Android SDK

Overview

Sola (Cardknox) Android SDK is a mobile SDK targeted towards Android developers, allowing developers to process transactions with the Sola Transactions API.

Due to the necessity of the API key in this integration method, we strongly recommend reserving these features for integrations to be used solely on merchant-owned devices.

Getting started

To start, download the SDK framework file:

Android SDK download

Integrate the SDK file into your Android Studio project by referring to the technical documentation.

Choose your integration path

The SDK offers developers a couple of ways to process transactions:

In scope function
Out of scope function
Custom UI set of functions
Payment Engine set of functions

Out of scope

Use the out of scope function when the user needs to provide their credit card information. This function displays the SDK user interface, effectively giving the control over to the SDK to acquire the sensitive credit card data from the user. The user provides the sensitive information either via a form or via a credit card device, and then the SDK processes the transaction with the gateway.

In scope

Use the in scope function when there is no need for the SDK to interact with the user through a user interface. The developer should either pass in a card number + an expiration date, or provide a tokenized card data via the xToken parameter to this function to quickly process the transaction and retrieve back the results.

Custom UI

Custom-UI integration consists of a set of functions to control the card reader device via the SDK. Currently supported card reader device is a Bluetooth VP3300 card reader and USB connection. This integration path is useful when the developer has an existing UI and wishes to use a card reader device to obtain users' card sensitive information and then process the transaction with the gateway. The SDK offers a set of functions to control the card reader device. The SDK takes care of processing with the gateway and notifying the Developer’s application with the processing results.

Payment Engine

The Payment Engine feature inside the SDK enables you to create transactions with a card reader over IP. The Payment Engine supports different card readers from Pax, Verifone, and Ingenico brands. See a full list of supported devices in the table below. The feature doesn't contain any UI. The developer provides device and transaction parameters to Payment Engine functions. The SDK takes care of communicating with the card reader and processing with the gateway. Finally, the SDK returns the device and transaction status and states.

Brand

Model

Suffix

Parameter value

Pax

SP30

Pax_SP30.3

S300

Pax_S300.3

S920

Pax_S920.3

A35

Pax_A35.3

A60

Pax_A60.3

A77

Pax_A773

A80

Pax_A80.3

A920

Pax_A920.3

PX5

Pax_PX5.3

PX7

Pax_PX7.3

D210

Pax_D210.3

D220

Pax_D22.3

Aries6

Pax_Aries6.3

Aries8

Pax_Aries8.3

Verifone

MX915

Verifone_MX915.4

MX925

Verifone_MX925.4

P200

Verifone_P200.4

P400

Verifone_P400.4

M400

Verifone_M400.4

E285

Verifone_E2854

Ingenico

ICT250

Ingenico_ICT250.2

Desk500

Ingenico_Desk5000.2

Move500

Ingenico_Move5000.2

Transaction workflows

Download our sample applications:

Java sample app

Basic parameters

Name

Required

Description

Sample data

xKey

Yes

Sola account key

Sola

xVersion

Yes

Gateway version

4.5.9

xSoftwareName

Yes

Name of your software

My app

xSoftwareVersion

Yes

Version number of your software

1.0.0

Basic parameter functions

Prior to any processing, the Sola SDK needs to be configured with user’s metadata and the account key. These functions can be called anywhere in the application any number of times to change the metadata and/or current account key.

Function

Description

Sample data

setSoftwareConfigurations

Specifies the name of your software (xSoftwareName), version number of your software (xSoftwareVersion) and the gateway version (xVersion)

CardknoxSDK.setSoftwareConfigurations("Your app name", "0.0.1", "4.5.9");

setPrincipalKey

Accepts the xKey.

xKey is a Sola account key.

All transactions being processed after calling this function will be associated to the account that was passed in into the function.

CardknoxSDK.setPrincipalKey("ps_demo_cardknox");

Transaction required parameters

Each integration path has a “process” function that accepts a “transaction parameters” object. Developers specify required values for transaction processing through that object. The same object can be used to specify optional; parameters to associate with a transaction, such as invoice numbers, billing address, etc.

Name

Description

Sample data

xCommand

Sola transaction type

cc:sale

Transaction optional parameters

Optional transaction parameters further complement the transaction processing. All the parameters are sent to the Gateway during processing.

Name

Description

Sample data

VP3300TransactionTimeout

Start transaction timeout, in seconds.

Once the transaction with the VP3300 reader is started; the SDK times out if the card is not provided in the time frame specified by this timeout value.

This parameter is only applicable for SDK integrations that use a VP3300 card reader; such as CustomUI or OutOfScope integrations.

Refer to the Custom UI flow or Out Of Scope flow for samples.

xCardNum

Card number

4444333322221111

xExpDate

Card expiration date.

Expected format is MMYY where MM is a month, and YY are last 2 year digits

“1126” for (November 2026)

“0122” for “January 2022”

xToken

From Transaction API:

The Cardknox token that references a previously used payment method. When using a token, xCardNum, xExp and xMagstripe should not be used.

61h72mmh68phn9q233634ph3g54p1499m69qhp4816pn528h84

xRefNum

Used to reference a previous transaction when doing a follow-up transaction, typically a refund, void, or capture.

12345678

xInvoice

The merchant’s invoice number for the transaction. xInvoice is recommended when available for improved duplicate handling.

xPoNum

The merchant’s purchase order number for the transaction.

123485

xDescription

This is a description

xName

The cardholder’s name.

John Doe

xBillFirstName

The customer’s first name for their billing profile.

John

xBillLastName

The customer’s last/family name for their billing profile.

Doe

xBillCompany

The customer’s company name for their billing profile.

Acme

xBillStreet

The customer’s street address for their billing profile.

123 Any Street

xBillStreet2

The customer’s second street address for their billing profile.

123 Any Street

xBillCity

The customer’s city for their billing profile.

Anytown

xBillState

The customer’s state for their billing profile.

xBillZip

The customer’s zip code for their billing profile.

12345

xBillCountry

The customer’s phone number for their billing profile.

USA

xBillPhone

The customer’s phone number for their billing profile.

8005551212

xShipFirstName

The customer’s last/family name for their shipping profile.

John

xShipLastName

The customer’s last/family name for their shipping profile.

Doe

xShipCompany

The customer’s company name for their shipping profile.

Acme

xShipStreet

The customer’s street address for their shipping profile.

123 Any Street

xShipStreet2

The customer’s second street address for their shipping profile.

123 Any Street

xShipCity

The customer’s city for their shipping profile.

Anytown

xShipState

The customer’s state for their shipping profile.

xShipZip

The customer’s zip code for their shipping profile.

12345

xShipCountry

The customer’s country for their shipping profile.

USA

xShipPhone

The customer’s phone number for their shipping profile.

