The Online Payments Android SDK helps you with accepting payments in your Android app, supporting API level 19 and up, through the Online Payments platform.
The SDK's main function is to establish a secure channel between your Android app and our server. This channel processes security credentials to guarantee the safe transit of your customers' data during the payment process.
The Online Payments SDK helps you with:
- Handling encryption of the payment context
- Convenient Java wrappers for API responses
- User-friendly formatting of payment data, such as card numbers and expiry dates
- Validating user input
- Determining the card's associated payment provider
- Online Payments - Android SDK
Add a dependency to the SDK in your app's build.gradle file, where x.y.z is the version number:
dependencies {
// other dependencies
implementation 'com.worldline-solutions:sdk-client-android:x.y.z'
}
For your convenience, the SDK comes with an example app in both Kotlin and Java that you can use as a basis for your own implementation. The Kotlin example app offers a Jetpack Compose implementation as well as a traditional XML based implementation, whereas the Java example app offers only a traditional XML implementation. If you are fine with the look-and-feel of the example app, you do not need to make any changes at all. Take a look at the Kotlin or Java example apps.
To accept your first payment using the SDK, complete the steps below. Also see the section Payment Steps for more details on these steps.
- Request your server to create a Client Session, using one of our available Server SDKs. Return the session details to your app.
- Initialize the SDK using the session details.
Session session = new Session(
"47e9dc332ca24273818be2a46072e006", // client session id
"9991-0d93d6a0e18443bd871c89ec6d38a873", // customer id
"https://clientapi.com", // client API URL
"https://assets.com", // asset URL
false, // states if the environment is production, this property is used to determine the Google Pay environment
"Android Example Application/v2.0.4", // application identifier
true // if true, requests and responses will be logged to the console; not supplying this parameter means it is false; should be false in production
);- Configure your payment context.
AmountOfMoney amountOfMoney = new AmountOfMoney(
1298L, // in cents as a Long
"EUR" // three letter currency code as defined in ISO 4217
);
PaymentContext paymentContext = new PaymentContext(
amountOfMoney,
"NL", // two letter country code as defined in ISO 3166-1 alpha-2
false // true, if it is a recurring payment
);- Retrieve the available Payment Products. To handle retrieving the Payment Products and any possible errors, you will have to declare and use a
BasicPaymentItemsResponseListener. After successfully retrieving the Payment Products, display theBasicPaymentItemandAccountOnFilelists and request your customer to select one.
private BasicPaymentItemsResponseListener basicPaymentItemsResponseListener = new BasicPaymentItemsResponseListener() {
@Override
public void onSuccess(@NonNull BasicPaymentItems basicPaymentItems) {
// Display the contents of basicPaymentItems & accountsOnFile to your customer
}
@Override
public void onApiError(ErrorResponse errorResponse) {
// Handle API failure of retrieving the available Payment Products
}
@Override
public void onException(Throwable throwable) {
// Handle failure of retrieving the available Payment Products
}
};
session.getBasicPaymentItems(
context, // Context, used for retrieving device metadata
paymentContext, // PaymentContext
groupPaymentProducts, // states if the retrieved payment items will be grouped, will always be false
basicPaymentItemsResponseListener // listener to be called when payment items are retrieved or an error occured
);- Once the customer has selected the desired payment product, retrieve the enriched
PaymentProductdetailing what information the customer needs to provide to authorize the payment. To handle retrieving the enrichedPaymentProductand any possible errors, you will have to declare and use aPaymentProductResponseListener. After successfully retrieving thePaymentProduct, display the required information fields to your customer.
private PaymentProductResponseListener paymentProductResponseListener = new PaymentProductResponseListener() {
@Override
public void onSuccess(@NonNull PaymentProduct paymentProduct) {
// Display the fields to your customer
}
@Override
public void onApiError(ErrorResponse errorResponse) {
// Handle API failure of retrieving a Payment Product by id
}
@Override
public void onException(Throwable throwable) {
// Handle failure of retrieving a Payment Product by id
}
};
session.getPaymentProduct(
context, // Context, used for retrieving device metadata
"1", // id of the payment product you want to retrieve
paymentContext, // PaymentContext
paymentProductResponseListener // listener to be called when the payment product is retrieved or an error occured
);- Save the customer's input for the required information fields in a
PaymentRequest.
