Build on Android

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While the In-App Payments SDK supports payments for physical and digital sales, using the In-App Payments SDK to process digital sales might not be allowed by some mobile application distribution services (such as App Store and Google Play) and might result in your application being removed. Examples of digital sales include intangible goods (such as in-game assets), online services (such as upgrades in application functionality), and digital subscriptions (such as cloud or streaming services).

To avoid the potential removal from application distribution platforms, the In-App Payments SDK should only be used to process sales of goods or services that are consumed outside the application. You should review the terms of service for the respective mobile application distribution services you use to ensure that you're compliant with their guidelines.

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Requirements and limitations

  • Your application minSdkVersion is API 24 (Nougat, 7.0) or later.

  • You have added the In-App-Payments SDK to your Android project. For more information, see Install In-App-Payments SDK.

  • You have a Square account enabled for payment processing. If you haven't enabled payment processing on your account (or you're not sure), visit

  • You must keep the payment form open when processing payments. The In-App Payments SDK provides two ways to access the payment token depending on whether you want to keep the payment form open while processing payments. The payment processing steps in this guide assume that the form stays open. To process payments in the background, see Connect to a Backend Service for the relevant changes.

  • You're generally familiar with developing applications on Android. If you're new to Android development, you should read the Getting Started Guide on the Android Developers site before continuing.

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1. Collect card information and generate a payment token

Complete the following items to start the card entry flow.

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Register the activity onActivityResult as a callback

  1. Set a click listener on a button.

  2. In the button click listener, call startCardEntryActivity on CardEntry and pass a reference to the activity that starts the card entry flow.

    public class CheckoutActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { //Find the add card button and set a click listener that starts the CardEntry activity sheetView.findViewById( -> { CardEntry.startCardEntryActivity(CheckoutActivity.this, true, DEFAULT_CARD_ENTRY_REQUEST_CODE); }); }


    When testing your application in the Square Sandbox, be sure to use Sandbox test values to enter card information.

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Get the card payment token in the activity result

In the onActivityResult method, call the static CardEntry.handleActivityResult method with the activity results object (CardEntryActivityResult) and an anonymous method that contains your logic for responding to the card entry completion.

In the anonymous method, get a CardDetails object from the activity result and then call the getNonce() function to get the payment token.

@Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { CardEntry.handleActivityResult(data, result -> { if (result.isSuccess()) { CardDetails cardResult = result.getSuccessValue(); Card card = cardResult.getCard(); String nonce = cardResult.getNonce(); } else if (result.isCanceled()) { Toast.makeText(MainActivity.this, "Canceled", Toast.LENGTH_SHORT) .show(); } }); }
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2. Process the payment token

Declare a class that implements CardNonceBackgroundHandler to call your backend service and process the payment token while the payment form is still open.

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Server-side payment completion

The previous example refers to myBackendService, which is a placeholder for the backend service that you must create so that your application can process the payment token received from the In-App Payments SDK. The backend service calls the Payments API to create a payment that charges the card entered by a buyer in your mobile client. For more information about taking a payment, see Accept payments in your application.

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Save a card on file

When your backend service has received the payment token from your mobile application, it can take a payment but it can also use the token to store a card on file for the customer. Your mobile application must provide enough customer information for the backend to find the customer using the SearchCustomers endpoint. For example, if your mobile application has the buyer's email address and sends it to your backend along with the payment token.

To learn about how to save a card on file from your backend, see Create a Card on File and a Payment.

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3. Set the CardEntry background handler

In your application class, set CardEntry.cardNonceBackgroundHandler to reference CardEntryBackgroundHandler.


The CardEntryBackgroundHandler must be set in the application class so that it's set again if the application process is stopped and later restarted on the card entry flow.

public class ExampleApplication extends Application { @Override public void onCreate() { super.onCreate(); CardEntryBackgroundHandler cardHandler = new CardEntryBackgroundHandler(); CardEntry.setCardNonceBackgroundHandler(cardHandler); } }