Reopening Android App from background with timer or countdown

Can someone point me in the right direction to have an Android Application reopen itself to the forefront after a user has pressed the home key? It should be able to be linked to some kind of countdown (which I already have setup, and runs when pushed to background).

I just can't find the开发者_JS百科 function to force this action

*And yes, this is what the user will want, don't worry, I know this doesn't sound user friendly (forcing open) but in this case the user wants it.

Thanks

I needed the exact same thing before -> an app being displayed upon an event but I was sure I read on the Android developers site that this can't be done and that's what notifications are used for, although starting a new activity does bring an app to front. I found this link however to a NEW_TASK_LAUNCH flag with startactivity that might solve your problem -
http://developer.android.com/guide/appendix/faq/framework.html#4