This sample app demonstrates how to make an app using a drawer, or commonly known as hamburger menu, as the main method of navigation. On Android the default DrawerLayout is availble, however natively on iOS this doesn't exist. Because of that we've added a custom controller that mimics a drawer while keeping as much code cross platform as possible.
The menu itself is its own controller as well, which works cross platform and is included as the <LeftView> on Android and as an overlay on iOS.
The overlay on iOS is a transparent <Window> with an animate in and out of the menu. You can see the iOS specific code in the /ios/drawer controller.
This sample app is intended as a template to how to use a cross platform app drawer app. The basis of the app is a <NavigationWindow> so you could use the <NavigationWindow> as the navigation interface. When comparing production apps that have a drawer menu use different strategies. Most of them either open the new window using the NavigationWindow or use modal windows. For android this would be Alloy.createController('myController').getView().open() and for iOS you'd need to set the modal flag.
The menu is a view located in the menu controller. This is a view that is wrapped in the <LeftView> property on Android and wrapped in a <Window> on iOS. Furthermore there is an extra nested <View> in the menu controller so padding can be generated based on safeAreaPadding on iOS (see the /ios/drawer controller).
If you want to use that extra padding to your advantage you can just nest your entire menu content inside <View id="menuContent"> and it will automatically follow the safeAreaPadding.
The width of the menu is currently defined as deviceWidth minus 100dp on iPhones. On iPad it is defined as half the deviceWidth. This can be fully configured in the /ios/drawer controller. On Android the width can be defined by setting leftWidth on the DrawerLayout.