queryPurchases（）方法未显示android.test.purchased已拥有

Question

我想在我的应用程序中添加一个简单的非消费产品。按照此 billing_library_overview和此billing_testing指令中，我决定从保留的产品ID android.test.purchased开始。我收到“付款成功”消息，但是当我在queryPurchases()方法中调用android.test.purchased方法时，它似乎只有一次返回了onResume()的购买清单。此后每次调用queryPurchases()时，我都会拥有purchasesResult.getPurchasesList（）等于null。

这是代码的重要组成部分：

public class MySettings extends PreferenceActivity
        implements SharedPreferences.OnSharedPreferenceChangeListener, PurchasesUpdatedListener {

    private BillingClient mBillingClient;
    private Boolean bought = false;
    private String product_id = "android.test.purchased";

    @Override
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        mBillingClient = BillingClient.newBuilder(this).setListener(this).build();
        mBillingClient.startConnection(new BillingClientStateListener() {
            @Override
            public void onBillingSetupFinished(@BillingClient.BillingResponse int billingResponseCode) {
        if (billingResponseCode == BillingClient.BillingResponse.OK) {
                    List<String> skuList = new ArrayList<>();
                    skuList.add("android.test.purchased");      //I know it is not necessary
                    SkuDetailsParams.Builder params = SkuDetailsParams.newBuilder();
                    params.setSkusList(skuList).setType(BillingClient.SkuType.INAPP);
                    mBillingClient.querySkuDetailsAsync(params.build(),
                            new SkuDetailsResponseListener() {
                                @Override
                                public void onSkuDetailsResponse(int responseCode, List<SkuDetails> skuDetailsList) {
                                        if (responseCode == BillingClient.BillingResponse.OK
                                                && skuDetailsList != null) {
                                            for (SkuDetails skuDetails : skuDetailsList) {
                                            }
                                        }
                                }
                            });
                }   
            }
            @Override
            public void onBillingServiceDisconnected() {
            }
        });

        checkPurchase();
        createPreferenceScreen();
    }

    @Override
    protected void onResume(){
        checkPurchase();
        createPreferenceScreen();
        super.onResume();
    }

    @Override
    public void onPurchasesUpdated(int responseCode, @Nullable List<Purchase> purchases) {
        if (responseCode == BillingClient.BillingResponse.OK) {
        }
        else {
        }
    }

    private void checkPurchase(){
        Purchase.PurchasesResult purchasesResult = mBillingClient.queryPurchases(BillingClient.SkuType.INAPP);
        if (purchasesResult.getPurchasesList() != null) {
            for (Purchase purchase : purchasesResult.getPurchasesList()){
                if (product_id.equals(purchase.getSku())) {
                    bought = true;
                }
            }
        }
    }

    ...
}

在我的createPreferenceScreen()方法中，我检查Boolean bought是对还是错。如何在不使用自己的后端服务器的情况下恢复已购买的android.test.purchased？

编辑：我听不懂，但是当我将应用内结算逻辑移至主要活动时，它开始起作用。