UI Implementation Guide

The Get Mini framework is a “Headless” SDK. It does not provide built-in payment screens or storyboards. Instead, it delivers real-time events and data through delegate methods, allowing you to build a user interface that matches your application’s native design.

UI Requirements

Your application must implement UI for three distinct phases of the transaction lifecycle:

1. Discovery: Listing paired Bluetooth or Wi-Fi PIN pads.
2. Transaction Progress: Showing current hardware states (e.g., “Insert Card,” “Enter PIN”).
3. User Interaction: Modals for specific choices like Currency Conversion (DCC) or Installments.

1. Monitoring Transaction Progress

The onPaymentProcess method in the RedsysBTPinpadPaymentDelegate is your primary tool for updating the UI. The SDK sends string status updates or state objects during the hardware handshake.

Progress Updates (Swift)

func onPaymentProcess(_ result: Any!, orError error: Error!) {
    if let statusMessage = result as? String {
        // Update your UI label on the main thread
        DispatchQueue.main.async {
            self.statusLabel.text = statusMessage
        }
    }
}

Common status messages include:

• “Esperando tarjeta…” (Waiting for card)
• “Introduzca PIN…” (Enter PIN)
• “Conectando con el host…” (Connecting to host)

2. Handling Interaction (The Feedback Loop)

When the SDK encounters a card that supports multiple payment options (like Dynamic Currency Conversion), it triggers the onPaymentFeedback method.

Critical Implementation Rule: This method requires a synchronous return value (“true” or “false”). Because UI interaction is asynchronous, you must use a blocking pattern with NSCondition.

Selection UI Pattern (Objective-C)

-(id)onPaymentFeedback:(RespuestaTransaccionDTO *)result orError:(NSError *)error {
    // 1. result contains DCC data: ImporteOriginal, ImporteDivisa, TasaCambio

    // 2. Trigger your UI (e.g. UIAlertController) on the main thread
    dispatch_async(dispatch_get_main_queue(), ^{
        [self showDCCPromptWithData:result];
    });

    // 3. Block this background thread until the user clicks a button
    [self.userDecisionCondition lock];
    [self.userDecisionCondition wait];
    [self.userDecisionCondition unlock];

    // 4. Return the user's choice to the SDK
    return self.userAcceptedChoice ? @"true" : @"false";
}

3. Digital Signatures

If a transaction requires a signature (check result.reciboSoloCliente == false and result.autenticadoPorPin == false), you must provide a signature pad UI.

Once the user signs, send the image to the Get Mini server using the envioFirmaDigitalizada method:

let firmaDTO = EnvioFirmaDTO(
    terminal: activeTerminal,
    withFirma: signatureImage,
    format: 2, // 2 = JPG
    andOperacion: lastOperation
)

RedsysConfigurationManager.envioFirmaDigitalizada(firmaDTO) { result, error in
    // Handle signature upload result
}

UI Best Practices

• Main Thread Safety: Always wrap UI updates in DispatchQueue.main.async. SDK callbacks may arrive on background threads used for hardware communication.
• Blocking Navigation: Once payWithPinpadBluetooth starts, disable the “Back” button and side menus. Interrupting the connection during key exchange can lock the terminal.
• Clarity: Ensure your status text is large and legible, as users often look at the iPhone screen for instructions rather than the PIN pad’s small display.
• DCC Transparency: When showing currency choices, legally you must display the exchange rate and the commission markup found in the RespuestaTransaccionDTO.

Troubleshooting UI Issues

UI Hangs during DCC If you use the NSCondition wait pattern, ensure that your button actions (Accept/Decline) call .signal() on the condition. If you forget to signal, the entire payment process will wait forever.

No Status Updates Verify that your class correctly conforms to RedsysBTPinpadPaymentDelegate and that you have assigned self as the delegate in the payWithPinpadBluetooth call.