How To Create a Android App With ICS UI That Works With Gingerbread and Froyo?

Question

How apps like Hacker News beta have use the Ice Cream Sandwich 4.0 UI on their app and at time work without any problems on 2.3 Gingerbread and 2.2 Froyo? I want to create apps that should work on 4.0 and have backward compatibility like that, but how to do it?

Answer 1

You have to use the Support Package and its support libraries (v4, V7, v13) - Android Developer.

Some APIs are not yet included in this support package, it may not cover everything that you use.