var lastOpenScreenString="";
function loadLastScreen()
{
    lastOpenScreenString=Ti.App.Properties.getString("lastWindow", "home");

    if (lastOpenScreenString=="home") {
        scrHomepage.open();
    } else if (lastOpenScreenString=="anotherscreen") {
        scrPlaying.open();
    } else {
        scrDefault.open();
    }
}

loadLastScreen();