Paywalls

[vegaro]

We created a PaywallProxyActivity, instead of using the regular fragment we normally use for presenting paywalls in the hybrids. The reason is that we can't use Unity apps use UnityPlayerActivity as the main activity, which is not FragmentActivity. In Flutter we ask devs to implement FragmentActivity in their Activity, but it's not easy to do that in Unity.

For callbacks we use UnitySendMessage, since that's the simplest way without having to rewrite the way we present paywalls to be able to communicate paywall results. It Unity's built-in GameObject messaging system, which I tested and acts as a queue, which is nice since it means the message will come back as soon as PaywallProxyActivity is closed, behaving very similar to onActivityResult. This avoids rewriting existing paywall presentation architecture, which was in progress and we can still do if we want to support real-time paywall notifications.

To hold the Java code, I created a androidlib folder, following the docs https://docs.unity3d.com/Manual/android-library-plugin-create.html. The reason is that it's the only way to include an AndroidManifest.xml, the alternative is building an aar, which wuld require external build process and complicate development workflow.

EDIT: The circular dependency issue is not an issue anymore and has been solved with #649 (comment), but keeping it here for reference

Circular dependency issue

This is how the Gradle dependencies look like:

unityLibrary (main) → depends on → RevenueCatUI.androidlib (our plugin)
RevenueCatUI.androidlib → CANNOT depend on → unityLibrary (circular!)

We need to call Unity functions (see UnityBridge) using reflection. The androidlib is converted into a module, and the unityLibrary module depends on it (implementation project(':RevenueCatUI.androidlib'). That means adding a dependency on unityLibrary in RevenueCatUI.androidlib would create a circular dependency. That's why I build the UnityBridge.

Usage

using RevenueCat.UI;

// Basic paywall presentation
var ui = GetComponent<RevenueCatUI>();
var result = await ui.PresentPaywall();

// Paywall with options
var options = new PaywallOptions {
    OfferingIdentifier = "premium_monthly",
    DisplayCloseButton = true
};
var result = await ui.PresentPaywall(options);

// Conditional paywall
var result = await ui.PresentPaywallIfNeeded("premium_features", options);

Followups

• Font support
• PresentedOfferingContext support

[tonidero]

I think the approach makes sense... I just have that question about how the presentPaywallIfNeeded method would look like and whether that could cause any UI glitches by presenting the proxy activity without need though.

[vegaro]

This PR requires RevenueCat/purchases-android#2695

[tonidero]

Looking pretty good! Just some minor questions and comments

[tonidero]

All makes sense to me. Amazing job on this! Only question is whether we want to get the improvements in #682 before shipping this, since it could be a breaking change later otherwise.