教學課程

如果您是透過 Google Play 商店發布 Android 應用程式,就可以將該應用程式與 Google Pay API 整合。您也可以將該應用程式設為接受付款卡。如要整合應用程式並設為接受付款卡,請按照本教學課程的步驟操作。

步驟 1:定義 Google Pay API 版本

宣告應用程式使用的 Google Pay API 版本。主要版本和次要版本會影響每個傳送物件中預期的欄位,並且會包含在回應中。

建立基本要求物件,其中包含所有其他要求物件中存在的屬性。

Kotlin

    private val baseRequest = JSONObject().apply {
        put("apiVersion", 2)
        put("apiVersionMinor", 0)
    }

Java

  private static JSONObject getBaseRequest() throws JSONException {
    return new JSONObject().put("apiVersion", 2).put("apiVersionMinor", 0);
  }

步驟 2:替付款服務供應商申請付款權杖

Google 會將付款人所選卡片的相關資訊加密,以便付款服務供應商安全地處理。

Kotlin

private fun gatewayTokenizationSpecification(): JSONObject {
    return JSONObject().apply {
        put("type", "PAYMENT_GATEWAY")
        put("parameters", JSONObject(mapOf(
                "gateway" to "example",
                "gatewayMerchantId" to "exampleGatewayMerchantId")))
    }
}

Java

  private static JSONObject getGatewayTokenizationSpecification() throws JSONException {
    return new JSONObject() {{
      put("type", "PAYMENT_GATEWAY");
      put("parameters", new JSONObject() {{
        put("gateway", "example");
        put("gatewayMerchantId", "exampleGatewayMerchantId");
      }});
    }};
  }

exampleexampleGatewayMerchantId 替換為適用於付款服務供應商的值。請參閱下表,找出服務供應商適用的特定 gatewaygatewayMerchantId 值:

閘道 參數和文件
ACI
  "gateway": "aciworldwide"
  "gatewayMerchantId": "YOUR_ENTITY_ID"

開發人員說明文件

Adyen
  "gateway": "adyen"
  "gatewayMerchantId": "YOUR_MERCHANT_ACCOUNT_NAME"

開發人員說明文件

Alfa-Bank
  "gateway": "alfabank"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

AllPayments
  "gateway": "allpayments"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

APPEX
  "gateway": "epos"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Assist
  "gateway": "assist"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Billing Systems
  "gateway": "billingsystems"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Bizzon
  "gateway": "bizzon"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Blue Media
  "gateway": "bluemedia"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

BlueSnap
  "gateway": "bluesnap"
  "gatewayMerchantId": "YOUR_shopToken"

開發人員說明文件

Braintree
  "gateway": "braintree"
  "braintree:apiVersion": "v1"
  "braintree:sdkVersion": "braintree.client.VERSION"
  "braintree:merchantId": "YOUR_BRAINTREE_MERCHANT_ID"
  "braintree:clientKey": "YOUR_BRAINTREE_TOKENIZATION_KEY"

開發人員說明文件

Braspag
  "gateway": "cielo"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

CardConnect
  "gateway": "cardconnect"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Cathay United Bank
  "gateway": "cathaybk"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Chase Merchant Services
  "gateway": "chase"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Checkout.com
  "gateway": "checkoutltd"
  "gatewayMerchantId": "YOUR_PUBLIC_KEY"

開發人員說明文件

CloudPayments
  "gateway": "cloudpayments"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Computop
  "gateway": "computop"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

ConcordPay
  "gateway": "concordpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Credorax
  "gateway": "credorax"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Cybersource
  "gateway": "cybersource"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Datatrans
  "gateway": "datatrans"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

dLocal
  "gateway": "dlocal"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Dotpay
  "gateway": "dotpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

e-SiTef - Software Express
  "gateway": "softwareexpress"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

EasyPay
  "gateway": "easypay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

EBANX
  "gateway": "ebanx"
  "gatewayMerchantId": "YOUR_PUBLIC_INTEGRATION_KEY"

開發人員說明文件

EBANX Pay
  "gateway": "ebanxpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

eCard
  "gateway": "ecard"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

ECPay
  "gateway": "ecpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

沒有可用的開發人員說明文件

eGHL
  "gateway": "eghl"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

eSafe
  "gateway": "esafe"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

沒有可用的開發人員說明文件

Evopay
  "gateway": "evopay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Evo Payment Gateway
  "gateway": "evopaymentgateway"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

沒有可用的開發人員說明文件

Fat Zebra
  "gateway": "fatzebra"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

First Data (Payeezy)
  "gateway": "firstdata"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

FreedomPay
  "gateway": "freedompay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Gestpay
  "gateway": "gestpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Global One Pay
  "gateway": "globalonepay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

沒有可用的開發人員說明文件

Global Payments
  "gateway": "globalpayments"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

GMO Payment Gateway
  "gateway": "gmopg"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

GoPay
  "gateway": "gopay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

GP Webpay
  "gateway": "gpwebpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

沒有可用的開發人員說明文件

HiTrust
  "gateway": "hitrustpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

InPlat
  "gateway": "inplat"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

IntellectMoney
  "gateway": "intellectmoney"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

iPay88
  "gateway": "ipay88"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

iQmetrix
  "gateway": "iqmetrixpaymentservicesgateway"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

IXOPAY
  "gateway": "ixopay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

JudoPay
  "gateway": "judopay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

沒有可用的開發人員說明文件

Kassa
  "gateway": "kassacom"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Kineox
  "gateway": "kineox"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

LiqPay
  "gateway": "liqpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

LogPay
  "gateway": "logpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Lyra
  "gateway": "lyra"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Mastercard Payment Gateway Services
  "gateway": "mpgs"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

MOBI.Money
  "gateway": "mobimoney"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Molpay
  "gateway": "molpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

沒有可用的開發人員說明文件

Moneris
  "gateway": "moneris"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Moneta
  "gateway": "moneta"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

沒有可用的開發人員說明文件

Monext
  "gateway": "monext"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Money.Mail.Ru
  "gateway": "moneymailru"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Multicarta
  "gateway": "mulitcarta"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Mundipagg
  "gateway": "mundipagg"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

MyCheck
  "gateway": "mycheck"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

MyPay
  "gateway": "mypay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

沒有可用的開發人員說明文件

Newebpay (原為「STPath」、「Pay2Go」)
  "gateway": "newebpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Nexi
  "gateway": "nexi"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

NMI
  "gateway": "gatewayservices"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Nuvei
  "gateway": "nuvei"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Onelya
  "gateway": "onelya"
  "gatewayMerchantId": "YOUR_GATWAY_MERCHANT_ID"

Developer docs

Payfacto
  "gateway": "payfacto"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

paygent
  "gateway": "paygent"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

PayLane
  "gateway": "paylane"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Payler
  "gateway": "payler"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Payload
  "gateway": "payload"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Paymark
  "gateway": "paymark"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Paymentwall
  "gateway": "paymentwall"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Paymo
  "gateway": "paymo"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

PayOnline
  "gateway": "payonline"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Paysafe
  "gateway": "paysafe"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Payture
  "gateway": "payture"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

PayU
  "gateway": "payu"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Payway
  "gateway": "payway"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Platon
  "gateway": "platon"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Portmone
  "gateway": "portmonecom"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Primer
  "gateway": "primer"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Przelewy24
  "gateway": "przelewy24"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Radial
  "gateway": "radial"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

RBK.money
  "gateway": "rbkmoney"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Rebilly
  "gateway": "Rebilly"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Redsys
  "gateway": "redsys"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Sberbank
  "gateway": "sberbank"
  "gatewayMerchantId": "YOUR_ORGANIZATION_NAME"

