Unofficial Nextion/TJC User Forum

C/C++ library to connect Nextion display to PC

Hello,

I need to connect Nextion display to standart PC. I can implement Nextion instruction set in my programm, but I would like to get library that has already done all communication issues. Is there any library that allows to communicate to Nextion display via serial port ?

That doesn’t exist, as far as I know. But there is a Nextion blog article about how easy handling the communication stuff is in Python (which exists for Windows, Mac, Linux, and much more platforms): The Sunday Blog: Talking to your Nextion HMI – Part 3: Let your PC talk to your Nextion with Python - Nextion

Then, you have to take care: Native COM ports on (older) PCs have bipolar signals and will most probably destroy your Nextion. But if you go through a (virtual) COM port over USB with a FTDI adapter, you are safe.

There are no communication issues it is serial ASCII you can make it so that any object on the display sends a set of characters that you put onto it for example you could have 5 buttons on the display and when pressed they send B1 - B5 which makes it simple to parse the serial data. I use a carage return after the data as a standard way to know the end of it. You can also use CRC error checking to confirm the data is ok.

I thought of something similar when I first started using this screen, but unfortunately, there was no such library.

I have been playing with Home Assistant for several years now. Just recently I upgraded to a newer version of the system on a RPi 4, with ESPHome to control a 4 channel pro relay control for an irrigation control. I am having some problems, but I think most is me and not the software end of it.

In any case back to your question, when you use ESPHome to connect any of the ESP series chips to a nextion display it generate/includes source code that the system needs. They are in C++.

This is part of the header file, I believe that it is available on github:


#include "esphome/core/component.h"
#include "esphome/core/defines.h"
#include "esphome/components/uart/uart.h"
#include "esphome/components/binary_sensor/binary_sensor.h"

#ifdef USE_TIME
#include "esphome/components/time/real_time_clock.h"
#endif

namespace esphome {
namespace nextion {

class NextionTouchComponent;
class Nextion;

using nextion_writer_t = std::function<void(Nextion &)>;

