Before you start

In this step-by-step guide you will learn how to integrate Sign in with Klarna into your Android app.

Before starting to add the Sign in with Klarna button or using the Sign in with Klarna SDK you will need to do two things:

1.
Setting the return URL
2.
Defining an event handler

1. Setting the Return URL

To ensure the Sign in flow initiated by the SDK can correctly redirect back to your application, you must configure a unique return URL (deep link) for your app and provide this URL string to the SDK. This value is required specifically for the Sign in flow initiated by the SDK.

Important: This configuration is distinct from any other return URLs the SDK might require for handling redirects from external third-party applications. Ensure you are configuring the URL for the SDK's Sign in flow.

Add this snippet to your manifest file in order to set your return URL value for the SDK’s activity.

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<activity android:name="com.klarna.mobile.sdk.activity.KlarnaRedirectReceiverActivity" android:exported="true" tools:node="replace">
   <intent-filter>
      <action android:name="android.intent.action.VIEW"/>
      <category android:name="android.intent.category.DEFAULT"/>
      <category android:name="android.intent.category.BROWSABLE"/>
      <data android:scheme="<YOUR-SCHEME>" android:host="<YOUR-HOST>"/>
   </intent-filter>
</activity>

In version 2.6.11 and later, a new activity called **KlarnaRedirectReceiverActivity** has been introduced in the Android SDK.

When setting the returnURL parameter for KlarnaSignInButton or KlarnaSignInSDK , you need to concatenate the scheme and host you specified in AndroidManifest.xml into one value using :// as the separator, as shown here:

KOTLIN

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val button = KlarnaSignInButton(... returnURL =  “<YOUR-SCHEME>://<YOUR-HOST>”)

Utilizing **FLAG_ACTIVITY_NEW_DOCUMENT** when initializing an activity that proceeds to the Sign in with Klarna operation can interfere with the user navigation within the app. This flag might induce Android to spawn a new app instance upon returning to the app via the return URL deep linking, consequently disrupting the login process. To evade potential user inconveniences, we recommend avoiding FLAG_ACTIVITY_NEW_DOCUMENT when launching an activity that may trigger the Sign in with Klarna procedure.

2. Defining an Event Handler

While the user is interacting with the Sign in with Klarna flow or when the flow is completed, you'll receive events by setting an event handler when creating an instance of KlarnaSignInSDK.

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val eventHandler = object : KlarnaEventHandler {
   override fun onEvent(klarnaComponent: KlarnaComponent, event: KlarnaProductEvent) {
      when(event.action) {
         KlarnaSignInEvent.USER_TAPPED_BUTTON -> {
            // User tapped the KlarnaSignInButton, auth process starting
         }
         KlarnaSignInEvent.USER_AUTH -> {
            // User completed interactive auth, tokens will be fetched
         }
         KlarnaSignInEvent.USER_CANCELLED -> {

KlarnaEventHandler reference will be kept weak in the SDK to avoid memory leaks, thus it's required for integrator to keep the strong reference.

To integrate the button for Sign in with Klarna as a native view in your Android app, you need to create an instance of it, add it to your view hierarchy, and receive the results once the flow is completed.

Create the Button

The button for Sign in with Klarna native view in Android is called KlarnaSignInButton. You can create an instance programmatically or inflate it from an XML layout file. You can set the parameters of the button both programatically or in the XML layout file.

Create the Button Programmatically

You can create the Sign in with Klarna button programmatically and place it in your app with desired layout options. You can see a sample on the right.

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//Create an instance of KlarnaSignInButton
val button = KlarnaSignInButton(...)

// Add it to your container with desired layout parameters
val layoutParams = ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT)
containerViewGroup.addView(button, 0, layoutParams)

Create the Button in XML

You can also add the Sign in with Klarna button into your XML layout file and get the view instance programmatically either by findViewById or by the generated View Binding instance of your layout (if you're using View Binding).

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 <com.klarna.mobile.sdk.api.signin.KlarnaSignInButton
      android:id="@+id/klarnaSignInButton"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      …
/>

Settings the Parameters

You can set the parameters of the Sign in with Klarna button either by setting them on the button instance or by setting them as attributes in the XML layout file.

