17.1 Android Setup
From your Google Developer Console Account > Setup > Payment Profile, you need to add your payment profile. Like adding your bank account. If you have already added that, you can ignore it.
In this step, you need to add some testers who can test the IAP product in the app and purchase points without any real payment.
From your Google Developer Console Account > Setup > License testing, Add some email addresses.
To activate IAP for your app in the Google Play Store, you need to add the billing permission in the code section and upload an initial build at the Google Play Store as Close Testing. (Only the testers you will assign in the upcoming step can test the app). You shouldn't upload it on production.
From the App source code, Go to the quiz_app/android/app/src/main/AndroidManifest.xml file and enable the selected line shown in the picture below. This permission will enable the billing and IAP at the google play store.
If you already uploaded your app in production and released it at the google play store, you also need to follow the same step (Add billing permission and upload it as a Close Testing version).
Without uploading any new version in the Closed Testing, you won't get the IAP features.
Before going to the next steps, make sure you have uploaded a new build in the Closed Testing and published it.
After publishing a new version with Close testing, you will get an In-App purchases option on your app sidebar.
From Your App > Monetize > In-app products, create an IAP product by clicking on the Create product button.
Add Product ID.
Product ID can be anything but unique. If you are using the IAP in iOS also, then make sure that both product IDs are the same.
Add Product Name which will be shown on the app. You should write how many points you want to sell here. Like 60 Points. Add a Description of the product. This can be anything.
Don't enter anything else in the Name. Just write how many points you want to sell (Like in the picture below)
Set your price and Click on Apply Changes.
Save the product. That's it.
You can create as many IAP products as you want in this way.