InAppBillingPlugin

Cross-platform In App Billing Plugin for .NET

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Project maintained by jamesmontemagno Hosted on GitHub Pages — Theme by mattgraham

Getting Started

Setup

• NuGet: Plugin.InAppBilling
• PM> Install-Package Plugin.InAppBilling
• Install into ALL of your projects, include client projects.

Using InAppBilling APIs

It is drop dead simple to gain access to the In-App Billing APIs in any project. All you need to do is get a reference to the current instance of IInAppBilling via CrossInAppBilling.Current. Before making any calls to InAppBilling you must use ConnectAsync to ensure a valid connection to the app store of the device and always ensure that you call DisconnectAsync when you are finished. It is recommended to call DisconnectAsync inside of a finally block.

public async Task<bool> MakePurchase()
{
    var billing = CrossInAppBilling.Current;
    try
    {
        var connected = await billing.ConnectAsync();
        if(!connected)
            return false;
        
        //make additional billing calls
    }
    finally
    {
        await billing.DisconnectAsync();
    }
}

There may be instances where you install a plugin into a platform that it isn’t supported yet. This means you will have access to the interface, but no implementation exists. You can make a simple check before calling any API to see if it is supported on the platform where the code is running. This if nifty when unit testing:

public async Task<bool> MakePurchase()
{
    if(!CrossInAppBilling.IsSupported)
        return false;

    try
    {
        var billing = CrossInAppBilling.Current;
        var connected = await billing.ConnectAsync();
        if(!connected)
            return false;
        
        //make additional billing calls
    
    }
    finally
    {
        await billing.DisconnectAsync();
    }
}

In-App Billing Recommended Reading

Due to the complex nature of In-App Billing I highly recommend reading exactly how they work on each platform before you start using this plugin:

• Apple’s iOS/tvOS Documentation
• Android Documentation
• Microsoft’s UWP Documentation

In addition to this core reading I recommend the following:

• Xamarin.iOS Setup Documentation
• Google Play service Security and Design

Creating an In-App Purchase

Each app store has you create them in a different area.

• Apple: Go to iTunes Connect -> Select App -> Features -> In-App Purchases
• Android: Go to Google Play Console -> Select App -> Store presence -> In-app products (you can only create on if you have uploaded a version of your app with this plugin or the Vending permission set).
• Microsoft: Go to Dashboard -> Select App -> Add-ons

Permissions & Additional Setup

iOS

ONLY if you are enabling “promoted items” through the app store:

iOS also has the ability to make In-App Purchases from the app store if you mark them as so. To support this you must open your AppDelegate and add the following to your FinishedLaunching.

Plugin.InAppBilling.InAppBillingImplementation.OnShouldAddStorePayment = OnShouldAddStorePayment;
var current = Plugin.InAppBilling.CrossInAppBilling.Current; //initializes

Then add this method in the AppDelegate:

 bool OnShouldAddStorePayment(SKPaymentQueue queue, SKPayment payment, SKProduct product)
{
    //Process and check purchases
    return true;
}

For .NET MAUI apps you can override FinishedLaunching in the AppDelegate or you can implement this in your MauiProgram file like this:

using Microsoft.Extensions.Logging;
using Microsoft.Maui.LifecycleEvents;
#if IOS
using StoreKit;
#endif

namespace MauiApp4;

public static class MauiProgram
{
    public static MauiApp CreateMauiApp()
    {
        var builder = MauiApp.CreateBuilder();
        builder
            .UseMauiApp<App>()
            .ConfigureFonts(fonts =>
            {
                fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
                fonts.AddFont("OpenSans-Semibold.ttf", "OpenSansSemibold");
            })
             .ConfigureLifecycleEvents(AppLifecycle =>
             {
#if IOS
                 AppLifecycle.AddiOS(ios =>
                     ios.FinishedLaunching((del, b) =>
                    {
                        Plugin.InAppBilling.InAppBillingImplementation.OnShouldAddStorePayment = OnShouldAddStorePayment;
                        var current = Plugin.InAppBilling.CrossInAppBilling.Current;
                        return true;
                    }));
#endif
             });

#if IOS
        bool OnShouldAddStorePayment(SKPaymentQueue queue, SKPayment payment, SKProduct product)
        {
            //Process and check purchases
            return true;
        }
#endif

#if DEBUG
        builder.Logging.AddDebug();
#endif


        return builder.Build();
    }
}

Android

For Xamarin.Android apps, in version 4 we use Xamarin.Essentials so you must ensure you initialize it in your Android project. It is setup by default in new projects:

protected override void OnCreate(Bundle savedInstanceState) {
    //...
    base.OnCreate(savedInstanceState);
    Xamarin.Essentials.Platform.Init(this, savedInstanceState); // add this line to your code, it may also be called: bundle
    //...

This is not needed in .NET 6 or .NET MAUI apps as we use built in .NET MAUI APIs to handle this for us.

You may also need to add the following metadata into your AndroidManifext.xml

<meta-data
            android:name="com.google.android.play.billingclient.version"
            android:value="6.1.0" />

Ensure the 6.1.0 matches the version of billing library you are using.

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