Android 인앱 구매, 1부: 환경 설정 및 프로젝트에 추가

implementation "com.android.billingclient:billing:4.0.0"

import android.content.Contextnimport com.android.billingclient.api.*nnclass BillingClientWrapper(context: Context) : PurchasesUpdatedListener {nn   private val billingClient = BillingClientn       .newBuilder(context)n       .enablePendingPurchases()n       .setListener(this)n       .build()nn   override fun onPurchasesUpdated(billingResult: BillingResult, purchaseList: MutableListu0026lt;Purchaseu003e?) {n       // here come callbacks about new purchasesn   }n}

interface OnQueryProductsListener {n  fun onSuccess(products: List u0026lt; SkuDetails u003e )n  fun onFailure(error: Error)n}nnclass Error(val responseCode: Int, val debugMessage: String)

fun queryProducts(listener: OnQueryProductsListener) {
   val skusList = listOf("premium_sub_month", "premium_sub_year", "some_inapp")n
   queryProductsForType(
       skusList,
       BillingClient.SkuType.SUBS
   ) { billingResult, skuDetailsList -u003e
       if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
           val products = skuDetailsList ?: mutableListOf()
           queryProductsForType(
               skusList,
               BillingClient.SkuType.INAPP
           ) { billingResult, skuDetailsList -u003e
               if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                   products.addAll(skuDetailsList ?: listOf())
                   listener.onSuccess(products)
               } else {
                   listener.onFailure(
                       Error(billingResult.responseCode, billingResult.debugMessage)
                   )
               }
           }
       } else {
           listener.onFailure(
               Error(billingResult.responseCode, billingResult.debugMessage)
           )
       }
   }
}nnprivate fun queryProductsForType(
   skusList: Listu0026lt;Stringu003e,
   @BillingClient.SkuType type: String,
   listener: SkuDetailsResponseListenern) {
   onConnected {
       billingClient.querySkuDetailsAsync(
           SkuDetailsParams.newBuilder().setSkusList(skusList).setType(type).build(),
           listener
       )
   }
}

import android.content.Contextnimport com.android.billingclient.api.*nclass BillingClientWrapper(context: Context) : PurchasesUpdatedListener {
   interface OnQueryProductsListener {
       fun onSuccess(products: Listu0026lt;SkuDetailsu0026gt;)
       fun onFailure(error: Error)
   }
   class Error(val responseCode: Int, val debugMessage: String)
   private val billingClient = BillingClient
       .newBuilder(context)
       .enablePendingPurchases()
       .setListener(this)
       .build()
   fun queryProducts(listener: OnQueryProductsListener) {
       val skusList = listOf("premium_sub_month", "premium_sub_year", "some_inapp")
       queryProductsForType(
           skusList,
           BillingClient.SkuType.SUBS
       ) { billingResult, skuDetailsList -u003e
           if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
               val products = skuDetailsList ?: mutableListOf()
               queryProductsForType(
                   skusList,
                   BillingClient.SkuType.INAPP
               ) { billingResult, skuDetailsList -u003e
                   if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                       products.addAll(skuDetailsList ?: listOf())
                       listener.onSuccess(products)
                   } else {
                       listener.onFailure(
                           Error(billingResult.responseCode, billingResult.debugMessage)
                       )
                   }
               }
           } else {
               listener.onFailure(
                   Error(billingResult.responseCode, billingResult.debugMessage)
               )
           }
       }
   }
   private fun queryProductsForType(
       skusList: Listu0026lt;Stringu0026gt;,
       @BillingClient.SkuType type: String,
       listener: SkuDetailsResponseListener
   ) {
       onConnected {
           billingClient.querySkuDetailsAsync(
               SkuDetailsParams.newBuilder().setSkusList(skusList).setType(type).build(),
               listener
           )
       }
   }
   private fun onConnected(block: () -u003e Unit) {
       billingClient.startConnection(object : BillingClientStateListener {
           override fun onBillingSetupFinished(billingResult: BillingResult) {
               block()
           }
           override fun onBillingServiceDisconnected() {
               // Try to restart the connection on the next request to
               // Google Play by calling the startConnection() method.
           }
       })
   }
   override fun onPurchasesUpdated(billingResult: BillingResult, purchaseList: MutableListu0026lt;Purchaseu003e?) {
       // here come callbacks about new purchases
   }
}