I want to create an iOS app using React Native. One of the primary features of the app is that it runs constantly in the background. It also requires using GPS btw (in case that is important).
I have had a number of devs tell me its not possible to do this for iOS, however I have read that it is do-able.
Is this possible to do in the iOS environment? Mainly, if the app is running when the phone is powered off, can you make it open when the device is restarted without the user opening it?
I should say that I am a RN novice and any help is much appreciated.
If your app gets permission to get location while it's not in the foreground, then you will get periodic updates and some time to process it.
For example, if you are giving driving directions.
https://developer.apple.com/library/content/documentation/UserExperience/Conceptual/LocationAwarenessPG/CoreLocation/CoreLocation.html#//apple_ref/doc/uid/TP40009497-CH2-SW10
If there is no good user benefit for you to get the location in the background constantly, you might be rejected. Apple suggests region monitoring instead
iOS supports the delivery of location events to apps that are suspended or no longer running. The delivery of location events in the background supports apps whose functionality would be impaired without them, so configure your app to receive background events only when doing so provides a tangible benefit to the user. For example, a turn-by-turn navigation app needs to track the user’s position at all times and notify the user when it’s time to make the next turn. If your app can make do with alternate means, such as region monitoring, it should do so.
I have no idea how RN wraps this behavior, but no matter what it does (or what a plugin might do), the core iOS behavior is how it is described in that URL.
I verified yesterday (at least on iOS 11.2 simulator) that automatically restarting the app (and the location tracking) after phone reboot works.
The key point is that startMonitoringSignificantLocationChanges needs to be on to wake up the app after reboot. For me the difficult part was figuring out when to turn it on, because I couldn't find a reliable way to detect when the phone is being rebooted or run any code at that point. However, based on initial testing it looks like startMonitoringSignificantLocationChanges is independent and doesn't negatively impact the usual location updates, so now I just leave it on all the time and toggle startUpdatingLocation / stopUpdatingLocation on top of it based on Core Motion-detected activity.
Otherwise requirements are the same as for any location tracking on the background, i.e. handle permissions and don't process too much. Apple documentation explains how to detect that the app was relaunched by a location event.
Here's a react native module which basically helps you achieve what you're describing: https://github.com/transistorsoft/react-native-background-geolocation
Related
I’m trying to make a focus timer app like Forest, that detects if you leave the app, either by going to the home screen, switching to another app or by first locking the phone and later proceeding to a different app through notifications, widgets, camera etc..
What I can’t figure out is how to monitor such state changes even after the phone has been locked for a while. There are no “background modes” covering this use case, so I would expect the app to get suspended after a while in the background. Nevertheless, apps like Forest do this successfully. Do I need a workaround to keep the app awake, or am I missing some approach that doesn’t require background execution at all?
Help much appreciated!
If I had to guess, it's probably a combination of a few things:
Use the normal app delegate callbacks for app state transitions to determine if the app is still able to execute code. That's the easy part.
You could do something with string and regex processing of console logs to detect when other apps open, close, etc. and other activity which would allow you to detect activity on the device coming from places other than your app.
You need to use some sort of framework that Apple says can get data even in background state. One such framework is Core Motion. There may be others as well that suit your app's specific needs better.
See Execution States for Apps.
See Background Execution.
See Cocoanetics: Accessing the iOS System Log.
See Keep iOS App Awake To Monitor Movement.
See Apple System Log Facility.
I am developing a client/server app for a client where the clients are iOS devices.
One client module is for traveling salespeople.
My client wants the salesperson's app to automatically download it's local database when the salesperson leaves the office, and when the salesperson returns to the office.
I am setting up a geofence using the location manager's startMonitoringForRegion method, and will look for the UIApplicationLaunchOptionsLocationKey on launch, as well as looking for calls to the location manager locationManager:didEnterRegion/locationManager:didExitRegion methods from the background.
My question is, how do I ask the system to allow me time to make a network connection and download new data in response to either an app launch with a UIApplicationLaunchOptionsLocationKey, or background calls to locationManager:didEnterRegion/locationManager:didExitRegion?
None of the background mode keys (UIBackgroundModes) look like the right fit.
I don't need the location key, since I don't need live location information, just geofence enter/exit messages. The fetch key isn't what I need either, since that causes the system to wake my app up in the background at times it chooses.
