How to let application know whether the user's focus is in Home Screen

After letting an application run background, I want the application always to catch an event to notify whether the user's focus is in Home Screen or not. (For instance, Home Screen is shown when user push the home button). Any solutions or hints are appreciated!

RWindowTreeNode::EnableFocusChangeEvents, then RWsSession will deliver these events.

[QUOTE=wizard_hu_;773146]RWindowTreeNode::EnableFocusChangeEvents, then RWsSession will deliver these events.[/QUOTE]

As the application sometimes runs background, sometimes runs foreground. Where to receive these events to trigger what I want to do in general. For instance, using HandleWsEventL(const TWsEvent& aEvent, CCoeControl* aDestination) only can catch the event when application is focused when running foreground. How to receive "WS" events when application is sent to backgorund. Thanks.

[QUOTE=sikamedia;773433]For instance, using HandleWsEventL(const TWsEvent& aEvent, CCoeControl* aDestination) only can catch the event when application is focused when running foreground.[/QUOTE]That is not true.

This example gives you the foreground application UID every time it changes. You can use it to detect when the home screen is on top:

[URL="http://wiki.forum.nokia.com/index.php/Capturing_foreground_events"]http://wiki.forum.nokia.com/index.php/Capturing_foreground_events[/URL]

Thanks! my problem is solved:)