Klarna Docs - Klarna Payments (Native)

Klarna Payments (Native)

Adding Klarna Payments to your application is as easy as adding a view and performing a few operations on it. You can read more about the flow here.

This guide will teach you how to:

  • Render a Payment View
  • Operate on a payment method via its Payment View.

RENDERING A PAYMENT VIEW

A Payment View in iOS is called a KlarnaPaymentView. Rendering a payment view consists of creating an instance of the view, passing it an event listener and, adding it to your view hierarchy.

Creating the View

You can initialize the KlarnaPaymentView by providing a return URL and the event listener.

ParamTypeDescription
categoryStringThe payment method category that should be rendered in the view.
eventListenerKlarnaPaymentEventListenerListener that receives events during the payment process.
SWIFT
// Create the view
let paymentView = KlarnaPaymentView(category: "pay_over_time", eventListener: self)

// Add as subview
paymentView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(paymentView)

// Create a height constraint that we'll update as its height changes.
self.heightConstr = paymentView.heightAnchor.constraint(equalToConstant: 0)
heightConstr.isActive = true

The Payment View Event Listener

The SDK will notify you of events via an event listener that you’ll need to implement. It acts like a conventional delegate on iOS, however, unlike a delegate, it’s not optional.

Handling Height Changes

The payment view does not define any height internally. This is because we want to allow you to handle height changes in whichever way is most convenient to you.

The payment view instead notifies you through the event listener you provide it.

SWIFT
func klarnaResized(paymentView: KlarnaPaymentView, to newHeight: CGFloat) {
    self.heightConstr.constant = newHeight
}

WORKING WITH A PAYMENT VIEW

We expose six methods on the payment view that you can use to interact with the payment method it’s presenting

Initializing the View

Before content is rendered into a payment view, it needs to be configured. You can do this by initializing the view.

Initialization

After the view has been added and set up, you’ll need to call initialize() with the clientToken you received from the back-end and a returnURL.

ParamTypeDescription
clientTokenStringToken that was returned when you created the session.
returnUrlURLURL schema as defined in your app’s Plist to return from external applications.
SWIFT
paymentView.initialize(clientToken: clientToken, returnUrl: returnUrl)

Result

If successful, klarnaInitialized() will be called in the listener you supplied. If it’s not successful klarnaFailed() will be called instead.

ParamTypeDescription
paymentViewKlarnaPaymentViewThe payment view that was initialized.
SWIFT
func klarnaInitialized(paymentView: KlarnaPaymentView) {
    klarnaPaymentView.load()
}

Loading the View

Once you’ve initialized the view and you’re ready to display the KlarnaPaymentView.

Loading

Simply call load(), supplying an optional string with updated order data to update the session. This string should be formatted as valid JSON.

ParamTypeDescription
jsonDataStringAn optional string with the order data to update the session. Formatted as JSON.
SWIFT
klarnaPaymentView.load()

Result

If successful, klarnaLoaded() will be called in your listener. If anything went wrong, klarnaFailed() will be called. If you’ve loaded several views, you should keep track of which view your user selected to know what to authorize in the next step.

ParamTypeDescription
paymentViewKlarnaPaymentViewThe payment view that was loaded.
SWIFT
func klarnaLoaded(paymentView: KlarnaPaymentView) {
    // Content has finished loading and if you have any loader you could hide it here.
}

Authorizing the Session

When the payment view is loaded, and the user has confirmed that they want to pay with one of Klarna’s selected payment methods, it’s time to authorize the session.

Authorize

When you are ready to authorize the session, call authorize(). As with load, you can supply an optional string to update the session. You can also specify whether auto-finalization should be turned off; if it is, the user may need to be prompted a second time to input data.

ParamTypeDescription
autoFinalizeBoolean?An optional flag used to turn off auto-finalization for direct bank transfer.
jsonDataString?An optional string to update the session. Formatted as JSON.
SWIFT
paymentView.authorize()

Result

If successful, klarnaAuthorized() will be called in your listener. If not, klarnaFailed() will be called.

