Detect Android density and select folder

Hi,

I'm trying to make some code work in my app.js for detect the device density and use adapted images for tab icons. Maybe there's a better solution, but i suppose that this one should work, but there's no return... Maybe i'm doing it wrong ?

Here's a sample of my app.js (I've removed the Titanium.UI.createWindow part).

if (Titanium.Platform.osname == "android"){
 
if (Titanium.Platform.displayCaps.dpi <= 160){
    var density =  'low';
}
else if (Titanium.Platform.displayCaps.dpi > 160 && Titanium.Platform.displayCaps.dpi < 240){
    var density =  'medium';
}
else if (Titanium.Platform.displayCaps.dpi >= 240 && Titanium.Platform.displayCaps.dpi < 320){
    var density =  'high';
}
else if (Titanium.Platform.displayCaps.dpi >= 320 && Titanium.Platform.displayCaps.dpi < 480){
    var density =  'xhigh';
}
else if (Titanium.Platform.displayCaps.dpi >= 480 && Titanium.Platform.displayCaps.dpi < 640){
    var density =  'xxhigh';
}
else{
    var density = 'xxxhigh'; 
}
 
var folder = 'android/images/'+ density + '/';
 
    var tab1 = Titanium.UI.createTab({ 
        icon: folder + 'radioandroid.png',
        title:'Radio',
        window:win1
    });
    var tab2 = Titanium.UI.createTab({  
        icon: folder + 'newsandroid.png',
        title:'Actualités',
        window:win2
    });
    var tab3 = Titanium.UI.createTab({  
        icon: folder + 'playlistandroid.png',
        title:'Playlist',
        window:win3
    });
    var tab4 = Titanium.UI.createTab({  
        icon: folder + 'podcastandroid.png',
        title:'Podcasts',
        window:win4
    });
};
 
 
var tabGroup = Titanium.UI.createTabGroup();
tabGroup.addTab(tab1);  
tabGroup.addTab(tab2);
tabGroup.addTab(tab3);
tabGroup.addTab(tab4); 
tabGroup.open();