添加恢复购买应用内结算＆＃34; premium＆＃34;

Question

我应该添加什么来恢复购买的＆＃34; premium＆＃34;？我还有一些不应该恢复的元素。我正在使用此https://github.com/googlesamples/android-play-billing/tree/master/TrivialDrive/app/src/main/java/com/example/android/trivialdrivesample/util

PurchaseActivity.class

    public class PurchaseActivity extends AppCompatActivity {
        final String OBJECT_TO_BUY = "this_app_object"; //not restorable
        final String PREMIUM = "this_app_premium"; //to restore
        public IabHelper mHelper;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.purchases);
            String base64EncodedPublicKey = "<my_wonderful_base64encodedpublicKey>";
            mHelper = new IabHelper(this, base64EncodedPublicKey);
            mHelper.startSetup(new IabHelper.OnIabSetupFinishedListener() {
                public void onIabSetupFinished(IabResult result) {}
            });
        }


    public void purchasePremium(View v) {
        mHelper.launchPurchaseFlow(this, PREMIUM, 10001, mPurchaseFinishedListener, "premium");
    }


    public void purchaseObject(View v) {
        mHelper.launchPurchaseFlow(this, OBJECT_TO_BUY, 10001, mPurchaseFinishedListener, "object");
    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode,
                                    Intent data) {
        if (!mHelper.handleActivityResult(requestCode,
                resultCode, data)) {
            super.onActivityResult(requestCode, resultCode, data);
        }
    }

    IabHelper.OnIabPurchaseFinishedListener mPurchaseFinishedListener
            = new IabHelper.OnIabPurchaseFinishedListener() {
        public void onIabPurchaseFinished(IabResult result,
                                          Purchase purchase) {
            if (result.isFailure()) {
                return;
            } else if (purchase.getSku().equals(PREMIUM)) {
                consumeItem();
            } else if (purchase.getSku().equals(OBJECT_TO_BUY) {
                consumeItem();
            }

        }
    };

    public void consumeItem() {
        mHelper.queryInventoryAsync(mReceivedInventoryListener);
    }

    IabHelper.QueryInventoryFinishedListener mReceivedInventoryListener
            = new IabHelper.QueryInventoryFinishedListener() {
        public void onQueryInventoryFinished(IabResult result,
                                             Inventory inventory) {

            if (result.isFailure()) {
                // Handle failure
            } else {
                mHelper.consumeAsync(inventory.getPurchase(PREMIUM),
                        mConsumeFinishedListener);
            }
        }
    };
    IabHelper.OnConsumeFinishedListener mConsumeFinishedListener =
            new IabHelper.OnConsumeFinishedListener() {
                public void onConsumeFinished(Purchase purchase,
                                              IabResult result) {

                    if (result.isSuccess()) {
                        if (purchase.getSku() == PREMIUM) getSharedPreferences("MyApp", Context.MODE_PRIVATE).edit().putBoolean("Premium", true).apply();
                        if (purchase.getSku() == OBJECT_TO_BUY) {
                               int objects = getSharedPreferences("MyApp", Context.MODE_PRIVATE).getInt("objects", 0);
                               getSharedPreferences("MyApp", Context.MODE_PRIVATE).edit().putInt("objects", objects++).apply();}
                    } else {
                        // nothink
                    }
                }
            };

    @Override
    public void onDestroy() {
        super.onDestroy();
        if (mHelper != null) mHelper.dispose();
        mHelper = null;
    }
}