You’ll learn how to integrate one of the most used payment gateways, GPay, into your existing Android app. Along with the integration, this article also includes whether the user can pay using GPay and the execution process.

您将学习如何将最常用的支付网关之一GPay集成到现有的Android应用中。 除了集成之外，本文还包括用户是否可以使用GPay进行支付以及执行过程。

为什么选择GPay？ (Why GPay?)

As humans, our tendency to do work is mostly dependent on our ability to do it.

作为人类，我们的工作倾向主要取决于我们的工作能力。

Sure, the customer can pick their card and enter their details, but why not make it a bit easier for the customer by using the payment details that already exist in their mobile, like GPay.

当然，客户可以选择他们的卡并输入他们的详细信息，但是为什么不使用GPay这样的移动设备中已有的付款详细信息来使客户更轻松一些。

Implementing payment gateways like this in your app will increase the chances of the user actually paying.

在您的应用中实现像这样的支付网关将增加用户实际支付的机会。

Almost every Android user, in one way or another, depends on Google for some reason, such as Google Assistant for reminders, Keep for note-taking, and recently, Google Pay for payments.

几乎每个Android用户出于某种原因都依赖Google，例如Google Assistant进行提醒，Keep进行笔记以及最近使用Google Pay进行付款。

积分 (Integration)

Here, we use the Google Pay API to integrate the GPay payment gateway. To integrate this, add the following line under the dependencies node in the app level build.gradle file.

在这里，我们使用Google Pay API集成GPay付款网关。 要集成此功能，请在应用程序级别build.gradle文件中的dependencies节点下添加以下行。

implementation "com.google.android.gms:play-services-wallet:18.0.0"

We need to add the following metadata in the manifest file to enable the API.

我们需要在清单文件中添加以下元数据以启用API。

<meta-data    android:name="com.google.android.gms.wallet.api.enabled"    android:value="true" />

配置Google Pay API (Configure the Google Pay API)

Now that we’re done with the integration part, it’s time to configure the API. To use the API, we have to instantiate a client object, through which we can make calls to the Google Pay API. Have a look:

现在我们已经完成了集成部分，是时候配置API了。 要使用该API，我们必须实例化一个客户端对象，通过该对象我们可以调用Google Pay API。 看一看：

For the development purpose here, I used ENVIRONMENT_TEST, but when you’re ready to roll out to production, you can change the environment to production by changing it to ENVIRONMENT_PRODUCTION.

出于开发目的，我使用了ENVIRONMENT_TEST ，但是当您准备将其投入生产时，可以通过将ENVIRONMENT_PRODUCTION更改为ENVIRONMENT_PRODUCTION来将ENVIRONMENT_PRODUCTION更改为生产ENVIRONMENT_PRODUCTION 。

创建一个请求 (Create a Request)

To create a request, first, we need to create a JSON object, including all the card types and payment authentications that we support. Have a look:

要创建请求，首先，我们需要创建一个JSON对象，包括我们支持的所有卡类型和付款身份验证。 看一看：

You can find a complete list of card parameters you can use to configure the request in the documentation.

您可以在文档中找到可用于配置请求的卡参数的完整列表。

About card authentication mechanisms: When processing payments, cards can be picked as to how the transaction is authenticated against the processor or gateway.

关于卡身份验证机制：处理付款时，可以选择卡以了解如何根据处理器或网关对交易进行身份验证。

While using the primary account number (PAN) authentication, the card account number and expiry month and year are sent to the payment processor. This allows your users to use previously stored cards.

在使用主帐号(PAN)身份验证时，卡帐号以及有效期月和年被发送到付款处理器。 这使您的用户可以使用以前存储的卡。

Dynamic cryptogram based authentication works in combination with card tokenization, a mechanism that replaces your customer’s card information with a random value that no one, other than your customer’s card issuer, can understand.

基于动态密码的身份验证与卡令牌化结合使用，该机制用随机值替换客户的卡信息，而客户的发卡机构则无法理解。

This, in combination with dynamic cryptograms, ensures that the token sent to the processor is always different for every transaction, significantly increasing security in these operations. API docs.

结合动态密码，可以确保发送到处理器的令牌对于每个事务始终是不同的，从而显着提高了这些操作的安全性。 API文档 。

Along with that, we should also specify which API version of Google Pay you’re connecting to. Have a look:

除此之外，我们还应该指定您要连接的Google Pay API版本。 看一看：

Now that we have what we need to create a request, it’s time to create one and verify whether they can pay through the Google Pay API. Have a look:

现在我们有了创建请求所需的内容，是时候创建一个请求并验证他们是否可以通过Google Pay API进行付款了。 看一看：

Here, first, we’re creating an IsReadyToPayRequest, which we use to invokethe isreadyToPay function, which results in a task object.

在这里，首先，我们创建一个IsReadyToPayRequest ，我们将使用它来调用isreadyToPay函数，该函数将生成一个task对象。

Next on the task object, we have to add addOnCompleteListener to check whether the Google Pay API is available or not. Finally, when we get a successful response, we can enable the Google Pay button.

接下来，在task对象上，我们必须添加addOnCompleteListener来检查Google Pay API是否可用。 最后，当我们获得成功的响应时，我们可以启用Google Pay按钮。

现在该付款了 (It’s Time to Pay)

Finally, it’s time to pay. To create a transaction, we need two sets of data, such as transactionInfo and merchantInfo.

最后，该付款了。 要创建交易，我们需要两组数据，例如transactionInfo和merchantInfo 。

交易信息 (TransactionInfo)

This is where we can define details like the amount they have to pay and in which currency. Have a look:

在这里，我们可以定义详细信息，例如必须支付的金额以及使用哪种货币。 看一看：

MerchantInfo (MerchantInfo)

This is where we can define merchant details like their name and merchant ID. Have a look:

在这里，我们可以定义商家详细信息，例如其名称和商家ID。 看一看：

Now, it’s time to combine the payment configuration that we created previously with transactionInfo and merchantInfo. Have a look:

现在，是时候将我们先前创建的付款配置与transactionInfo和merchantInfo结合起来了。 看一看：

Finally, we’ve created a paymentDataRequest by passing the paymentDataRequestJson, then executing the task using the resolveTask function, which has three parameters, Task<TResult>, Activity, and Int as request-id. Have a look:

最后，我们通过传递paymentDataRequestJson创建了一个paymentDataRequest ，然后使用resolveTask函数执行任务，该函数具有三个参数， Task<TResult> ， Activity和Int作为request-id 。 看一看：

Now the user will proceed with the Google Pay transaction, and after completing it, you’ll receive the response of the transaction in onActivityResult. You can handle all success and failure states, as shown below.

现在，用户将继续进行Google Pay交易，完成交易后，您将在onActivityResult收到交易的响应。 您可以处理所有成功和失败状态，如下所示。

Thank you for reading.

感谢您的阅读。