Getting Started with the Tap to Pay on Android Solution {#tap-to-phone-get-started-intro}
=========================================================================================

Use this information to get started with integrating the Tap to Pay on Android Solution. When the integration is completed, your application will be ready to start processing payments. For more information, see [Tap to Pay on Android Payment Services](/docs/cybs/en-us/tap-to-phone/integration/all/rest/tap-to-phone/tap-to-phone-payment-txn-intro.md "").

Configuring the Tap to Pay on Android SDK {#tap-to-phone-configure-ttp-intro}
=============================================================================

Use this information to configure the Tap to Pay on Android SDK.

Configure the Project *settings.gradle* File {#tap-to-phone-configure-project-settings-gradle}
==============================================================================================

Follow this step to configure your project's *settings.gradle* file.

1. Add the repository to your project's *settings.gradle* file.

   ```
   dependencyResolutionManagement {
       repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
       repositories {
           mavenCentral()
           google()
           exclusiveContent {
               forRepository {
                   maven {
                       setUrl("https://repo.visa.com/mpos-releases/")
                   }
               }
               filter {
                   includeGroup("io.payworks")
               }
           }
       }
   }
   ```

Configure the Project *build.gradle* File {#tap-to-phone-configure-project-build-gradle}
========================================================================================

Follow this step to configure your project's *build.gradle* file.

1. Add the Kotlin Gradle plug-in, which is required to use this solution. Note that Kotlin version 2.1 or later and Android Gradle version 8.2 or later are required.

   ```
   plugins {
       id("com.android.application") version "8.2.0" apply false
       id("org.jetbrains.kotlin.android") version "2.1.0" apply false
   }
   ```

Configure the Module *build.gradle* File {#tap-to-phone-configure-module-build-gradle}
======================================================================================

Follow these steps to configure your module *build.gradle* file.

1. In the Android section, add these exclusion rules to your module's *build.gradle* file.

   ```
   android {
       ...
       packaging {
           resources {
               excludes.add("META-INF/*")
               excludes.add("LICENSE.txt")
               excludes.add("asm-license.txt")
           }
       }
   }
   ```
2. In order for the app to support Java 17 features, you must set the compatibility levels.

   ```
   android {
       ...
       compileOptions {
           sourceCompatibility = JavaVersion.VERSION_17
           targetCompatibility = JavaVersion.VERSION_17
       }
       kotlinOptions {
           jvmTarget = "17"
       }
   }
   ```
3. The Tap to Pay on Android Solution library publishes a release build type only. The debug build type is not available, so set the matchingFallbacks field value to `release`.

   ```
   android {
       ...
       buildTypes {
           ...
           debug {
               matchingFallbacks.apply {
                   clear()
                   add("release")
               }
           }
       }
   }
   ```
4. > IMPORTANT Stay current with the latest SDK. The SDK repository is continuously updated to make available the six latest versions. When a new version is released, the oldest is removed and can no longer be used for new application builds. Establish a regular process for updating to the newest available SDK version to avoid potential build failures and to ensure that your application runs with the latest features, performance enhancements, and security updates.
   > Add the required Default UI and Tap to Pay on Android libraries to the Dependencies section of your module's *build.gradle* file.

   ```
   dependencies {
       ...
       // This is the Default UI dependency
       implementation("io.payworks:paybutton-android:2.113.0")

       // This is the Tap to Pay dependency
       implementation("io.payworks:mpos.android.taptophone:2.113.0")   
   }
   ```

Update the *AndroidManifest.xml* File {#tap-to-phone-configure-android-manifest-xml}
====================================================================================

To support a large heap size and ensure the necessary permissions for the Default UI, update your `AndroidManifest.xml` file. Enabling a larger heap is essential for scenarios where terminal updates require the handling and transfer of large volumes of data. WARNING

> Do not enable automatic backup in your app's *AndroidManifest* file. The Tap to Pay on Android SDK uses the Android Keystore to install and store cryptographic keys in your app. Using automatic backup restores the default encryption preferences and causes a functionality error in the Tap to Pay on Android SDK.
> Follow these steps to update your *AndroidManifest.xml* file:

1. Set the `android:allowBackup` attribute to `false` and the `android:largeHeap` attribute to `true`.

   ```
   <application
       ...
       android:allowBackup="false"
       android:largeHeap="true"
       >
       ...
   </application>
   ```
2. Enable the needed permissions for the Default UI.

