Android Payment

The Alogame SDK wraps Google Play Billing with server-side receipt verification and crash-safe pending purchase recovery.

Purchase — showPayment

Build a GameData object with the current player context, then call OegSdk.showPayment. The SDK opens the IAP UI, handles the Google Play billing flow, and verifies the receipt with the Alogame server automatically.

Kotlin

import vn.oeg.sdk.v2.legacy.domain.pojo.GameData

val gameData = GameData(
    userId  = 0L,           // not used by SDK — pass 0
    serverId = serverId,    // Int
    roleId   = roleId,      // Int
    level    = level,       // Int
    roleIdString = roleIdString,  // String? — preferred character ID
    extInfo  = extInfo      // String? — extra info passed through to game server
)

OegSdk.showPayment(
    activity  = this,
    gameData  = gameData,
    callBack  = iabCallback,
    productId = "com.oeg.game.pack1"
)

Java

import vn.oeg.sdk.v2.legacy.domain.pojo.GameData;

GameData gameData = new GameData(
    0L,             // userId — not used, pass 0
    serverId,       // Int
    roleId,         // Int
    level,          // Int
    roleIdString,   // String? — preferred character ID
    extInfo         // String? — extra info
);

OegSdk.INSTANCE.showPayment(
    this,
    gameData,
    iabCallback,
    "com.oeg.game.pack1"
);

Define the callback once (e.g. a field on your Activity):

Kotlin

private val iabCallback = object : IabCallBack {
    override fun onIabResult(iabResult: WorkResult<PurchaseInfo>) {
        if (iabResult.isSuccess) {
            // Payment verified by OEG server. Item delivery is performed by the
            // game server via the OEG entitlement webhook — DO NOT grant items
            // locally. Refresh player inventory from your game server.
        } else {
            // Error — iabResult.message contains a human-readable reason.
            // The SDK saves the transaction locally and retries on the next
            // restorePurchases call — no action needed from the game.
        }
    }
}

Java

private final IabCallBack iabCallback = iabResult -> {
    if (iabResult.isSuccess()) {
        // Payment verified by OEG server. Item delivery is performed by the
        // game server via the OEG entitlement webhook — DO NOT grant items
        // locally. Refresh inventory from your game server.
    } else {
        // Error — iabResult.getMessage() contains a human-readable reason.
    }
};

Server-authoritative delivery

isSuccess only confirms that the Alogame backend verified the receipt with Google Play. It is not a signal to grant items from the client. Item entitlement is performed by your game server, which receives a delivery callback from the Alogame backend after verification.

Your game server must implement the Mobile IAP server APIs. See Server Integration → Mobile IAP for the API contract.

Pending Purchase Recovery — restorePurchases

Call this after the player enters the game and GameData is known. It re-verifies any purchases that were interrupted by a crash or network failure.

Kotlin

OegSdk.restorePurchases(gameData, object : IabCallBack {
    override fun onIabResult(iabResult: WorkResult<PurchaseInfo>) {
        if (iabResult.isSuccess) {
            // Pending purchase verified and delivered — refresh inventory
        } else {
            // No pending purchases, or error — safe to ignore
        }
    }
})

Java

OegSdk.INSTANCE.restorePurchases(gameData, iabResult -> {
    if (iabResult.isSuccess()) {
        // Pending purchase verified and delivered — refresh inventory
    } else {
        // No pending purchases, or error — safe to ignore
    }
});

How It Works

1. Player taps Buy → showPayment opens the IAP UI
2. SDK queries Google Play for ProductDetails, then launches the billing flow
3. On purchase confirmed: SDK saves transaction + GameData to SharedPreferences — does NOT call consumeAsync yet
4. SDK sends purchaseToken to Alogame server for S2S verification
5. On server success or HTTP 409: SDK calls consumeAsync, removes the pending entry, fires onIabResult(success)
6. If the app crashes before step 4, the entry survives → recovered by restorePurchases

Duplicate Transaction (HTTP 409)

If the app crashes after the server grants items but before consumeAsync is called, the next restorePurchases re-verifies and the server returns HTTP 409. The SDK handles this automatically — calls consumeAsync, removes the entry, and fires a success result.

Multi-Account Safety

Each pending entry is tagged with the purchasing user's UUID. restorePurchases filters by currentUUID — no cross-account item delivery.

TTL

Entries older than 3 days are pruned automatically. The 3-day threshold matches Google's auto-refund window — after this point consumeAsync would return ITEM_NOT_OWNED. A [CS-ALERT] warning is logged for any pruned entries.

Level Gating

Gate purchases by level requirements configured remotely:

Kotlin

OEGPayment.isIAPEnabled(level = currentLevel) { isEnabled ->
    if (isEnabled) {
        // Show payment button
    } else {
        // Show "Reach level X to unlock the shop"
    }
}

Java

OEGPayment.INSTANCE.isIAPEnabled(currentLevel, isEnabled -> {
    if (isEnabled) {
        // Show payment button
    } else {
        // Show "Reach level X to unlock the shop"
    }
});