開發人員說明文件

Sipay
  "gateway": "sipay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Softbank Payment Service
  "gateway": "sbps"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Solid
  "gateway": "solid"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Sony Payment Services
  "gateway": "sonypaymentservices"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Spreedly
  "gateway": "spreedly"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Square
  "gateway": "square"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Stripe
  "gateway": "stripe"
  "stripe:version": "2018-10-31"
  "stripe:publishableKey": "YOUR_PUBLIC_STRIPE_KEY"

開發人員說明文件

TapPay (喬睿科技)
  "gateway": "tappay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

TAS Link
  "gateway": "taslink"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Tatra banka (CardPay)
  "gateway": "tatrabanka"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

沒有可用的開發人員說明文件

Tinkoff
  "gateway": "tinkoff"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

theMAP
  "gateway": "themap"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

TPay.com
  "gateway": "tpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Tranzzo
  "gateway": "tranzzo"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

UAPAY
  "gateway": "uapay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Uniteller
  "gateway": "uniteller"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

UPC
  "gateway": "upc"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Vantiv
  "gateway": "vantiv"
  "vantiv:merchantPayPageId": "YOUR_PAY_PAGE_ID"
  "vantiv:merchantOrderId": "YOUR_ORDER_ID"
  "vantiv:merchantTransactionId": "YOUR_TRANSACTION_ID"
  "vantiv:merchantReportGroup": "*web"

開發人員說明文件

Veritrans
  "gateway": "veritrans"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Vindicia
  "gateway": "vindicia"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

WayForPay
  "gateway": "wayforpay"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Windcave
  "gateway": "windcave"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Wirecard
  "gateway": "wirecard"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Worldnet
  "gateway": "worldnet"
  "gatewayMerchantId": "YOUR_GATEWAY_MERCHANT_ID"

開發人員說明文件

Worldpay
  "gateway": "worldpay"
  "gatewayMerchantId": "YOUR_WORLDPAY_MERCHANT_ID"

開發人員說明文件

Yandex.Checkout
  "gateway": "yandexcheckout"
  "gatewayMerchantId": "YOUR_SHOP_ID"

開發人員說明文件

PAYMENT_GATEWAY 權杖化類型是商家最常在 Google Pay API 中實作的卡片付款方式。如果系統不支援您的付款服務供應商,您或許可以透過 DIRECT 整合的方式接受透過 Google Pay 付款。詳情請參閱直接權杖化說明文件

步驟 3:定義支援的付款卡發卡機構

定義應用程式接受的發卡機構。

Kotlin

private val allowedCardNetworks = JSONArray(listOf(
        "AMEX",
        "DISCOVER",
        "INTERAC",
        "JCB",
        "MASTERCARD",
        "VISA"))

Java

private static JSONArray getAllowedCardNetworks() {
  return new JSONArray()
      .put("AMEX")
      .put("DISCOVER")
      .put("INTERAC")
      .put("JCB")
      .put("MASTERCARD")
      .put("VISA");
}

Google Pay API 可能會傳回在 Google.com 中已有記錄的卡片 (PAN_ONLY),或傳回 Android 裝置上已透過 3-D 安全密文驗證的裝置權杖 (CRYPTOGRAM_3DS)。

Kotlin

private val allowedCardAuthMethods = JSONArray(listOf(
        "PAN_ONLY",
        "CRYPTOGRAM_3DS"))

Java

private static JSONArray getAllowedCardAuthMethods() {
  return new JSONArray()
      .put("PAN_ONLY")
      .put("CRYPTOGRAM_3DS");
}

詳情請參閱 JSON 物件參考資料中的 CardParameters。如要取得 Android 裝置權杖的相關支援,請洽詢閘道或處理方以確認支援的發卡機構。

步驟 4:說明允許的付款方式

為了說明應用程式對 CARD 付款方式的支援狀況,請結合支援的驗證方法和支援的發卡機構。

Kotlin

    private fun baseCardPaymentMethod(): JSONObject {
        return JSONObject().apply {

            val parameters = JSONObject().apply {
                put("allowedAuthMethods", allowedCardAuthMethods)
                put("allowedCardNetworks", allowedCardNetworks)
                put("billingAddressRequired", true)
                put("billingAddressParameters", JSONObject().apply {
                    put("format", "FULL")
                })
            }

            put("type", "CARD")
            put("parameters", parameters)
        }
    }

Java

  private static JSONObject getBaseCardPaymentMethod() throws JSONException {
    JSONObject cardPaymentMethod = new JSONObject();
    cardPaymentMethod.put("type", "CARD");

    JSONObject parameters = new JSONObject();
    parameters.put("allowedAuthMethods", getAllowedCardAuthMethods());
    parameters.put("allowedCardNetworks", getAllowedCardNetworks());
    // Optionally, you can add billing address/phone number associated with a CARD payment method.
    parameters.put("billingAddressRequired", true);

    JSONObject billingAddressParameters = new JSONObject();
    billingAddressParameters.put("format", "FULL");

    parameters.put("billingAddressParameters", billingAddressParameters);

    cardPaymentMethod.put("parameters", parameters);

    return cardPaymentMethod;
  }

擴充基本卡片付款方式物件,以說明預期傳回至應用程式的資訊,其中必須包含權杖化付款資料。

Kotlin

    private fun cardPaymentMethod(): JSONObject {
        val cardPaymentMethod = baseCardPaymentMethod()
        cardPaymentMethod.put("tokenizationSpecification", gatewayTokenizationSpecification())

        return cardPaymentMethod
    }

Java

  private static JSONObject getCardPaymentMethod() throws JSONException {
    JSONObject cardPaymentMethod = getBaseCardPaymentMethod();
    cardPaymentMethod.put("tokenizationSpecification", getGatewayTokenizationSpecification());

    return cardPaymentMethod;
  }

如要進一步瞭解支援的 parameters,請參閱 JSON 物件參考資料中的 CardParameters

除了 CARD 之外,Google Pay 也支援 PAYPAL 付款方式。如要進一步瞭解如何將 PayPal 新增為 Google Pay 付款方式,請參閱 PayPal 的開發人員說明文件

步驟 5:建立 PaymentsClient 執行個體

ActivityonCreate 方法中建立 PaymentsClient 執行個體。PaymentsClient 的用途是與 Google Pay API 互動。

Kotlin

    fun createPaymentsClient(activity: Activity): PaymentsClient {
        val walletOptions = Wallet.WalletOptions.Builder()
                .setEnvironment(Constants.PAYMENTS_ENVIRONMENT)
                .build()

        return Wallet.getPaymentsClient(activity, walletOptions)
    }

Java

  public static PaymentsClient createPaymentsClient(Activity activity) {
    Wallet.WalletOptions walletOptions =
        new Wallet.WalletOptions.Builder().setEnvironment(Constants.PAYMENTS_ENVIRONMENT).build();
    return Wallet.getPaymentsClient(activity, walletOptions);
  }

步驟 6:判斷是否已準備好使用 Google Pay API 付款

使用下列程式碼片段,替基本要求物件新增允許的付款方式:

Kotlin

    fun isReadyToPayRequest(): JSONObject? {
        return try {
            baseRequest.apply {
                put("allowedPaymentMethods", JSONArray().put(baseCardPaymentMethod()))
            }

        } catch (e: JSONException) {
            null
        }
    }

Java

  public static Optional<JSONObject> getIsReadyToPayRequest() {
    try {
      JSONObject isReadyToPayRequest = getBaseRequest();
      isReadyToPayRequest.put(
          "allowedPaymentMethods", new JSONArray().put(getBaseCardPaymentMethod()));

      return Optional.of(isReadyToPayRequest);

    } catch (JSONException e) {
      return Optional.empty();
    }
  }

在顯示 Google Pay 按鈕之前,請呼叫 isReadyToPay API,以判斷使用者是否能透過 Google Pay API 付款。如需完整的設定屬性清單,請參閱 IsReadyToPayRequest JSON 物件說明文件

