Android 4.0 (Ice Cream Sandwich) is the latest version of the Android platform for phones, tablets, and more. It builds on the things people love most about Android — easy multitasking, rich notifications, customizable home screens, resizable widgets, and deep interactivity — and adds powerful new ways of communicating and sharing.       
Focused on bringing the power of Android to the
 surface, Android 4.0 makes common actions more visible and lets you navigate with simple, intuitive gestures. Refined animations and feedback throughout the system make interactions engaging and interesting. An entirely new typeface optimized for high-resolution screens improves readability and brings a polished, modern feel to the user interface.
Virtual buttons in the System Bar let you navigate instantly to Back, Home, and Recent Apps. The System Bar and virtual buttons are present across all apps, but can be dimmed by applications for full-screen viewing. You can access each application's contextual options in the Action Bar, displayed at the top (and sometimes also at the bottom) of the screen.
Multitasking is a key strength of Android and it's made even easier and more visual on Android 4.0. The Recent Apps button lets you jump instantly from one task to another using the list in the System Bar. The list pops up to show thumbnail images of apps used recently — tapping a thumbnail switches to the app.
Rich and interactive notifications let you keep in constant touch with incoming messages, play music tracks, see real-time updates from apps, and much more. On smaller-screen devices, notifications appear at the top of the screen, while on larger-screen devices they appear in the System Bar.