Android Action Bar Backward Compatibility

The Action Bar is a consistently formatted navigation and option selection area at the top of a screen with an overflow area at the bottom.

 

Key aspects of the Action Bar include:

• It's a replacement for the menu feature.
• It was introduced in Android 3.0 and refined in Android 4.0.
• It's included in activities that use the Holo theme family.

Elements of the Action Bar graphic include:

• Application icon.
• Application name.
• Up navigation to a parent screen.
• Built-in tab navigation for switching between fragments.
• Drop-down list for alternative navigation such as sort by a different criteria.
• Important actions for a given app such as search and share.

Google has recently developed a set of classes to give the Action Bar backward compatibility for pre Android 3.0 devices.  These classes invoke the action bar design pattern on pre-API 11 devices and the built-in Action Bar on devices supporting API 11 or greater.

This is part of a larger set of capabilities for supporting application compatibility with multiple device environments including tablets and handsets and various screen sizes.