帮助Android应用开发的开源项目列表

A lot of open source libraries that aid in Android application development have sprung up with time. IMO looking at source code of good projects helps learn the system better, faster and not to mention reduces development time. Is there a recommended list of such projects or if not, can we build such a list? I think it will really be useful to other developers.A lot of open source libraries that aid in Andr