Kotlin

    private fun possiblyShowGooglePayButton() {

        val isReadyToPayJson = PaymentsUtil.isReadyToPayRequest() ?: return
        val request = IsReadyToPayRequest.fromJson(isReadyToPayJson.toString()) ?: return

        // The call to isReadyToPay is asynchronous and returns a Task. We need to provide an
        // OnCompleteListener to be triggered when the result of the call is known.
        val task = paymentsClient.isReadyToPay(request)
        task.addOnCompleteListener { completedTask ->
            try {
                completedTask.getResult(ApiException::class.java)?.let(::setGooglePayAvailable)
            } catch (exception: ApiException) {
                // Process error
                Log.w("isReadyToPay failed", exception)
            }
        }
    }

Java

  private void possiblyShowGooglePayButton() {

    final Optional<JSONObject> isReadyToPayJson = PaymentsUtil.getIsReadyToPayRequest();
    if (!isReadyToPayJson.isPresent()) {
      return;
    }

    // The call to isReadyToPay is asynchronous and returns a Task. We need to provide an
    // OnCompleteListener to be triggered when the result of the call is known.
    IsReadyToPayRequest request = IsReadyToPayRequest.fromJson(isReadyToPayJson.get().toString());
    Task<Boolean> task = paymentsClient.isReadyToPay(request);
    task.addOnCompleteListener(this,
        new OnCompleteListener<Boolean>() {
          @Override
          public void onComplete(@NonNull Task<Boolean> task) {
            if (task.isSuccessful()) {
              setGooglePayAvailable(task.getResult());
            } else {
              Log.w("isReadyToPay failed", task.getException());
            }
          }
        });
  }

如範例所示,最好在收到來自 isReadyToPay 函式的成功結果後,才將 Google Pay 顯示為付款選項。實作付款選項時,在版面配置中透過 include 顯示 Google Pay 付款按鈕是最常見的做法。如要進一步瞭解應用程式可用的 Google Pay 付款按鈕、標誌和標記,請參閱品牌宣傳指南

步驟 7:建立 PaymentDataRequest 物件

PaymentDataRequest JSON 物件會說明在 Google Pay 付款畫面中,要求付款人提供的資訊。

請提供交易價格和所提供價格的狀態相關資訊。詳情請參閱 TransactionInfo JSON 物件說明文件

以下範例說明如何取得價格、價格狀態和幣別交易資訊。

Kotlin

    private fun getTransactionInfo(price: String): JSONObject {
        return JSONObject().apply {
            put("totalPrice", price)
            put("totalPriceStatus", "FINAL")
            put("countryCode", Constants.COUNTRY_CODE)
            put("currencyCode", Constants.CURRENCY_CODE)
        }
    }

Java

  private static JSONObject getTransactionInfo(String price) throws JSONException {
    JSONObject transactionInfo = new JSONObject();
    transactionInfo.put("totalPrice", price);
    transactionInfo.put("totalPriceStatus", "FINAL");
    transactionInfo.put("countryCode", Constants.COUNTRY_CODE);
    transactionInfo.put("currencyCode", Constants.CURRENCY_CODE);
    transactionInfo.put("checkoutOption", "COMPLETE_IMMEDIATE_PURCHASE");

    return transactionInfo;
  }

提供可讓使用者查看的商家名稱。詳情請參閱 MerchantInfo JSON 物件說明文件

以下範例顯示如何取得商家名稱:

Kotlin

private val merchantInfo: JSONObject =
        JSONObject().put("merchantName", "Example Merchant")

Java

  private static JSONObject getMerchantInfo() throws JSONException {
    return new JSONObject().put("merchantName", "Example Merchant");
  }

將基本要求物件指派給新的 PaymentDataRequest JSON 物件。接下來,請新增應用程式支援的付款方式,包括設定回應中應包含的任何其他資料。最後,請新增交易和提出要求商家的相關資訊。

以下範例說明如何要求付款資料:

Kotlin

fun getPaymentDataRequest(price: String): JSONObject? {
    try {
        return baseRequest.apply {
            put("allowedPaymentMethods", JSONArray().put(cardPaymentMethod()))
            put("transactionInfo", getTransactionInfo(price))
            put("merchantInfo", merchantInfo)

            // An optional shipping address requirement is a top-level property of the
            // PaymentDataRequest JSON object.
            val shippingAddressParameters = JSONObject().apply {
                put("phoneNumberRequired", false)
                put("allowedCountryCodes", JSONArray(listOf("US", "GB")))
            }
            put("shippingAddressParameters", shippingAddressParameters)
            put("shippingAddressRequired", true)
        }
    } catch (e: JSONException) {
        return null
    }
}

Java


  public static Optional<JSONObject> getPaymentDataRequest(long priceCents) {

    final String price = PaymentsUtil.centsToString(priceCents);

    try {
      JSONObject paymentDataRequest = PaymentsUtil.getBaseRequest();
      paymentDataRequest.put(
          "allowedPaymentMethods", new JSONArray().put(PaymentsUtil.getCardPaymentMethod()));
      paymentDataRequest.put("transactionInfo", PaymentsUtil.getTransactionInfo(price));
      paymentDataRequest.put("merchantInfo", PaymentsUtil.getMerchantInfo());

      /* An optional shipping address requirement is a top-level property of the PaymentDataRequest
      JSON object. */
      paymentDataRequest.put("shippingAddressRequired", true);

      JSONObject shippingAddressParameters = new JSONObject();
      shippingAddressParameters.put("phoneNumberRequired", false);

      JSONArray allowedCountryCodes = new JSONArray(Constants.SHIPPING_SUPPORTED_COUNTRIES);

      shippingAddressParameters.put("allowedCountryCodes", allowedCountryCodes);
      paymentDataRequest.put("shippingAddressParameters", shippingAddressParameters);
      return Optional.of(paymentDataRequest);

    } catch (JSONException e) {
      return Optional.empty();
    }
  }

詳情請參閱 PaymentDataRequest JSON 物件說明文件

步驟 8:針對使用者手勢註冊事件處理常式

如要在使用者啟用 Google Pay 付款按鈕後顯示 Google Pay 付款畫面,請定義 OnClickListener

Kotlin

        googlePayButton.setOnClickListener { requestPayment() }

Java

    googlePayButton.setOnClickListener(
        new View.OnClickListener() {
          @Override
          public void onClick(View view) {
            requestPayment(view);
          }
        });

PaymentDataRequest 物件是代表付款資料要求的 ParcelablePaymentDataRequest 會提供支援付款所需的資訊。使用 AutoResolveHelper 類別自動解析 Task,然後再處理 Activity 類別中 onActivityResult 方法 的結果。

步驟 9:處理回應物件

當付款人成功在 Google Pay 付款畫面中提供要求的資訊後,系統就會將 PaymentData 物件傳回給 onActivityResult

如要將付款資訊傳送至處理方,並向使用者顯示確認購買的訊息,請將成功的回應轉換為 JSON。如果傳送至 PaymentDataRequesttransactionInfo.totalPriceStatusESTIMATED,你必須先顯示最終價格,才能向傳回的付款方式扣款。

擷取 paymentData 回應中的付款代碼。如果你執行了閘道整合,請將這個權杖傳送至閘道,不要進行任何修改。

Kotlin

    public override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        when (requestCode) {
            // Value passed in AutoResolveHelper
            LOAD_PAYMENT_DATA_REQUEST_CODE -> {
                when (resultCode) {
                    RESULT_OK ->
                        data?.let { intent ->
                            PaymentData.getFromIntent(intent)?.let(::handlePaymentSuccess)
                        }

                    RESULT_CANCELED -> {
                        // The user cancelled the payment attempt
                    }