Do I have to have one of the background mode keys set in order to make a beginBackgroundTaskWithExpirationHandler call?
I guess what I should do is submit my network request in my beginBackgroundTaskWithExpirationHandler in my locationManager:didEnterRegion/locationManager:didExitRegion methods. Will the system allow me to do that without having a UIBackgroundModes key set?
And can I make a call to beginBackgroundTaskWithExpirationHandler if I'm already running from the background? (In the case where the app is running but not frontmost and a locationManager:didEnterRegion or locationManager:didExitRegion call comes in.) My goal is to ask for enough background time to process my network download and save the data to my local database.
Any guidance from somebody who's done something like this would be a big help. The docs are pretty vague, and figuring out how to use the background APIs by trial and error is likely to be pretty time-consuming.
P.S. I'm developing this app in Swift, although I'm a longtime Objective-C developer. I'm comfortable translating Objective-C to Swift or mixing Objective-C and Swift as needed, so examples in either language would be useful.
It is OK to call beginBackgroundTaskWithExpirationHandler from background. As of iOS8 this call will extend your run time to 180 seconds from 10s.
Keep in mind that you need to request Always authorization for location services, that's what is required to run region monitoring.
I suggest you do use the background location key. I forgot to set it in one of my apps, and it still was receiving the region enter/exit events. However,
-- the behavior might change with minor iOS upgrade, and also
-- the app might be rejected by Apple
I am looking to make an App similar to that of the iOS reminders app. Where a user can essentially set reminders to go off when a user has entered or left a certain area.
I am new to iOS app development and have been doing some research into what might be needed but I am getting a bit confused and was wondering if someone could clarify a few things for me.
From my understanding:
Core Location is used to get your current location details
iBeacon is used to set your device as a Beacon for others to discover
Region Monitoring is used to monitor for when you enter a specific region
Am I correct in my assumptions? If not could someone please correct me. Also am I looking at the right kits that will help me achieve this?
What I would like to do is have a table of saved records that are triggered individually when they enter or leave there specified locations. (Do I use Region Monitoring for this)
Also how would I make this app still run in the background, once it is closed, and still trigger events (like the iOS Reminders App).
I have found a few basic tutorials that help me get my current location with CoreLocation but does anyone know of any other tutorials that might help me out? Or know themselves how I can go about accomplishing this.
Would really appreciate some help. Thanks!
I think that the best choice for your app is using Region Monitoring:
You could register up to 20 regions;
iOS will launch your app automatically if iPhone enters the observed region.
From Apple docs:
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.
An app can register up to 20 regions at a time. In order to report
region changes in a timely manner, the region monitoring service
requires network connectivity.
I am creating a private distribution app and I am wondering if it is possible, using any methods or private API's, to open my app when a bluetooth connection has been made.
What I have discovered so far is that with iOS 7 and the ability to use iBeacons you can enter into bluetooth proximity and you can have your app send a notification to allow the user to then open the app.
What I am hoping to do then is have the app running in the background and listen for an iBeacon connection and, if one has been made, actually launch the app without the users control instead of just sending a notification.
I realize this would never be allowed publically, however is there anything private I can look at to achieve this without jailbreaking? I know to launch some apps you can do [[UIApplication sharedApplication] openURL:[NSURL URLWithString:url]]; however I want my app to listen for an iBeacon and then open itself up.
Is there any way or work around to achieve this?
Moving app from background to foreground without user interaction is pain in the ass. Sorry, don't have a solution, just want to share some information:
I asked the same question here and posted a bounty on it and got no good response:
Show some UI from background in audio player or VOIP app on iOS
At some moment I found a solution with the help of another person. It was based on usage of GSEvent (sending clicks to UI). You can look following questions. However, as I know, in iOS 7 these API became protected by entitlement. So, this method is dead (most likely).
Using GraphicsServices.h/GSEvent as well as compiling CLI iPhone tools with Xcode
Use GSEvent to send touch event,but it's invalid.
Simulating System Wide Touch Events on iOS
iPhone, how to fire a button event in programmatically
Apps can use region monitoring to be notified when the user crosses geographic boundaries or when the user enters or exits the vicinity of a beacon. While a beacon is in range of the user’s device, apps can also monitor for the relative distance to the beacon.
