Creating different Builds for the same Android Source Code

I have a Android project for SDK1.5 and now I want to convert it for SDK2.1 with some constant changes for the UI. Should I create 开发者_C百科a complete new Project or the existing project can be manipulated for including the lastest changes. I'm using Eclipse for Development.

You can use reflection and conditional class loading in many cases to allow you to support multiple API versions in a single app.