I have an app which uses the users location in the background and foreground. In the background when the user stops the vehicle the app automatically goes to sleep and calls stopUpdatingLocation. Everything works as expected.
Now I want to make sure the app relaunches it self when the user starts driving again. To achieve this I add a region with 200m radius with the last location just before I call stopUpdatingLocation. With the method didExitRegion I just call startUpdatingLocation again.
This gives me mixed results, it seems that sometimes the simulator works as expected but when driving around I cannot get this to work. The exitRegion works because I can receive a localNotification.
My question:
Is above possible, so is it possible to wake the app and start updating the users location in the background ?
Are there any code examples available achieving this ?
I suggest you to use startMonitoringSignificantLocationChanges and stopMonitoringSignificantLocationChanges
From Apple;
The significant location change service delivers events normally while an app is running in the foreground or background. For a terminated iOS app, this service relaunches the app to deliver events. Use of this service requires “Always” authorization from the user.
Related
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
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.
I am working on an iPhone app that notifies a user when he enters in the region of an iBeacon.
I have a few question regarding the same:
From documents:
Monitoring launches app when entered in the region of iBeacon being
monitored.
But the behavior is:
It only works when phone is awakened i.e. When display is turned on.
But when app is not running and display is off nothing happens same is the case when display is on and user enters in the region of the beacon.
Is it possible to launch application when users enter/exits the region even when display is off or on not just when phone is awakened?
I checked this iBeacon Notification when the app is not running link, which shows it is possible. I am monitoring an iBeacon but not able to get the expected behavior. Am I missing something??
Any help is appreciated.
Yes, you can get notified on entering a region in the background. This will happen as long as:
The app has been opened at least once
The user did not kill the app directly (by quitting the process, not just dismissing it)
Now understanding how it behaves a a little more nuanced.
At my company we've done a fair amount of research on this. In fact a colleague of mine wrote a great blog post about the behavior: iBeacon Monitoring in the Background and Foreground.
What was unexpected was how long it can take to get a didEnterRegion in the background:
Condition Max time to detect a region change
-------------------------------------------- ----------------------------------
Phone awakened,notifyEntryStateOnDisplay=YES 1 second
Phone awakened, notifyEntryStateOnDisplay=NO NEVER
UIBackgroundModes=location ON up to 15 minutes
UIBackgroundModes=location OFF up to 15 minutes
There are a couple of properties you can set on a CLBeaconRegion to alter when your app will be notified about a change to the user's location in relation to that region:
notifyOnEntry - you will be notified via locationManager:didEnterRegion: when the user enters the region
notifyOnExit - you will be notified via locationManager:didExitRegion: when the user exits the region
notifyEntryStateOnDisplay - you will be notified via locationManager:didDetermineState:forRegion: when the user wakes their device's screen up and they are inside the region
Note that you must completely exit a region before didEnterRegion: is called again, and sometimes it can take a minute or more for the device to properly register that you have left a region. Because a beacon can broadcast up to 30 or 50 meters (or perhaps more), you either have to move a long way away from a beacon to leave a region or otherwise turn the beacons off , wait for a minute or so, and then back on to trigger a change.
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.