Parameter	Type	Required	Description
`context`	Context	Yes	The context of the Activity the button is in.
`clientId`	String	Yes (optional in the constructor)	The UUID you get when creating your Klarna OAuth 2.0 app. The XML attribute of this parameter is `app:KlarnaSignInButtonClientId.`
`scope`	String	Yes (optional in the constructor)	A space-separated list of scopes you would like to request from the user. For example, request `billing_address` if you need the billing address in your account creation. The XML attribute of this parameter is `app:KlarnaSignInButtonScope.` The claims of the requested scopes will be returned as part of the JWT token `id_token`. Note: `openid` is always requested by default even if you don't request it explicitly. Available scopes are as follows: offline_access profile:email profile:phone profile:name profile:date_of_birth profile:billing_address profile:national_identification profile:country payment:request:create
`market`	String	Yes (optional in the constructor)	The market or the country where this integration is available, for example, `SE` for Sweden. The XML attribute of this parameter is `app:KlarnaSignInButtonMarket.`
`locale`	String	Yes (optional in the constructor)	The language in which the Sign in with Klarna button is presented to the user, for example, `sv-SE` or `en-SE` for Sweden. The XML attribute of this parameter is `app:KlarnaSignInButtonLocale`.
`eventHandler`	KlarnaEventHandler	Yes (optional in the constructor)	The interface to receive the results from the Sign in with Klarna flow. Will be kept as weak reference.
`environment`	KlarnaEnvironment	No	Configures the endpoints and other behaviors that the SDK will be operating with. When set to `production`, the SDK will make requests to production endpoints and perform real validation, whereas for other environments will not. The XML attribute of this parameter is `app:klarnaEnvironment`.
`region`	KlarnaRegion	No	Defines the regional API endpoints to which the SDK will send requests. The XML attribute of this parameter is `app:klarnaRegion`.
`theme`	KlarnaTheme	No	Defines the theming for the Sign in with Klarna UI, but not the button itself. The XML attribute of this parameter is `app:klarnaTheme`.
`returnURL`	String	Yes (optional in the constructor)	The URL you defined in your `AndroidManifest.xml` file in the preparation section. The XML attribute of this parameter is `app:klarnaReturnUrl`.
`loggingLevel`	KlarnaLoggingLevel	No	The logging level which will be used when logging messages to the Logcat. The XML attribute of this parameter is `app:klarnaLoggingLevel`.
`resourceEndpoint`	KlarnaResourceEndpoint	No	Defines the cloud provider to which the SDK will send requests. Please note that this should not be changed or overridden. The XML attribute of this parameter is `app:klarnaResourceEndpoint`.

Customizing the Look and Feel of the Button

In addition the the parameters list above, Klarna offers several themes, labels, and shapes to customize the button's appearance to match the look and feel of your app.

Parameter	Type	Description
`buttonTheme`	KlarnaButtonTheme	Enumerated value to style the button in the light or dark theme.
`buttonShape`	KlarnaButtonShape	Enumerated value specifying the button's shape.
`buttonLabel`	KlarnaButtonLabel	Enumerated value specifying the text that will be displayed on the button.

Button Theme

The KlarnaButtonTheme enumeration defines which style is applied to the button, depending on either the app’s configuration or the system settings.

Value	Description
`KLARNA`	Renders the button in the Klarna pink theme. We recommend this theme as it has the highest brand recognition and the likelihood of usage by your customers.
`LIGHT`	Renders the button in white. We recommend this theme for dark backgrounds.
`DARK`	Renders the button in black. We recommend this theme for light backgrounds.
`AUTO`	Automatic theme (light or dark) that will depend on the system’s UI theme.

Button Shape

In order for the button to fit into the aesthetic of your app, we offer different button shapes:

Value	Description
`ROUNDED_RECT`	Renders the button as a rectangle with rounded corners.
`PILL`	Renders the button as a pill-shaped button.
`RECTANGLE`	Renders the button as a rectangle with square corners.

To integrate the Sign in with Klarna SDK in your Android app, you need to create an instance of KlarnaSignInSDK, call its signIn() function, and receive the results once the flow is completed.

To create an instance of the SDK you need to specify the following parameters:

Parameter	Type	Required	Description
`activity`	Activity	Yes	The activity instance of your app.
`returnURL`	String	Yes	The URL you defined in your `AndroidManifest.xml` file in the preparation section.
`eventHandler`	KlarnaEventHandler	Yes (optional in the constructor)	The interface to receive the results from the Sign in with Klarna flow.
`environment`	KlarnaEnvironment	No	Enumerated value to set the working environment for the SDK.
`region`	KlarnaRegion	No	Enumerated value to set the regional API endpoints to which the SDK will send requests.
`theme`	KlarnaTheme	No	Defines the theming for the Sign in with Klarna UI, but not the button itself.
`loggingLevel`	KlarnaLoggingLevel	No	The logging level which will be used when logging messages to the Logcat.
`resourceEndpoint`	KlarnaResourceEndpoint	No	Defines the cloud provider to which the SDK will send requests.

To initiate the sign in flow for the user, you need to call the signIn() function of the SDK and specify the following parameters:

Parameter	Type	Required	Description
`clientId`	String	Yes	The UUID you get when creating your Klarna OAuth 2.0 app.
`scope`	String	Yes	A space-separated list of scopes you would like to request from the user. For example, request `billing_address` if you need the billing address in your account creation. The claims of the requested scopes will be returned as part of the JWT token `id_token`. Note: `openid` is always requested by default even if you don't request it explicitly. Available scopes are as follows: offline_access profile:email profile:phone profile:name profile:date_of_birth profile:billing_address profile:national_identification profile:country payment:request:create
`market`	String	Yes	The market or the country where this integration is available, for example, `SE` for Sweden.
`locale`	String	No	The language to present to the user, for example, `sv-SE` or `en-SE` for Sweden.

After calling the signIn() function you will receive the events in the event handler that you've passed to the SDK.

Before you start

1. Setting the Return URL

2. Defining an Event Handler

Sign in with Klarna Button

Create the Button

Create the Button Programmatically

Create the Button in XML

Settings the Parameters

Customizing the Look and Feel of the Button

Button Theme

Button Shape

Sign in with Klarna SDK

Calling the signIn() function