PaymentRequest paymentRequest = new PaymentRequest();
paymentRequest.setValue(
"cardNumber", // field id
"12451254457545" // unmasked value
);
paymentRequest.setValue("cvv", "123");
paymentRequest.setValue("expiryDate", "1225");- Validate and encrypt the payment request. To handle encrypting the
PaymentRequest, you will have to declare and use aPaymentRequestPreparedListener. After successfully encrypting thePaymentRequest, you will have access to the encrypted version,PreparedPaymentRequest. The encrypted customer data should then be sent to your server.
private PaymentRequestPreparedListener paymentRequestPreparedListener = new PaymentRequestPreparedListener() {
@Override
public void onPaymentRequestPrepared(PreparedPaymentRequest preparedPaymentRequest) {
// Forward the encryptedFields to your server
}
@Override
public void onFailure(EncryptDataException e) {
// Handle failure of encrypting a PaymentRequest
}
};
session.preparePaymentRequest(
paymentRequest, // the payment request that should be encrypted
context, // Context, used for retrieving device metadata
paymentRequestPreparedListener // listener to be called when the payment request is encrypted
);- Request your server to create a payment request, using the Server API's Create Payment call. Provide the encrypted data in the
encryptedCustomerInputfield.
For all interactions with the SDK an instance of Session is required. The following code fragment shows how Session is initialized. The session details are obtained by performing a Create Client Session call using the Server API.
Session session = new Session(
"47e9dc332ca24273818be2a46072e006", // client session id
"9991-0d93d6a0e18443bd871c89ec6d38a873", // customer id
"https://clientapi.com", // client API URL
"https://assets.com", // asset URL
false, // states if the environment is production, this property is used to determine the Google Pay environment
"Android Example Application/v2.0.4", // application identifier
true // if true, requests and responses will be logged to the console; not supplying this parameter means it is false; should be false in production
);Almost all methods that are offered by Session are simple wrappers around the Client API. They create the request and convert the response to Java objects that may contain convenience functions.
You are able to log requests made to the server and responses received from the server. By default logging is disabled, and it is important to always disable it in production. You are able to enable the logging in two ways. Either by setting its value when creating a Session - as shown in the code fragment above - or by setting its value after the Session was already created.
session.setLoggingEnabled(true);PaymentContext is an object that contains the context/settings of the upcoming payment. It is required as an argument to some of the methods of the Session instance. This object can contain the following details:
public class PaymentContext {
private AmountOfMoney amountOfMoney; // contains the total amount and the ISO 4217 currency code
private String countryCode; // ISO 3166-1 alpha-2 country code
private boolean isRecurring; // Set `true` when payment is recurring. Default false.
}This object contains the available Payment Items for the current payment. Use the session.getBasicPaymentItems function to request the data. To handle retrieving the Payment Products and any possible errors, you will have to use a BasicPaymentItemsResponseListener.
The object you will receive is BasicPaymentItems, which contains two lists. One for all available BasicPaymentItems and one for all available AccountOnFiles.
The code fragment below shows how to get the BasicPaymentItems instance.
private BasicPaymentItemsResponseListener basicPaymentItemsResponseListener = new BasicPaymentItemsResponseListener() {
@Override
public void onSuccess(@NonNull BasicPaymentItems basicPaymentItems) {
// Display the contents of basicPaymentItems & accountsOnFile to your customer
}
@Override
public void onApiError(ErrorResponse errorResponse) {
// Handle API failure of retrieving the available Payment Products
}
@Override
public void onException(Throwable throwable) {
// Handle failure of retrieving the available Payment Products
}
};
session.getBasicPaymentItems(
context, // Context, used for retrieving device metadata
paymentContext, // PaymentContext
groupPaymentProducts, // states if the retrieved payment items will be grouped, will always be false
basicPaymentItemsResponseListener // listener to be called when payment items are retrieved or an error occured
);The SDK offers two types to represent information about payment products:
BasicPaymentProduct and PaymentProduct. Practically speaking, instances of BasicPaymentProduct contain only the information that is required to display a simple list of payment products from which the customer can select one.
