How do you know what apps run in the background?

Discussion in 'iOS 9' started by vexorg, Mar 31, 2016.

  1. vexorg, Mar 31, 2016
    Last edited: Mar 31, 2016

    vexorg macrumors 6502a

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    #1
    Some apps must update in the background, and some only update when run. Is there somewhere to see which are running?

    And if you kill an app from the double click home button, does the app automatically run again?

    For example, I had to install wechat to talk to some chinese partners, it only updates if I run the app. Where as mail or messenger will still update if they have not been run, or been killed off.
     
  2. rovolisgiorgos macrumors newbie

    rovolisgiorgos

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    #2
    Go to Settings -> General -> Background App refresh and there select the apps you wish to be updated in the background. However, wechat (i use it too) has push notifications which do not require app refresh enabled. I suggest you reinstall the app.
     
  3. vexorg thread starter macrumors 6502a

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    #3
    Ok, thanks, I thought I seen that before at some point. Wechat is enabled for background update, so will try and reinstall. Will that need re-verification and contacts added again, or will it remember?

    In general for these background refreshes, do they actually run the apps, or is it only a quick notification check somehow?
     
  4. C DM macrumors Westmere

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    Oct 17, 2011
    #4
    Notifications come regardless of whether or not the app is running. Background refresh will actually let the app run at times outside of what's normally allowed to perform some actions like updating content or something like that.
     
  5. Ashin macrumors 6502a

    Ashin

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    #5
    Anyone else wish there was a more aggressive way to stop apps running in the background?

    Even with Background Refresh off some apps just have a field day in the background.
     
  6. C DM macrumors Westmere

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    #6
    Typically the option for those is to close them, essentially the same kind of option as it is on a desktop computer.
     
  7. Armen macrumors 604

    Armen

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    #7
    A little bit of clarity on how iOS works

    • All apps are not equal. system level apps like Mail and Phone are always running regardless if you close them in the task switcher (they will also relaunch)
    • Media apps like Spotify, Pandora, Music, etc have special permission to run in the background regardless of where you are in iOS (for obvious reasons).
    • Some apps will run in the background for a short period of time after you close them (press home or go to another app). Waze for example will linger a little before it closes down.
    • The Apps listed in the task switcher are a cocktail of apps launched recently(shortcut) and apps that are reserving Ram in case you need to get to them quickly without them having to load all over again.
    • iOS' memory management system will kill any apps that are using memory that have been idle for a long time if it needs more memory.
    • Apps that are reserving memory and show up in the task switcher are NOT consuming battery. It takes less energy to hold on to RAM then to relaunch an app if you keep closing it.
    • Background app refresh was designed to refresh the contents of apps you use often in the background based on your usage. Example: If you open the news app every morning at 8am to read news while you have coffee eventually iOS will learn your habit and refresh the content right before you open the news app so you are looking at current data.
     
  8. ZEEN0j macrumors 6502a

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    #8
    To add to Armens post.

    Media apps such as Spotify use an Api that lets it play only music in the background, it can't do anything else.
    Same with navigation apps when you are navigating. It will continue to run the gps when you close the app. If you stop navigating and then close the app, the app won't do anything in the background.
    Apps can also download data in the background but only for 10 min after you close the app. This is all to save battery.

    I've also noticed that background app refresh will auto update my unread counter on my pocket app when added. This happens instantly, not only when it thinks I want to use it.
    Also, for app refresh to work apps will need to be opened once and stay idle in the task switcher. Other wise it will not work. So if you keep closing your apps you might as well turn off app refresh.
     
  9. Armen macrumors 604

    Armen

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    #9
    Good catch. I forgot about GPS apps. They are given the run in background permission as well. :)

    I think VoIP apps as well? not sure since I don't use Skype or other apps.
     
  10. ZEEN0j macrumors 6502a

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    #10
    VoIP as well. I think this was one of the reasons the Facebook app could keep on running in the background and drain battery.
     
  11. electronicsguy macrumors 6502a

    electronicsguy

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    #11
    "facetime" is a voip app, which, yes, runs in the background if you need. Nice explanation you gave, rather than someone saying "oh just double-click the home button" :)
     
  12. Armen, Mar 31, 2016
    Last edited: Mar 31, 2016

    Armen macrumors 604

    Armen

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    #12
    Just passing on knowledge. :)
     
  13. lolkthxbai macrumors 65816

    lolkthxbai

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    #13
    Apps are running while open on the screen and for a few minutes (2-3) when sent to the background. After the 2-3 minutes of being in the background, the apps goes into a suspended state and is no longer running in the background unless one of the following is true:

    • The app is using location services.
    • The app is using VOIP.
    • The app is playing audio.
    • The app is recording audio.
    • The app has background app refresh turned on.

