I am creating an application that sends updated location to server regardless of app state. I have tried silent push to wake my application in background but it didnt work (it works fine except if my app is killed by user from app switcher). I am using location manager for getting current location.
Does IOS7 provides this feature to launch your application in background (even if app is killed by user from app switcher)??
I have spent five days without any success on this. If anyone can help me that would be highly appreciable.
Thanks in advance!!
If you need precise GPS locations you can set add the "location" value to the UIBackgroundModes array in your Info.plist as described in "UIBackgroundModes location and significant location changes with region monitoring". If you need only approximate locations you can use the startMonitoringSignificantLocationChanges method of CLLocationManager. As it is written in the documentation: "If you start this service and your application is subsequently terminated, the system automatically relaunches the application into the background if a new event arrives."
You can wake your app by using significantlocationchange.
You have to start significant location change while you switch your app to background.
Then system will wake your app after significant location change.
The frequency is not faster than 5 min and for every 500 meters.
You will have to catch the event by checking for LocationKey in didFinishLaunchingWithOptions in projects AppDelegate.
Related
Will iOS region monitoring launch my app in the background if the user enters a region that was successfully being monitored for prior to the app being terminated?
I know that the significant change API will do so and will let me know at launch time via the inclusion of the UIApplicationLaunchOptionsLocationKey key. If region monitoring will wake my app up out of a terminated state too, then what does the launch process look like? Is there a special key I should be looking for?
Yes, see Region Monitoring
In iOS, regions associated with your app are tracked at all times,
including when your app is not running. If a region boundary is
crossed while an app is not running, that app is relaunched into the
background to handle the event. Similarly, if the app is suspended
when the event occurs, it is woken up and given a short amount of time
(around 10 seconds) to handle the event.
I have been searching for similar answer, but came across this: Region monitoring in ios 7
Seems like if the app is manually terminated by the user in iOS 7, location notifications will not wake the app to process it. Apple employee has commented here https://devforums.apple.com/thread/209302?tstart=0
Is it possible to update location when application is in suspended/terminate state.
i want to update location every 500 meters when app is in suspended/terminate state.
thanks in advance.
When terminated the only real way to get updates is to use Region Monitoring but you will only get major updates so I doubt it will work for 500 meters.
From the documentation:
If your app is terminated either by a user or by the system, the
system doesn't automatically restart your app when new location
updates arrive. A user must explicitly relaunch your app before the
delivery of location updates resumes. The only way to have your app
relaunched automatically is to use region monitoring or
significant-change location service. However, when a user disables the
Background App Refresh setting either globally or specifically for
your app, the system doesn't relaunch your app for any location
events, including significant change or region monitoring events.
Further, while Background App Refresh is off your app won't receive
significant change or region monitoring events even when it's in the
foreground.
There are good reasons for this. Firstly people don't want apps that 'snoop' on them all the time and even if there is a good reason imagine having 10 apps doing this constantly. It's going to start causing you performance and battery life issues.
EDIT
There appears to be some confusion by a lot of people over this issue so I will attempt to clear things up a bit.
Your app is NOT supposed to be continually tracking location while terminated (or suspended really). You are just not allowed to do this both for privacy reasons and so that you don't drain the battery excessively.
While your app is in the foreground you can use location services via startUpdatingLocation to monitor the device location. Assuming the app has been granted permission this will use all available hardware (GPS, WiFi, Cellular).
Now from the documentation itself:
If you start this service and your app is suspended, the system stops
the delivery of events until your app starts running again (either in
the foreground or background). If your app is terminated, the delivery
of new location events stops altogether. Therefore, if your app needs
to receive location events while in the background, it must include
the UIBackgroundModes key (with the location value) in its Info.plist
file.
So once suspended and terminated your options are really to monitor regions and to monitor for significant location changes. Neither of these are particularly accurate or frequent. One reason for this is that they only use low power methods to get the position (WiFi and Cellular) they don't use the GPS.
So no accurate and/or frequent location tracking while an app is suspended or terminated. This just has to be accepted and you need to design your apps accordingly.
let locationManager = CLLocationManager()
locationManager.startMonitoringSignificantLocationChanges()
After returning a current location fix, the receiver generates update events only when a significant change in the user’s location is detected. It does not rely on the value in the distanceFilter property to generate events
If you start this service and your app is subsequently terminated, the system automatically relaunches the app into the background if a new event arrives. In such a case, the options dictionary passed to the application(:willFinishLaunchingWithOptions:) and application(:didFinishLaunchingWithOptions:) methods of your app delegate contains the key location to indicate that your app was launched because of a location event. Upon relaunch, you must still configure a location manager object and call this method to continue receiving location events. When you restart location services, the current event is delivered to your delegate immediately. In addition, the location property of your location manager object is populated with the most recent location object even before you start location services.