The type PaymentProduct contains additional information, such as the specific form fields that the customer is required to fill out. This type is typically used when creating a form that asks the customer for their details. See the PaymentProduct section for more info.
Below is an example for how to obtain display names and assets for the Visa product.
BasicPaymentItem basicPaymentProduct = paymentItems.getBasicPaymentItemById("1");
String id = basicPaymentProduct.getId();
String label = basicPaymentProduct.getDisplayHintsList().get(0).getLabel();
String logoUrl = basicPaymentProduct.getDisplayHintsList().get(0).getLogoUrl();An instance of AccountOnFile represents information about a stored card product for the current customer. AccountOnFile IDs available for the current payment must be provided in the request body of the Server API's Create Client Session call. If the customer wishes to use an existing AccountOnFile for a payment, the selected AccountOnFile should be added to the PaymentRequest. The code fragment below shows how display data for an account on file can be retrieved. This label can be shown to the customer, along with the logo of the corresponding payment product.
// All available accounts on file for the payment product
List<AccountOnFile> allAccountsOnFile = basicPaymentProduct.getAccountsOnFile();
// Get specific account on file for the payment product
AccountOnFile accountOnFile = null;
for (AccountOnFile aof : basicPaymentProduct.getAccountsOnFile()) {
if (Objects.equals(aof.getId(), identifier)) { // 'identifier' is the ID of the AccountOnFile selected by the customer
accountOnFile = aof;
break;
}
}
// Shows a mask based formatted value for the obfuscated cardNumber.
// The mask that is used is defined in the displayHints of this accountOnFile
// If the mask for the "cardNumber" field is {{9999}} {{9999}} {{9999}} {{9999}} {{999}}, then the result would be **** **** **** 7412
String maskedValue = accountOnFile.getMaskedValue("cardNumber");BasicPaymentProduct only contains the information required by a customer to distinguish one payment product from another. However, once a payment product or an account on file has been selected, the customer must provide additional information, such as a bank account number, a credit card number, or an expiry date, before a payment can be processed. Each payment product can have several fields that need to be completed to process a payment. Instances of BasicPaymentProduct do not contain any information about these fields.
Information about the fields of payment products are represented by instances of PaymentProductField, which are contained in instances of PaymentProduct. The class PaymentProductField is described further down below. To handle retrieving the desired PaymentProduct and any possible errors, you will have to use a PaymentProductResponseListener.
The Session instance can be used to retrieve instances of PaymentProduct, as shown in the following code fragment.
private PaymentProductResponseListener paymentProductResponseListener = new PaymentProductResponseListener() {
@Override
public void onSuccess(@NonNull PaymentProduct paymentProduct) {
// Display the fields to your customer
}
@Override
public void onApiError(ErrorResponse errorResponse) {
// Handle API failure of retrieving a Payment Product by id
}
@Override
public void onException(Throwable throwable) {
// Handle failure of retrieving a Payment Product by id
}
};
session.getPaymentProduct(
context, // Context, used for retrieving device metadata
"1", // id of the payment product you want to retrieve
paymentContext, // PaymentContext
paymentProductResponseListener // listener to be called when the payment product is retrieved or an error occured
);The fields of payment products are represented by instances of PaymentProductField. Each field has an identifier, a type, a definition of restrictions that apply to the value of the field, and information about how the field should be presented graphically to the customer. Additionally, an instance of a field can be used to determine whether a given value is valid for the field.
In the code fragment below, the field with identifier "cvv" is retrieved from a payment product. The data restrictions of the field are inspected to see whether the field is a required field or an optional field. Additionally, the display hints of the field are inspected to see whether the values a customer provides should be obfuscated in a user interface.
PaymentProductField ccvField = paymentProduct.getPaymentProductFieldById("cvv");
Boolean isRequired = ccvField.getDataRestrictions().isRequired(); // state if value is required for this field
Boolean shouldObfuscate = ccvField.getDisplayHints().isObfuscate(); // state if field value should be obfuscatedOnce a payment product has been selected and an instance of PaymentProduct has been retrieved, a payment request can be constructed. This class must be used as a container for all the values the customer provides.