    There is no need to be constantly killing apps. It actually drains your battery much quicker to be constantly killing and reloading apps than to leave it in its suspended state and resume when you receive a notification. Background app refresh may be disabled for wechat. You should still be able to receive notifications from others. The app may require a few seconds to refresh content after a suspended state.
     
  14. vexorg thread starter macrumors 6502a

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    #14
    Skype used to be a killer on mine, if it was left running then the battery wold be dead in under half a day.

    It would be good if we had a bit more insight or control over the apps running. So we can kill off or limit the background running of apps we want and don't want.
     
  15. Ashin macrumors 6502a

    Ashin

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    #15
    This is only partially true. While some app developers code their apps properly to sleep nicely in the background, others (Facebook is a prime example) basically exploit loopholes in iOS to remain active in the background doing god knows what (IIRC Facebook added in non-existent VOIP to keep it active for extended periods).
     
  16. vexorg thread starter macrumors 6502a

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    #16
    Very useful to know.

    So how does the notification process work for apps that are not running?
    Does the app's remote server tell the phone without the app running?
    or does the app need to be alive in some way to pick up the notification?

    Facebook's messenger is very fast with instant notifications, yet Facebook app can take some time or only when you go into the app before the notification is seen.
     
  17. C DM macrumors Westmere

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    #17
    Apple provides an app push notification service that devrlopers can use to push notifications which don't really rely on the apps and just iOS receiving the push notification.
     
  18. vexorg, Apr 1, 2016
    Last edited: Apr 2, 2016

    vexorg thread starter macrumors 6502a

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    #18
    So, the remote service (of the app) sends a message to your phone when there's a notification. And the app doesn't need to run at all?
     
  19. C DM macrumors Westmere

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    #19
    That's basically it.
     
  20. daniel1948 macrumors 6502

    daniel1948

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    #20
    Gosh. Thanks to everyone who posted info above. As a new iPhone user (about 29 hours of iPhone ownership as of this writing) the above has answered a lot of questions I had and didn't know who to ask. :)
     
  21. lolkthxbai, Apr 1, 2016
    Last edited: Apr 1, 2016

    lolkthxbai macrumors 65816

    lolkthxbai

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    #21
    It might not be obvious to the user but I mentioned that apps that use music, be it silent music or actual music, are still active in the background.
    --- Post Merged, Apr 1, 2016 ---
    Apple provides developers with a certificate that validates any notifications you want to push out to the user's device. The developer sets up their own server to handle the push notifications and attaches the certificate to each notification. Apple validates it (which requires a handshake with the user's device to also confirm the user has turned on notifications for that app) and the notification is sent to the device. If you tap the notification, the corresponding app is opened. This all happens behind the scenes without the app needing to be open.

    For example: FB processes an incoming message sent to you and the app is closed. The FB server generates a push notification with their certificate and relevant info (Mike has sent you a message.) and pushes it out to your device. Apple validates it and makes sure the certificate is valid, you have opted to receive notifications and some other security stuff. If everything runs smooth, the notification appears. The app is never involved, just the "ID" of the app to make sure you actually have the developer's app installed.

    The certificate is renewed and reissued by Apple on a regular basis as well as encrypted to ensure the certificate can't be faked. If the certificate isn't renewed, it expires and can't be used to send users push notifications any longer.
     
  22. vexorg thread starter macrumors 6502a

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    #22
    It makes the double click home button a bit of a nonsense, as you don't know what apps are running, or in the background, or just have been opened recently, or will run again regardless.
     
  23. ZEEN0j macrumors 6502a

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    #23
    It's function is app switching and the ability to close an app if its misbehaving. You don't get more info than that. I've learnt to not care what states my apps are in as long as everything keeps working and my battery is fine. Apple don't want you do have to worry about these things.
     
  24. Damolee macrumors 6502

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    Nov 20, 2012
    #24
    I'm still not entirely sure of what the point of background app refresh is. If I turn it off, everything feels and works the same to me.
     
  25. daniel1948 macrumors 6502

    daniel1948

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    #25
    I'm not entirely sure what background app refresh even actually is: Does it mean that the app is constantly calling home and eating up my data allowance? Or does it just mean the phone is receiving the occasional micro-packet letting iOS know that there's information available next time I bring up the app?

    I don't think I have any apps that I want using my data unless I'm actually using the app at the moment. E.g. a navigation app during actual use, a web browser or mail program while I'm actually using it. Etc. Otherwise, let it refresh when I call on it.

    What am I missing here?
     

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