BillingResult のレスポンス コードを処理する

// Initialize the BillingClient.
private val billingClient = BillingClient.newBuilder(context)
    .setListener(this)
    .enablePendingPurchases(PendingPurchasesParams.newBuilder().enableOneTimeProducts().build())
    .build()

private val coroutineScope = kotlinx.coroutines.CoroutineScope(
    kotlinx.coroutines.SupervisorJob() + kotlinx.coroutines.Dispatchers.Main.immediate
)

private var connectionJob: kotlinx.coroutines.Job? = null

// Establish a connection to Google Play.
fun startBillingConnection() {
    connectionJob?.cancel()
    connectionJob = coroutineScope.launch {
        connectWithRetry()
    }
}

// Suspended helper to perform a single connection attempt
private suspend fun connectBilling(): BillingResult =
    kotlinx.coroutines.suspendCancellableCoroutine { continuation ->
        billingClient.startConnection(object : BillingClientStateListener {
            override fun onBillingSetupFinished(billingResult: BillingResult) {
                if (continuation.isActive) {
                    continuation.resume(billingResult)
                }
            }

            override fun onBillingServiceDisconnected() {
                Log.e(TAG, "Google Play Billing Service disconnected")
                if (continuation.isActive) {
                    continuation.resume(
                        BillingResult.newBuilder()
                            .setResponseCode(BillingClient.BillingResponseCode.SERVICE_DISCONNECTED)
                            .setDebugMessage("Service disconnected during connection setup")
                            .build()
                    )
                } else {
                    startBillingConnection()
                }
            }
        })
    }

// Billing connection retry logic. This is a simple max retry pattern
private suspend fun connectWithRetry() {
    val maxTries = 3
    var tries = 1
    var isConnectionEstablished = false
    while (tries <= maxTries && !isConnectionEstablished) {
        val billingResult = connectBilling()
        if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
            isConnectionEstablished = true
            Log.d(TAG, "Billing response OK")
        } else {
            Log.e(TAG, "Billing connection retry failed: ${billingResult.debugMessage}")
            tries++
            if (tries <= maxTries) {
                delay(2000L) // Wait 2 seconds before retrying
            }
        }
    }
}

fun cleanUp() {
    coroutineScope.cancel()
}
// ...
Errors.kt

private suspend fun acknowledge(purchaseToken: String): BillingResult =
    kotlinx.coroutines.suspendCancellableCoroutine { continuation ->
        val params = AcknowledgePurchaseParams.newBuilder()
            .setPurchaseToken(purchaseToken)
            .build()
        billingClient.acknowledgePurchase(params) { billingResult ->
            continuation.resumeWith(Result.success(billingResult))
        }
    }

private suspend fun queryPurchases(productType: String): Pair<BillingResult, List<Purchase>> =
    kotlinx.coroutines.suspendCancellableCoroutine { continuation ->
        val params = QueryPurchasesParams.newBuilder()
            .setProductType(productType)
            .build()
        billingClient.queryPurchasesAsync(params) { billingResult, purchaseList ->
            continuation.resumeWith(Result.success(Pair(billingResult, purchaseList)))
        }
    }

suspend fun acknowledgePurchase(purchaseToken: String) {
    val retryDelayMs = 2000L
    val retryFactor = 2
    val maxTries = 3

    var tries = 1
    var currentDelay = retryDelayMs
    var acknowledgePurchaseResult: BillingResult

    do {
        acknowledgePurchaseResult = acknowledge(purchaseToken)
        val playBillingResponseCode = acknowledgePurchaseResult.responseCode

        when (playBillingResponseCode) {
            BillingClient.BillingResponseCode.OK -> {
                Log.i(TAG, "Acknowledgement was successful")
                return
            }

            BillingClient.BillingResponseCode.ITEM_NOT_OWNED -> {
                Log.d(TAG, "Acknowledgement failed with ITEM_NOT_OWNED")
                val (billingResult, purchaseList) = queryPurchases(BillingClient.ProductType.SUBS)
                if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                    purchaseList.forEach { purchase ->
                        acknowledge(purchase.purchaseToken)
                    }
                }
                return
            }

            in setOf(
                BillingClient.BillingResponseCode.ERROR,
                BillingClient.BillingResponseCode.SERVICE_DISCONNECTED,
                BillingClient.BillingResponseCode.SERVICE_UNAVAILABLE,
            ) -> {
                Log.d(
                    TAG,
                    "Acknowledgement failed, but can be retried -- " +
                        "Response Code: ${acknowledgePurchaseResult.responseCode} -- " +
                        "Debug Message: ${acknowledgePurchaseResult.debugMessage}"
                )
                if (tries < maxTries) {
                    delay(currentDelay)
                    currentDelay *= retryFactor
                    tries++
                } else {
                    break
                }
            }

            else -> {
                Log.e(
                    TAG,
                    "Acknowledgement failed and cannot be retried -- " +
                        "Response Code: ${acknowledgePurchaseResult.responseCode} -- " +
                        "Debug Message: ${acknowledgePurchaseResult.debugMessage}"
                )
                throw Exception("Failed to acknowledge the purchase!")
            }
        }
    } while (tries <= maxTries)

    throw Exception("Failed to acknowledge the purchase after $maxTries attempts!")
}
Errors.kt

when {
    billingClient.isReady -> {
        val billingResult =
            billingClient.isFeatureSupported(BillingClient.FeatureType.IN_APP_MESSAGING)
        if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
            // use Feature
        }
    }
}
Errors.kt