class Nextion : public PollingComponent, public uart::UARTDevice {
 public:
  /**
   * Set the text of a component to a static string.
   * @param component The component name.
   * @param text The static text to set.
   *
   * Example:
   * ```cpp
   * it.set_component_text("textview", "Hello World!");
   * ```
   *
   * This will set the `txt` property of the component `textview` to `Hello World`.
   */
  void set_component_text(const char *component, const char *text);
  /**
   * Set the text of a component to a formatted string
   * @param component The component name.
   * @param format The printf-style format string.
   * @param ... The arguments to the format.
   *
   * Example:
   * ```cpp
   * it.set_component_text_printf("textview", "The uptime is: %.0f", id(uptime_sensor).state);
   * ```
   *
   * This will change the text on the component named `textview` to `The uptime is:` Then the value of `uptime_sensor`.
   * with zero decimals of accuracy (whole number).
   * For example when `uptime_sensor` = 506, then, `The uptime is: 506` will be displayed.
   */
  void set_component_text_printf(const char *component, const char *format, ...) __attribute__((format(printf, 3, 4)));
  /**
   * Set the integer value of a component
   * @param component The component name.
   * @param value The value to set.
   *
   * Example:
   * ```cpp
   * it.set_component_value("gauge", 50);
   * ```
   *
   * This will change the property `value` of the component `gauge` to 50.
   */
  void set_component_value(const char *component, int value);
  /**
   * Set the picture of an image component.
   * @param component The component name.
   * @param value The picture name.
   *
   * Example:
   * ```cpp
   * it.set_component_picture("pic", "4");
   * ```
   *
   * This will change the image of the component `pic` to the image with ID `4`.
   */
  void set_component_picture(const char *component, const char *picture) {
    this->send_command_printf("%s.val=%s", component, picture);
  }
  /**
   * Set the background color of a component.
   * @param component The component name.
   * @param color The color (as a string).
   *
   * Example:
   * ```cpp
   * it.set_component_background_color("button", "17013");
   * ```
   *
   * This will change the background color of the component `button` to blue.
   * Use this [color picker](https://nodtem66.github.io/nextion-hmi-color-convert/index.html) to convert color codes to
   * Nextion HMI colors.
   */
  void set_component_background_color(const char *component, const char *color);
  /**
   * Set the pressed background color of a component.
   * @param component The component name.
   * @param color The color (as a string).
   *
   * Example:
   * ```cpp
   * it.set_component_pressed_background_color("button", "17013");
   * ```
   *
   * This will change the pressed background color of the component `button` to blue. This is the background color that
   * is shown when the component is pressed. Use this [color
   * picker](https://nodtem66.github.io/nextion-hmi-color-convert/index.html) to convert color codes to Nextion HMI
   * colors.
   */
  void set_component_pressed_background_color(const char *component, const char *color);
  /**
   * Set the font color of a component.
   * @param component The component name.
   * @param color The color (as a string).
   *
   * Example:
   * ```cpp
   * it.set_component_font_color("textview", "17013");
   * ```
   *
   * This will change the font color of the component `textview` to a blue color.
   * Use this [color picker](https://nodtem66.github.io/nextion-hmi-color-convert/index.html) to convert color codes to
   * Nextion HMI colors.
   */
  void set_component_font_color(const char *component, const char *color);
  /**
   * Set the pressed font color of a component.
   * @param component The component name.
   * @param color The color (as a string).
   *
   * Example:
   * ```cpp
   * it.set_component_pressed_font_color("button", "17013");
   * ```
   *
   * This will change the pressed font color of the component `button` to a blue color.
   * Use this [color picker](https://nodtem66.github.io/nextion-hmi-color-convert/index.html) to convert color codes to
   * Nextion HMI colors.
   */
  void set_component_pressed_font_color(const char *component, const char *color);
  /**
   * Set the coordinates of a component on screen.
   * @param component The component name.
   * @param x The x coordinate.
   * @param y The y coordinate.
   *
   * Example:
   * ```cpp
   * it.set_component_coordinates("pic", 55, 100);
   * ```
   *
   * This will move the position of the component `pic` to the x coordinate `55` and y coordinate `100`.
   */
  void set_component_coordinates(const char *component, int x, int y);
  /**
   * Set the font id for a component.
   * @param component The component name.
   * @param font_id The ID of the font (number).
   *
   * Example:
   * ```cpp
   * it.set_component_font("textview", "3");
   * ```
   *
   * Changes the font of the component named `textveiw`. Font IDs are set in the Nextion Editor.
   */
  void set_component_font(const char *component, uint8_t font_id);
#ifdef USE_TIME
  /**
   * Send the current time to the nextion display.
   * @param time The time instance to send (get this with id(my_time).now() ).
   */
  void set_nextion_rtc_time(time::ESPTime time);
#endif

  /**
   * Show the page with a given name.
   * @param page The name of the page.
   *
   * Example:
   * ```cpp
   * it.goto_page("main");
   * ```
   *
   * Switches to the page named `main`. Pages are named in the Nextion Editor.
   */
  void goto_page(const char *page);
  /**
   * Hide a component.
   * @param component The component name.
   *
   * Example:
   * ```cpp
   * hide_component("button");
   * ```
   *
   * Hides the component named `button`.
   */
  void hide_component(const char *component);
  /**
   * Show a component.
   * @param component The component name.
   *
   * Example:
   * ```cpp
   * show_component("button");
   * ```
   *
   * Shows the component named `button`.
   */
  void show_component(const char *component);
  /**
   * Enable touch for a component.
   * @param component The component name.
   *
   * Example:
   * ```cpp
   * enable_component_touch("button");
   * ```
   *
   * Enables touch for component named `button`.
   */
  void enable_component_touch(const char *component);
  /**
   * Disable touch for a component.
   * @param component The component name.
   *
   * Example:
   * ```cpp
   * disable_component_touch("button");
   * ```
   *
   * Disables touch for component named `button`.
   */
  void disable_component_touch(const char *component);
  /**
   * Add waveform data to a waveform component
   * @param component_id The integer component id.
   * @param channel_number The channel number to write to.
   * @param value The value to write.
   */

The nextion is a smart display why do people keep treating it like a dumb one.


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