                    AutoResolveHelper.RESULT_ERROR -> {
                        AutoResolveHelper.getStatusFromIntent(data)?.let {
                            handleError(it.statusCode)
                        }
                    }
                }

                // Re-enables the Google Pay payment button.
                googlePayButton.isClickable = true
            }
        }
    }

Java

  public void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
      // value passed in AutoResolveHelper
      case LOAD_PAYMENT_DATA_REQUEST_CODE:
        switch (resultCode) {

          case Activity.RESULT_OK:
            PaymentData paymentData = PaymentData.getFromIntent(data);
            handlePaymentSuccess(paymentData);
            break;

          case Activity.RESULT_CANCELED:
            // The user cancelled the payment attempt
            break;

          case AutoResolveHelper.RESULT_ERROR:
            Status status = AutoResolveHelper.getStatusFromIntent(data);
            handleError(status.getStatusCode());
            break;
        }

        // Re-enables the Google Pay payment button.
        googlePayButton.setClickable(true);
    }
  }

如要進一步瞭解回應的內容和結構,請參閱 PaymentData JSON 物件參考資料

完整的實作範例

下列程式碼片段顯示了正確設定的完整專案範例。如需專案層級的設定步驟,請參閱設定專案一節。

CheckoutActivity.kt (Kotlin)

範例 Activity 假設你的版面配置中含有 id 屬性為 googlepay_button 的 Google Pay 付款按鈕。

/*
 * Copyright 2018 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.android.gms.samples.wallet.activity

import android.app.Activity
import android.content.Intent
import android.os.Bundle
import android.text.Html
import android.util.Log
import android.view.View
import android.widget.Toast
import com.google.android.gms.common.api.ApiException
import com.google.android.gms.samples.wallet.util.PaymentsUtil
import com.google.android.gms.samples.wallet.R
import com.google.android.gms.samples.wallet.util.Json
import com.google.android.gms.wallet.*
import kotlinx.android.synthetic.main.activity_checkout.*
import org.json.JSONArray
import org.json.JSONException
import org.json.JSONObject

/**
 * Checkout implementation for the app
 */
class CheckoutActivity : Activity() {

    private val SHIPPING_COST_CENTS = 9 * PaymentsUtil.CENTS.toLong()

    /**
     * A client for interacting with the Google Pay API.
     *
     * @see [PaymentsClient](https://developers.google.com/android/reference/com/google/android/gms/wallet/PaymentsClient)
     */
    private lateinit var paymentsClient: PaymentsClient

    private lateinit var garmentList: JSONArray
    private lateinit var selectedGarment: JSONObject

    /**
     * Arbitrarily-picked constant integer you define to track a request for payment data activity.
     *
     * @value #LOAD_PAYMENT_DATA_REQUEST_CODE
     */
    private val LOAD_PAYMENT_DATA_REQUEST_CODE = 991

    /**
     * Initialize the Google Pay API on creation of the activity
     *
     * @see Activity.onCreate
     */
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_checkout)

        // Set up the mock information for our item in the UI.
        selectedGarment = fetchRandomGarment()
        displayGarment(selectedGarment)

        // Initialize a Google Pay API client for an environment suitable for testing.
        // It's recommended to create the PaymentsClient object inside of the onCreate method.
        paymentsClient = PaymentsUtil.createPaymentsClient(this)
        possiblyShowGooglePayButton()

        googlePayButton.setOnClickListener { requestPayment() }
    }

    /**
     * Determine the viewer's ability to pay with a payment method supported by your app and display a
     * Google Pay payment button.
     *
     * @see [](https://developers.google.com/android/reference/com/google/android/gms/wallet/PaymentsClient.html.isReadyToPay
    ) */
    private fun possiblyShowGooglePayButton() {

        val isReadyToPayJson = PaymentsUtil.isReadyToPayRequest() ?: return
        val request = IsReadyToPayRequest.fromJson(isReadyToPayJson.toString()) ?: return

        // The call to isReadyToPay is asynchronous and returns a Task. We need to provide an
        // OnCompleteListener to be triggered when the result of the call is known.
        val task = paymentsClient.isReadyToPay(request)
        task.addOnCompleteListener { completedTask ->
            try {
                completedTask.getResult(ApiException::class.java)?.let(::setGooglePayAvailable)
            } catch (exception: ApiException) {
                // Process error
                Log.w("isReadyToPay failed", exception)
            }
        }
    }

    /**
     * If isReadyToPay returned `true`, show the button and hide the "checking" text. Otherwise,
     * notify the user that Google Pay is not available. Please adjust to fit in with your current
     * user flow. You are not required to explicitly let the user know if isReadyToPay returns `false`.
     *
     * @param available isReadyToPay API response.
     */
    private fun setGooglePayAvailable(available: Boolean) {
        if (available) {
            googlePayButton.visibility = View.VISIBLE
        } else {
            Toast.makeText(
                    this,
                    "Unfortunately, Google Pay is not available on this device",
                    Toast.LENGTH_LONG).show();
        }
    }

    private fun requestPayment() {

        // Disables the button to prevent multiple clicks.
        googlePayButton.isClickable = false

        // The price provided to the API should include taxes and shipping.
        // This price is not displayed to the user.
        val garmentPrice = selectedGarment.getDouble("price")
        val priceCents = Math.round(garmentPrice * PaymentsUtil.CENTS.toLong()) + SHIPPING_COST_CENTS

        val paymentDataRequestJson = PaymentsUtil.getPaymentDataRequest(priceCents)
        if (paymentDataRequestJson == null) {
            Log.e("RequestPayment", "Can't fetch payment data request")
            return
        }
        val request = PaymentDataRequest.fromJson(paymentDataRequestJson.toString())

        // Since loadPaymentData may show the UI asking the user to select a payment method, we use
        // AutoResolveHelper to wait for the user interacting with it. Once completed,
        // onActivityResult will be called with the result.
        if (request != null) {
            AutoResolveHelper.resolveTask(
                    paymentsClient.loadPaymentData(request), this, LOAD_PAYMENT_DATA_REQUEST_CODE)
        }
    }

    /**
     * Handle a resolved activity from the Google Pay payment sheet.
     *
     * @param requestCode Request code originally supplied to AutoResolveHelper in requestPayment().
     * @param resultCode Result code returned by the Google Pay API.
     * @param data Intent from the Google Pay API containing payment or error data.
     * @see [Getting a result
     * from an Activity](https://developer.android.com/training/basics/intents/result)
     */
    public override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        when (requestCode) {
            // Value passed in AutoResolveHelper
            LOAD_PAYMENT_DATA_REQUEST_CODE -> {
                when (resultCode) {
                    RESULT_OK ->
                        data?.let { intent ->
                            PaymentData.getFromIntent(intent)?.let(::handlePaymentSuccess)
                        }

                    RESULT_CANCELED -> {
                        // The user cancelled the payment attempt
                    }

                    AutoResolveHelper.RESULT_ERROR -> {
                        AutoResolveHelper.getStatusFromIntent(data)?.let {
                            handleError(it.statusCode)
                        }
                    }
                }

                // Re-enables the Google Pay payment button.
                googlePayButton.isClickable = true
            }
        }
    }

    /**
     * PaymentData response object contains the payment information, as well as any additional
     * requested information, such as billing and shipping address.
     *
     * @param paymentData A response object returned by Google after a payer approves payment.
     * @see [Payment
     * Data](https://developers.google.com/pay/api/android/reference/object.PaymentData)
     */
    private fun handlePaymentSuccess(paymentData: PaymentData) {
        val paymentInformation = paymentData.toJson() ?: return

        try {
            // Token will be null if PaymentDataRequest was not constructed using fromJson(String).
            val paymentMethodData = JSONObject(paymentInformation).getJSONObject("paymentMethodData")
            val billingName = paymentMethodData.getJSONObject("info")
                    .getJSONObject("billingAddress").getString("name")
            Log.d("BillingName", billingName)

