Creating A Pro Key

I want to make a Pro Key app for my application. I have read very interesting answers in this web (like this one). I will upload that apk to PlayStore so people will need to buy it

Solution 1:

The PackageManager class supplies the getInstallerPackageName method that will tell you the package name of whatever installed the package you specify. Side-loaded apps will not contain a value.

source: https://stackoverflow.com/a/10809481/1932105

google's package name: com.android.vending