   ```
   <manifest ... >
       ...
       <!-- Needed for Default UI ! -->
       <uses-permission android:name="android.permission.INTERNET"/>
       <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
       <uses-permission android:name="android.permission.READ_PHONE_STATE"/>                   
       ...
   </manifest>
   ```

Configure ProGuard Rules to Enable Obfuscation {#tap-to-phone-configure-proguard-rules}
=======================================================================================

Follow these steps to configure ProGuard rules that enable obfuscation.

1. To enable obfuscation for any of your build types, define the setting in the relevant *build.gradle* file for your app.

   ```
   buildTypes {
       release {
           isMinifyEnabled = true
           proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
       }
   }
   ```
2. If you are using ProGuard as an obfuscation tool in your app, add these rules to the *proguard-rules.pro* file.

   ```
   # OkHttp
   -keepattributes Signature
   -keepattributes *Annotation*
   -dontwarn com.squareup.okhttp.**
   -keep class com.squareup.okhttp.* { *; }
   -dontwarn okio.**

   # Acceptance Devices
   -keep class io.mpos.** { *; }
   -dontwarn io.mpos.**
   -keep class com.visa.vac.tc.** {*;}
   -keep class com.nimbusds.jose.** {*;}
   -keep class org.bouncycastle.** {*;}
   -keep class retrofit2.** { *; }
   -keep interface retrofit2.** { *; }
   -keep class com.visa.auth.** { *; }
   -dontwarn com.visa.auth.**
   -keep class androidx.** { *; }

   # Visa Sensory Branding
   -keep class com.visa.SensoryBrandingView

   # Mastercard Sonic Branding 
   -keep class com.mastercard.sonic.BuildConfig {*;}
   ```

Installing the Tap to Pay Ready App {#ttp-comply-pci-mpoc-install-app-intro}
============================================================================

The Tap to Pay Ready app must be installed on your Android device to support PCI-compliant payment processing. This app is a core component of the PCI-Certified MPoC Solution. For more information, see [PCI MPoC Standard Compliance](/docs/cybs/en-us/tap-to-phone/integration/all/rest/tap-to-phone/tap-to-phone-intro/ttp-comply-pci-mpoc-intro.md "") and [Transaction Workflow for the PCI-Certified MPoC Solution](/docs/cybs/en-us/tap-to-phone/integration/all/rest/tap-to-phone/tap-to-phone-intro/ttp-comply-pci-mpoc-txn-workflow.md "").

Install the Tap to Pay Ready App {#ttp-comply-pci-mpoc-install-app-task}
========================================================================

Use one of these options to install the Tap to Pay Ready App on your device:

* Click this [Google Play store link](https://play.google.com/store/apps/details?id=com.visa.kic.app.kernel "") to install the app directly on your Android device. No additional set up is required.
* Download the app when prompted during device enrollment. For more information, see [Enroll a Device](/docs/cybs/en-us/tap-to-phone/integration/all/rest/tap-to-phone/tap-to-phone-get-started-intro/ttp-device-enroll-intro/ttp-device-enroll-device.md "").
  {#ttp-comply-pci-mpoc-install-app-task_ul_efj_qrt_tfc}

Generating a Secret Key for an Existing Merchant ID {#ttp-mid-secret-key-generate-intro}
========================================================================================

You must enter a secret key and MID in the `mposUi` instance that you create.  
Use this information to generate a secret key for an existing merchant ID (MID) through the `Business Center` or by submitting a REST API request.  
For more information about the `mposUi` instance, see [Creating an mposUI Instance](/docs/cybs/en-us/tap-to-phone/integration/all/rest/tap-to-phone/tap-to-phone-get-started-intro/tap-to-phone-mposui-instance-create-intro.md "").

