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.
Related
I’m putting an app into background.
Assuming that I’m not doing anything to keep the app alive in the background, then the app goes through suspended state in a matter of 5 seconds. Right?
What happens if I then tap on the app icon? That’s not suppose to trigger a didFinishLaunch right? It will just bring me back to the last screen I was at and also trigger didbecomeActive & willenterforeground notifications. I won't be getting any other callback. Right?
Assuming there is no restart of the phone, point 2 is true even if there are hours between me tapping home and then tapping back the app icon. Right? Does it also persist device restarts but not force-restart?
The only time I won’t be brought back to the screen I was at (before hitting home) is if the device receives a memory warning and my app is flushed out of suspended state. At this point tapping on the app icon will result in didFinishLaunch. Right?
(I’m asking all of this because sometimes after putting the app in the background and tapping the app icon again (e.g. 10 minutes later), the app is going through it’s launch phase. Most of the time it just goes back to its previous screen)
I've already seen Will ios terminate the app running in background after a specific time? but that doesn't address all aspects I want.
It will just bring me back to the last screen I was at and also trigger didbecomeActive & willenterforeground notifications.
Right, if your app was not terminated in the background.
I won't be getting any other callback.
Not necessarily true. If you were summoned to the front by a local notification, for example, you'll also get an event about that.
Assuming there is no restart of the phone, point 2 is true even if there are hours between me tapping home and then tapping back the app icon.
Not necessarily. The app might well be terminated silently in the background.
Does it also persist device restarts but not force-restart?
Absolutely not. How can the app run when the device is off? Shutting down the app terminates every app.
I’m asking all of this because sometimes after putting the app in the background and tapping the app icon again (e.g. 10 minutes later), the app is going through it’s launch phase
It's not a matter of time. The watchdog process is constantly combing the suspended apps looking for the ones that take up too much memory so that other apps can run. You must not be surprised if yours is one of them.
You can come back to the front launching from scratch or by coming back to life from suspension; it's the most basic fact of iOS app life! You just need to accept it.
But there are lots of things you can do to reduce your chances of being terminated in the background. Giving up memory-consuming objects as you background is first on the list.
I am developing an iOS app to monitor iBeacons. It works well in both foreground and background. I also need it to keep monitoring even when the screen is off. Now my problem is, when I turn off the screen with the shoulder button, NSLog shows that the iBeacon signal goes off (RSSI=0, beacon.accuracy=-1.0) accordingly, and 10 seconds later, there is no beacon found at all, while the delegate method locationManager:didRangeBeacons:inRegion: is called continuously. It seems that the app is running when the screen is off but iOS turns off the location service for iBeacon ranging. I tried to set "locationManager.pausesLocationUpdatesAutomatically = NO;" but still doesn't work. Is there any advice on this issue? Thanks in advance.
It seems that you're doing ranging instead of monitoring. Ranging only works when the app is active—either in the foreground or in the background. The catch is, iOS will automatically put an app to sleep a few seconds after you navigate away from it, or lock the screen.
What you have to keep in mind is, there's really no such thing as "permanent background state" on iOS. Apps run in the background for some limited time while transitioning to the suspended state (to let them, e.g., finish uploads/downloads), and there are also Background Modes that sometimes enable an app to run in the background, but these are usually reserved for very specific apps—e.g., the "audio" Background Mode means an app can be running in the background as long as it plays music, etc. There is a Background Mode for "location" services, but it's reserved for turn-by-turn navigation apps.
Beacon monitoring however continues running even if your app goes to sleep, or gets terminated by the iOS due to memory pressure. When you go in or out of range of a beacon, iOS will launch your app into the background to handle the event, giving it a few seconds (which you can extend up to a few minutes with a Background Execution Task) to do so (you can range during that time), but then it's back to sleep.
You might also want to take a look at this question:
Receive signal from beacon while app is in the background
I have a music signal processor app I want to publish and it needs to run in the back ground. I used to Info-plist to do so with UIBackgroundModes. It runs on IOS7 or less, and the problem I am having is once the phone locks and the app goes into the background I can't get it to come out of the background and its keeps running with the red banner at the top. Some of this I have learned as I go, but I have noticed some run on a timer, but I want mine, since its a music processor to keep going until the phone either unlocks or whatever interrupted it stops.
The app is basically a stomp box used with iRig. If that helps.
Thanks
Can you clarify about what you mean when the phone locks, the app goes into the background and yo can't get it to come out of the background? Are you saying like the app is playing music while the app is locked?
I'm making a background tracking GPS app for iOS 7.0+.
I'm having issues when tracking position while in background, it's killed after exactly 5 minutes, even if we are in the middle of a highway, with 1 location per second. It's not killed when constantly in active state.
This seems to occur only on iOS 7.0 version, not on later versions.
I already registered the plist location background activity.
I need maximum accuracy and shortest update time, so I'm not using the significant change method but the basic startUpdatingLocation. This application is used mainly plugged inside a car (no mercy for battery).
I set the location delegate to the app delegate so it's less subject to be deallocated.
Even with all of this done, it's still impossible to take this app alive in background more than 5 minutes.
I'm fighting on iOS which always find a way to terminate my app, even with app state restoration.
So the question is, is there a way to know why my application is killed ?
List of threads that didn't help me or does not respond to my needs, and that I already visited :
How to keep GPS app running in background without pauses
iOS Multi-Tasking Track GPS Location
Periodic iOS background location updates
The system will not tell you why the app was terminated.
I set the location delegate to the app delegate so it's less subject to be deallocated.
The delegate has no effect on whether the location manager is deallocated or not. You must keep a strong reference to the location manager itself.
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.