Google Play 支付文档：https://developer.android.com/google/play/billing/integrate
Google Play 支付库已经升级到5.0了，相对之前的版本有不少的变化，现在记录下！
接入Google Play 流程还是和之前一样：
1.去Google console 申请开发者账号 https://play.google.com/console/
2.创建项目，上传APK
3.去Google console项目后台开始设置商品：点击左侧Products—->In-app products(内购商品)或者Subscription(订阅商品)
4.等Google Pay Console 后台创建好商品后，客户端和后端就可以开始集成了：
4.1：将 Google Play 结算库依赖项添加到应用的
dependencies {val billing_version = "5.0.0"implementation("com.android.billingclient:billing:$billing_version")
}4.2：初始化支付SDK(也就是初始化BillingClient):支付过程中BillingClient用的比较多，一般项目中只创建一个BillingClient
private BillingClient billingClient = BillingClient.newBuilder(context).setListener(purchasesUpdatedListener).enablePendingPurchases().build();初始化的时候需要一个：PurchasesUpdatedListener，PurchasesUpdatedListener是监听应用中所有购买交易的更新，这个listener非常重要，当用户购买或者订阅后都会走这个回调
private PurchasesUpdatedListener purchasesUpdatedListener = new PurchasesUpdatedListener() {@Overridepublic void onPurchasesUpdated(BillingResult billingResult, List<Purchase> purchases) {// To be implemented in a later section.}
};4.3初始化SDK后，需要与 Google Play 建立连接，使用startConnection()方法，startConnection是异步进行，这个时候需要一个BillingClientStateListener进行回调连接的结果，当连接完成会走onBillingSetupFinished()回调，通过返回的billingResult.getResponseCode()去判断是否真正的链接成功，这个code 有下面几个值，这个BillingClientStateListener还有一个Google Play 失去连接的回调，这个时候我们需要实现重试逻辑，就是再次调用startConnection()函数。
@Retention(RetentionPolicy.SOURCE)public @interface BillingResponseCode {int SERVICE_TIMEOUT = -3;int FEATURE_NOT_SUPPORTED = -2;int SERVICE_DISCONNECTED = -1;int OK = 0;int USER_CANCELED = 1;int SERVICE_UNAVAILABLE = 2;int BILLING_UNAVAILABLE = 3;int ITEM_UNAVAILABLE = 4;int DEVELOPER_ERROR = 5;int ERROR = 6;int ITEM_ALREADY_OWNED = 7;int ITEM_NOT_OWNED = 8;} public void startConnection() {mBillingClient.startConnection(new BillingClientStateListener() {@Overridepublic void onBillingSetupFinished(BillingResult billingResult) {if (billingResult.getResponseCode() == BillingClient.BillingResponseCode.OK) {// The BillingClient is ready. You can query purchases here.queryProductDetailsParams();queryOldOrder();}}@Overridepublic void onBillingServiceDisconnected() {// Try to restart the connection on the next request to// Google Play by calling the startConnection() method.}});}4.4 获取商品
当startConnection()回调成功时，这个时候我们就可以根据ProductId去Google Play获取具体的商品了，这个时候一般会通过API去自己的Server 获取一个ProductIdList，然后根据后台返回的productId去Google Play 获取商品详情。
查询内购的商品：
List<String> skuList = new ArrayList<>();skuList.add("ProductId01");skuList.add("ProductId02");skuList.add("ProductId03");skuList.add("ProductId04");SkuDetailsParams.Builder params = SkuDetailsParams.newBuilder();params.setSkusList(skuList).setType(BillingClient.SkuType.INAPP);mBillingClient.querySkuDetailsAsync(params.build(), new SkuDetailsResponseListener() {@Overridepublic void onSkuDetailsResponse(BillingResult billingResult, List<SkuDetails> skuDetailsList) {// Process the result.Log.i(TAG, "querySkuDetailsAsync 1 onSkuDetailsResponse billingResult.getResponseCode : " + billingResult.getResponseCode() + " skuDetailsList :" + skuDetailsList);mInAppSkuDetailsHashMap.clear();if (skuDetailsList != null && skuDetailsList.size() > 0) {for (SkuDetails skuDetails : skuDetailsList) {mInAppSkuDetailsHashMap.put(skuDetails.getSku(), skuDetails);}}}});查询订阅的商品：
