InAppPurchase

InAppPurchase is a Android Library to implement Google Billing Library integration easily in Android App.It is simple, lightweight and used for quick setup.

Prerequisite

• In order to implement an In-App purchase or a Subscription, you need an account in the Google play console and Payment profile setup with your application published in either beta/alpha/ or in Release mode.

Installation

1. Add the following to the settings.gradle file.

   dependencyResolutionManagement {
      repositories {
          maven { url 'https://jitpack.io' }
    }}

2. Add library dependency to the app level build.gradle file.

    dependencies {
       implementation 'com.github.mdrafi786:in-app-purchase-module:$latest_stable_version'
    }

3. Once you’ve added the library dependency, build a Release APK of your app and upload it to the Google Play Console in Internal Testing (Beta Testing).

4. Once you’ve uploaded the APK, you can use the Google Play Console to start adding In-App Products or Subcriptions to sell in your app. Under Montetize >> Products in play console, you’ll see a section for In-App products and Subscriptions. This is where you can set up two types of items:

• In App Products (or one-time purchases)

• Subscriptions

• When you create new In-App Products and Subcriptions, you are required to enter a Product ID, or SKU, for the item. This same Product ID is going to be used again later in your application code as we’ll see in the next step. Before creating a managed product, make sure to plan your Product IDs carefully. Product IDs need to be unique for your app, and they can’t be changed or reused after they’ve been created.

Usage

• Firstly, you need to declare variable of InAppPurchaseClient with lazy initailization in your activity or fragment.

     private val billingClient: InAppPurchaseClient by lazy {
        InAppPurchaseClientImpl(this)
    }

• Set up billing connection by calling startBillingConnection() with required parameter in onCreate() of your activity or fragment :

  Note: Here this is InAppPurchaseUpdateListener that you have to implement in your activty or fragment.

     override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
          setContentView(R.layout.activity_main)
          billingClient.startBillingConnection(this)
    }

• Implement InAppPurchaseUpdateListener and override methods to get callback of purchase state .

   class MainActivity : AppCompatActivity(),InAppPurchaseUpdateListener {
    
      override fun onCreate(savedInstanceState: Bundle?) {
       super.onCreate(savedInstanceState)
       setContentView(R.layout.activity_billing)
     }
  
     override fun onBillingClientReady(billingResult: BillingResult) {
       // The BillingClient is ready. You can query purchases and product details here
    }
  
     override fun onPurchasesSuccess(purchaseList: List<Purchase?>) {
       // handle new purchase success here and also check state of purchase
    }
  
     override fun onPurchaseCancelled() {
       // handle  purchase cancelled by user here
    }
  
     override fun onQueryProductDetailSuccess(productDetailsMap: Map<String, ProductDetails>) {
       // handle product details here
       // Here map key is productId and value is Product details
    }
  
     override fun onQueryPurchasesSuccess(purchaseList: List<Purchase?>) {
       // handle existing purchase list here
    }
  
     override fun onError(error: String) {
     // Get any occur during setup or purchase
    }
  
     override fun onAcknowledgementResponse(isAcknowledged: Boolean) {
       // Get acknowledgement status for purchase
    }
  }

  Prouduct Type Enum Constants

  BillingClient.ProductType.INAPP ( One time purchase) BillingClient.ProductType.SUBS (Subscription)

  Query For Existing Purchase

  • You can Query Google Play Biliing for existing purchases with specific product Type

    billingClient.queryPurchases(BillingClient.ProductType.INAPP)

  Query for Prouducts Available to sell

  • You can Query Google Play Biliing for existing purchases with specific product Type

    val listOfProductQuery = listOf(
          ProductQuery(
              productId = "your_proudct_id",
              purchaseType = "your_prouduct_type"
          )
      )
    billingClient.queryProductDetails(listOfProductQuery)

  Launch the flow for specific product

  • Firstly get the ProductDetails Map from onQueryProductDetailSuccess() overriden method.

      private var productDetailsMap: Map<String, ProductDetails>? = emptyMap()
      
      override fun onQueryProductDetailSuccess(productDetailsMap: Map<
      String, ProductDetails>) {
           // handle product details here
           // Here map key is productId and value is Product details
           this.productDetailsMap = productDetailsMap
    }
    

  • Launch the flow on button click

    val productDetails =
      productDetailsMap?.getOrDefault("your_prouduct_id", null)
       productDetails?.let {
          val billingParams = billingClient.billingFlowParamsBuilder(
                  productDetails = it
              )
              billingClient.launchBillingFlow(this, billingParams)
      }

  Termintate the Billing connection to avoid memory leaks

  • Close the connection of blilling library when activity has been destroyed to avoid memory leaks

     override fun onDestroy() {
       super.onDestroy()
       billingClient.terminateBillingConnection()
    }

License

• BigOhNotation