Generate a Secret Key for an Existing Merchant ID in the Business Center {#ttp-mid-secret-key-generate-ebc-task}
================================================================================================================

You can generate an secret key for an existing merchant ID (MID) in the `Business Center`. Enter these values in the `mposUi` instance that you create. For more information, see [Creating an mposUI Instance](/docs/cybs/en-us/tap-to-phone/integration/all/rest/tap-to-phone/tap-to-phone-get-started-intro/tap-to-phone-mposui-instance-create-intro.md "").  
Follow these steps to generate a secret key for an existing MID in the `Business Center`:

1. In the `Business Center`, go to the left navigation panel and choose Payment Configuration **\>** Key Management. The Key Management page appears.

2. From the Merchant drop-down list, choose the merchant ID for which you want to generate a secret key.

3. Click Generate Key.

4. In the Recommended Key Types list, scroll down and choose Acceptance Devices Secret Key.

5. Click Generate Key. The Key Generation page appears.

6. Click Generate Key. Your MID and secret key appear on the page.

7. Click the Copy or Download icon to obtain the MID and secret key.

   #### ADDITIONAL INFORMATION

   > IMPORTANT
   > If you choose to copy the secret key information instead of downloading it, be sure to save it locally. After you leave the ` Business Center ` Key Generation page, you will not be able to retrieve the same secret key again. To obtain a new key, you must restart the key generation process.

Generate a Secret Key for an Existing Merchant ID Using a REST API Request {#ttp-mid-secret-key-generate-rest-api-task}
=======================================================================================================================

You can submit a REST API request to generate a secret key for an existing merchant ID (MID). Enter these values in the `mposUi` instance you create. For more information, see [Creating an mposUI Instance](/docs/cybs/en-us/tap-to-phone/integration/all/rest/tap-to-phone/tap-to-phone-get-started-intro/tap-to-phone-mposui-instance-create-intro.md "").  
You must authenticate each request that you send to a `Cybersource` API. In order to authenticate an API request, you can use a REST shared secret key or a REST certificate. For more information about authentication requirements, see [*Getting Started with REST Developer Guide*](https://developer.cybersource.com/docs/cybs/en-us/platform/developer/all/rest/rest-getting-started/restgs-intro.md "").

Endpoints:
----------

**Test:** `POST ``https://apitest.cybersource.com``/kms/v2/keys-sym-pos`  
**Production:** `POST ``https://api.cybersource.com``/kms/v2/keys-sym-pos`

Required Fields for Generating a Secret Key for an Existing Merchant ID Using a REST API Request {#ttp-mid-secret-key-generate-api-reqfields}
=============================================================================================================================================

keyInformation.organizationId
:

REST Example: Generating a Secret Key for an Existing Merchant ID Using a REST API Request {#ttp-mid-secret-key-generate-api-ex-rest}
=====================================================================================================================================

Request

```
{
    "keyInformation":
    [
        {
            "organizationId": "transacting_MID"
        }
    ]
}
```

Response to a Successful Request

```
{
    "submitTimeUtc": "2023-08-07T13:07:17Z",
    "status": "ACCEPTED",
    "keyInformation": [
      {
           "organizationId": "transacting_MID",
           "externalOrganizationId": "MerchantId",
           "key": "SecretKey",
           "keyId": "af922a42-6d2c-41fd-92f7-09d908647de4",
           "status": "ACTIVE",
           "expirationDate": "2033-08-07T13:07:17Z"
      }
   ]
}
```

Creating an mposUI Instance {#tap-to-phone-mposui-instance-create-intro}
========================================================================

Use this information to create and configure an `mposUI` instance.

Create an `mposUI` Instance {#tap-to-phone-mposui-instance-create-task}
=======================================================================

Before starting this procedure, you must obtain secret key and merchant ID (MID) values to enter in to your `mposUI` instance. For more information, see [Generating a Secret Key for an Existing Merchant ID](/docs/cybs/en-us/tap-to-phone/integration/all/rest/tap-to-phone/tap-to-phone-get-started-intro/ttp-mid-secret-key-generate-intro.md ""). Create an `mposUI` instance to access the functionality of the Tap to Pay on Android SDK.  
Follow these steps to create an `mposUI` instance.