// The BillingClient is ready. You can query purchases here.List<String> subscribeSkuList = new ArrayList<>();subscribeSkuList.add("Subscribe01");subscribeSkuList.add("Subscribe01");subscribeSkuList.add("Subscribe01");SkuDetailsParams.Builder subscribeParams = SkuDetailsParams.newBuilder();subscribeParams.setSkusList(subscribeSkuList).setType(BillingClient.SkuType.SUBS);mBillingClient.querySkuDetailsAsync(subscribeParams.build(), new SkuDetailsResponseListener() {@Overridepublic void onSkuDetailsResponse(BillingResult billingResult, List<SkuDetails> skuDetailsList) {// Process the result.Log.i(TAG, "querySkuDetailsAsync 2 onSkuDetailsResponse billingResult.getResponseCode : " + billingResult.getResponseCode() + " skuDetailsList :" + skuDetailsList);mSubscribeSkuDetailsHashMap.clear();if (skuDetailsList != null && skuDetailsList.size() > 0) {for (SkuDetails skuDetails : skuDetailsList) {mSubscribeSkuDetailsHashMap.put(skuDetails.getSku(), skuDetails);}}}});当商品查询成功后就可以结合Server返回的商品信息给用户展示商品列表了
注意：有些 Android 设备安装的可能是旧版 Google Play 商店应用，不支持订阅等某些商品类型。在您的应用进入结算流程之前，您可以调用 isFeatureSupported() 以确定设备是否支持您要销售的商品。如需查看可支持的商品类型的列表，请参阅 BillingClient.FeatureType。
4.5.启动购买流程(开始购买)
当用户点击某个商品时，从应用发起购买请求，请从应用的主线程调用 launchBillingFlow() 方法。此方法接受对 BillingFlowParams 对象的引用，该对象包含通过调用 queryProductDetailsAsync() 获取的相关 ProductDetails 对象。如需创建 BillingFlowParams 对象，请使用 BillingFlowParams.Builder 类。
购买内购的商品：
public void buyInAppProduct(SkuDetails skuDetails) {if (skuDetails == null) {return;}BillingFlowParams billingFlowParams = BillingFlowParams.newBuilder().setSkuDetails(skuDetails).build();mBillingClient.launchBillingFlow(ActivityUtils.getTopActivity(), billingFlowParams).getResponseCode();}购买订阅的商品：
public void buySubscribeProduct(SkuDetails skuDetails) {if (skuDetails == null) {return;}BillingFlowParams billingFlowParams = BillingFlowParams.newBuilder().setSkuDetails(skuDetails).build();mBillingClient.launchBillingFlow(ActivityUtils.getTopActivity(), billingFlowParams).getResponseCode();}// An activity reference from which the billing flow will be launched.
Activity activity = ...;ImmutableList productDetailsParamsList =ImmutableList.of(ProductDetailsParams.newBuilder()// retrieve a value for "productDetails" by calling queryProductDetailsAsync().setProductDetails(productDetails)// to get an offer token, call ProductDetails.getSubscriptionOfferDetails()// for a list of offers that are available to the user.setOfferToken(selectedOfferToken).build());BillingFlowParams billingFlowParams = BillingFlowParams.newBuilder().setProductDetailsParamsList(productDetailsParamsList).build();// Launch the billing flow
BillingResult billingResult = billingClient.launchBillingFlow(activity, billingFlowParams);4.6购买成功的回调
在咱们4.2初始化SDK的时候添加了一个PurchasesUpdatedListener，当用户购买成功后Google Play 会调用 onPurchasesUpdated()，我们根据responseCode去区分用户购买成功与否.
