SlidingMenu is an Open Source Android library that allows developers to easily create applications with sliding menus like those made popular in the Google+, YouTube, and Facebook apps.
ActionBarSherlock is an extension of the support library designed to facilitate the use of the action bar design pattern across all versions of Android with a single API.
ViewFlow is an Android UI widget providing a horizontally scrollable ViewGroup with items populated from an Adapter.
- Java Wikipedia API (Bliki engine)
The Java Wikipedia API (Bliki engine) is a parser library for converting Wikipedia wikitext notation to HTML.
Pinyin4j is a popular Java library supporting convertion between Chinese characters and most popular Pinyin systems. The output format of pinyin could be customized.