PaymentRequest paymentRequest = new PaymentRequest();
paymentRequest.setPaymentProduct(paymentProduct);A PaymentProduct has a property tokenize, which is used to indicate whether a payment request should be stored as an account on file. The code fragment below shows how a payment request should be constructed when the request should be stored as an account on file. By default, tokenize is set to false.
PaymentRequest paymentRequest = new PaymentRequest(); // tokenize is false by default
paymentRequest.setPaymentProduct(paymentProduct);
// you can set the request's tokenize property after having initialized the paymentRequest
paymentRequest.setTokenize(true);If the customer selected an account on file, both the account on file and the corresponding payment product must be supplied while constructing the payment request, as shown in the code fragment below. Instances of AccountOnFile can be retrieved from instances of BasicPaymentProduct and PaymentProduct.
PaymentRequest paymentRequest = new PaymentRequest(); // accountOnFile is null by default
paymentRequest.setPaymentProduct(paymentProduct);
// you can set the request's accountOnFile property after having initialized the paymentRequest
paymentRequest.setAccountOnFile(accountOnFile);Once a payment request has been configured, the value for the payment product's fields can be supplied as shown below. The identifiers of the fields, such as "cardNumber" and "cvv" in the example below, are used to set the values of the fields using the payment request.
PaymentRequest paymentRequest = new PaymentRequest();
paymentRequest.setValue(
"cardNumber", // field id
"12451254457545" // unmasked value
);
paymentRequest.setValue("cvv", "123");
paymentRequest.setValue("expiryDate", "1225");Once all values have been supplied, the payment request can be validated. Behind the scenes the validation uses the DataRestrictions class for each of the fields that were added to the PaymentRequest. After the validation, a list of errors is available, which indicates any issues that have occured during validation. If there are no errors, the payment request can be encrypted and sent to our platform via your erver. If there are validation errors, the customer should be provided with feedback about these errors.
// validate all fields in the payment request
List<ValidationErrorMessage> errorMessages = paymentRequest.validate();
// check if the payment request is valid
if (errorMessages.isEmpty()) {
// payment request is valid
} else {
// payment request has errors
}The validations are the Validators linked to the PaymentProductField and are returned as a ValidationErrorMessage, for example:
for (ValidationErrorMessage validationResult : errorMessages) {
// do something with the error, like displaying it to the user
}The PaymentRequest is ready for encryption once the PaymentProduct is set, the PaymentProductField values have been provided and validated, and potentially the selected AccountOnFile or tokenize properties have been set. The PaymentRequest encryption is done by using session.prepare. To handle the result of the encrypted PaymentRequest, you will have to use the PaymentRequestPreparedListener. After successfully encrypting the PaymentRequest, you will have access to the encrypted version, PreparedPaymentRequest which contains the encrypted payment request fields and encoded client meta info.
private PaymentRequestPreparedListener paymentRequestPreparedListener = new PaymentRequestPreparedListener() {
@Override
public void onPaymentRequestPrepared(PreparedPaymentRequest preparedPaymentRequest) {
// Forward the encryptedFields to your server
}
@Override
public void onFailure(EncryptDataException e) {
// Handle failure of encrypting a PaymentRequest
}
};
session.preparePaymentRequest(
paymentRequest, // the payment request that should be encrypted
context, // Context, used for retrieving device metadata
paymentRequestPreparedListener // listener to be called when the payment request is encrypted
);Although it is possible to use your own encryption algorithms to encrypt a payment request, we advise you to use the encryption functionality that is offered by the SDK.
The first six digits of a payment card number are known as the Issuer Identification Number (IIN). As soon as the first 6 digits of the card number have been captured, you can use the session.getIinDetails call to retrieve the payment product and network that are associated with the provided IIN. Then you can verify the card type and check if you can accept this card.
An instance of Session can be used to check which payment product is associated with an IIN. This is done via the session.getIinDetails function. The result of this check is an instance of IinDetailsResponse. This class has a property status that indicates the result of the check and a property paymentProductId that indicates which payment product is associated with the IIN. The returned paymentProductId can be used to provide visual feedback to the customer by showing the appropriate payment product logo.
