#define NEXSERIAL Serial2     // Define serial communication channel
#define BAUD 115200     // Define baud rate. esp32 uses a baud rate of 115200
#define RX 16     // Define receiving data pin (RX)
#define TX 17     // Define transmission data pin (TX)

#include "NextionSerialString.h"      // Include NextionSerialString Library
#include "NextionConfig.h"      // Include NextionConfig

NextionSerialString myNextion(NEXSERIAL, BAUD, RX, TX);    // Create an object of NextionSerialString class with the name < myNextion >                  

void setup(){
  myNextion.begin();     // This function must be called to reset the baud rate on the Nextion, to match that of the esp32
}

void loop(){
  myNextion.listen();      // This function must be called repeatedly to respond to touch events from the Nextion panel
}

_serial->println(_serialData);      // Prints the string data received from the Nextion

/*!
  * Put your code here and create any custom function to read the incoming serial data
  * Utilise the string.h library for optimal efficiency
  */

/*!
 * NextionConfig.h - Configuration Library for Serial Communication between ESP32 & Nextion Display using strings
 * Copyright (c) 2020 Darren Osborne < darren@ozzyimages.com >
 * All rights reserved under the library's licence
 */

// Define library only once
#ifndef NextionConfig_h
#define NextionConfig_h

#include <arduino.h>

#define NEXSERIAL Serial2     // Define serial communication channel
#define BAUD 115200     // Define baud rate. esp32 uses a baud rate of 115200
#define RX 16     // Define receiving data pin (RX)
#define TX 17     // Define transmission data pin (TX)
#define LEDPIN 4     // Define a gpio output pin for testing a led

#endif

/*!
 * BlinkSketch.ino - Ozzy Images NextionSerialString Simple Example Code
 * Copyright (c) 2020 Darren Osborne < darren@ozzyimages.com > 
 * All rights reserved under the library's licence
 */

#include <arduino.h>
#include "NextionSerialString.h"      // Include NextionSerialString
#include "NextionConfig.h"      // Include NextionConfig

NextionSerialString myNextion(NEXSERIAL, BAUD, RX, TX);    // Create an object of NextionSerialString class with the name < myNextion >

void setup(){
  pinMode(LEDPIN, OUTPUT);
  myNextion.begin();       // This function must be called to reset the baud rate on the Nextion, to match that of the esp32
}

void loop(){  
  myNextion.listen();        // This function must be called repeatedly to respond to touch events from the Nextion panel
}

/*!
 * HMIFunctions.cpp - Function Handler between ESP32 & Nextion Display
 * Copyright (c) 2020 Darren Osborne < darren@ozzyimages.com >
 * All rights reserved under the library's licence
 */

#include <arduino.h>
#include <string.h>
#include "NextionSerialString.h"      // Include NextionSerialString
#include "NextionConfig.h"      // Include NextionConfig

/*!
 * Function handler which reads the incoming serial data and hands off to a custom function
 * Separated from NextionSerialString.cpp in order to see code modifications/custom functions more clearly
 */
void NextionSerialString::_handleData(String _serialData){
  if(_serialData != ""){      // Check for blank string
    if(_serialData == "on"){
      digitalWrite(LEDPIN, HIGH);
      _serial->println("Switching the LEDPIN to HIGH");
    }else if(_serialData == "off"){
      digitalWrite(LEDPIN, LOW);
      _serial->println("Switching the LEDPIN to LOW");
    }else{
      // Do nothing
    } 
  }
}

print "on"      // Button b0
print "off"     // Button b1