在后台或设备锁定时，iOS应用程序会使用电池吗？

Question

I am working on an iOS project where the gyro and accelerometer is always on, has animations running as well as a timer.

What actually happens to the app on iOS 7 - iOS 10 when switching apps and the app is relegated to the background or when the device is locked -- does the gyro and accelerometer, running animations and timers automatically pause and turn off?

Should I expect when an app is relegated to the background or when the device is locked, the app stops drawing battery?

Or should I manually pause or turn off the gyro and accelerometer, running animations and timers when applicationDidEnterBackground is triggered and then recommence everything when applicationDidEnterForeground is triggered?

Answer 1

Your app will stop, and without enabled specific background mode like location updates or Background Fetching it won't return to "run" until it will be in the foreground

The NSTimes will stop also. I think it's better practice to update the state in the applicationDidEnterBackground and applicationDidEnterForeground

Answer 2

Check Apple Documentation to know about background execution.

By default, when your app goes to background state then it's not performing any task.

You have to made setup for continue execution in background mode. And that have limitations also like you can not perform everything or anything that you want. You have limitations like, finite length task,location update,background music play, downloading, voip etc..! You can know more from above link.

So, if you have configured anything that's capable to works continue in background, then your app will consumes battery in background otherwise not.

Apple allows only some kind of tasks in background, and one major reason is long battery life !!!!