How to notify user when the application thread is on background ?

[dridk]

I have a Qt Application and I want to show information to the user, when app is on background!
I was trying unsuccessfully to find how to do the following exemple :

- Show the application from background to foreground ! ==> Don't know how to process ?.
- Show a banner message ==> Don't know... InfoBanner QML element stay in main application
- Show a dialog Box on the homeScreen.. => Like Sms notification...
- Show a message in the notification pannel where blutooth, wifi are.. Like push notification

So, please help me to find a solution ! I suppose I should use Symbian native code, but I never used it .
Thanks for your helping !

[Devnull]

Using Native APIs or the Notification API.