The IinDetailsResponse has a status property represented through the IinStatus enum. The IinStatus enum values are:
SUPPORTEDindicates that the IIN is associated with a payment product that is supported by our platform.UNKNOWNindicates that the IIN is not recognized.NOT_ENOUGH_DIGITSindicates that fewer than six digits have been provided and that the IIN check cannot be performed.EXISTING_BUT_NOT_ALLOWEDindicates that the provided IIN is recognized, but that the corresponding product is not allowed for the current payment.
To handle retrieving the desired IinDetailsResponse and any possible errors, you will have to declare and use the IinLookupResponseListener.
private IinLookupResponseListener iinLookupResponseListener = new IinLookupResponseListener() {
@Override
public void onSuccess(@NonNull IinDetailsResponse response) {
// check the status of the associated payment product
IinStatus iinStatus = response.getStatus();
}
@Override
public void onApiError(ErrorResponse errorResponse) {
// Handle API failure of retrieving IIN details
}
@Override
public void onException(Throwable throwable) {
// Handle failure of retrieving IIN details
}
};
session.getIinDetails(
context, // Context, used for retrieving device metadata
"123456", // partial credit card number
iinLookupResponseListener, // listener to be called when iin details are retrieved or an error occured
paymentContext // PaymentContext
);Some cards are dual branded and could be processed as either a local card (with a local brand) or an international card (with an international brand). In case you are not setup to process these local cards, this API call will not return that card type in its response.
To help in formatting field values based on masks, the SDK offers the OPStringFormatter class. It allows you to format field values and apply and unapply masks on a string.
let formatter = StringFormatter()
let mask = "{{9999}} {{9999}} {{9999}} {{9999}} {{999}}"
let value = "1234567890123456"
// apply masked value
let maskedValue = formatter.formatString(string: value, mask: mask) // "1234 5678 9012 3456"
// remove masked value
let unmaskedValue = formatter.unformatString(string: value, mask: mask) // "1234567890123456"Setting up and completing a payment using the Android SDK involves the following steps:
This is done using information such as session and customer identifiers, connection URLs and payment context information like currency and total amount.
Session session = new Session(
"47e9dc332ca24273818be2a46072e006", // client session id
"9991-0d93d6a0e18443bd871c89ec6d38a873", // customer id
"https://clientapi.com", // client API URL
"https://assets.com", // asset URL
false, // states if the environment is production, this property is used to determine the Google Pay environment
"Android Example Application/v2.0.4", // application identifier
true // if true, requests and responses will be logged to the console; not supplying this parameter means it is false; should be false in production
);
AmountOfMoney amountOfMoney = new AmountOfMoney(
1298L, // in cents as a Long
"EUR" // three letter currency code as defined in ISO 4217
);
PaymentContext paymentContext = new PaymentContext(
amountOfMoney,
"NL", // two letter country code as defined in ISO 3166-1 alpha-2
false // true, if it is a recurring payment
);A successful response from Create Session can be used directly as input for the Session constructor.
clientSessionId/customerIdproperties are used to authentication purposes. These can be obtained your server, using one of our available Server SDKs.- The
clientApiUrlandassetBaseUrlare the URLs the SDK should connect to. The SDK communicates with two types of servers to perform its tasks. One type of server offers the Client API as discussed above. And the other type of server stores the static resources used by the SDK, such as the logos of payment products. - Payment information (
paymentContext) is not needed to construct a session, but you will need to provide it when requesting any payment product information. The payment products that the customer can choose from depend on the provided payment information, so the Client SDK needs this information to be able to do its job. The payment information that is needed is:- the total amount of the payment, defined as property
amountOfMoney.amount - the currency that should be used, defined as property
amountOfMoney.currencyCode - the country of the person that is performing the payment, defined as property
countryCode - whether the payment is a single payment or a recurring payment
- the total amount of the payment, defined as property
Retrieve the payment products and accounts on file that can be used for this payment. Your application can use this data to create the payment product selection screen.
