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phirstube

macrumors regular
Original poster
Aug 20, 2011
245
6
Ohio
How do you close down applications that are running on the Apple Watch? In theory this should save battery life.
 

Tokenfreak

macrumors 6502a
Oct 31, 2011
639
362
I don't think it supports multitasking? So when you leave the app it closes automatically? I could be wrong, but that is my guess. Kind of like the old iPhone/iOS...
 

CobraPA

macrumors 6502a
Mar 12, 2011
733
175
Lansdale, PA, USA
Yeah, there's no indication that regular apps(*) run in the background on the watch. Background is only available for the parent iphone application. (The watch extension on the iphone for an app seems to sleep when the watch app sleeps as well.)

(*) Apple apps may have their own rules...
 

jabingla2810

macrumors 68020
Oct 15, 2008
2,271
938
You don't need to do this on the iPhone, so I can't see you needing to do it on the Watch.

And no, it doesn't save battery life.
 

phirstube

macrumors regular
Original poster
Aug 20, 2011
245
6
Ohio
You don't need to do this on the iPhone, so I can't see you needing to do it on the Watch.

And no, it doesn't save battery life.


Please explain in more detail. In theory, an application running in the background will still use CPU cycles. How is this prevented on the iPhone? So you are saying if I am listening to music on Spotify in the background, it is not using any more battery than if the Spotify app was closed all together? I don't buy it.
 

simonx314

macrumors regular
Apr 21, 2015
191
12
How do you close down applications that are running on the Apple Watch?

Press the crown button.

In theory this should save battery life.

No, that's not how iOS or Watch OS works. Apps can't "run in the background", there is no multitasking equivalent to how desktop operating systems can run multiple apps simultaneously.

When you press the home button on your iOS device, the app is suspended. However, apps can request that they continue to run background tasks such as GPS tracking or music, but the app is not actually running, just a background service. An app can use the GPS in the background even if it does not show up in the "recent apps" tray.

When you double press the home button on your iOS device, you are seeing a list of recent apps, not running apps. The most recent one or two may be in memory so that they resume quickly, but this does not affect battery life. RAM is always charged with voltage regardless if it is storing active data. "Force quitting" these in-memory apps makes the app take longer to load, more time spent loading is more battery wasted. People who believe they need to remove apps from their recent apps list are actually decreasing the performance of their device. Don't be one of these people.
 
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T-Will

macrumors 65816
Sep 8, 2008
1,048
438
I wish more people understood iOS multitasking. I cringe every time I see someone manually closing apps as a habit (probably since they had to manually manage apps with Android).
 

simonx314

macrumors regular
Apr 21, 2015
191
12
In theory, an application running in the background will still use CPU cycles. How is this prevented on the iPhone?

A desktop application is either open or closed. iOS apps are not like that, they have multiple states described here:

https://developer.apple.com/library...e.html#//apple_ref/doc/uid/TP40007072-CH2-SW3

So you are saying if I am listening to music on Spotify in the background, it is not using any more battery than if the Spotify app was closed all together? I don't buy it.

In this example, Spotify is in the "background execution" state, which is different from the "active" state which could be equated with the desktop equivalent of "running". The app is not updating the interface or listening for touch events.

You bring up an interesting point about background audio. On iOS, we can force quit Spotify to force the app into "not running" state, but if we are listening to music with some 3rd-party Watch OS app then how would we force quit the app? The answer is we should not need to force quit the app if the app is well designed. If you pause the music on the Watch OS app, then press the crown button, the app should not request background audio tasks, therefore would not be consuming CPU cycles. Apple does not approve apps that fail to properly switch execution states to ensure that users experience good battery life.
 
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phirstube

macrumors regular
Original poster
Aug 20, 2011
245
6
Ohio
I appreciate the responses. I am a desktop software engineer and did not fully understand the various states of an iOS app. It will be interesting to see how this is handled now and in the future as this new OS grows and morphs like the iOS did.
 

heeloliver

macrumors 6502a
Sep 6, 2014
639
423
I wish more people understood iOS multitasking. I cringe every time I see someone manually closing apps as a habit (probably since they had to manually manage apps with Android).

same here - they always tell me it saves battery life. I tell them it actually harms their battery life and they look at me like I'm stupid.
 

simonx314

macrumors regular
Apr 21, 2015
191
12
same here - they always tell me it saves battery life. I tell them it actually harms their battery life and they look at me like I'm stupid.

There is an easy way to prove to them that the apps are not running. Have them close an app (app enters "suspended" in memory state). Reopen the app, the app instantly resumes to the same state. Then have them open an app, or several apps, that uses a lot of memory like games. Now reopen the original app which was terminated by iOS to free up memory for the game. The app now starts up from scratch, therefore the app was not running.

You can also blow their minds by pointing out that apps that are running do not show up in the recent apps tray. Force quit Mail and Phone. Do you still get calls and emails? Yes, those system apps instantly restart themselves without reappearing in the recent apps tray. Newstand also shows up in the recents tray even though it is not even an app, it is a folder! If you reboot your device, the recents tray is completely empty even though all the apps that you approved to use your location in the background continue to do so.
 
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simonx314

macrumors regular
Apr 21, 2015
191
12
There is a way to force quit apps.

  1. Hold side button until "Power Off" appears
  2. Hold side button again to force quit current app

I tried it on my Watch and it works. My banking app was stuck in a screen that said "Unable to connect to iPhone", even if I pressed the home button and reopened the app. I force quit and then the banking app was able to get data and show my current balance.
 

zmunkz

macrumors 6502a
Nov 4, 2007
921
229
same here - they always tell me it saves battery life. I tell them it actually harms their battery life and they look at me like I'm stupid.

Of course it saves battery life… applications are given access to certain API calls / events allowed for background services... They may not use them, but they can. When they do it requires memory and cpu, and therefore battery. Think about it… If Spotify is playing in the background, that doesn't mean you're getting it for free. Of course the application is doing work and accessing the network. I don't pretend to be an iOS expert, but I am a software engineer and have published an iOS app. I'll defer to the prodigious Ray Wenderlich to explain fully:

http://www.raywenderlich.com/29948/backgrounding-for-ios
 
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mkruck

macrumors regular
Apr 30, 2008
229
16
San Antonio, TX
There is a way to force quit apps.

  1. Hold side button until "Power Off" appears
  2. Hold side button again to force quit current app

I tried it on my Watch and it works. My banking app was stuck in a screen that said "Unable to connect to iPhone", even if I pressed the home button and reopened the app. I force quit and then the banking app was able to get data and show my current balance.

Thank you!!! My USAA app was continually giving me "cannot communicate with your USAA iPhone App" message since Friday. I'd completely given up on it - working great now.
 

Munchio

macrumors newbie
Apr 24, 2015
25
2
UK
I think you can double press the crown and it will show you the last 2 recent apps you used. I don't know if you can close them though. I can't test this now as my watch is dead pending a return :(
 

simonx314

macrumors regular
Apr 21, 2015
191
12
Thank you!!! My USAA app was continually giving me "cannot communicate with your USAA iPhone App" message since Friday. I'd completely given up on it - working great now.

Haha yea it was the USAA app that was giving me trouble too. Glad I was able to help.
 
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