example updatefunction

function LifeP1Update(self)
    p1_lifebar = 0.5;
    p1_lifebar = SCREENMAN:GetTopScreen():GetLifeMeter('PlayerNumber_P1');
    if p1_lifebar ~= nil then
        p1_lifebar = SCREENMAN:GetTopScreen():GetLifeMeter('PlayerNumber_P1');
        local life_pa = p1_lifebar:GetLife();
        self:GetChild("PlayerOneLifeMeter"):finishtweening();
        self:GetChild("PlayerOneLifeMeter"):diffuse(color("1,0.25,0,1"));
        self:GetChild("PlayerOneLifeMeter"):stretchto(SCREEN_LEFT+102,SCREEN_TOP+2,SCREEN_LEFT+102+(300*life_pa),SCREEN_TOP+28);
    end;
end

...

t[#t+1] = Def.ActorFrame{
    Name="ScreenGameplayOverlayActorFrameActualDanceMeter";
    InitCommand=function(self)
        self:SetUpdateFunction(LifeP1Update);
        self:SetUpdateRate(0.001);
    end;
    -- Actor (Front Life Meter P1)
    Def.Quad{
        Name="PlayerOneLifeMeter";
        InitCommand=cmd(stretchto,SCREEN_LEFT+102,SCREEN_TOP+2,SCREEN_LEFT+402,SCREEN_TOP+28;diffuse,color("1,0.25,0,1"));
    },
};

...