如果成功购买商品，系统还会生成一个token，它是一个唯一标识符，表示用户及其所购应用内商品的商品 ID。可以在本地存储token，可以将令牌传递到安全的后端服务器（推荐用该方法）
private PurchasesUpdatedListener purchasesUpdatedListener = new PurchasesUpdatedListener() {@Overridepublic void onPurchasesUpdated(BillingResult billingResult, List<Purchase> purchases) {if (billingResult == null) {return;}int responseCode = billingResult.getResponseCode();switch (responseCode) {case BillingClient.BillingResponseCode.OK:for (Purchase purchase : purchases) {SkuDetails skuDetails = null;String json = purchase.getOriginalJson();if (!TextUtils.isEmpty(json)) {PurchaseData purchaseData = GsonConverter.fromJson(json, PurchaseData.class);if (purchaseData != null) {skuDetails = getSkuDetailsDependProductId(purchaseData.getProductId());}}handlePurchase(purchase, (skuDetails != null && (BillingClient.SkuType.SUBS.equals(skuDetails.getType()))), "onPurchasesUpdated");}break;case BillingClient.BillingResponseCode.USER_CANCELED:Log.i(TAG, "purchasesUpdatedListener 3 user cancel ");break;default:Log.i(TAG, "purchasesUpdatedListener 4 error " + responseCode);break;}}};@Override
void onPurchasesUpdated(BillingResult billingResult, List<Purchase> purchases) {if (billingResult.getResponseCode() == BillingResponseCode.OK&& purchases != null) {for (Purchase purchase : purchases) {handlePurchase(purchase);}} else if (billingResult.getResponseCode() == BillingResponseCode.USER_CANCELED) {// Handle an error caused by a user cancelling the purchase flow.} else {// Handle any other error codes.}
}4.7.处理购买交易(消费订单)
当用户购买成功后，订单必须消费，如果不消费，三天后Google会自动退款，撤销购买交易。
消费内购的商品：
void handlePurchase(Purchase purchase) {// Purchase retrieved from BillingClient#queryPurchasesAsync or your PurchasesUpdatedListener.Purchase purchase = ...;// Verify the purchase.// Ensure entitlement was not already granted for this purchaseToken.// Grant entitlement to the user.ConsumeParams consumeParams =ConsumeParams.newBuilder().setPurchaseToken(purchase.getPurchaseToken()).build();ConsumeResponseListener listener = new ConsumeResponseListener() {@Overridepublic void onConsumeResponse(BillingResult billingResult, String purchaseToken) {if (billingResult.getResponseCode() == BillingResponseCode.OK) {// Handle the success of the consume operation.}}};billingClient.consumeAsync(consumeParams, listener);
}消费订阅商品：订阅的处理方式与非消耗型商品类似。您可以使用 Google Play 结算库中的 BillingClient.acknowledgePurchase() 或 Google Play Developer API 中的 Purchases.Subscriptions.Acknowledge 确认订阅。所有初始订阅购买交易都需要确认。订阅续订不需要确认
BillingClient client = ...
AcknowledgePurchaseResponseListener acknowledgePurchaseResponseListener = ...void handlePurchase(Purchase purchase) {if (purchase.getPurchaseState() == PurchaseState.PURCHASED) {if (!purchase.isAcknowledged()) {AcknowledgePurchaseParams acknowledgePurchaseParams =AcknowledgePurchaseParams.newBuilder().setPurchaseToken(purchase.getPurchaseToken()).build();client.acknowledgePurchase(acknowledgePurchaseParams, acknowledgePurchaseResponseListener);}}
}4.8 查询历史订单，消费待处理的交易
public void queryOldOrder() {mBillingClient.queryPurchasesAsync(BillingClient.SkuType.INAPP, new PurchasesResponseListener() {@Overridepublic void onQueryPurchasesResponse(@NonNull BillingResult billingResult, @NonNull List<Purchase> list) {if (billingResult.getResponseCode() == BillingClient.BillingResponseCode.OK) {onHandlerQueryPurchases(list, false);}}});mBillingClient.queryPurchasesAsync(BillingClient.SkuType.SUBS, new PurchasesResponseListener() {@Overridepublic void onQueryPurchasesResponse(@NonNull BillingResult billingResult, @NonNull List<Purchase> list) {if (billingResult.getResponseCode() == BillingClient.BillingResponseCode.OK) {onHandlerQueryPurchases(list, true);}}});4.9 处理多件购买交易：
Google Play 允许客户在一笔交易中购买多件相同的应用内商品，只需在购物车中指定商品数量即可（4.0 及更高版本的 Google Play 结算库支持该功能）。应用应根据指定购买数量来处理多件购买并授予权利。注意：多件购买适用于消耗型应用内商品，即可以购买、消耗及再次购买的产品。请勿为不支持重复购买的商品启用该功能。
为了实现多件购买，应用的配置逻辑需要检查商品数量。可以从以下 API 访问 quantity 字段：
- Google Play 结算库中的 getQuantity()。
- Google Play Developer API 中的 Purchases.products.quantity。
添加用于处理多件购买的逻辑后，需要在 Google Play 管理中心的应用内商品管理页面上为相应的商品启用多件购买功能。
注意：请确保应用接受多件购买，然后再在 Play 管理中心启用该功能。您能需要强制更新到提供支持的应用版本，然后才能对商品启用该功能。