1. Create an `mposUI` instance using the `create` function.

2. Set the merchantId field value to the merchant ID that you obtained.

3. Set the merchantSecret field value to the secret key that you obtained.

4. Specify the environment by setting the providerMode field value to `TEST` or to `LIVE`.

   * Use the ProviderMode.TEST setting to test your integration without charging a real payment card. Use the merchant ID and secret key you obtained from the test environment.
   * Use the ProviderMode.LIVE setting to process live transactions. Use the merchant ID and secret key you obtained from the production environment.
5. Configure the accessory as Tap to Phone.

   ```
   val mposUi = MposUi.create( 
               providerMode = ProviderMode.LIVE, // ProviderMode.TEST 
               merchantId = "MerchantId", 
               merchantSecret = "SecretKey",
               terminalParameters = AccessoryParameters.Builder(AccessoryFamily.TAP_TO_PHONE).integrated().build()
           )
   ```

Configure an mposUI Instance {#tap-to-phone-uiconfig-instance-create-intro}
===========================================================================

To use the `mposUI` instance with the Tap to Pay on Android SDK, you must configure the `mposUI` instance by creating a `UiConfiguration` instance.

Create a `UiConfiguration` Instance {#tap-to-phone-uiconfig-instance-configure-task}
====================================================================================

Use a `UiConfiguration` instance to configure the UI functionality of the Tap to Pay on Android SDK.  
You can configure these parameters in the `UiConfiguration` instance that you create:

* Configure these Summary screen features:
  * Refund a transaction (`REFUND_TRANSACTION`).
  * Send a receipt by email (`SEND_RECEIPT_VIA_EMAIL`).
  * Capture a transaction (`CAPTURE_TRANSACTION`).
  * Retry a failed transaction (`RETRY_TRANSACTION`).
  * Increment a transaction (`INCREMENT_TRANSACTION`).
    {#tap-to-phone-uiconfig-instance-configure-task_ul_mkm_dm3_lyb}
* Configure the Summary screen so that it can be skipped (`SKIP_SUMMARY_SCREEN`) or so that it closes after 5 seconds (`CLOSE_AFTER_TIMEOUT`). The default setting is to show the Summary screen.
* Configure the signature capture so that it prints on the paper receipt (`ON_RECEIPT`) or is skipped (`NONE`). The default setting is on-screen signature capture.

{#tap-to-phone-uiconfig-instance-configure-task_ul_kpy_gl3_lyb}  
Follow this step to create the `UiConfiguration` instance in your app:

1. Create and configure the `UiConfiguration` instance.

   ```
   mposUi.configuration = UiConfiguration(
     summaryFeatures = setOf(
               SummaryFeature.REFUND_TRANSACTION,
               SummaryFeature.SEND_RECEIPT_VIA_EMAIL,
               SummaryFeature.CAPTURE_TRANSACTION,
               SummaryFeature.RETRY_TRANSACTION,
               SummaryFeature.INCREMENT_TRANSACTION
         )
   // Use this to skip the summary screen
   // resultDisplayBehavior = UiConfiguration.ResultDisplayBehavior.SKIP_SUMMARY_SCREEN,
   // Use this to set signature capture to be on paper receipt
   // signatureCapture = SignatureCapture.ON_RECEIPT,
   )
   ```

Create a `TapToPhoneConfiguration` Instance {#ttp-taptophone-config-instance}
=============================================================================

Create a `TapToPhoneConfiguration` instance to configure the device enrollment process of the Tap to Pay on Android SDK.  
You can configure these parameters in the `TapToPhoneConfiguration` instance that you create:

* Configure the enrollment process to prompt the merchant to enter the serial number of a previously enrolled device (`MANUAL_INPUT`). The default setting is to show a list of previously enrolled devices and prompt the merchant to select a device from the list (`DEVICE_LIST`).
* Configure the Serial Number Confirmation screen to be skipped (`SKIP`). The default setting is to show the screen (`SHOW_WITH_SERIAL_NUMBER`).