            Toast.makeText(this, getString(R.string.payments_show_name, billingName), Toast.LENGTH_LONG).show()

            // Logging token string.
            Log.d("GooglePaymentToken", paymentMethodData
                    .getJSONObject("tokenizationData")
                    .getString("token"))

        } catch (e: JSONException) {
            Log.e("handlePaymentSuccess", "Error: " + e.toString())
        }

    }

    /**
     * At this stage, the user has already seen a popup informing them an error occurred. Normally,
     * only logging is required.
     *
     * @param statusCode will hold the value of any constant from CommonStatusCode or one of the
     * WalletConstants.ERROR_CODE_* constants.
     * @see [
     * Wallet Constants Library](https://developers.google.com/android/reference/com/google/android/gms/wallet/WalletConstants.constant-summary)
     */
    private fun handleError(statusCode: Int) {
        Log.w("loadPaymentData failed", String.format("Error code: %d", statusCode))
    }

    private fun fetchRandomGarment() : JSONObject {
        if (!::garmentList.isInitialized) {
            garmentList = Json.readFromResources(this, R.raw.tshirts)
        }

        val randomIndex:Int = Math.round(Math.random() * (garmentList.length() - 1)).toInt()
        return garmentList.getJSONObject(randomIndex)
    }

    private fun displayGarment(garment:JSONObject) {
        detailTitle.setText(garment.getString("title"))
        detailPrice.setText("\$${garment.getString("price")}")

        val escapedHtmlText:String = Html.fromHtml(garment.getString("description")).toString()
        detailDescription.setText(Html.fromHtml(escapedHtmlText))

        val imageUri = "@drawable/${garment.getString("image")}"
        val imageResource = resources.getIdentifier(imageUri, null, packageName)
        detailImage.setImageResource(imageResource)
    }
}

    

PaymentsUtil.kt (Kotlin)

這個範例檔案會建構適合建立 IsReadyToPayRequestPaymentDataRequest 的 JSON 物件。

/*
 * Copyright 2017 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.android.gms.samples.wallet.util

import android.app.Activity
import com.google.android.gms.samples.wallet.Constants
import com.google.android.gms.wallet.PaymentsClient
import com.google.android.gms.wallet.Wallet
import org.json.JSONArray
import org.json.JSONException
import org.json.JSONObject
import java.math.BigDecimal
import java.math.RoundingMode

/**
 * Contains helper static methods for dealing with the Payments API.
 *
 * Many of the parameters used in the code are optional and are set here merely to call out their
 * existence. Please consult the documentation to learn more and feel free to remove ones not
 * relevant to your implementation.
 */
object PaymentsUtil {
    val CENTS = BigDecimal(100)

    /**
     * Create a Google Pay API base request object with properties used in all requests.
     *
     * @return Google Pay API base request object.
     * @throws JSONException
     */
    private val baseRequest = JSONObject().apply {
        put("apiVersion", 2)
        put("apiVersionMinor", 0)
    }

    /**
     * Gateway Integration: Identify your gateway and your app's gateway merchant identifier.
     *
     *
     * The Google Pay API response will return an encrypted payment method capable of being charged
     * by a supported gateway after payer authorization.
     *
     *
     * TODO: Check with your gateway on the parameters to pass and modify them in Constants.java.
     *
     * @return Payment data tokenization for the CARD payment method.
     * @throws JSONException
     * @see [PaymentMethodTokenizationSpecification](https://developers.google.com/pay/api/android/reference/object.PaymentMethodTokenizationSpecification)
     */
    private fun gatewayTokenizationSpecification(): JSONObject {
        return JSONObject().apply {
            put("type", "PAYMENT_GATEWAY")
            put("parameters", JSONObject(Constants.PAYMENT_GATEWAY_TOKENIZATION_PARAMETERS))
        }
    }

    /**
     * `DIRECT` Integration: Decrypt a response directly on your servers. This configuration has
     * additional data security requirements from Google and additional PCI DSS compliance complexity.
     *
     *
     * Please refer to the documentation for more information about `DIRECT` integration. The
     * type of integration you use depends on your payment processor.
     *
     * @return Payment data tokenization for the CARD payment method.
     * @throws JSONException
     * @see [PaymentMethodTokenizationSpecification](https://developers.google.com/pay/api/android/reference/object.PaymentMethodTokenizationSpecification)
     */
    private fun directTokenizationSpecification(): JSONObject {
        if (Constants.DIRECT_TOKENIZATION_PUBLIC_KEY == "REPLACE_ME" ||
                (Constants.DIRECT_TOKENIZATION_PARAMETERS.isEmpty() ||
                 Constants.DIRECT_TOKENIZATION_PUBLIC_KEY.isEmpty())) {

            throw RuntimeException(
                    "Please edit the Constants.java file to add protocol version & public key.")
        }

        return JSONObject().apply {
            put("type", "DIRECT")
            put("parameters", JSONObject(Constants.DIRECT_TOKENIZATION_PARAMETERS))
        }
    }

    /**
     * Card networks supported by your app and your gateway.
     *
     *
     * TODO: Confirm card networks supported by your app and gateway & update in Constants.java.
     *
     * @return Allowed card networks
     * @see [CardParameters](https://developers.google.com/pay/api/android/reference/object.CardParameters)
     */
    private val allowedCardNetworks = JSONArray(Constants.SUPPORTED_NETWORKS)

    /**
     * Card authentication methods supported by your app and your gateway.
     *
     *
     * TODO: Confirm your processor supports Android device tokens on your supported card networks
     * and make updates in Constants.java.
     *
     * @return Allowed card authentication methods.
     * @see [CardParameters](https://developers.google.com/pay/api/android/reference/object.CardParameters)
     */
    private val allowedCardAuthMethods = JSONArray(Constants.SUPPORTED_METHODS)

    /**
     * Describe your app's support for the CARD payment method.
     *
     *
     * The provided properties are applicable to both an IsReadyToPayRequest and a
     * PaymentDataRequest.
     *
     * @return A CARD PaymentMethod object describing accepted cards.
     * @throws JSONException
     * @see [PaymentMethod](https://developers.google.com/pay/api/android/reference/object.PaymentMethod)
     */
    // Optionally, you can add billing address/phone number associated with a CARD payment method.
    private fun baseCardPaymentMethod(): JSONObject {
        return JSONObject().apply {

            val parameters = JSONObject().apply {
                put("allowedAuthMethods", allowedCardAuthMethods)
                put("allowedCardNetworks", allowedCardNetworks)
                put("billingAddressRequired", true)
                put("billingAddressParameters", JSONObject().apply {
                    put("format", "FULL")
                })
            }

            put("type", "CARD")
            put("parameters", parameters)
        }
    }

    /**
     * Describe the expected returned payment data for the CARD payment method
     *
     * @return A CARD PaymentMethod describing accepted cards and optional fields.
     * @throws JSONException
     * @see [PaymentMethod](https://developers.google.com/pay/api/android/reference/object.PaymentMethod)
     */
    private fun cardPaymentMethod(): JSONObject {
        val cardPaymentMethod = baseCardPaymentMethod()
        cardPaymentMethod.put("tokenizationSpecification", gatewayTokenizationSpecification())

        return cardPaymentMethod
    }

    /**
     * An object describing accepted forms of payment by your app, used to determine a viewer's
     * readiness to pay.
     *
     * @return API version and payment methods supported by the app.
     * @see [IsReadyToPayRequest](https://developers.google.com/pay/api/android/reference/object.IsReadyToPayRequest)
     */
    fun isReadyToPayRequest(): JSONObject? {
        return try {
            baseRequest.apply {
                put("allowedPaymentMethods", JSONArray().put(baseCardPaymentMethod()))
            }

