c# - UWP: Detect app gaining/losing focus

Question

I want to be able to prevent the screen saver from triggering while my app is in use by using the DisplayRequest class, but I only want to do this while it's the active app. If the user switches to another window/app then I want to act like a good citizen and allow the screensaver again.

I can't see an obvious way to detect when a UWP app gets/loses focus (or is activated/deactivated) and a quick search around doesn't offer any insights. Can anyone point me in the right direction?

Answer 1

It's actually quite simple:

Window.Current.Activated += Current_Activated;

private void Current_Activated(object sender, Windows.UI.Core.WindowActivatedEventArgs e)
{
    if (e.WindowActivationState == CoreWindowActivationState.Deactivated)
    {
        // do stuff
    }
    else
    {
        // do different stuff
    }
}