每当用户打开应用程序时，如何检查用户是否购买了应用内购买？

Question

注意：我说的是一次性购买，可以从应用程序中删除广告。

谷歌说你应该打电话BillingClient.queryPurchases()给你onResume()的，onCreate()但我不知道该怎么做。

首先，这是实际应用内购买的代码，我刚刚从 YouTube 教程中获得它，我什至不知道它是否完整：

private void setupBillingClient(Context c) { //connect to google play
    billingClient = BillingClient.newBuilder(c)
            .enablePendingPurchases()
            .setListener(this)
            .build();
    billingClient.startConnection(new BillingClientStateListener() {
        @Override
        public void onBillingSetupFinished(@NonNull BillingResult billingResult) {
            if (billingResult.getResponseCode() == BillingClient.BillingResponseCode.OK) {
                //The BillingClient is setup successfully
                loadAllSkus();
            }
        }

        @Override
        public void onBillingServiceDisconnected() {
            //TODO: implement retry logic to handle lost connections to Google Play by calling startConnection() again
        }
    });
}

private void loadAllSkus() {
    if (billingClient.isReady()) { //first check if BillingClient is ready
        final SkuDetailsParams params = SkuDetailsParams.newBuilder()
                .setSkusList(skuList)
                .setType(BillingClient.SkuType.INAPP)
                .build();

        billingClient.querySkuDetailsAsync(params, new SkuDetailsResponseListener() {
            @Override
            public void onSkuDetailsResponse(@NonNull final BillingResult billingResult, @Nullable List<SkuDetails> skuDetailsList) {
                if (billingResult.getResponseCode() == BillingClient.BillingResponseCode.OK) {
                    assert skuDetailsList != null;
                    for (Object skuDetailsObject : skuDetailsList) {
                        final SkuDetails skuDetails = (SkuDetails) skuDetailsObject;
                        if (skuDetails.getSku().equals(sku)) { //if it found the sku in play store you can start billing flow
                            Purchase.PurchasesResult result = billingClient.queryPurchases(BillingClient.SkuType.INAPP); //use play store cache, no network
                            List<Purchase> purchases = result.getPurchasesList();
                            boolean isOwned = false;
                            if (purchases != null) //first check if he has already purchased
                                for (Purchase purchase : purchases) {
                                    String thisSKU = purchase.getSku();
                                    if (thisSKU.equals(sku)) {
                                        isOwned = true;
                                        Toast.makeText(getContext(), "You are a premium user", Toast.LENGTH_LONG).show();//TODO: Delete this toast
                                        //TODO: Remove purchase options and ads here
                                        break;
                                    }
                                }

                            if (!isOwned) {
                                buyButton.setEnabled(true);
                                buyButton.setOnClickListener(new View.OnClickListener() {
                                    @Override
                                    public void onClick(View v) {
                                        BillingFlowParams billingFlowParams = BillingFlowParams
                                                .newBuilder()
                                                .setSkuDetails(skuDetails)
                                                .build();

                                        if (getActivity() != null)
                                            billingClient.launchBillingFlow(getActivity(), billingFlowParams);
                                        dismiss();
                                    }
                                });
                            }
                        }
                        /* else if (skuDetails.getSku().equals("something else")) { //add other products

                        }*/
                    }
                }
            }
        });
    } else Toast.makeText(getContext(), R.string.billing_not_ready, Toast.LENGTH_LONG).show();
}

@Override
public void onPurchasesUpdated(@NonNull BillingResult billingResult, @Nullable List<com.android.billingclient.api.Purchase> purchases) {
    int responseCode = billingResult.getResponseCode();

    if (responseCode == BillingClient.BillingResponseCode.OK && purchases != null) {
        for (Purchase purchase : purchases) {
            handlePurchase(purchase); //acknowledge the purchase
        }
    } else if (responseCode == BillingClient.BillingResponseCode.ITEM_ALREADY_OWNED) {
        //already owned
    } else if (responseCode == BillingClient.BillingResponseCode.USER_CANCELED) {

    }
}

private void handlePurchase(Purchase purchase) {
    if (purchase.getSku().equals(sku) && purchase.getPurchaseState() == Purchase.PurchaseState.PURCHASED) {
        if (!purchase.isAcknowledged()) {
            AcknowledgePurchaseParams acknowledgePurchaseParams =
                    AcknowledgePurchaseParams.newBuilder()
                            .setPurchaseToken(purchase.getPurchaseToken())
                            .build();
            billingClient.acknowledgePurchase(acknowledgePurchaseParams, new AcknowledgePurchaseResponseListener() {
                @Override
                public void onAcknowledgePurchaseResponse(@NonNull BillingResult billingResult) {
                    if (billingResult.getResponseCode() == BillingClient.BillingResponseCode.OK) {
                        Toast.makeText(getContext(), "Purchase Acknowledged", Toast.LENGTH_LONG).show();//TODO: Delete this maybe?
                    }
                }
            });
        }
        Toast.makeText(getContext(), R.string.purchase_done, Toast.LENGTH_LONG).show();
    }
}

所以显然要调用BillingClient.queryPurchases()我必须在每个活动中重写所有上述代码？

Answer 1

如您所知， BillingClient.queryPurchases()方法返回所有当前拥有的购买项目的列表。

一次又一次地复制相同的代码始终是错误的方法/设计。您需要做的就是封装您的代码并使其尽可能独立于任何 Activity 或任何其他组件，以便可以重用。

要获得更好的方法，请查看 Google 的官方计费示例。您将看到所有计费逻辑都被封装起来，因此可以轻松地重用。

Java： https: //github.com/android/play-billing-samples/tree/main/ClassyTaxiJava

Kotlin：https://github.com/android/play-billing-samples/tree/main/ClassyTaxiAppKotlin

如果您发现示例与订阅有关并且您需要非消耗品，则需要进行一些说明，反之亦然。两者的计费库是相同的，区别只是要查询的数据，例如订阅使用BillingClient.SkuType.SUBS，非消耗品使用BillingClient.SkuType.INAPP。但其余的，如何连接计费、如何确认、启动购买流程等，两者都是完全相同的。没有单独的 API 或不同的实现方式，您使用相同的 API 和相同的实现，只是更改正在查询的内容。