How to Build a Custom Pay Button (Your Own UI)

@Composable
fun CheckoutScreen(session: Session) {
    var status by remember { mutableStateOf<ActionResult?>(null) }
    val launcher = rememberPayrailsPaymentLauncher(session) { result ->
        status = result
    }
    // ... your UI below
}

class CheckoutActivity : ComponentActivity() {
    private lateinit var launcher: PayrailsPaymentLauncher

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        launcher = Payrails.createPaymentLauncher(this, session) { result ->
            render(result)
        }
    }
}

var selected by remember { mutableStateOf(PaymentMethod.googlePay) }

DropdownMenuForYourMethods(
    selected = selected,
    onSelect = { selected = it }
)

Button(onClick = { launcher.authorize(selected) }) {
    Text("Pay")
}

// By method type — SDK opens the Google Pay sheet / Custom Tab as required
launcher.authorize(PaymentMethod.googlePay)
launcher.authorize(PaymentMethod.payPal, saveInstrument = true)
launcher.authorize(PaymentMethod.genericRedirect, paymentMethodCode = "klarna")

// A previously saved instrument
launcher.authorize(storedInstrument = savedCard)

// An already-encrypted card — 3DS handled in a Custom Tab when required
launcher.authorize(encryptedCardData = encrypted, saveInstrument = true)

when (val result = status) {
    ActionResult.Success -> showReceipt()
    is ActionResult.Failed -> when (result.failure.code) {
        AuthorizationFailureReason.USER_CANCELLED -> { /* user dismissed the sheet / tab — no action */ }
        AuthorizationFailureReason.VALIDATION_FAILED -> showBlocked(result.failure.message) /* your own gate refused it — not a decline */
        else -> showDeclined(result.failure.message)
    }
    null -> { /* no payment attempted yet */ }
}

@Composable
fun CustomCheckout(session: Session) {
    var selected by remember { mutableStateOf(PaymentMethod.googlePay) }
    var encrypted by remember { mutableStateOf("") }
    var status by remember { mutableStateOf<String?>(null) }

    val launcher = rememberPayrailsPaymentLauncher(session) { result ->
        status = when (result) {
            ActionResult.Success -> "Approved"
            is ActionResult.Failed -> "Declined: ${result.failure.code}"
        }
    }

    Column {
        // Your own method selector
        PaymentMethodDropdown(selected) { selected = it }

        // Optional: your own card field that yields an ENCRYPTED string
        OutlinedTextField(
            value = encrypted,
            onValueChange = { encrypted = it },
            label = { Text("Encrypted card payload") }
        )

        Button(
            onClick = {
                if (encrypted.isNotBlank()) launcher.authorize(encryptedCardData = encrypted)
                else launcher.authorize(selected)
            }
        ) { Text("Pay") }

        status?.let { Text(it) }
    }
}