private BasicPaymentItemsResponseListener basicPaymentItemsResponseListener = new BasicPaymentItemsResponseListener() {
@Override
public void onSuccess(@NonNull BasicPaymentItems basicPaymentItems) {
// Display the contents of basicPaymentItems & accountsOnFile to your customer
}
@Override
public void onApiError(ErrorResponse errorResponse) {
// Handle API failure of retrieving the available Payment Products
}
@Override
public void onException(Throwable throwable) {
// Handle failure of retrieving the available Payment Products
}
};
session.getBasicPaymentItems(
context, // Context, used for retrieving device metadata
paymentContext, // PaymentContext
groupPaymentProducts, // states if the retrieved payment items will be grouped, will always be false
basicPaymentItemsResponseListener // listener to be called when payment items are retrieved or an error occured
);For some payment products, customers can indicate that they want the Online Payments platform to store part of the data they entered while using such a payment product. For example, it is possible to store the card holder name and the card number for most credit card payment products. The stored data is referred to as an AccountOnFile or token. AccountOnFile IDs available for the current payment must be provided in the request body of the Server API's Create Client Session call. When the customer wants to use the same payment product for another payment, it is possible to select one of the stored accounts on file for this payment. In this case, the customer does not have to enter the information that is already stored in the AccountOnFile. The list of available payment products that the SDK receives from the Client API also contains the accounts on file for each payment product. Your application can present this list of payment products and accounts on file to the customer.
If the customer wishes to use an existing AccountOnFile for a payment, the selected AccountOnFile should be added to the PaymentRequest.
Retrieve all the details about the payment product - including it's fields - that the customer needs to provide based on the selected payment product or account on file. Your app can use this information to create the payment product details screen.
private PaymentProductResponseListener paymentProductResponseListener = new PaymentProductResponseListener() {
@Override
public void onSuccess(@NonNull PaymentProduct paymentProduct) {
// Display the fields to your customer
}
@Override
public void onApiError(ErrorResponse errorResponse) {
// Handle API failure of retrieving a Payment Product by id
}
@Override
public void onException(Throwable throwable) {
// Handle failure of retrieving a Payment Product by id
}
};
session.getPaymentProduct(
context, // Context, used for retrieving device metadata
"1", // id of the payment product you want to retrieve
paymentContext, // PaymentContext
paymentProductResponseListener // listener to be called when the payment product is retrieved or an error occured
);Once the customer has selected a payment product or stored account on file, the SDK can request which information needs to be provided by the customer in order to perform a payment. When a single product is retrieved, the SDK provides a list of all the fields that should be rendered, including display hints and validation rules. If the customer selected an account on file, information that is already in this account on file can be prefilled in the input fields, instead of requesting it from the customer. The data that can be stored and prefilled on behalf of the customer is of course in line with applicable regulations. For instance, for a credit card transansaction the customer is still expected to input the CVC. The details entered by the customer are stored in a PaymentRequest. Again, the example app can be used as the starting point to create your screen. If there is no additional information that needs to be entered, this screen can be skipped.
Encrypt all the provided payment information in the PaymentRequest using session.preparePaymentRequest. This function will return a PreparedPaymentRequest which contains the encrypted payment request fields and encoded client meta info. The encrypted fields result is in a format that can be processed by the Server API. The only thing you need to provide to the SDK are the values the customer provided in your screens. Once you have retrieved the encrypted fields String from the PreparedPaymentRequest, your application should send it to your server, which in turn should forward it to the Server API.
private PaymentRequestPreparedListener paymentRequestPreparedListener = new PaymentRequestPreparedListener() {
@Override
public void onPaymentRequestPrepared(PreparedPaymentRequest preparedPaymentRequest) {
// Forward the encryptedFields to your server
}
@Override
public void onFailure(EncryptDataException e) {
// Handle failure of encrypting a PaymentRequest
}
};
session.preparePaymentRequest(
paymentRequest, // the payment request that should be encrypted
context, // Context, used for retrieving device metadata
paymentRequestPreparedListener // listener to be called when the payment request is encrypted
);All the heavy lifting, such as requesting a public key from the Client API, performing the encryption and BASE-64 encoding the result into one string, is done for you by the SDK. You only need to make sure that the PaymentRequest object contains all the information entered by the user.
From your server, make a create payment request, providing the encrypted data in the encryptedCustomerInput field.
It is up to you and your application to show the customer the correct screens based on the response of the Server API call. In some cases, the payment has not finished yet since the customer must be redirected to a third party (such as a bank or PayPal) to authorise the payment. See the Server API documentation on what kinds of responses the Server API can return. The Client API has no part in the remainder of the payment.