1113333444

xCustom01

Custom field 1. Use this for any additional data

xCustom02

Custom field 2. Use this for any additional data

xCustom03

Custom field 3. Use this for any additional data

xAuthCode

xAuthCode is a verification number provided by the issuing bank to be used with the cc:postauth command.

xAllowDuplicate

By default, Cardknox rejects duplicate transactions within 10 minutes of the original transaction. This command overrides that safeguard. True/False allowed.

False

xCustReceipt

True/False value indicating if the email address specified in xEmail should receive a receipt containing the transaction details.

False

xEmail

The customer’s email address.

[email protected]

Device_name

PE device name

Verifone_P400.4

(The 4. column in Payment engine support device table)

Device_IP_Address

IP address of PE device

172.21.2.7

Device_Port

Port of PE device

9006

Device_Timeout

Timeout for PE device connecting

120

VP3300StartTransactionMethod

The card reader can scan a card in a few different ways: swipe, tap, or insert a card. This property defines how the card reader expects the card to be scanned.

See SetVP3300StartTransactionMethod in Custom UI with USB section.

Possible values:

CTLS - tap a card (NFC)
EMV - insert card
MSR - swipe card
DEVICE - swipe, insert and tap a card

EnableTipPrompt

Prompts the user on the device to add a tip to the transaction. This functionality is only available when the device is enabled. The response to the transaction will include two parameters: "xTip" (the tip amount) and "xAuthAmount" (the final authorized amount on the card, including the tip amount).

Available in the Payment Engine integration.

Retrieving results with callbacks

The SDK can notify the application about various events during processing, such as about different card reader events during out of scope processing, or perhaps about a completed bluetooth device scan during custom UI processing.

Developers opt in to receive callbacks by registering BroadcastReceivers with IntentFilters, using a predefined value from the SDK for the “action” parameter.

The SDK uses the same “action” value to report results & various information back to subscribers.

Available callback types and integrations where they are applicable in are as follows:

Callback type

Description

Available in integration

Transaction result

The SDK processes a payment with the Gateway and delivers an object containing all processed transaction details.

Out of scope

Custom UI Payment Engine

Card reader event

The SDK keeps informing the subscribers about various events taking place between the application and the card reader device; such as “connected”, “disconnected”, “transaction started”, “on bluetooth disabled error”, etc.

Out of scope

Custom UI

Scanned bluetooth device

Trigger a bluetooth device scanning process with the “start scanning” function.

During the scanning process, the SDK keeps informing subscribers with objects that encapsulate all the information about each newly discovered Bluetooth device.

The SDK expects one of the objects as an argument in the “connect to device” function.

Custom UI

Scan completed

Trigger a bluetooth device scanning process with the “start scanning” function.

Stop the process with a “stop scanning” function.

Once the scanning process is stopped, the SDK reports back a list of all scanned bluetooth devices.

The SDK expects one of the objects as an argument in the “connect to device” function.

Custom UI

Device status

The SDK is sending information to subscribers about the device initialization process and the actions that the device expects from the user of the card scanner.

For example, waiting for the insert or swipe of a credit card.

Payment Engine

Transaction status

The transaction status sends information about the card scanning process.

Payment Engine

Result as JSON

The result of created transaction return in JSON format.

Payment Engine

Payment engine LogCat logging

The payment engine supports two types of event logging. One prints logs directly to the LogCat console, while the other delivers logs via callbacks, allowing the app to handle them programmatically.

Payment Engine

Callback subscriptions & result handling

Based on your integration path choice, choose an available callback type for that integration path and register a BroadcastReceiver to receive appropriate information back from the SDK.

Transaction result callback subscription

This callback delivers a “transaction processed response” object to the subscriber.

Subscription can be made in the appropriate Fragment lifecycle method:

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;

import cardknox.payments.sdk.CardknoxSDK;
import cardknox.payments.sdk.PaymentTransactionResponse;

public class TransactionResultExampleFragment extends Fragment {

    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        RegisterIntentFilters();
    }

    @Override
    public void onDetach() {
        super.onDetach();
        UnregisterIntentFilters();
    }

    private void RegisterIntentFilters()
    {
        Context c = getContext();

        if(c != null)
        {
            c.registerReceiver(Receiver_TransactionProcessing, new IntentFilter(CardknoxSDK.TRANSACTION_CALLBACK_INTENTFILTER_ACTION()));
        }
    }

    private void UnregisterIntentFilters()
    {
        Context c = this.getContext();

        if(c != null)
        {
            c.unregisterReceiver(Receiver_TransactionProcessing);
        }
    }

    private final BroadcastReceiver Receiver_TransactionProcessing = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent)
        {
            String action = intent.getAction();

            // Verify that the Cardknox SDK broadcasted the Intent
            if(action.equals(CardknoxSDK.TRANSACTION_CALLBACK_INTENTFILTER_ACTION()))
            {
                String extraKey = CardknoxSDK.TRANSACTION_CALLBACK_INTENTFILTER_EXTRA();
                java.lang.Object extra = intent.getParcelableExtra(extraKey);

                // Cast the 'extra' to the Cardknox SDK response type
                PaymentTransactionResponse response = (PaymentTransactionResponse)extra;

                if(response.GetIsSuccess())
                {
                    // Transaction successfully processed
                    String xRefNum = response.GetxRefNum();
                    // approved, declined, ...
                    String xStatus = response.GetxStatus();
                    String cvv = response.GetxCvvResult();
                    String avs = response.GetxAvsResult();
                    // ... other properties ...

                    Output("Transaction approved. Ref num: " + xRefNum);
                }
                else
                {
                    // Transaction processing resulted in an error; message can be extracted from this property:
                    String errorMessage = response.GetErrorMessage();
                    String errorCode = response.GetxErrorCode();
                    String error = response.GetxError();

                    Output("Transaction declined/errored. Ref num: " + response.GetxRefNum());
                }
            }
        }
    };

    private void Output(String text)
    {
        android.util.Log.d("ExampleTag", text);
    }
}

Card reader event callback subscription

This callback delivers information about various events happening between the application & the card reader.

For example, while out-of-scope processing the SDK can report back error events related to bluetooth device pairing, such as “bluetooth not turned on” to indicate that the mobile device wanted to use the bluetooth service to find a nearby card reader device but the service is unavailable, or an error such as “waiting for device bluetooth response” to indicate that the mobile device found an eligible bluetooth card reader device and is expecting the card reader to respond back with bluetooth data. This could mean that the bluetooth button on the card reader needs to be pressed.

After a bluetooth pairing is established, the SDK reports back events related to obtaining the card data via the card reader. For example, a “connected” event means that the mobile device & the card reader are connected and a card data transaction can start. A “transaction started” event means that the SDK initiated a card data transaction with the card reader and the physical card can be tapped onto the card reader.

