I have three projects in my eclipse workspace:
EventKitchenCore
EventKitchenDesktop
EventKitchenAndroid
EventKitchenCore
contains
This is the way i follow to add library to my projects
PHASE 1: Creating Library Project
Here on image you can see 2 projects named library and ListSamples which is using library
To make the project library as a library project right click on the project and select properties
Mark IsLibrary check box to make it library
you can see .jar file in bin folder of library project
Now the library project is created
PHASE 2 : Adding Library Project to android Project
Now Right click on your android project and select its property. then click on Add button inside library area and set the path of your library project to it
Then a pop- will appear showing a list of library projects you have created in eclipse which is presently active (closed library projects will not shown)
Here i got only one project so it is listed here
Select which all library you needed and click OK. Now the library projects will be added to your project
While checking your android project you can see the .jar file of your project is been added to your android project
NOTE :- If you are using android support package(android-support-v4.jar) in library project , There is no need to add it again in your Android Project .
You can also use ant to add library to projects. But i don't have knowledge about that .