arduino - Nextion buttons are not working with Arduino

Question

I would like some help here. For some reason the buttons on Nextion are not working. Does anyone knows what's the problem?
It is suppose to change a NexText (a text box in Nextion) while I press the button bOn but it does nothing. Only the button of emergency (bEmergencia) is working, it just changes the page0 to page 1.

 #include <SoftwareSerial.h>
//bibliotecas nextion
#include <doxygen.h>
#include <NexButton.h>
#include <NexCheckbox.h>
#include <NexConfig.h>
#include <NexCrop.h>
#include <NexDualStateButton.h>
#include <NexGauge.h>
#include <NexGpio.h>
#include <NexHardware.h>
#include <NexHotspot.h>
#include <NexNumber.h>
#include <NexObject.h>
#include <NexPage.h>
#include <NexPicture.h>
#include <NexProgressBar.h>
#include <NexRadio.h>
#include <NexRtc.h>
#include <NexScrolltext.h>
#include <NexSlider.h>
#include <NexText.h>
#include <NexTimer.h>
#include <Nextion.h>
#include <NexTouch.h>
#include <NexUpload.h>
#include <NexVariable.h>
#include <NexWaveform.h>
#include "Nextion.h"

SoftwareSerial mySerial(0,1);

int contacto1 = 0;
int contacto2 = 0;
int contacto3 = 0;

int n0 = 0;
int n1 = 0;
int n2 = 0;


//pagina inicial block
NexButton bOn = NexButton(0, 9, "b0");
NexButton bOff = NexButton(0, 7, "b1");
NexButton bEmergencia = NexButton(0, 8, "b2");
NexText pecas_tapete1 = NexText(0, 10, "t0");
NexText pecas_tapete2 = NexText(0, 11, "t3");
NexText pecas_tapete3 = NexText(0, 12, "t4");
NexText estado_sistema = NexText(0, 2, "t1");

NexTouch *nex_listen_list[] =
{
  //Eventos que são aguardados via interface serial
  &bOn,
  &bOff,
  &bEmergencia,
  NULL
};

void sistema_ligado(){
  estado_sistema.setText("Sistema Ligado!");
  }


void sistema_desligado(){
  estado_sistema.setText("Sistema Desligado!");
}

void sistema_emergencia(){
  //mudar p pagina 1
}

void setup()
{
  //Inicializa a comunicacao com o display
  nexInit();
  //Define os pinos dos reles como entrada
  pinMode (8, INPUT);
  pinMode (9, INPUT);
  pinMode (10, INPUT);
  
  //Inicia a serial
  Serial.begin(9600);

  //Define a rotina que sera executada quando o Arduino
  //receber dados do display
  bOn.attachPush(sistema_ligado);
  bOff.attachPush(sistema_desligado);
  bEmergencia.attachPush(sistema_emergencia);
}

void loop()
{
  delay(1000);
  nexLoop(nex_listen_list);
  
  if (sistema_ligado == true){
    
  contacto1 = digitalRead(8);
  contacto2 = digitalRead(9);
  contacto3 = digitalRead(10);

  Serial.write("n0.val=");
  Serial.println(n0);
  Serial.write(0xff);
  Serial.write(0xff);
  Serial.write(0xff);

  Serial.write("n1.val=");
  Serial.println(n1);
  Serial.write(0xff);
  Serial.write(0xff);
  Serial.write(0xff);

  Serial.write("n2.val=");
  Serial.println(n2);
  Serial.write(0xff);
  Serial.write(0xff);
  Serial.write(0xff);
 
  
if (contacto1 == HIGH && contacto2 == LOW && contacto3 == LOW){
  n0++;  
  //delay(1000);
}


if (contacto2 == HIGH && contacto3 == LOW && contacto1 == LOW){
  n1++;
  //delay(1000);
}


if (contacto3 == HIGH && contacto1 == LOW && contacto2 == LOW){
  n2++;
  //delay(1000);
    }
  }
  }