Subscription can be made in the appropriate Fragment lifecycle method:

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;

import cardknox.payments.sdk.CardknoxCardReaderCallback;
import cardknox.payments.sdk.CardknoxCardReaderCallbackType;
import cardknox.payments.sdk.CardknoxSDK;

public class CardReaderEventsExampleFragment extends Fragment {
    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        RegisterIntentFilters();
    }

    @Override
    public void onDetach() {
        super.onDetach();
        UnregisterIntentFilters();
    }

    private void RegisterIntentFilters()
    {
        Context c = getContext();

        if(c != null)
        {
            c.registerReceiver(Receiver_CardReaderEvents, new IntentFilter(CardknoxSDK.CARDREADER_CALLBACK_INTENTFILTER_ACTION()));
        }
    }

    private void UnregisterIntentFilters()
    {
        Context c = this.getContext();

        if(c != null)
        {
            c.unregisterReceiver(Receiver_CardReaderEvents);
        }
    }

    private final BroadcastReceiver Receiver_CardReaderEvents = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent)
        {
            String action = intent.getAction();

            // Verify that the Cardknox SDK broadcasted the Intent
            if(action.equals(CardknoxSDK.CARDREADER_CALLBACK_INTENTFILTER_ACTION()))
            {
                String extraKey = CardknoxSDK.CARDREADER_CALLBACK_INTENTFILTER_EXTRA();
                CardknoxCardReaderCallback callback = intent.getParcelableExtra(extraKey);

                // Read the event code
                int code = callback.GetCode();

                // Read the event name
                String name = callback.GetName();

                Output("Card reader event: " + name);

                // Match the non-error code; for example "connected"
                if(code == CardknoxCardReaderCallbackType.CONNECTED){
                    Output("Connected!");
                }

                // Extract the message when there's an error
                if(code == CardknoxCardReaderCallbackType.ERROR){
                    String message = callback.GetMessage();
                    Output("Card reader event: " + message);
                }
            }
        }
    };

    private void Output(String text)
    {
        android.util.Log.d("ExampleTag", text);
    }
}

Card reader events

When a card reader event happens, the SDK delivers an object, of a type named similarly to “CardknoxCardReaderCallback”, back into the app.

The object encapsulates two things:

an event integer code
an event name; such as “connected”, “disconnected”, etc.

Event integer codes are enumerated in a type named similarly to "CardknoxCardReaderCallbackType".

Developers can match the received integer code value with the enumeration of interest to pinpoint a wanted event.

Event name

Description

connecting

The Cardknox SDK calls into the card reader SDK to connect with the reader, in scenarios such as:

“connect to device” method in the “custom ui” integration
when it presents its own UI in “process out of scope” integration

The card reader SDK starts searching for nearby IDTech card readers & notifies the Cardknox SDK with a “connecting” event.

The Cardknox SDK raises a “connecting” callback which notifies the app.

waitingForDeviceResponse

This event is raised whenever the Cardknox SDK scans for nearby card readers. Awake readers are usually auto connected straight away.

Asleep or not, this event is always raised from the SDK to indicate that some action is required on the device.

This event is raised in the “custom ui” integration when:

a developer calls the “start scanning” method and the underlying bluetooth adapter starts scanning
or when a Developer calls the “connect to device” method. Sola SDK will call the card reader SDK to “connect” and raise this event

This event is raised in the “process out of scope” integration when:

the Cardknox SDK presents its user interface; automatically starting a bluetooth scan for a nearby card reader, expecting a response back

connected

Raised when the app & the card reader establish a bluetooth connection.

Bluetooth connection is established when the Cardknox SDK scans for card readers, and card readers respond back with some bluetooth payload.

disconnected

Card reader SDK sends this event to the Cardknox SDK whenever a bluetooth card reader goes to sleep.

This event is never raised explicitly by the Cardknox SDK.

transactionStarting

Informational event.

Cardknox SDK raises this event before it places a call to the underlying card reader SDK in order to start a transaction with the card reader.

transactionStarted

Cardknox SDK attempts a “start transaction” call with the card reader SDK.

Card reader SDK successfully starts the transaction and notifies the Cardknox SDK with this event.

Cardknox SDK calls back with this event to the app.

transactionStartErrorTimeout

Cardknox SDK attempts a “start transaction” call with the card reader SDK.

The card reader never receives a card in a specified timeout frame window (about 20 seconds) and the transaction times out.

transactionStartDeviceDisconnected

Cardknox SDK wants to start the transaction with a disconnected device.

transactionCancelled

Generally, this is raised whenever an error occurs at any point between starting a transaction with the reader and obtaining the card data.

See the “error” event for error examples.

The Cardknox SDK in cases of these errors preventively calls the “cancel any pending transactions” internally to clean up.

Specifically, this event is raised in the “custom ui” integration when:

a “cancel transaction” method is called & the card reader SDK cancels all pending transactions between the app & the card reader

Furthermore, this event is raised in the “process out of scope” integration when:

the Cardknox SDK’s user interface is closed; either via a pull down gesture or via a “close” UI element; to clean things up
the charge amount gets modified via UI and becomes invalid, effectively invalidating any pending transactions between the app & the card reader

scanStop

Indicates that the Cardknox SDK stopped its own bluetooth scanning.

Raised in the “custom ui” integration when:

a Developer explicitly calls the “stop scanning” method
when the “start scanning” method was called with a timeout value and the timeout expired or was cancelled / interrupted
in the “disconnect from current device” call if the “connect to device” method was called beforehand but there is no connected device to disconnect from

Raised in the “process out of scope” integration when:

the SDK shows its' UI and automatically starts scanning for nearby readers. User can explicitly stop the scanning process

scanStart

Indicates that the Cardknox SDK started a bluetooth scanning process.

Raised in the “custom ui” integration when:

the “start scanning” method was called, with or without a timeout value

Raised in the “process out of scope” integration when:

the SDK shows its' UI and automatically starts scanning for nearby readers

error

This is raised whenever an error occurs at any point between starting a transaction with the reader and obtaining the card data.

Things that could go wrong (list is not exhaustive) are:

transaction with the card reader failed to start
emv card readings are corrupted
transaction started but the card was not tapped / swiped / inserted in time

A descriptive error message is always accompanying this event.

swipe says use chip reader

This card reader event is raised when the card with a chip is swiped, to indicate that a “fallback Swipe” was blocked. Reach out to Sola support to consult about “fallback Swipe”.

card inserted when ctls swipe requested

in some scenarios, the VP3300 will expect a Swipe, but will receive a card Insert. In such cases this event is raised.

contactless in msr card read event

this event is raised when a Contactless MSD transaction is performed on a VP3300 device.

USB detached

This event occurs when the USB cable is unplugged, causing the connection between the mobile device and the card reader to be interrupted. As a result, any ongoing communication or data transfer between the two devices is immediately stopped.

Note: Only available for Custom UI with USB integration.

USB device not found

This is raised when you try to connect to the card reader that's not plugged in with a USB cable.

Note: Only available for Custom UI with USB integration.

USB unsupported product

This means that the connected USB device is not supported by the system or the driver.

