MainActivityF2.java

// Button onClick method
public void submit(View view) {
  
  // Start MercadoPago PaymentVault activity
  new MercadoPago.StartActivityBuilder()
    .setActivity(activity)
    .setPublicKey(PUBLIC_KEY)
    .setAmount(BigDecimal.valueOf(MONTO))
    .setPurchaseTitle(NOMBRE_PRODUCTO)
    .startPaymentVaultActivity();
    
}

@Override
protected void onActivityResult(int requestCode, int resultCode, 
Intent data) {

    if(requestCode == MercadoPago.PAYMENT_VAULT_REQUEST_CODE) {
      if(resultCode == RESULT_OK) {
        Issuer selectedIssuer = 
          (Issuer) data.getSerializableExtra("issuer");
        PayerCost selectedPayerCost = 
          (PayerCost) data.getSerializableExtra("payerCost");
        Token createdToken = 
          (Token) data.getSerializableExtra("token");
        PaymentMethod selectedPaymentMethod = 
          (PaymentMethod) data.getSerializableExtra("paymentMethod");
      
        // Debes enviar estos datos a tu servidor para finalizar el pago.
            
        } else {

            if ((data != null) && 
                (data.getSerializableExtra("apiException") != null)) {
                ApiException apiException 
                    = (ApiException) data.getSerializableExtra("apiException");
                Toast.makeText(getApplicationContext(), apiException.getMessage(), 
                  Toast.LENGTH_LONG).show();
            }
        }
    }
}