Apps can expect a notification as soon as the device moves 500 meters or more from its previous notification. It should not expect notifications more frequently than once every five minutes. If the device is able to retrieve data from the network, the location manager is much more likely to deliver notifications in a timely manner.
Hope It helps
I want to get location updates of the user in a regular interval of time even if the app is not running in foreground.
In most of the articles i have read, they said that the OS will forcefully stop or suspend the background service the app have started.
What i need is the app should regularly check the user location and when that location becomes greater than say 10Kms the app should trigger a local notification.
We were able to do the functionality correctly when the app is ran again by the user. But it wont work in background. And if we inegrated it as a background service , then it is causing the app to crash. :(
this part caught my attention after a long time of search
https://developer.apple.com/library/content/documentation/UserExperience/Conceptual/LocationAwarenessPG/CoreLocation/CoreLocation.html#//apple_ref/doc/uid/TP40009497-CH2-SW8
As far as I understood, they say that the OS will wakeup the app to get the current location when it senses a change in location.
But I didnt get any helping tutorial to accomplish the same
These are the tutorials which I refered
Periodic iOS background location updates
How do I get a background location update every n minutes in my iOS application?
Getting user location every n minutes after app goes to background
iOS Not the typical background location tracking timer issue
iOS long-running background timer with "location" background mode
What i need is preferably a background service or something which does the job done which check of the current location calculate distance and makes a local notification.
But as far as i know all the background services will be suspended or killed by the OS within some time after the app is gone in background.
Please guys I am desperate, Its been 2 weeks i am on in its tail.
Building the same for Android was a piece of cake actually.
Any help ???
You can get background location updates easily, you need to enable "Location updates" under "Background Modes" section in capabilities.
You also need to request for Always Authorisation and finally add this
if #available(iOS 9.0, *) {
locationManager.allowsBackgroundLocationUpdates = true
}
Make sure "Location updates" is activated else the above code will lead to a crash.
Also, write the CLLocationManager Delegate Methods in your AppDelegate class as this would increases chances of those methods being called as mentioned on Raywenderlich Background Location tutorial
Ok, so I currently have an app where I register a geofence to be monitored using the CLLocationManager startMonitoringForRegion method. This works fine when the app is in the foreground and background.
I also have the appropriate plist values set:
UIBackgroundModes :{location}
UIRequiredDeviceCapabilities: {location-services}
What doesn't work
After a device restart, the app is not being relaunched. I can force this to happen if I set startMonitoringSignificantLocationChanges before entering background. But this method uses much more battery life and I don't need the location all the time, just whenever I break a geofence.
The docs for regions say:
In iOS, the regions you register with the location manager persist between launches of your application. If a region crossing occurs while your iOS app is not running, the system automatically wakes it up (or relaunches it) in the background so that it can process the event. When relaunched, all of the regions you configured previously are made available in the monitoredRegions property of any location manager objects you create.
Question
Is it possible (when using geofencing regions) to have the system restart my app AFTER a system reboot, WITHOUT using startMonitoringSignificantLocationChanges ?
Edit: I am targeting iOS6 & iOS7
Answering my own question here.
While you do need to use the startMonitoringSignificantLocationChanges to get the system to wake up the app after a device reboot. Nothing will wake up the app if the user has force closed it.
For my purposes, I did not need to set UIBackgroundModes to location. This setting is usually used for applications that only need fine-grained location updates (E.g. using startUpdatingLocation). Setting the background mode is not required when using startMonitoringSignificantLocationChanges.
Will iOS region monitoring launch my app in the background if the user enters a region that was successfully being monitored for prior to the app being terminated?
I know that the significant change API will do so and will let me know at launch time via the inclusion of the UIApplicationLaunchOptionsLocationKey key. If region monitoring will wake my app up out of a terminated state too, then what does the launch process look like? Is there a special key I should be looking for?
Yes, see Region Monitoring
In iOS, regions associated with your app are tracked at all times,
including when your app is not running. If a region boundary is
crossed while an app is not running, that app is relaunched into the
background to handle the event. Similarly, if the app is suspended
when the event occurs, it is woken up and given a short amount of time
(around 10 seconds) to handle the event.
I have been searching for similar answer, but came across this: Region monitoring in ios 7
Seems like if the app is manually terminated by the user in iOS 7, location notifications will not wake the app to process it. Apple employee has commented here https://devforums.apple.com/thread/209302?tstart=0