How to know if an app is downloaded for first time or many times from market?

I am placing an app for开发者_开发百科 free in the Market. I want to restrict the downloads (i.e only 1 download per account). If the person uninstalls my app and tries to download again and re-install it with same gmail account, I want to restrict it.

Is that possible? Please help. I am stuck here. Thanks in advance!

I strongly recommend to skip what ever you try in that direction for the given reason:

• you will upset your user!
• you will lose user when they had to reset their device or if they bought a new one

and finally: its not supported!

Guillaume Brunerie mentioned the Application Licensing, but that will only work after they have downloaded the app the second time and you will just piss off your user when they can't start the app after downloading it the second time.

Seriously: drop the idea!

You have to create a server.

When you app starts for first time after installation, it should make a request to your server and send some unique information about the user like gmail address, but it is highly recomended that you hash this information to protect user's privacy. The server should check the hash if exists in it`s database and return an appropriative response to the application.

The standard way to do this kind of things is to use Application Licensing, but this is only available for paid apps.

So I don’t think this is possible if you want your app to be free.