{#ttp-taptophone-config-instance_ul_jcd_rsn_rgc}  
Follow this step to create and configure the `TapToPhoneConfiguration` instance in your app:

1. Create and configure the instance.

   ```
   mposUi.tapToPhone.tapToPhoneConfiguration = TapToPhoneConfiguration(
   	serialNumberInputMethod = SerialNumberInputMethod.DEVICE_LIST,
   	confirmationScreenOption = ConfirmationScreenOption.SHOW_WITH_SERIAL_NUMBER
   	)
   ```

Customizing the Default User Interface {#ttp-customize-default-ui-intro}
========================================================================

Use this information to customize the Default UI so that it matches your brand's visual identity. The included screenshots highlight several style elements with labels for reference. Note that not all available style elements are shown. A detailed description of the style elements follows the screenshots.

#### Figure: {#ttp-customize-default-ui-intro_fig_w4y_1q4_5fc}

Tap to Pay on Android Default UI Style Elements  
![Example 1, Tap to Pay on Android Default UI style elements showing icons, labeled
buttons, colors, and text](/content/dam/documentation/cybs/en-us/topics/payments-processing/card-processing/tap-to-phone/images/ttp-customize-ui1.png/jcr:content/renditions/original)

#### Figure: {#ttp-customize-default-ui-intro_fig_gk1_fq4_5fc}

Tap to Pay on Android Default UI Style Elements  
![Example 2, Tap to Pay on Android Default UI style elements showing icons, labeled
buttons, colors, and text](/content/dam/documentation/cybs/en-us/topics/payments-processing/card-processing/tap-to-phone/images/ttp-customize-ui2.png/jcr:content/renditions/original)

#### Figure: {#ttp-customize-default-ui-intro_fig_iv4_jq4_5fc}

Tap to Pay on Android Default UI Style Elements  
![Example 3, Tap to Pay on Android Default UI style elements showing icons, labeled
buttons, colors, and text](/content/dam/documentation/cybs/en-us/topics/payments-processing/card-processing/tap-to-phone/images/ttp-customize-ui3.png/jcr:content/renditions/original) This list describes the style elements that you can customize in the Default UI:

`animationStrokeColor`
:
Stroke or outline color for animations.

`approvedStateColor`
:
Indicator color that appears for the approved transaction badge and animation.

`cardPresentAnimationStrokeColor`
:
Overrides the `animationStrokeColor` style element in the card reader drawing on present-card animations. By default, this element is the same color as the `animationStrokeColor` style element.

`colorControlActivated`
:
Color applied to switch controls in their active state.

`colorOnPrimary`
:
Primary color that appears for the filled button text and animation details.

`colorOnSurface`
:
Color for text that appears over the content view, transaction status badges text, and outlined button stroke.

`colorPrimary`
:
Primary color that appears for the filled buttons and animations.

`colorSurface`
:
Background color that appears for the content view.

`colorSurfaceOnSurface`
:
Background color for displayed lists such as transaction history.

`contactlessStateActiveColor`
:
Active indicator color that appears when the contactless interface is ready or when a payment card is tapped on the device.

`contactlessStateErrorColor`
:
Error indicator color that appears when a problem occurs when the device attempts to read a card on the contactless interface.

`contactlessStateInactiveColor`
:
Inactive indicator color that appears when the contactless interface is not active.

`declinedErrorStateColor`
:
Indicator color that appears for these elements:

    * Declined transaction badges and animation
    * Error transaction badges and animation
    * Error dialog boxes
    * Input field error messages
    {#ttp-customize-default-ui-intro_ul_pqr_1qj_bqb}

`notificationColor`
:
Alert notification color that appears with *Poor connection* and *Low battery* notifications. The default color is yellow.

`preAuthorizedStateColor`
:
Indicator color that appears for the pre-authorized transaction badge.

`smallComponentCornerSize`
:
Defines the corner radius of the buttons and transaction status badge. Set this element to `0dp` for square corners, `4dp` for slightly square corners (default), or `32dp` for round corners.

`toolBarLogo`
:
Logo that appears during transaction processing. The image must be rectangular, have the minimum dimensions of 144 x 36 pixels, and a 4:1 ratio.

Customize Style Elements Using a Theme {#ttp-customize-default-ui-style-theme}
==============================================================================

Follow these steps to customize the Default UI style elements.

