Android paywall custom package tag

[simonmitchell]

Checklist

• If applicable, unit tests
• If applicable, create follow-up issues for purchases-ios and hybrids

Motivation

This is motivated by a need for us to provide discount offers to our users whilst also using the revenuecat footer UI. We run our offer codes using specifically tagged SubscriptionOption like so:

rcPackage.product.subscriptionOptions?.withTag(offerCode)?.getOrNull(0)

without this change to allow overriding the SubscriptionOption the user is purchasing using the footer component, we cannot apply offer codes in our custom paywall implementation.

Description

A new interface has been added to the ui package called SubscriptionOptionProvider with a single function:

fun subscriptionOption(rcPackage: Package): SubscriptionOption?

This provider can be provided to the library via the paywall options builder.

If provided, the PaywallViewModel will call the function, and if the subscriptionOption function returns non-null then it will use awaitPurchase function that takes a SubscriptionOption rather than a Package.

These changes were tested locally by running our app from the branch on our fork, and has been in the production version of our Android app for the past few weeks.

Note that I have not written any unit tests, as I am unsure if required here, but would be more than happy to if you deem necessary! 😄