ParamTypeDescription
paymentViewKlarnaPaymentViewThe payment view that was authorized.
approvedBoolWhether the authorization was approved or not.
authTokenString?If the session was authorized, the token will not be null.
finalizedRequiredBoolWill be true ifautoFinalizewas false and this payment method needs a second confirmation step.
SWIFT
func klarnaAuthorized(paymentView: KlarnaPaymentView, approved: Bool, authToken: String?, finalizeRequired: Bool) {
    if approved == true {
        // the authorization was successful
    } else {
        // user is not approved or might require finalization
    }

    if let token = authToken {
        // authorization is successful, backend may create order
    }

Reauthorizing the Session

There are cases when you might want to allow your customer to change their order after it has been authorized (e.g. in some form of order/summary view). In these cases, if the order or customer details have changed, you’ll need to reauthorize the session.

Reauthorize

ParamTypeDescription
jsonDataString?An optional string to update the session. Formatted as JSON
SWIFT
paymentView.reauthorize()

Result

If successful, klarnaReauthorized() will be called, and if not, klarnaFailed() will be called instead.

ParamTypeDescription
paymentViewKlarnaPaymentViewThe payment view that was reauthorized.
approvedBoolWhether the reauthorization was approved or not.
authTokenString?If the session was previously authorized, the token will not be null.
SWIFT
func klarnaReauthorized(paymentView: KlarnaPaymentView, approved: Bool, authToken: String?) {
    if approved == true {
        // the reauthorization was successful
    } else {
        // user is not approved or might require finalization
    }

    if let token = authToken {
        // reauthorization is successful, backend may create order
    }

Finalizing the Session

If the session needs to be finalized, you’ll need to perform this last step to get an authorization token.

Finalize

Call finalise() in order to get the token.

While we tend to name all finalize operations “finalize” with a “z”, all classes subclassing fromNSObjectalready have a a conflictingfinalize()method. In this specific case, we use the alternative british-english spelling.

ParamTypeDescription
sessionDataString?An optional string to update the session. Formatted as JSON
SWIFT
paymentView.finalise()

Result

If successful, klarnaFinalized() will be called in your listener. If not successful, klarnaFailed() will be called.

ParamTypeDescription
paymentViewKlarnaPaymentViewThe payment view that was finalized.
approvedBoolWhether the user was approved on finalize or not.
authTokenString?If the finalization went through, the token will not be null.
SWIFT
func klarnaFinalized(paymentView: KlarnaPaymentView, approved: Bool, authToken: String?) {
    if approved == true {
        // the finalization was successful
    } else {
        // user is not approved or might require finalization
    }

    if let token = authToken {
        // finalization is successful, backend may create order
    }

Loading a Payment Review

If you’d like to allow the user to review their payment after it’s authorized, this can be done in two ways:

  1. Render it in a new view:
    undefinedundefinedundefined
  2. Render it in the existing payment view:
    undefined

Only specific payment method categories and countries are currently supported. Contact us to make sure that you can call this method.

Load the Payment Review

This will load/replace the view’s content with a description of how your customer will have to perform payment.

SWIFT
paymentView.loadPaymentReview()

Result

If successful klarnaLoadedPaymentReview() will be called in your listener. If not, klarnaFailed() will be called instead.

ParamTypeDescription
paymentViewKlarnaPaymentViewThe payment view that dsplayed payment review.
SWIFT
func klarnaLoadedPaymentReview(paymentView: KlarnaPaymentView) {
    // Payment review loaded
}

Handling Errors

This will handle all the errors from the previous implementations. KlarnaPaymentError will contain the information needed to show to the user and also to handle all the states of the listener.

ParamTypeDescription
paymentViewKlarnaPaymentViewThe payment view that had the error.
errorKlarnaPaymentError?lass that contains the information (name, message, isFatal, debugDescription) about the error.
SWIFT
func klarnaFailed(inPaymentView paymentView: KlarnaPaymentView, withError error: KlarnaPaymentError) {
    // handle error
}