Use features introduced in a later SDK version in an earlier version

I want to implement a pinch to zoom function in one of my apps, my problem is that this is only supported by Android 2.2 and most but not all of my user base is 2.1. So my question 开发者_JAVA技巧is, can I implement this feature without causing incompatibility with 2.1?

See this article on backward compatibility for a suggested approach on dealing with newer apis in older versions.