Note: Only available for Custom UI with USB integration.

USB permission not granted

This error occurs when the application does not have the necessary permission to access the connected USB device. The user must explicitly grant permission for the device to be recognized and used.

Note: Only available for Custom UI with USB integration.

Scanned bluetooth device callback subscription

One of the Custom UI integration functions is a “start scanning” function. The function keeps scanning for nearby bluetooth devices until it is manually stopped with the “stop scanning” function or if it times out.

During the scanning process, for every scanned device the SDK sends a “scanned device” object that contains all the necessary metadata about the scanned device, such as the devices' display name or its internal name.

Subscription can be made in the appropriate Fragment lifecycle method:

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;

import cardknox.payments.sdk.CardknoxSDKCustomUI;
import cardknox.payments.sdk.CardknoxSDKCustomUIScannedDevice;

public class ScannedDeviceExampleFragment extends Fragment {
    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        RegisterIntentFilters();
    }

    @Override
    public void onDetach() {
        super.onDetach();
        UnregisterIntentFilters();
    }

    private void RegisterIntentFilters()
    {
        Context c = getContext();

        if(c != null)
        {
            c.registerReceiver(Receiver_ScannedDevice, new IntentFilter(CardknoxSDKCustomUI.SCANNED_DEVICE_INTENTFILTER_ACTION()));
        }
    }

    private void UnregisterIntentFilters()
    {
        Context c = this.getContext();

        if(c != null)
        {
            c.unregisterReceiver(Receiver_ScannedDevice);
        }
    }

    private final BroadcastReceiver Receiver_ScannedDevice = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent)
        {
            String action = intent.getAction();

            // Verify that the Cardknox SDK broadcasted the Intent
            if(action.equals(CardknoxSDKCustomUI.SCANNED_DEVICE_INTENTFILTER_ACTION()))
            {
                String extraKey = CardknoxSDKCustomUI.SCANNED_DEVICE_INTENTFILTER_EXTRA();
                java.lang.Object extra = intent.getParcelableExtra(extraKey);

                CardknoxSDKCustomUIScannedDevice device = (CardknoxSDKCustomUIScannedDevice) extra;
                // Can be used with a 'connect' method, like so:
                String address = device.GetAddress();
                CardknoxSDKCustomUI example = null;
                example.connectWithAddress(address);
                
                // Output various data about the device
                Output("Scanned device name: " + device.GetName());
                Output("Scanned device display name: " + device.GetDisplayName());
                Output("Scanned device address: " + device.GetAddress());
            }
        }
    };

    private void Output(String text)
    {
        android.util.Log.d("ExampleTag", text);
    }
}

Scan completed callback subscription

Once the scanning process ends, the SDK sends a list of scanned device objects to all subscribers. Any object in the retrieved list can be used as an argument to the “connect to device” method.

Subscription can be made in the appropriate Fragment lifecycle method:

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;

import cardknox.payments.sdk.CardknoxSDKCustomUI;
import cardknox.payments.sdk.CardknoxSDKCustomUIScanCompleted;
import cardknox.payments.sdk.CardknoxSDKCustomUIScannedDevice;

public class ScanCompletedExampleFragment extends Fragment {
    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        RegisterIntentFilters();
    }

    @Override
    public void onDetach() {
        super.onDetach();
        UnregisterIntentFilters();
    }

    private void RegisterIntentFilters()
    {
        Context c = getContext();

        if(c != null)
        {
            c.registerReceiver(Receiver_ScanCompleted, new IntentFilter(CardknoxSDKCustomUI.SCAN_COMPLETED_INTENTFILTER_ACTION()));
        }
    }

    private void UnregisterIntentFilters()
    {
        Context c = this.getContext();

        if(c != null)
        {
            c.registerReceiver(Receiver_ScanCompleted, new IntentFilter(CardknoxSDKCustomUI.SCAN_COMPLETED_INTENTFILTER_ACTION()));
        }
    }

    private final BroadcastReceiver Receiver_ScanCompleted = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent)
        {
            String action = intent.getAction();

            // Verify that the Cardknox SDK broadcasted the Intent
            if(action.equals(CardknoxSDKCustomUI.SCAN_COMPLETED_INTENTFILTER_ACTION()))
            {
                String extraKey = CardknoxSDKCustomUI.SCAN_COMPLETED_INTENTFILTER_EXTRA();
                java.lang.Object extra = intent.getParcelableExtra(extraKey);
                CardknoxSDKCustomUIScanCompleted scanCompleted = (CardknoxSDKCustomUIScanCompleted) extra;

                if(scanCompleted != null && scanCompleted.scannedDevices() != null &&
                        scanCompleted.scannedDevices().size() > 0)
                {
                    for (Object device : scanCompleted.scannedDevices()) {
                        CardknoxSDKCustomUIScannedDevice device = (CardknoxSDKCustomUIScannedDevice)d;

                        // Can be used with a 'connect' method, like so:
                        String address = device.GetAddress();
                        CardknoxSDKCustomUI example = null;
                        example.connectWithAddress(address);

                        // Output various data about the device
                        Output("Scanned device name: " + device.GetName());
                        Output("Scanned device display name: " + device.GetDisplayName());
                        Output("Scanned device address: " + device.GetAddress());
                    }
                }
            }
        }
    };

    private void Output(String text)
    {
        android.util.Log.d("ExampleTag", text);
    }
}

Device status callback subscription

This callback provides information about the status of the card reader. It sends information about the initialization process of the device, the connection process of the card reader, and the mobile device. It also sends notifications about the actions expected by the user of the credit card.

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;

import cardknox.payments.sdk.CardknoxPaymentEngineSDK;

public class DeviceStatusExampleFragment extends Fragment {

    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        RegisterIntentFilters();
    }

    @Override
    public void onDetach() {
        super.onDetach();
        UnregisterIntentFilters();
    }

    private void RegisterIntentFilters()
    {
        Context c = getContext();

        if(c != null)
        {
            c.registerReceiver(Receiver_DeviceStatus, new IntentFilter(CardknoxPaymentEngineSDK.DEVICE_STATUS_INTENTFILTER_ACTION()));
        }
    }

    private void UnregisterIntentFilters()
    {
        Context c = this.getContext();

        if(c != null)
        {
            c.unregisterReceiver(Receiver_DeviceStatus);
        }
    }

    private final BroadcastReceiver Receiver_DeviceStatus = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();

            // Verify that the Cardknox SDK broadcasted the event
            if(action.equals(CardknoxPaymentEngineSDK.DEVICE_STATUS_INTENTFILTER_ACTION()))
            {
                String extraKey = CardknoxPaymentEngineSDK.DEVICE_STATUS_INTENTFILTER_EXTRA();
                String deviceStatus = intent.getStringExtra(extraKey);
                Output(deviceStatus);
            }
        }
    };

    private void Output(String text)
    {
        android.util.Log.d("ExampleTag", text);
    }
}

Transaction status callback subscription

The transaction status callback sends information about the card scanning process. This callback starts triggering when the user inserts or swipes the credit card and ends with the result of card scanning.