        } catch (e: JSONException) {
            null
        }
    }

    /**
     * Information about the merchant requesting payment information
     *
     * @return Information about the merchant.
     * @throws JSONException
     * @see [MerchantInfo](https://developers.google.com/pay/api/android/reference/object.MerchantInfo)
     */
    private val merchantInfo: JSONObject =
            JSONObject().put("merchantName", "Example Merchant")

    /**
     * Creates an instance of [PaymentsClient] for use in an [Activity] using the
     * environment and theme set in [Constants].
     *
     * @param activity is the caller's activity.
     */
    fun createPaymentsClient(activity: Activity): PaymentsClient {
        val walletOptions = Wallet.WalletOptions.Builder()
                .setEnvironment(Constants.PAYMENTS_ENVIRONMENT)
                .build()

        return Wallet.getPaymentsClient(activity, walletOptions)
    }

    /**
     * Provide Google Pay API with a payment amount, currency, and amount status.
     *
     * @return information about the requested payment.
     * @throws JSONException
     * @see [TransactionInfo](https://developers.google.com/pay/api/android/reference/object.TransactionInfo)
     */
    @Throws(JSONException::class)
    private fun getTransactionInfo(price: String): JSONObject {
        return JSONObject().apply {
            put("totalPrice", price)
            put("totalPriceStatus", "FINAL")
            put("countryCode", Constants.COUNTRY_CODE)
            put("currencyCode", Constants.CURRENCY_CODE)
        }
    }

    /**
     * An object describing information requested in a Google Pay payment sheet
     *
     * @return Payment data expected by your app.
     * @see [PaymentDataRequest](https://developers.google.com/pay/api/android/reference/object.PaymentDataRequest)
     */
    fun getPaymentDataRequest(priceCemts: Long): JSONObject? {
        return try {
            baseRequest.apply {
                put("allowedPaymentMethods", JSONArray().put(cardPaymentMethod()))
                put("transactionInfo", getTransactionInfo(priceCemts.centsToString()))
                put("merchantInfo", merchantInfo)

                // An optional shipping address requirement is a top-level property of the
                // PaymentDataRequest JSON object.
                val shippingAddressParameters = JSONObject().apply {
                    put("phoneNumberRequired", false)
                    put("allowedCountryCodes", JSONArray(listOf("US", "GB")))
                }
                put("shippingAddressParameters", shippingAddressParameters)
                put("shippingAddressRequired", true)
            }
        } catch (e: JSONException) {
            null
        }
    }
}

/**
 * Converts cents to a string format accepted by [PaymentsUtil.getPaymentDataRequest].
 *
 * @param cents value of the price.
 */
fun Long.centsToString() = BigDecimal(this)
        .divide(PaymentsUtil.CENTS)
        .setScale(2, RoundingMode.HALF_EVEN)
        .toString()

    

CheckoutActivity.java (Java)

範例 Activity 假設你的版面配置中含有 id 屬性為 googlepay_button 的 Google Pay 付款按鈕。

/*
 * Copyright 2020 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.android.gms.samples.wallet.activity;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.text.Html;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

import com.google.android.gms.common.api.Status;
import com.google.android.gms.samples.wallet.databinding.ActivityCheckoutBinding;
import com.google.android.gms.samples.wallet.util.PaymentsUtil;
import com.google.android.gms.samples.wallet.R;
import com.google.android.gms.samples.wallet.util.Json;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.android.gms.wallet.AutoResolveHelper;
import com.google.android.gms.wallet.IsReadyToPayRequest;
import com.google.android.gms.wallet.PaymentData;
import com.google.android.gms.wallet.PaymentDataRequest;
import com.google.android.gms.wallet.PaymentsClient;

import java.util.Locale;
import java.util.Optional;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

/**
 * Checkout implementation for the app
 */
public class CheckoutActivity extends AppCompatActivity {

  // Arbitrarily-picked constant integer you define to track a request for payment data activity.
  private static final int LOAD_PAYMENT_DATA_REQUEST_CODE = 991;

  private static final long SHIPPING_COST_CENTS = 90 * PaymentsUtil.CENTS_IN_A_UNIT.longValue();

  // A client for interacting with the Google Pay API.
  private PaymentsClient paymentsClient;

  private ActivityCheckoutBinding layoutBinding;
  private View googlePayButton;

  private JSONArray garmentList;
  private JSONObject selectedGarment;

  /**
   * Initialize the Google Pay API on creation of the activity
   *
   * @see Activity#onCreate(android.os.Bundle)
   */
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    initializeUi();

    // Set up the mock information for our item in the UI.
    try {
      selectedGarment = fetchRandomGarment();
      displayGarment(selectedGarment);
    } catch (JSONException e) {
      throw new RuntimeException("The list of garments cannot be loaded");
    }

    // Initialize a Google Pay API client for an environment suitable for testing.
    // It's recommended to create the PaymentsClient object inside of the onCreate method.
    paymentsClient = PaymentsUtil.createPaymentsClient(this);
    possiblyShowGooglePayButton();
  }

  /**
   * Handle a resolved activity from the Google Pay payment sheet.
   *
   * @param requestCode Request code originally supplied to AutoResolveHelper in requestPayment().
   * @param resultCode  Result code returned by the Google Pay API.
   * @param data        Intent from the Google Pay API containing payment or error data.
   * @see <a href="https://developer.android.com/training/basics/intents/result">Getting a result
   * from an Activity</a>
   */
  @Override
  public void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
      // value passed in AutoResolveHelper
      case LOAD_PAYMENT_DATA_REQUEST_CODE:
        switch (resultCode) {

          case Activity.RESULT_OK:
            PaymentData paymentData = PaymentData.getFromIntent(data);
            handlePaymentSuccess(paymentData);
            break;

          case Activity.RESULT_CANCELED:
            // The user cancelled the payment attempt
            break;

          case AutoResolveHelper.RESULT_ERROR:
            Status status = AutoResolveHelper.getStatusFromIntent(data);
            handleError(status.getStatusCode());
            break;
        }

        // Re-enables the Google Pay payment button.
        googlePayButton.setClickable(true);
    }
  }

  private void initializeUi() {

    // Use view binding to access the UI elements
    layoutBinding = ActivityCheckoutBinding.inflate(getLayoutInflater());
    setContentView(layoutBinding.getRoot());

    // The Google Pay button is a layout file – take the root view
    googlePayButton = layoutBinding.googlePayButton.getRoot();
    googlePayButton.setOnClickListener(
        new View.OnClickListener() {
          @Override
          public void onClick(View view) {
            requestPayment(view);
          }
        });
  }

  private void displayGarment(JSONObject garment) throws JSONException {
    layoutBinding.detailTitle.setText(garment.getString("title"));
    layoutBinding.detailPrice.setText(
        String.format(Locale.getDefault(), "$%.2f", garment.getDouble("price")));

    final String escapedHtmlText = Html.fromHtml(
        garment.getString("description"), Html.FROM_HTML_MODE_COMPACT).toString();
    layoutBinding.detailDescription.setText(Html.fromHtml(
        escapedHtmlText, Html.FROM_HTML_MODE_COMPACT));

    final String imageUri = String.format("@drawable/%s", garment.getString("image"));
    final int imageResource = getResources().getIdentifier(imageUri, null, getPackageName());
    layoutBinding.detailImage.setImageResource(imageResource);
  }

  /**
   * Determine the viewer's ability to pay with a payment method supported by your app and display a
   * Google Pay payment button.
   *
   * @see <a href="https://developers.google.com/android/reference/com/google/android/gms/wallet/
   * PaymentsClient.html#isReadyToPay(com.google.android.gms.wallet.
   * IsReadyToPayRequest)">PaymentsClient#IsReadyToPay</a>
   */
  private void possiblyShowGooglePayButton() {

    final Optional<JSONObject> isReadyToPayJson = PaymentsUtil.getIsReadyToPayRequest();
    if (!isReadyToPayJson.isPresent()) {
      return;
    }

