//create tab group
var tabGroup = Ti.UI.createTabGroup();

//create the window
var win1 = Titanium.UI.createWindow({
  width: 320,
  height: 480,
  top: 0,
  left: 0,
  backgroundImage: 'background.png',
  title: 'Loan Calculator',
  barImage: 'navbar.png'
});

//create the view, this will hold all of our UI controls 
//note the height of this view is the height of the window //minus 134px for the status bar and padding and adjusted for //navbar
var view = Titanium.UI.createView({
  width: 300,
  height: win1.height - 134,
  left: 10,
  top: 10,
  backgroundColor: '#fff',
  borderRadius: 5
});

//we will give the logo a left margin so it centers neatly //within our view
var _logoMarginLeft = (view.width - 253) / 2;

//now let's add our logo to an imageview and add that to our //view object
var logo = Titanium.UI.createImageView({
  image: 'logo.png',
  width: 253,
  height: 96,
  left: _logoMarginLeft,
  top: 0
});
view.add(logo);

//add the view to our window
win1.add(view);

//add the first tab and attach our window object (win1) to it
var tab1 = Ti.UI.createTab({  
    icon:'icon_calculator.png',
    title:'Calculate',

    window: win1
});

//create the second window for settings tab
var win2 = Titanium.UI.createWindow({
  width: 320,
  height: 480,
  top: 0,
  left: 0,
  backgroundImage: 'background.png',
  url: 'window2.js',
  title: 'Settings',
  barImage: 'navbar.png'
});

//add the second tab and attach our external window object //(win2 / window2.js) to it
var tab2 = Ti.UI.createTab({  
    icon:'icon_settings.png',
    title:'Settings',
    window: win2
});

//now add the tabs to our tabGroup object
tabGroup.addTab(tab1);  
tabGroup.addTab(tab2);  

//finally, open the tabgroup to launch the app
tabGroup.open();