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;

import cardknox.payments.sdk.CardknoxPaymentEngineSDK;

public class TransactionStatusExampleFragment extends Fragment {

    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        RegisterIntentFilters();
    }

    @Override
    public void onDetach() {
        super.onDetach();
        UnregisterIntentFilters();
    }

    private void RegisterIntentFilters()
    {
        Context c = getContext();

        if(c != null)
        {
            c.registerReceiver(Receiver_TransactionStatus, new IntentFilter(CardknoxPaymentEngineSDK.TRANSACTION_STATUS_INTENTFILTER_ACTION));
        }
    }

    private void UnregisterIntentFilters()
    {
        Context c = this.getContext();

        if(c != null)
        {
            c.unregisterReceiver(Receiver_TransactionStatus);
        }
    }

    private final BroadcastReceiver Receiver_TransactionStatus = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();

            // Verify that the Cardknox SDK broadcasted the event
            if(action.equals(CardknoxPaymentEngineSDK.TRANSACTION_STATUS_INTENTFILTER_ACTION()))
            {
                String extraKey = CardknoxPaymentEngineSDK.TRANSACTION_STATUS_INTENTFILTER_EXTRA();
                String deviceStatus = intent.getStringExtra(extraKey);
                Output(deviceStatus);
            }
        }
    };

    private void Output(String text)
    {
        android.util.Log.d("ExampleTag", text);
    }
}

Result as JSON callback subscription

The callback for a basic processed transaction response returns information about the transaction as an object with properties. Each property of the object corresponds to a specific piece of transaction data. However, the payment engine has an additional callback for the transaction result, which is returned as JSON. In this callback, instead of returning the transaction as an object, the processed transaction is provided as a text representation of a JSON object.

To receive the transaction response as JSON using this callback, you must call the SetSendResponseAsJSON(true) method on CardknoxPaymentEngineSDKobject . Otherwise, the transaction result will return the response as an object. The transaction response can only be received through a single callback at any given time. This means that only one callback handler is allowed to process the response for a specific transaction, ensuring consistency and avoiding potential conflicts or duplicate processing.

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;

import androidx.fragment.app.Fragment;

import cardknox.payments.sdk.CardknoxPaymentEngineSDK;
import cardknox.payments.sdk.CardknoxPaymentEngineSDKRequest;
import cardknox.payments.sdk.CardknoxPaymentEngineSDKResponseJSON;
import cardknox.payments.sdk.CardknoxPaymentEngineSDKSettings;
import cardknox.payments.sdk.CardknoxSDK;

public class PaymentEngineExampleFragment extends Fragment {

    private void SetupReceivePaymentEngineResponseAsJSON(){
        Context applicationContext = null;
        CardknoxSDK.create().getPaymentEngine().SetSendResponseaAsJSON(true);
        try { applicationContext.unregisterReceiver(Result_PaymentEngineResponseAsJSON);} catch(Exception e) {}
        applicationContext.registerReceiver(Result_PaymentEngineResponseAsJSON, new IntentFilter(CardknoxPaymentEngineSDK.PAYMENTENGINE_JSON_INTENTFILTER_ACTION()));
    }

    private final BroadcastReceiver Result_PaymentEngineResponseAsJSON = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {

            String action = intent.getAction();
            // Verify that the Cardknox SDK broadcasted the Intent
            if (action != null && action.equals(CardknoxPaymentEngineSDK.PAYMENTENGINE_JSON_INTENTFILTER_ACTION())) {

                String extraKey = CardknoxPaymentEngineSDK.PAYMENTENGINE_JSON_INTENTFILTER_EXTRA();
                java.lang.Object extra = intent.getParcelableExtra(extraKey);
                // Cast
                CardknoxPaymentEngineSDKResponseJSON response = (CardknoxPaymentEngineSDKResponseJSON) extra;
                String json = response.GetJSON();
            }
        }
    };

    private void SetupPaymentEngineBroadcastsLogCatMessages(){
        Context context = null;
        CardknoxPaymentEngineSDK paymentEngine = CardknoxSDK.create().getPaymentEngine();
        // PaymentEngine logging, 2 options:
        // 1. SDK writes the PE log to LogCat directly
        // 2. SDK sends the PE log it wants to write to this app (via BroadcastReceiver)
        // Note: calling 1 method negates the other one
        boolean broadcast = false;
        boolean writeDirectly = true;
        if(broadcast && writeDirectly)
            throw new RuntimeException("PE logs can either be directly written to LogCat or broadcasted back to this app, not both");

        if(writeDirectly){
            paymentEngine.enableLogCatOutput("LogCatTag");
        }
        else if(broadcast){
            paymentEngine.enableLogCatBroadcasts(true);
            // subscribe to logcat broadcasts
            try { context.unregisterReceiver(Receiver_LogcatMessages);} catch(Exception e) {}
            context.registerReceiver(Receiver_LogcatMessages, new IntentFilter(CardknoxPaymentEngineSDK.LOGGER_INTENTFILTER_ACTION()));
        }
    }

    private final BroadcastReceiver Receiver_LogcatMessages = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            if(intent != null) {
                String action = intent.getAction();
                if (action != null && action.equals(CardknoxPaymentEngineSDK.LOGGER_INTENTFILTER_ACTION())) {
                    String logcatMessage = "unknown";

                    String extraKey= CardknoxPaymentEngineSDK.LOGGER_INTENTFILTER_EXTRA();
                    if(intent.hasExtra(extraKey))
                        logcatMessage = intent.getStringExtra(extraKey);

                    android.util.Log.d("SomeTag", logcatMessage);
                }
            }
        }
    };


    private void Device_ReprintReceipt_Example(){
        CardknoxPaymentEngineSDKSettings settings = new CardknoxPaymentEngineSDKSettings();
        settings.SetDevice_IP_Address("specify IP");
        settings.SetDevice_IP_Port("specify port");
        settings.SetDevice_Name("specify device name, such as PAX_A77.3");
        settings.SetDevice_Timeout(5 * 1000); /* milliseconds to seconds */

        CardknoxPaymentEngineSDKRequest request = new CardknoxPaymentEngineSDKRequest();
        request.SetxAuthCode("add auth code here");

        String response = CardknoxSDK.create().getPaymentEngine().Device_ReprintReceipt(settings, request);
        boolean success = response.equals("OK");
    }

}

Payment engine LogCat logging callback subscription

LogCat callback logging is a feature that allows the payment engine to send log messages directly to the application through callbacks. When enabled—by setting the EnableLogcatBroadcasts property to true—the app receives log events programmatically instead of relying only on the standard LogCat console output.

This method gives developers more control over how logs are used. Logs can be captured, filtered, stored, or forwarded to external monitoring systems, making it especially useful in production environments where console access is limited. It also enables building custom logging tools within the app for advanced debugging and diagnostics.