    // The call to isReadyToPay is asynchronous and returns a Task. We need to provide an
    // OnCompleteListener to be triggered when the result of the call is known.
    IsReadyToPayRequest request = IsReadyToPayRequest.fromJson(isReadyToPayJson.get().toString());
    Task<Boolean> task = paymentsClient.isReadyToPay(request);
    task.addOnCompleteListener(this,
        new OnCompleteListener<Boolean>() {
          @Override
          public void onComplete(@NonNull Task<Boolean> task) {
            if (task.isSuccessful()) {
              setGooglePayAvailable(task.getResult());
            } else {
              Log.w("isReadyToPay failed", task.getException());
            }
          }
        });
  }

  /**
   * If isReadyToPay returned {@code true}, show the button and hide the "checking" text. Otherwise,
   * notify the user that Google Pay is not available. Please adjust to fit in with your current
   * user flow. You are not required to explicitly let the user know if isReadyToPay returns {@code
   * false}.
   *
   * @param available isReadyToPay API response.
   */
  private void setGooglePayAvailable(boolean available) {
    if (available) {
      googlePayButton.setVisibility(View.VISIBLE);
    } else {
      Toast.makeText(this, R.string.googlepay_status_unavailable, Toast.LENGTH_LONG).show();
    }
  }

  /**
   * PaymentData response object contains the payment information, as well as any additional
   * requested information, such as billing and shipping address.
   *
   * @param paymentData A response object returned by Google after a payer approves payment.
   * @see <a href="https://developers.google.com/pay/api/android/reference/
   * object#PaymentData">PaymentData</a>
   */
  private void handlePaymentSuccess(PaymentData paymentData) {

    // Token will be null if PaymentDataRequest was not constructed using fromJson(String).
    final String paymentInfo = paymentData.toJson();
    if (paymentInfo == null) {
      return;
    }

    try {
      JSONObject paymentMethodData = new JSONObject(paymentInfo).getJSONObject("paymentMethodData");
      // If the gateway is set to "example", no payment information is returned - instead, the
      // token will only consist of "examplePaymentMethodToken".

      final JSONObject tokenizationData = paymentMethodData.getJSONObject("tokenizationData");
      final String token = tokenizationData.getString("token");
      final JSONObject info = paymentMethodData.getJSONObject("info");
      final String billingName = info.getJSONObject("billingAddress").getString("name");
      Toast.makeText(
          this, getString(R.string.payments_show_name, billingName),
          Toast.LENGTH_LONG).show();

      // Logging token string.
      Log.d("Google Pay token: ", token);

    } catch (JSONException e) {
      throw new RuntimeException("The selected garment cannot be parsed from the list of elements");
    }
  }

  /**
   * At this stage, the user has already seen a popup informing them an error occurred. Normally,
   * only logging is required.
   *
   * @param statusCode will hold the value of any constant from CommonStatusCode or one of the
   *                   WalletConstants.ERROR_CODE_* constants.
   * @see <a href="https://developers.google.com/android/reference/com/google/android/gms/wallet/
   * WalletConstants#constant-summary">Wallet Constants Library</a>
   */
  private void handleError(int statusCode) {
    Log.e("loadPaymentData failed", String.format("Error code: %d", statusCode));
  }

  public void requestPayment(View view) {

    // Disables the button to prevent multiple clicks.
    googlePayButton.setClickable(false);

    // The price provided to the API should include taxes and shipping.
    // This price is not displayed to the user.
    try {
      double garmentPrice = selectedGarment.getDouble("price");
      long garmentPriceCents = Math.round(garmentPrice * PaymentsUtil.CENTS_IN_A_UNIT.longValue());
      long priceCents = garmentPriceCents + SHIPPING_COST_CENTS;

      Optional<JSONObject> paymentDataRequestJson = PaymentsUtil.getPaymentDataRequest(priceCents);
      if (!paymentDataRequestJson.isPresent()) {
        return;
      }

      PaymentDataRequest request =
          PaymentDataRequest.fromJson(paymentDataRequestJson.get().toString());

      // Since loadPaymentData may show the UI asking the user to select a payment method, we use
      // AutoResolveHelper to wait for the user interacting with it. Once completed,
      // onActivityResult will be called with the result.
      if (request != null) {
        AutoResolveHelper.resolveTask(
            paymentsClient.loadPaymentData(request),
            this, LOAD_PAYMENT_DATA_REQUEST_CODE);
      }

    } catch (JSONException e) {
      throw new RuntimeException("The price cannot be deserialized from the JSON object.");
    }
  }

  private JSONObject fetchRandomGarment() {

    // Only load the list of items if it has not been loaded before
    if (garmentList == null) {
      garmentList = Json.readFromResources(this, R.raw.tshirts);
    }

    // Take a random element from the list
    int randomIndex = Math.toIntExact(Math.round(Math.random() * (garmentList.length() - 1)));
    try {
      return garmentList.getJSONObject(randomIndex);
    } catch (JSONException e) {
      throw new RuntimeException("The index specified is out of bounds.");
    }
  }
}

PaymentsUtil.java (Java)

這個範例檔案會建構適合建立 IsReadyToPayRequestPaymentDataRequest 的 JSON 物件。

/*
 * Copyright 2020 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.android.gms.samples.wallet.util;

import android.app.Activity;

import com.google.android.gms.samples.wallet.Constants;
import com.google.android.gms.wallet.PaymentsClient;
import com.google.android.gms.wallet.Wallet;

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Optional;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * Contains helper static methods for dealing with the Payments API.
 *
 * <p>Many of the parameters used in the code are optional and are set here merely to call out their
 * existence. Please consult the documentation to learn more and feel free to remove ones not
 * relevant to your implementation.
 */
public class PaymentsUtil {

  public static final BigDecimal CENTS_IN_A_UNIT = new BigDecimal(100d);

  /**
   * Create a Google Pay API base request object with properties used in all requests.
   *
   * @return Google Pay API base request object.
   * @throws JSONException
   */
  private static JSONObject getBaseRequest() throws JSONException {
    return new JSONObject().put("apiVersion", 2).put("apiVersionMinor", 0);
  }

  /**
   * Creates an instance of {@link PaymentsClient} for use in an {@link Activity} using the
   * environment and theme set in {@link Constants}.
   *
   * @param activity is the caller's activity.
   */
  public static PaymentsClient createPaymentsClient(Activity activity) {
    Wallet.WalletOptions walletOptions =
        new Wallet.WalletOptions.Builder().setEnvironment(Constants.PAYMENTS_ENVIRONMENT).build();
    return Wallet.getPaymentsClient(activity, walletOptions);
  }

  /**
   * Gateway Integration: Identify your gateway and your app's gateway merchant identifier.
   *
   * <p>The Google Pay API response will return an encrypted payment method capable of being charged
   * by a supported gateway after payer authorization.
   *
   * <p>TODO: Check with your gateway on the parameters to pass and modify them in Constants.java.
   *
   * @return Payment data tokenization for the CARD payment method.
   * @throws JSONException
   * @see <a href=
   * "https://developers.google.com/pay/api/android/reference/object#PaymentMethodTokenizationSpecification">PaymentMethodTokenizationSpecification</a>
   */
  private static JSONObject getGatewayTokenizationSpecification() throws JSONException {
    return new JSONObject() {{
      put("type", "PAYMENT_GATEWAY");
      put("parameters", new JSONObject() {{
        put("gateway", "example");
        put("gatewayMerchantId", "exampleGatewayMerchantId");
      }});
    }};
  }

