I'm trying to create a kind of alarm clock app with the swift but I could not figure out how to set an alarm model. I've tried UILocalnotification but I don't want my users to be involved the flow of alarm app other than setting the alarm. Then tried NSTimer and NSRunloop etc. but that didn't work either since those don't work when app gets background. So is there any alternative ways to do that? Any help and suggestion would be appreciated, thanks.
I have been doing research on this for quite some time now. But didn't find any concrete way to do it. You have to use one of the following from the list and make a logic to awake the app from the background.
For the alarm you can go through the blog here. It's having the details, which you can use to make a logic with UIApplicationExitsOnSuspend in info.plist file.
As already suggested, since iOS 7 the only way to have an App running in background is allowing one of the Background Modes.
You can find them in the Capabilities section in your project settings. As long as your App does not fall under one of these, you are out of luck :(...
I once tried to write a similar App to yours, and there is really no way to do that right now.
Cheers, TK
来源：https://stackoverflow.com/questions/30890766/how-to-create-an-alarm-clock-app-with-swift