问题
I am wondering how I can keep receiving motion sensor values while the app is in background mode. I realize that there are already several posts out there. For example, I have tried How Nike+ GPS on iPhone receives accelerometer updates in the background? which does not work for me.
I have also enabled background modes (location updates at the moment) in my App-Info.plist.
Are there any working examples out there? Also, if possible, I would not want to implement some of the hacks, e.g. play silent audio or get the user's location. Apps such as SleepCycle seem to be able to have achieved this without any workarounds.
I'd be grateful for any help.
来源：https://stackoverflow.com/questions/22459684/ios-7-1-get-core-motion-data-accelerometer-gyroscope-while-app-is-in-backgro