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;

import androidx.fragment.app.Fragment;

import cardknox.payments.sdk.CardknoxPaymentEngineSDK;
import cardknox.payments.sdk.CardknoxPaymentEngineSDKRequest;
import cardknox.payments.sdk.CardknoxPaymentEngineSDKResponseJSON;
import cardknox.payments.sdk.CardknoxPaymentEngineSDKSettings;
import cardknox.payments.sdk.CardknoxSDK;

public class PaymentEngineExampleFragment extends Fragment {

    private void SetupPaymentEngineBroadcastsLogCatMessages(){
        Context context = null;
        CardknoxPaymentEngineSDK paymentEngine = CardknoxSDK.create().getPaymentEngine();
        // PaymentEngine logging, 2 options:
        // 1. SDK writes the PE log to LogCat directly
        // 2. SDK sends the PE log it wants to write to this app (via BroadcastReceiver)
        // Note: calling 1 method negates the other one
        boolean broadcast = false;
        boolean writeDirectly = true;
        if(broadcast && writeDirectly)
            throw new RuntimeException("PE logs can either be directly written to LogCat or broadcasted back to this app, not both");

        if(writeDirectly){
            paymentEngine.enableLogCatOutput("LogCatTag");
        }
        else if(broadcast){
            paymentEngine.enableLogCatBroadcasts(true);
            // subscribe to logcat broadcasts
            try { context.unregisterReceiver(Receiver_LogcatMessages);} catch(Exception e) {}
            context.registerReceiver(Receiver_LogcatMessages, new IntentFilter(CardknoxPaymentEngineSDK.LOGGER_INTENTFILTER_ACTION()));
        }
    }

    private final BroadcastReceiver Receiver_LogcatMessages = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            if(intent != null) {
                String action = intent.getAction();
                if (action != null && action.equals(CardknoxPaymentEngineSDK.LOGGER_INTENTFILTER_ACTION())) {
                    String logcatMessage = "unknown";

                    String extraKey= CardknoxPaymentEngineSDK.LOGGER_INTENTFILTER_EXTRA();
                    if(intent.hasExtra(extraKey))
                        logcatMessage = intent.getStringExtra(extraKey);

                    android.util.Log.d("SomeTag", logcatMessage);
                }
            }
        }
    };
}

Out of scope integration

Out of scope processing feature allows the developer to show the Cardknox user interface for payment processing.

To show the user interface, create a request object that is capable of showing a user interface:

// Create the parameters object
TransactionParameters parameters = new TransactionParameters()
{
    {
        // Required parameters
        // 1. command to use. One of the Cardknox Transaction API commands
        SetxCommand("cc:sale");
        // 2. amount
        SetxAmount(1.23);

        // Supplementary parameters
        // 1. card number - will be prefilled on the keyed form
        SetxCardNum("4444333322221111");

        // 2. expiration date - will be prefilled on the keyed form
        // Format "MMYY"
        // For example: December 2024
        SetxExp("1224");

        // Optional parameters to supplement the transaction
        // All of the available parameters will be sent to the gateway
        SetxInvoice("1234");
        SetxBillCity("New York");
        // ... other optional parameters.
    }
};

PaymentTransactionRequestUI request = cardknoxSDKUI.createRequestWithParameters(parameters);

Check if the request object is in a valid state. If it is, call the method to show the UI. Otherwise, inspect the validation errors to see what is incorrect in the request object:

PaymentTransactionRequestUI request = cardknoxSDKUI.createRequestWithParameters(parameters);

if(request.GetIsValid()){
    // Supply the Activity reference here.
    // In fragments, that might be a 'getActivity()' call.
    android.app.Activity activity = null;
    
    // Show Cardknox SDK UI
    request.process(activity);
} else {
    // Extract all validation errors that block
    // the request object from showing the SDK UI
    String[] validationErrors = request.GetValidationErrors();
}

Available user interfaces

The SDK’s user interface consists of two fullscreen parts - a manual entry screen and a card reader screen. Manual entry screen is also abbreviated as a “keyed” screen. The card reader screen is also abbreviated as a “swipe” screen.

Showing the SDK user interface via a Request object will either show one of the screens, or both. Which screen will be visible depends on the global SDK configuration state prior to showing the SDK user interface via a Request object.

Note that if the SDK is configured to allow access to both processing screens, one of them will be shown by default and both of them will have some kind of a visual way to navigate to the other one.

The following table shows available functions to control which screen will be visible & accessible:

Function

Description

Sample data

EnableDeviceInsertSwipeTap

Globally configures the SDK to show the keyed screen that allows manual input interaction.

CardknoxSDKUI.SetEnableDeviceInsertSwipeTap(true);

EnableKeyedEntry

Globally configures the SDK to show the swipe screen that allows card reader interaction.

CardknoxSDKUI.SetEnableKeyedEntry(true);

The following mapping represents which screens will be available when the SDK shows its user interface:

EnableDeviceInsertSwipeTap

EnableKeyedEntry

Keyed screen available

Swipe screen available

false

Yes

true

false

Yes

false

true

Yes

true

Yes

The following mapping represents available Cardknox Transaction API commands on each user interface

Keyed

Swipe

Any Cardknox Transaction API command

Any of the following credit card commands:

cc:save
cc:credit
cc:authonly
cc:sale

Reference: Transaction API

Pre processing options

Developer using the Out Of Scope integration to process using the VP3300 card reader can specify a per-request transaction timeout value. The SDK will start a transaction with the VP3300 reader, and timeout in the specified time frame if the card is not tapped, swiped or inserted in that same time frame.

Function/property

Description

Sample data

VP3300TransactionTimeout

Start transaction value, in seconds.

CardknoxSDKUI ui = CardknoxSDKUI.create();
TransactionParameters parameters = new TransactionParameters();
parameters.SetVP3300TransactionTimeout(13);
PaymentTransactionRequestUI req = ui.createRequestWithParameters(parameters);
// Enable swipe screen in the Cardknox UI
CardknoxSDKUI.SetEnableDeviceInsertSwipeTap(true);
// Show Cardknox UI
Activity activity = null; // Obtain an Activity reference
req.process(activity);

Post processing options

After the out-of-scope function finishes with transaction processing, the SDK displays a popup containing a handful of information about the transaction.

The SDK can be configured to auto close the user interface immediately after the transaction processing has completed; regardless if the transaction was approved or not.

Function

Description

Sample data

CloseSDKUIOnProcessedTransaction

Globally configures the SDK to auto close the user interface after processing a transaction.

Default value is false.

CardknoxSDKUI.SetCloseSDKUIOnProcessedTransaction(false);

In scope integration

In scope processing feature allows the developer to quickly process a payment and retrieve the response object.