  /**
   * {@code DIRECT} Integration: Decrypt a response directly on your servers. This configuration has
   * additional data security requirements from Google and additional PCI DSS compliance complexity.
   *
   * <p>Please refer to the documentation for more information about {@code DIRECT} integration. The
   * type of integration you use depends on your payment processor.
   *
   * @return Payment data tokenization for the CARD payment method.
   * @throws JSONException
   * @see <a
   * href="https://developers.google.com/pay/api/android/reference/object#PaymentMethodTokenizationSpecification">PaymentMethodTokenizationSpecification</a>
   */
  private static JSONObject getDirectTokenizationSpecification()
      throws JSONException, RuntimeException {
    if (Constants.DIRECT_TOKENIZATION_PARAMETERS.isEmpty()
        || Constants.DIRECT_TOKENIZATION_PUBLIC_KEY.isEmpty()
        || Constants.DIRECT_TOKENIZATION_PUBLIC_KEY == null
        || Constants.DIRECT_TOKENIZATION_PUBLIC_KEY == "REPLACE_ME") {
      throw new RuntimeException(
          "Please edit the Constants.java file to add protocol version & public key.");
    }
    JSONObject tokenizationSpecification = new JSONObject();

    tokenizationSpecification.put("type", "DIRECT");
    JSONObject parameters = new JSONObject(Constants.DIRECT_TOKENIZATION_PARAMETERS);
    tokenizationSpecification.put("parameters", parameters);

    return tokenizationSpecification;
  }

  /**
   * Card networks supported by your app and your gateway.
   *
   * <p>TODO: Confirm card networks supported by your app and gateway & update in Constants.java.
   *
   * @return Allowed card networks
   * @see <a
   * href="https://developers.google.com/pay/api/android/reference/object#CardParameters">CardParameters</a>
   */
  private static JSONArray getAllowedCardNetworks() {
    return new JSONArray(Constants.SUPPORTED_NETWORKS);
  }

  /**
   * Card authentication methods supported by your app and your gateway.
   *
   * <p>TODO: Confirm your processor supports Android device tokens on your supported card networks
   * and make updates in Constants.java.
   *
   * @return Allowed card authentication methods.
   * @see <a
   * href="https://developers.google.com/pay/api/android/reference/object#CardParameters">CardParameters</a>
   */
  private static JSONArray getAllowedCardAuthMethods() {
    return new JSONArray(Constants.SUPPORTED_METHODS);
  }

  /**
   * Describe your app's support for the CARD payment method.
   *
   * <p>The provided properties are applicable to both an IsReadyToPayRequest and a
   * PaymentDataRequest.
   *
   * @return A CARD PaymentMethod object describing accepted cards.
   * @throws JSONException
   * @see <a
   * href="https://developers.google.com/pay/api/android/reference/object#PaymentMethod">PaymentMethod</a>
   */
  private static JSONObject getBaseCardPaymentMethod() throws JSONException {
    JSONObject cardPaymentMethod = new JSONObject();
    cardPaymentMethod.put("type", "CARD");

    JSONObject parameters = new JSONObject();
    parameters.put("allowedAuthMethods", getAllowedCardAuthMethods());
    parameters.put("allowedCardNetworks", getAllowedCardNetworks());
    // Optionally, you can add billing address/phone number associated with a CARD payment method.
    parameters.put("billingAddressRequired", true);

    JSONObject billingAddressParameters = new JSONObject();
    billingAddressParameters.put("format", "FULL");

    parameters.put("billingAddressParameters", billingAddressParameters);

    cardPaymentMethod.put("parameters", parameters);

    return cardPaymentMethod;
  }

  /**
   * Describe the expected returned payment data for the CARD payment method
   *
   * @return A CARD PaymentMethod describing accepted cards and optional fields.
   * @throws JSONException
   * @see <a
   * href="https://developers.google.com/pay/api/android/reference/object#PaymentMethod">PaymentMethod</a>
   */
  private static JSONObject getCardPaymentMethod() throws JSONException {
    JSONObject cardPaymentMethod = getBaseCardPaymentMethod();
    cardPaymentMethod.put("tokenizationSpecification", getGatewayTokenizationSpecification());

    return cardPaymentMethod;
  }

  /**
   * An object describing accepted forms of payment by your app, used to determine a viewer's
   * readiness to pay.
   *
   * @return API version and payment methods supported by the app.
   * @see <a
   * href="https://developers.google.com/pay/api/android/reference/object#IsReadyToPayRequest">IsReadyToPayRequest</a>
   */
  public static Optional<JSONObject> getIsReadyToPayRequest() {
    try {
      JSONObject isReadyToPayRequest = getBaseRequest();
      isReadyToPayRequest.put(
          "allowedPaymentMethods", new JSONArray().put(getBaseCardPaymentMethod()));

      return Optional.of(isReadyToPayRequest);

    } catch (JSONException e) {
      return Optional.empty();
    }
  }

  /**
   * Provide Google Pay API with a payment amount, currency, and amount status.
   *
   * @return information about the requested payment.
   * @throws JSONException
   * @see <a
   * href="https://developers.google.com/pay/api/android/reference/object#TransactionInfo">TransactionInfo</a>
   */
  private static JSONObject getTransactionInfo(String price) throws JSONException {
    JSONObject transactionInfo = new JSONObject();
    transactionInfo.put("totalPrice", price);
    transactionInfo.put("totalPriceStatus", "FINAL");
    transactionInfo.put("countryCode", Constants.COUNTRY_CODE);
    transactionInfo.put("currencyCode", Constants.CURRENCY_CODE);
    transactionInfo.put("checkoutOption", "COMPLETE_IMMEDIATE_PURCHASE");

    return transactionInfo;
  }

  /**
   * Information about the merchant requesting payment information
   *
   * @return Information about the merchant.
   * @throws JSONException
   * @see <a
   * href="https://developers.google.com/pay/api/android/reference/object#MerchantInfo">MerchantInfo</a>
   */
  private static JSONObject getMerchantInfo() throws JSONException {
    return new JSONObject().put("merchantName", "Example Merchant");
  }

  /**
   * An object describing information requested in a Google Pay payment sheet
   *
   * @return Payment data expected by your app.
   * @see <a
   * href="https://developers.google.com/pay/api/android/reference/object#PaymentDataRequest">PaymentDataRequest</a>
   */
  public static Optional<JSONObject> getPaymentDataRequest(long priceCents) {

    final String price = PaymentsUtil.centsToString(priceCents);

    try {
      JSONObject paymentDataRequest = PaymentsUtil.getBaseRequest();
      paymentDataRequest.put(
          "allowedPaymentMethods", new JSONArray().put(PaymentsUtil.getCardPaymentMethod()));
      paymentDataRequest.put("transactionInfo", PaymentsUtil.getTransactionInfo(price));
      paymentDataRequest.put("merchantInfo", PaymentsUtil.getMerchantInfo());

      /* An optional shipping address requirement is a top-level property of the PaymentDataRequest
      JSON object. */
      paymentDataRequest.put("shippingAddressRequired", true);

      JSONObject shippingAddressParameters = new JSONObject();
      shippingAddressParameters.put("phoneNumberRequired", false);

      JSONArray allowedCountryCodes = new JSONArray(Constants.SHIPPING_SUPPORTED_COUNTRIES);

      shippingAddressParameters.put("allowedCountryCodes", allowedCountryCodes);
      paymentDataRequest.put("shippingAddressParameters", shippingAddressParameters);
      return Optional.of(paymentDataRequest);

    } catch (JSONException e) {
      return Optional.empty();
    }
  }

  /**
   * Converts cents to a string format accepted by {@link PaymentsUtil#getPaymentDataRequest}.
   *
   * @param cents value of the price in cents.
   */
  public static String centsToString(long cents) {
    return new BigDecimal(cents)
        .divide(CENTS_IN_A_UNIT, RoundingMode.HALF_EVEN)
        .setScale(2, RoundingMode.HALF_EVEN)
        .toString();
  }
}