1. Introduce a new theme to your application that includes the `Theme.PayButton2` theme as a parent theme.

   ```
   <!-- Paybutton theme -->
   <style name="Theme.AppTheme.SampleTheme" parent="Theme.PayButton2">
       <!-- Text color -->
       <item name="colorOnSurface">@color/black</item>

       <!-- Background color -->
       <item name="colorSurface">@color/white</item>

       <!-- Contactless indicators -->
       <item name="contactlessStateActiveColor">@color/dui_green</item>
       <item name="contactlessStateInactiveColor">@color/dui_light_gray2</item>
       <item name="contactlessStateErrorColor">@color/dui_red</item>

       <!-- Transaction status -->
       <item name="approvedStateColor">@color/dui_green</item>
       <item name="declinedErrorStateColor">@color/dui_red</item> <!-- Also used for error messages and dialogs -->
       <item name="preAuthorizedStateColor">@color/dui_dark_gray</item>

       <!-- Filled buttons and animations primary color -->
       <item name="colorPrimary">@color/dui_blue</item>

       <!-- Used over the primary color for text on filled buttons and details on animations -->
       <item name="colorOnPrimary">@color/dui_white</item>

       <!-- Corner radius for the buttons and transaction status badges -->
       <item name="smallComponentCornerSize">4dp</item>

       <!-- Company logo -->
       <item name="toolBarLogo">@drawable/logo_140x36</item>

       <!-- Stroke color for icons and animations -->
       <item name="animationStrokeColor">@color/dui_black</item>
   </style>
   ```
2. Call one of these methods to set the theme:

   ```
   mposUi.themeRes = R.style.Theme_AppTheme_SampleTheme
   ```

Customize Style Elements Using a `UiConfiguration` Instance {#ttp-customize-default-ui-style-uiconfig}
======================================================================================================

Use this customization feature to dynamically change some Default UI style elements while the app is in use. These style elements can be customized using a `UiConfiguration` instance:

* `toolbarLogo`
* `colorScheme` (and its sub-elements)
* `cornerRadius`

{#ttp-customize-default-ui-style-uiconfig_ul_axl_lzd_1gc} Follow this step to customize Default User Interface style elements using a `UiConfiguration` instance:

1. Create the `UiConfiguration` instance.

   ```
   mposUi.configuration = UiConfiguration(
     // other UiConfiguration parameters
     toolbarLogo = "....",
     colorScheme = UiConfiguration.ColorScheme(
       colorPrimary = 0xFF1A1F71,
       colorOnPrimary = 0xFFFFFFFF,
       colorSurface = 0xFFFFFFFF,
       colorOnSurface = 0xFF1C1B1B,
     ),
     cornerRadius = UiConfiguration.CornerRadius.ROUND
   )
   ```

Enable Dark Mode in the Default User Interface {#ttp-customize-default-ui-dark-mode}
====================================================================================

When the payment device is set to dark mode, the Default UI payment screens automatically adjust to display darker, high-contrast colors compared to the default light mode settings. This feature is particularly useful in low-light environments such as restaurants and bars.  
By default, the dark mode background color is dark gray (`#121212`). To customize the background to pure black (`#000000`), define a new `Theme.PayButton2` theme in the `values-night` resource folder.  
For more information about the dark mode setting on Android devices, see the [Android documentation](https://developer.android.com/reference/androidx/appcompat/app/AppCompatDelegate#setDefaultNightMode(int) "").  
Follow this step to change dark mode behavior:

1. Use this Android method to enforce light or dark mode across your entire application and the Default UI, regardless of the system setting on the device. This example enforces night mode.

   ```
   AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES)
   ```

Enabling Device Enrollment {#ttp-device-enroll-intro}
=====================================================

Use this information to enable device enrollment and view the device enrollment result in the Tap to Pay on Android SDK. The enrollment workflow guides you through the device enrollment activity.