To process directly, create a request object:

// Create the parameters object
TransactionParameters parameters = new TransactionParameters()
{
    {
        // Required parameters
        SetxCommand("cc:sale");
        SetxAmount(1.23);
        SetxCardNum("4444333322221111");
        // Format "MMYY"
        // For example: December 2024
        SetxExp("1224");

        // Optional parameters to supplement the transaction
        SetxInvoice("1234");
    }
};

// Create the request object
PaymentTransactionRequestDirect request = cardknoxSDKDirect.createRequestWithParameters(parameters);

Check if the request object is in a valid state. If it is, call the method to process directly. Otherwise, inspect the validation errors to see what is incorrect in the request object:

PaymentTransactionRequestDirect request = cardknoxSDKDirect.createRequestWithParameters(parameters);

if(request.GetIsValid()) {
    PaymentTransactionResponse response = request.process();

    boolean isSuccess = response.GetIsSuccess();
    String errorMessage = response.GetErrorMessage();
    String errorCode = response.GetxErrorCode();
    String refNum = response.GetxRefNum();
} 
else {
    String[] errors = request.GetValidationErrors();  
}

Available commands

Check (ACH) commands
- Reference: Check (ACH)
Credit Card commands
- Reference: Credit Card
EBT Food Stamp commands
- Reference: EBT Food Stamp
EBT Cash Benefits
- Reference: EBT Cash Benefits
EBT Wic
- Reference: EBT Wic
Gift Card commands
- Reference: Gift Card

Custom UI integration

Custom UI integration is similar to the “out of scope” integration in a way that the exact same methods that the “out of scope” is using under the hood for controlling the card reader, are exposed via the SDK for the Developer to use.

The Developer can choose and use two connection method to create a transaction with the card reader device, the Bluetooth and USB. Bluetooth is a wireless method of communication between a card reader and a mobile device. To use Bluetooth, the mobile device must have Bluetooth capability and must have Bluetooth permissions enabled. The SDK takes care of the availability of Bluetooth and Bluetooth permissions. On the other hand, the USB connection method uses a wire for communication between the card reader and the mobile device. The USB method is the simplest and most direct method, as the connection between the card reader and the mobile phone is a strong connection. This means that the mobile device does not need to scan to find and communicate with the card reader. The USB method is also not affected by the card reader's sleep feature, while with Bluetooth, the connection is lost when the reader goes into sleep mode.

The SDK cannot automatically recognize what connection methods card reader supports and cannot automatically initiate communication between the reader and the mobile device. Therefore, the Developer must decide which connection method to use and for which card reader. The CardknoxSDK object has two different functions that return an instance of communication manager for card readers based on communication method. The getCustomUIBluetooth() for Custom UI with Bluetooth and getCustomUIUSB()for Custom UI with USB. Both Bluetooth and USB only support the VP3300 device.

The Developer provides the user interface and orchestrates the entire flow for obtaining the card data via the card reader by calling appropriate Custom UI functions at specific times.

Custom UI with Bluetooth

The CardknoxSDKtype provides a function to obtain the Custom UI manager:

CardknoxSDK.create().getCustomUIBluetooth();

Function

Description

Sample data

StartScanningWithTimeout

Starts the “scan for nearby bluetooth devices” process.

If the timeout value is 0 or a negative number, the scanning never times out.

A card reader event similar to “waiting for device response” will be raised once the scanning starts. This usually means that the user needs to press the physical button in order for the card reader device to be visible to nearby scanners.

// Indefinite scan until stopped 
CardknoxSDK.create().getCustomUIBluetooth().startScanningWithTimeout(0);

// Scan with a timeout
CardknoxSDK.create().getCustomUIBluetooth().startScanningWithTimeout(20);

StopScanning

Attempts to stop the bluetooth device scanning process.

Raises a “stop scan” card reader event.

Doesn’t do anything if scanning is not in progress.

If the method stops the scanning process, the SDK reports all scanned devices via a callback.

CardknoxSDK.create().getCustomUIBluetooth().stopScanning();

ConnectWithName

Accepts a device name.

Configures the SDK to be ready to establish a Bluetooth connection with the nearby VP3300 device with a name equal to the provided name.

After the call:

the card reader & the app are not connected immediately but rather the SDK notifies the developer about various card reader events taking place after this method is called; such as “connecting” and “waiting for device response”
if the VP3300 devices’ bluetooth is not asleep when this method is called, the card reader auto connects to the app

String deviceName = "IDTECH-VP3300-12345";
CardknoxSDK.create().getCustomUIBluetooth().connectWithName(deviceName);

ConnectWithAddress

Accepts a MAC address.

Configures the SDK to be ready to establish a Bluetooth connection with the nearby VP3300 device with the internal MAC address equal to the provided value.

String addr = "00:1C:97:1D:EA:50";
CardknoxSDK.create().getCustomUIBluetooth().connectWithAddress(addr);

DisconnectFromCurrentDevice

Attempts to break the connection between the application & the card reader. If the card reader is not connected to the app, a card reader event similar to “disconnected already” is raised.

Otherwise, the SDK attempts to disconnect the card reader. If successful, the “disconnected” card reader event is raised.

CardknoxSDK.create().getCustomUIBluetooth().disconnectFromCurrentDevice();

StartTransaction

Starts a transaction between an already connected application & the card reader.

Once the transaction starts, the card reader is ready to accept cards, either via swipe, tap or insert.

This method can timeout. Default value is 10 seconds. Developers can override this value via the “parameters” object.

Activity activity = null; // Provide this
TransactionParameters prms = new TransactionParameters();
prms.SetxAmount(1.23);
prms.SetxInvoice("1234");
prms.SetxCommand("cc:sale");
prms.SetVP3300TransactionTimeout(13);
CardknoxSDK.create().getCustomUIBluetooth().startTransactionWithArgs(prms);

CancelTransaction

Attempts to cancel an already started transaction between the application & the card reader.

If no transactions are started when this function is called, the function does not do anything.

CardknoxSDKCustomUI customUI = null; /* created object beforehand */

customUI.cancelTransaction();

Custom UI with USB

The CardknoxSDK object contains instance for connecting card reader with USB. Management of the card reader is done using the functions contained in the USB instance.

CardknoxSDK.create().getCustomUIUSB()

Function

Description

Sample data

ConnectVP3300

It tries to establish a communication channel between the application and the VP3300 card reader.

CardknoxSDK.create().getCustomUIUSB().connectVP3300();

DisconnectFromCurrentDevice

Termination of the communication channel between the currently connected card reader and the mobile device.

CardknoxSDK.create().getCustomUIUSB().disconnectFromCurrentDevice();

SetVP3300StartTransactionMethod

The SetVP3300StartTransactionMethod function is a method of the TransactionParameters object used to configure how a card reader initiates a card transaction. It accepts a parameter of type VP3300StartTransactionMethod, which defines the scanning method the card reader should use.

By calling this method, developers can control the specific way in which the reader should prompt and process a card during a transaction, depending on the desired input method.

