Full Integration of Google wallet in android

Question

I have develop an application that have payment functionality so i am using google wallet for getting payment so i did research and i get some link of tutorial Link so i could some code like this

  WalletFragmentStyle walletFragmentStyle = new WalletFragmentStyle()
            .setBuyButtonText(BuyButtonText.BUY_WITH_GOOGLE)
            .setBuyButtonWidth(Dimension.MATCH_PARENT);

    WalletFragmentOptions walletFragmentOptions = WalletFragmentOptions.newBuilder()
            .setEnvironment(WalletConstants.ENVIRONMENT_SANDBOX)
            .setFragmentStyle(walletFragmentStyle)
            .setTheme(WalletConstants.THEME_HOLO_LIGHT)
            .setMode(WalletFragmentMode.BUY_BUTTON)
            .build();

    mWalletFragment = SupportWalletFragment.newInstance(walletFragmentOptions);

    MaskedWalletRequest maskedWalletRequest =
            WalletUtil.createMaskedWalletRequest(Constant.ITEMS_FOR_SALE[0]);
    WalletFragmentInitParams.Builder startParamsBuilder = WalletFragmentInitParams.newBuilder()
            .setMaskedWalletRequest(maskedWalletRequest)
            .setMaskedWalletRequestCode(REQUEST_CODE_MASKED_WALLET)
            .setAccountName("abc");

    mWalletFragment.initialize(startParamsBuilder.build());

    getSupportFragmentManager().beginTransaction()
            .replace(R.id.dynamic_wallet_button_fragment, mWalletFragment)
            .commit();

but i dont think this working actually , this is look like dummy so i want to integrate actual flow of payment with google wallet so any one can suggest me code

thank you very much.