Enroll a Device {#ttp-device-enroll-device}
===========================================

Before starting the device enrollment process, make sure the Tap to Pay Ready app is installed on the Android device. Download the app using this [Google Play Store link](https://play.google.com/store/apps/details?id=com.visa.kic.app.kernel ""). If the app is not installed before device enrollment, you will be prompted to install it during the enrollment process. To learn more about the Tap to Pay Ready app, see [PCI MPoC Standard Compliance](/docs/cybs/en-us/tap-to-phone/integration/all/rest/tap-to-phone/tap-to-phone-intro/ttp-comply-pci-mpoc-intro.md "").  
Use the information in this section to enroll a device using the `enrollDevice` activity. This activity presents a merchant-facing UI that enables users to enroll a new device or a previously enrolled device by selecting or entering the device's serial number. Follow this step to enroll a device.

1. Use the `enrollDevice` activity to enroll the device.

   ```
   val mposUi: MposUi = ...
   mposUi.tapToPhone.enrollDevice(activity, requestCode)
   ...
   override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
       super.onActivityResult(requestCode, resultCode, data)

       val isEnrollmentSuccessful =
           resultCode == EnrollResultIntent.ENROLLMENT_RESULT_CODE &&
           data?.getStringExtra(EnrollResultIntent.ENROLLMENT_RESULT_EXTRA) ==
               EnrollResultIntent.ENROLLMENT_RESULT_EXTRA_ENROLLED

       if (isEnrollmentSuccessful) {
           val serialNumber = data?.getStringExtra(
               EnrollResultIntent.ENROLLMENT_RESULT_EXTRA_SERIAL_NUMBER
           )
           onEnrollmentComplete(serialNumber)
       } else {
           onEnrollmentFailed()
       }
   }
   ```

   #### Step Result

The `enroll` activity returns the result Intent.

Enroll a Previously Enrolled Device {#ttp-device-enroll-prev-device}
====================================================================

Use this information to enroll a previously enrolled device by using the `reEnrollDevice` activity. This activity enables you to perform device re-enrollment through the SDK by supplying a stored serial number. This streamlined workflow eliminates the need for the merchant to manually select or enter the serial number during re-enrollment.

1. Use the `reEnrollDevice` activity to enroll the previously enrolled device.

   ```
   val mposUi: MposUi = ...
   mposUi.tapToPhone.reEnrollDevice(activity, serialNumber, requestCode)
   ...
   override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
       super.onActivityResult(requestCode, resultCode, data)

       val isEnrollmentSuccessful =
           resultCode == EnrollResultIntent.ENROLLMENT_RESULT_CODE &&
           data?.getStringExtra(EnrollResultIntent.ENROLLMENT_RESULT_EXTRA) ==
               EnrollResultIntent.ENROLLMENT_RESULT_EXTRA_ENROLLED

       if (isEnrollmentSuccessful) {
           val serialNumber = data?.getStringExtra(
               EnrollResultIntent.ENROLLMENT_RESULT_EXTRA_SERIAL_NUMBER
           )
           onEnrollmentComplete(serialNumber)
       } else {
           onEnrollmentFailed()
       }
   }
   ```

   #### Step Result

The `enroll` activity returns the result `Intent`.

View the Device Enrollment Result {#ttp-device-enroll-view-result}
==================================================================

After completing device enrollment, use the `enroll` activity or `isDeviceEnrolled` function to view the device enrollment result.  
The `enroll` activity returns the result `Intent` when the device enrollment process is successful. This example shows the information that is returned in the result `Intent`:

```
RESULT_CODE: EnrollResultIntent.ENROLLMENT_RESULT_CODE (3489523)
EXTRA: EnrollResultIntent.ENROLLMENT_RESULT_EXTRA (enrollmentResult)
EXTRA: EnrollResultIntent.ENROLLMENT_RESULT_EXTRA_ENROLLED (deviceEnrolled)
EXTRA: EnrollResultIntent.ENROLLMENT_RESULT_EXTRA_SERIAL_NUMBER (serialNumber)
```

{#ttp-device-enroll-view-result_codeblock_z2v_5xg_ndc}  
The `isDeviceEnrolled` function returns a `true` value when the device is enrolled or a `false` value when not. This example shows how to use the function:

```
val isEnrolled = mposUi.tapToPhone.isDeviceEnrolled()
```