The VP3300StartTransactionMethod parameter is an enumerated type that supports the following constant values:

CTLS – Contactless card transaction
EMV – Chip (contact) card transaction
MSR – Magnetic stripe card transaction
DEVICE – Default or device-specific scanning behaviour.

TransactionParameters prms = new TransactionParameters(); prms.SetVP3300StartTransactionMethod(VP3300StartTransactionMethod.MSR); CardknoxSDK.create().getCustomUIUSB().startTransactionWithArgs(prms);

StartTransactionWithArgs

Starts a transaction between an already connected application & the card reader.

Once the transaction starts, the card reader is ready to accept cards, either via swipe, tap or insert.

Developers can override this value via the “parameters” object.

TransactionParameters prms = new TransactionParameters(); prms.SetxAmount(1.23); prms.SetxInvoice("1234"); prms.SetxCommand("cc:sale"); prms.SetVP3300TransactionTimeout(13); CardknoxSDK.create().getCustomUIUSB().startTransactionWithArgs(prms);

CancelTransaction

Attempts to cancel an already started transaction between the application & the card reader.

If no transactions are started when this function is called, the function does not do anything.

CardknoxSDK.create().getCustomUIUSB().cancelTransaction();

Available commands

Any of the following credit card commands are available for Custom UI:

cc:save
cc:credit
cc:authonly
cc:sale

Reference: Credit Card

Custom UI flow

First, create a “custom ui” object to get access to all the Custom UI functions. Afterwards, subscribe to all the relevant callbacks for this integration path:

transaction result callback - to receive the “response” object after the SDK has processed a transaction
card reader event callback - to be notified about various events that take place between the application & the card reader
scanned bluetooth device callback - to be notified about every new scanned bluetooth device during the “scan for devices” process
scan completed callback - to be notified about all the scanned devices once the “scan for devices” process ends

Next step is to establish a connection between the app and the card reader device. Use one of the “connect” methods on the “custom ui” to initiate a connection; such as “connect with name” or “connect with address”.

Device name or the MAC address can be obtained with the “scan for devices” flow. Initiate the “start scanning” function call, with or without a timeout.

The scanning process stops with a call to the “stop scanning” function or when the “start scanning” function times out.

After establishing a connection with the card reader by calling one of the “connect” methods and receiving a “connected” card reader event via the BroadcastReceiver subscription, call the “start transaction” function to make the card reader ready for a card.

The SDK will report a “transaction started” event if the transaction with the card reader was successfully started, otherwise an “error” card reader event is reported back. At this point the card can be tapped, swiped or inserted into the card reader. The SDK will read the card information, process a transaction & deliver the results to the application via a callback.

If no card is tapped, swiped or inserted after the transaction started - a “timeout” card reader is reported back. The default timeout value is about 10 seconds. The developer can override this value via the “transaction parameters” object.

Payment engine integration

The Payment Engine won't show any UI. The developer provides the user interface and uses three payment engine functions to create transactions with a card reader over IP. Data that is required to create a transaction is passed by developers as parameters to those SDK functions. The messages and results of creating a transaction with the Payments engine are obtained by the developer from transaction result callback, device status callback, and transaction status.

Function

Description

Sample data

Device_Initialize

This function makes sure that the mobile device can communicate with the card reader and saves data that is needed for connecting to the card reader.

The initialization process can take about 2 minutes. But it is sufficient to execute it once per card reader and IP address.

ProcessOutOfScopeWithSettings

Attempts to create a transaction with a card reader over IP.

This function will perform the initialization process if initialization has not been performed for the specific card reader.

CardknoxPaymentEngineSDKSettings settings = new CardknoxPaymentEngineSDKSettings(); settings.SetDevice_IP_Port("9001"); settings.SetDevice_IP_Address("127.21.2.7"); settings.SetDevice_Name("Verifone_P400.4"); settings.SetDevice_Timeout(120 * 1000); // 120 seconds; CardknoxPaymentEngineSDKRequest request = new CardknoxPaymentEngineSDKRequest(); request.SetxCommand("cc:sale"); request.SetxAmount(1.23); CardknoxSDK.create().getPaymentEngine().ProcessOutOfScope(settings, request);

Device_CancelTransaction

Attempts to cancel an already started transaction between the application & the card reader.

If no transactions are started when this function is called, the function does not do anything.

CardknoxSDK.create().getPaymentEngine().Device_CancelTransaction();

SetSendResponseaAsJSON

This function configures the SDK for Payment Engine integration. When the value is set to true, the SDK returns a processed transaction response via the Result as JSON callback. Otherwise, the transaction response is provided through the basic Transaction Result callback.

CardknoxSDK.create().getPaymentEngine().SetSendResponseaAsJSON(true);

EnableLogcatBroadcasts

The EnableLogcatBroadcasts property enables log delivery via callbacks. When set to true, the payment engine sends logs to the app instead of just printing them to the LogCat console, allowing custom handling of log messages.

CardknoxSDK.create().getPaymentEngine().enableLogCatBroadcasts(true);

Device_ReprintReceipt

This method is used to reprint a transaction receipt from the card reader. This function allows users to reprint receipts for any previous transaction. It is useful in situations where a receipt was not printed correctly, was lost, or when a customer requests a duplicate or previous transaction receipt

CardknoxPaymentEngineSDKSettings settings = new CardknoxPaymentEngineSDKSettings(); settings.SetDevice_IP_Address("specify IP"); settings.SetDevice_IP_Port("specify port"); settings.SetDevice_Name("specify device name, such as PAX_A77.3"); settings.SetDevice_Timeout(5 * 1000); /* milliseconds to seconds */ CardknoxPaymentEngineSDKRequest request = new CardknoxPaymentEngineSDKRequest(); request.SetxAuthCode("add auth code here"); String response = CardknoxSDK.create().getPaymentEngine().Device_ReprintReceipt(settings, request); boolean success = response.equals("OK");

Versioning

Developers can read from the cardknox.payments.sdk.BuildConfig class, properties are:

VERSION_NAME

Major SDK version

VERSION_CODE

Release number in the major SDK version

GIT_HASH

Git tag for troubleshooting

Logging

SDK verbose logging can be enabled or disabled with a function call:

Function

Description

Sample data

EnableLogging

Accepts a boolean.

Enables or disabled the verbose logging.

CardknoxSDK.enableLogging(false);

FAQ

As a Cardknox SDK user, I want to process without an internet connection. What will happen?
- The SDK will return a PaymentTransactionResponse object with a special xErrorCode value -1
As a Cardknox SDK user, I’ve encountered errors during transaction processing. What response can I expect?
- the PaymentTransactionRequest object will encapsulate all relevant information in respective fields; for example the xErrorCode property will return a code from the Cardknox Transaction API documentation, the xErrorMessage and xError properties can be used for a descriptive error message while the xRefNum gives back a unique ref num to follow up with the customer support

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Last updated 15 days ago

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