After I made some researches, I found out there is only one way to restart an app and bring it to foreground from background. They say I should use services to do that. But all of the answers refer to developer.android. And I'm not yet able to use developer.android. Don't ask why.
What I want?
When user goes out of my app (go to another app, menu, or going to settings) somehow, listen it with BroadcastReceiver or services. Then bring my app back to foreground.
What I did so far?
I've tried some code snippets but they didn't give me the solution. I guess I didn't understand the basic of services and broadcastreceiver. This is the only point that I stuck with.
I'm sure it will be a few lines of codes. I'm waiting help from you guys.