How to change Android App Name and ID of an existing application?

Question

I have two Android projects in Eclipse. I copied the one project from the other, then changed the app name (in strings.xml) and the project name

Answer 1

An application's unique identifier is the package name. If you change the package name and reinstall the app again, you will end up with two copies on your phone.

Eclipse can change it on all the places of your code automatically.

Just right click your project on the package explorer (project tree) and go to Android Tools->Rename Application Package

Voilà.