I'm doing an app to trigger a local notification when a region is entered.
However, sometimes when the phone is locked, the notifications didn't pop up even I've been in the region area for a while. The notification popup will show only when the power/home button is pressed(phone still in locked mode).
In general, all seems to be working except that sometimes the notification will show only when power/home button is pressed to awake the phone although it is still locked.
Hope someone can enlighten me please! =)
According to the developer documentation. In core-location framework, two services can give you the current location information.
The standard location service is a configurable, general-purpose solution for getting location data and tracking location changes for the specified level of accuracy.
The significant-change location service delivers updates only when there has been a significant change in the device’s location, such as 500 meters or more.
You need to use standard location services to keep monitoring location in background
If your iOS app must keep monitoring location even while it’s in the background, use the standard location service and specify the location value of the UIBackgroundModes key to continue running in the background and receiving location updates. (In this situation, you should also make sure the location manager’s pausesLocationUpdatesAutomatically property is set to YES to help conserve power.)
Related
I have an app which supports background monitoring. For my app to be able to register background movement of device I must call startMonitoringSignificantLocationChanges(). However, at some point in my code I must also call startUpdatingLocation().
My question is, if I call startMonitoringSignificantLocationChanges() and later in my code I call startUpdatingLocation(), will significant monitoring be overridden? Specifically, if I terminate my app will my location manager still receive updates on significant location changes?
After a few testings I’ve come to a conclusion that even if “live” location updates are activated, significant location changes notifications will still be received while running app in background or when terminated. Hope others will find this useful.
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 am implementing an App with continuous background updates on iOS 9. Even with allowsBackgroundUpdates set to YES, AlwaysUsage Description and with proper authorisation i am not getting location updates continuously. I am using Standard Location Services and Significant Location Services but not receiving any location updates when App is in Background. (App is in background/suspended but not terminated). Can anyone let me know if i have missed anything? Thanks in advance.
If your iOS app must keep monitoring location even while it’s in the background, use the standard location service and specify the location value of the UIBackgroundModes key to continue running in the background and receiving location updates. (In this situation, you should also make sure the location manager’s pausesLocationUpdatesAutomatically property is set to YES to help conserve power.) Examples of apps that might need this type of location updating are fitness or turn-by-turn navigation apps
I need to get exact location (as much accurate as possible) in background while making a call to a phone number (The call will be made from app). As far as I understand from documentation, I can listen to significant changes of location in background. I am wondering how accurate is a significant update and when will it trigger.
I need the location where the call is made because it will be an emergency call. And it's not a good idea to listen to location in foreground and then make a call because it will be an emergency situation - call will be made immediately.
Is there a solution to get accurate location of user in background? What do you recommend?
Edit: Location will be sent to server immediately.
As for the accuracy, you can get accurate location in the background, under those conditions:
Getting Location Events in the Background
If your application needs location updates delivered whether the application is in the foreground or background, there are multiple options for doing so. The preferred option is to use the significant location change service to wake your application at appropriate times to handle new events. However, if your application needs to use the standard location service, you can declare your application as needing background location services.
An application should request background location services only if the absence of those services would impair its ability to operate. In addition, any application that requests background location services should use those services to provide a tangible benefit to the user. For example, a turn-by-turn navigation application would be a likely candidate for background location services because of its need to track the user’s position and report when it is time to make the next turn.
As for getting location during phone call, I didn't use it myself, but navigation apps like 'waze' do inform turns and navigation events during a phone call so I guess what you ask is possible.
If I understand your needs, you have 2 options:
If you think that the user will be static then simply get the user location right before the call is made. Or better when your app is lunched to make the emergency call.
If the user is moving then you can 'ask' to get background location events. Even then you should consider using 'significant-change location service' as you don't need more then the user location. The standard 'location services' are used for navigation 'Turn by turn' services.
*LAST COMMENT *
If your app is an emergency app you shold read the "Tips for Conserving Battery Power" in the previous link. you don't want your user battery to empty while tracking his location.
Can't you like add that flag in your app plist file to request Location Service to be running in the background mode.
Then in your app, when the user presses the "call" button, you can do your normal CLLocationManager didUpdateToLocation, right before you perform the call.
In your didUpdateToLocation method, you can record the user's location either in a TXT file written to the application sandbox Library/Cache folder or you can use NSUserDefaults.
Note: I've written an app that records the user's GPS location as they drive even when the user presses the lock screen, so I am confident your app can write the GPS coordinate to a TXT file even when the app is minimized, as long as you start your location manager.
Registering for significant change location the app only receives coarse location updates (if the device moves from cell to cell), however according to this post
If background applications can't launch automatically how does Cardcase launch on a location change?
its also possible to use startMonitoringForRegion:desiredAccuracy: and have the app woken up when a location change occurs.
Presumably the desiredAccuracy can be pretty fine, so does this imply its a back-door way of registering for significant changes to location but with a fine grain?
Is it permissable by the app store therefore?
In my testing I have observed that the region monitoring is sometimes not very accurate, i.e If I drive past a region I might not get any indication of having entered or exited the region. (under the hood it might be using something similar to significant location change)
Also the desiredAccuracy here is really the buffer (in meters) around the region where notifications should not be generated , this is to prevent multiple notifications if you are at the edge of a region.
Not really. You have to specify a specific region, and you only get sent notifications when the region is entered/exited.
It's the same mechanism that the Reminders app uses for sending reminders, they create a region around the location, for instance work, and register for region notifications.
While it might theoretically be possible to create lots of little regions next to each other, it's not really intended for that and will probably cause problems down the line.