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. When necessary, an app can request more background execution time.
For detailed info:
https://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/LocationAwarenessPG/RegionMonitoring/RegionMonitoring.html#//apple_ref/doc/uid/TP40009497-CH9-SW1
There are two scenarios: you either want users to be able to do something with your device other then use your app, or you want them to always be locked into your app.
In the former case you should trust user. Just show the push, timer or location notification and let them decide to launch the app or not.
In the latter case just lock the device using guided access mode.
We are working in a groupon-like app where alerts are displayed to the user when he/she enters in the range of an offer.
The client insists on having alerts even when the app is in the background.
Due to the architecture of the system, the app gets the location of the client at intervals and checks with the server if there is any new alert. If so, the app does some processing in the local database and displays a notification.
APN cannot be used since changes in the server are out of reach for this project.
My question is whether Apple would accept it in AppleStore as I have read different opinions about it and Apple discourages its use as in this extract from iOS Developer Library
http://developer.apple.com/library/ios/#documentation/userexperience/conceptual/LocationAwarenessPG/CoreLocation/CoreLocation.html
At wake-up time, your app is put into the background and given a small amount of time to process the location data. Because your app is in the background, it should do minimal work and avoid any tasks (such as querying the network) that might prevent it from returning before the allocated time expires. If it does not, your app may be terminated
Thanks
How often does your app get location from the user? According to Apple's Background Execution and Multitasking, if you are getting the location updates on a regular schedule (I think it's less than 10 minutes), your app can still process in the background if you add location to UIBackgroundModes in your info.plist. With those CLLocation coordinates, you can then process your web service requests.
I personally have not done something like this, so I can't tell you for sure if Apple will reject your app or not. However, if everything is within the guideline and requirements set by Apple, I don't see why they would reject your app.
EDIT:
From the Apple doc:
An app that provides continuous location updates to the user (even
when in the background) can enable background location services by
including the UIBackgroundModes key (with the location value) in its
Info.plist file. The inclusion of this value in the UIBackgroundModes
key does not preclude the system from suspending the app, but it does
tell the system that it should wake up the app whenever there is new
location data to deliver. Thus, this key effectively lets the app run
in the background to process location updates whenever they occur.
I guess even if the app is suspended, it will wake up whenever there is a new location data to deliver.
I think you should reconsider your approach for this application. It sounds like you have decided to build a set of features which are not necessarily well informed by, or a good fit for, the characteristics of the devices the app will run on.
You write that "the app gets the location every n minutes" but that's not how iOS location services work. Querying location services for the current location occasionally is a good approach when your app is running in the foreground but that's not an option once it is suspended or terminated. Instead you need to subscribe to location events, at some level of accuracy, and your app will be notified when the device's location changes. There are no guarantees about the schedule on which you receive these events and it varies depending on the accuracy you request and the speed at which the device is moving.
Additionally, obtaining a location is an expensive operation and can quickly drain the device's battery. Burning through a user's available battery power in an hour or two is a very good way to get your app uninstalled quickly. Where possible you should be using the significant location change service to get low accuracy location updates with minimal power consumption. If you need more precision then consider using boundary crossing events for a defined region or at least reduce the accuracy your have requested as much as possible.
With all that out of the way you still need to work within the limited time your app has to run once started by a location update. That's probably not long enough to make a round trip to the server. If a network connection is already active and the device happens to have low latency you will probably get a response some of the time but I would expect to see the app terminated by the OS frequently. When that happens I don't know that you will continue to receive location updates which might otherwise re-launch the app.
Instead of downloading a list of alerts and displaying them locally a better solution might be to attempt to send your current location to the server via UDP when you see a significant location change. That way you can fire off a network request without waiting for a response. Only some of those requests will still succeed but at least your app won't be terminated. You can then process the locations you receive on the server and send push notifications when appropriate.
I realize that you don't seem to be able to make server side changes. In that case the best you might be able to do is pre-fetch alerts for the nearby region when the app runs (and if you ever manage to complete a round-trip while in the background). That way you could compare location updates to that list and not need to fire off a network request on every location update. Unfortunately it sounds like you might be backed into a corner here with no reliable solution available under your current constraints.