How to install an app I write twice?

I need to have both earlier and later versions of App I write in Eclipse. What do I need to change (activity name?) to upload new version开发者_运维百科 of the app to my phone without overwriting the old one? Any fast way to do it?

The package name in the manifest identifies the application (see here). So you also need to change the package name.

Change the app name in your manifest file.