
2. App downloads content from the network
Please suggest some help.
Please test this in a real situation, like actually driving while using the app with navigation type being SKNavigationTypeReal.
Background apps are suspended after some time and only activated when they actually receive GPS location updates. Your app will never resume if the device is not actually moving.
This is an optimization done by Apple to improve battery life.
Some more info about background modes:
https://developer.apple.com/library/ios/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/BackgroundExecution/BackgroundExecution.html
The next release will include an API to disable this behavior.
On iOS 8, I can enable background location service with the capability set.
My app can receive location update in background mode, and when in background mode there is a blue bar on top to indicate the background location service is running.
The app is using Google MAP Service plus CLLocationManager.
Question:
Can I turn off background capability in run time?
Description
I want to enable / disable this background location service in app's setting page.
Somehow I've tried stopUpdatingLocation, but in background the blue bar still exists.
Thank you.
Oh, I found the answer.
When an app is enabled background location service and you want to disable it at run time, you will need:
Release all CLLocationManager in your app when entering background mode.
Set your GMSMapView .myLocationEnabled to NO
I am seeing an issue with Location Services still being used by my app even if the app has been killed from the multitasking bar. If I go into Settings > Privacy > Location Services I notice that my app has a purple location icon even while there are NO apps in the background. If I turn off Location Services for my app, the icon in the status bar disappears.
I have ensured in my app that I am stopping location services when they are not needed. I have verified this numerous times in Instruments. GPS turns on when it is supposed to and when the task is finished using location services, the GPS is turned off.
In my applicationWillTerminate: delegate, I even set the lcoationManager to nil, set the delegate to nil and make sure all of that is cleaned up. I still see the icon in the statusbar when I KILL my app.
This particular app also has a bluetooth accessory that can make the app do certain things. So for instance, I press a button on my BLE accessory and it makes the app do something which will trigger a UILocalNotification, so I see a banner. I don't know how to reproduce this particular issue, but I've noticed that even if there are NO apps in the multitask bar and I press the button on my BLE accessory, it will trigger the action in the app and I will see the notification banner.
A few questions:
Has anyone else seen anything like this?
How can I ensure that my app is COMPLETELY killed even though I have cleaned up really good on application terminated?
Why would the location services still be running even though the app is killed. Also keeping in mind that I do NOT use any region monitoring or significant location update changes.
Update:
So I took a previous version of the app and reset Location & Privacy settings and to my surprise, backgrounding the app makes the location icon disappear (as it should have been doing all along. To me this means that iOS is keeping some residual information or settings from the app? Anyone have any insight as to what could be going on here?
Update 2:
Still occurs in iOS 8.1.x.
First of all I hope don't repeat any topic, I have spent a lot of time reading on internet about this before ask.
I'm developing an app for iOS => 5 and I need get the user location, but I don't need always a great accurate position, so when the app goes to background I change the normal location mode to Significant Location Changes and when the app come to foreground I stop the significant location change mode and get back the normal location mode, that's all goes fine,
my problem is when the app goes to background mode or even the user KILL the app the GPS signal (the purple arrow) still appear ALWAYS, even after restart the device, the only way to make disappear it is un-installing the or disabling the significant location changes when the app goes to background, but I need this mode working when the user goes to background mode, maybe not when the app is killed.
I don't know how to stop the service when the user kill the app... because event "applicationWillTerminate" is not called if you have multitask ON.
My main reason because I don't want the purple arrow appear always, even the app is killed is because I don't want the user think the app is drying the battery... so the user won't want the app installed.
First question: Is normal that the purple arrow appear always, even the app is killed if the Significant location change is enabled for the app?
Second question: Is any way to change this, to stop the service at least when the app is killed to hide the purple arrow?
Thank you all.
Sorry for my english if something is wrong.
After few days researching to be sure about this service, seems like there is NO way to use significant locations change in the background without the arrow in the top bar. I have been testing with different apps and reading through internet and nothing to solve this.
The only ""way to solve"" this is disable multitask mode in the app and disable the significant locations change in the event "applicationWillTerminate" but don't make sense... I'm losing the background location always not only when the app is killed... so is not useful.
It's bad... is a really good service to get locations saving battery but as user and developer I don't want an app that make appear this icon ALWAYS even after the app is killed, as developer I don't want that people uninstall the app for this reason and as normal user I don't know what mean this icon if is normal GPS or Significant locations change and what mean this... if my battery is being drain or not.
The other option to get locations in background task but has a big impact over the battery....
I hope apple fix this in future versions... adding at least a new arrow or showing only when a new location arrive instad of always or allowing to stooped when the app is killed.
All this has been researched over iOS - 6.1
Thanks to all.
When you use the significant location change service, the OS keeps your app running. If the app is in the background and is killed, the OS restarts it, so the purple arrow will always show. When a new location is detected, the app is restarted. From the docs:
If you leave this service running and your app is subsequently suspended or terminated, the service automatically wakes up your app when new location data arrives. At wake-up time, your app is put into the background and given a small amount of time to process the location data. ... To stop the significant change location service, call the stopMonitoringSignificantLocationChanges method.
Hmmm, interesting. I've just seen that problem with another app - seeing the arrow still active made me want to disable location updates for that app so the problem is real. Best thing I can think of is to have some kind of timer to disable the location monitoring after a certain amount of time if that is appropriate for your app.