Comment by scripturial
2 days ago
In google play the purchaser information is mostly privatized and hidden from the developer. I assume Amazon is the same.
The only way a developer would know a person is an existing user is if they have a user sign up process inside the app itself.
Using android.content.SharedPreferences, set one singaling the user purchased a license from the Amazon copy of the app, read it from the Google Play app.
It is doable, the main issues is: 1. Getting users to redownload the app from the Play store 2. Maintaining this registration transfer mechanism
I think issue #1 is a big one, how to download a paid app without paying for it? Not everything is freemium.
Shattered Pixel Dungeon was a good example of me paying on one platform, and then applying the upgrade to the free app after downloading on another.
That's on the dev of the app. They should absolutely have the ability to see that you download the app, and allow full access again.
This isn't any different from a user switching to a new device and having to download apps again. Not everyone restores from backup and prefers clean installs. Downloading an app again should not be the point of friction