Add the all.c files in the Widgets demo assets to project :

• Which include the image information ;

Add the the lv_demo_widgets.c and lv_demo_widgets.h in the Widgets demo to project;

• They are key files to call "lv_demo_widgets();";

Add the touch.h to my project;

• Modify the touchpad function according to the pre-set functions in touch.h, and pass the state of the touchpad to the LVGL graphics library.

     static lv_indev_drv_t indev_drv;
      lv_indev_drv_init(&indev_drv);
      indev_drv.type = LV_INDEV_TYPE_POINTER;
      indev_drv.read_cb = my_touchpad_read;
      lv_indev_drv_register(&indev_drv);
  
  void my_touchpad_read(lv_indev_drv_t *indev_driver, lv_indev_data_t *data)
  {
    if (touch_has_signal())
    {
      if (touch_touched())
      {
        data->state = LV_INDEV_STATE_PR;
  
  
        /*Set the coordinates*/
        data->point.x = touch_last_x;
        data->point.y = touch_last_y;
      }
      else if (touch_released())
      {
        data->state = LV_INDEV_STATE_REL;
      }
    }
    else
    {
      data->state = LV_INDEV_STATE_REL;
    }
  }

• When I use the GFX library， it is needed to define the GFX Library For the Arduino Interface pin.

  Arduino_ESP32RGBPanel *bus = new Arduino_ESP32RGBPanel(
      GFX_NOT_DEFINED /* CS */, GFX_NOT_DEFINED /* SCK */, GFX_NOT_DEFINED /* SDA */,
      40 /* DE */, 41 /* VSYNC */, 39 /* HSYNC */, 42 /* PCLK */,
      45 /* R0 */, 48 /* R1 */, 47 /* R2 */, 21 /* R3 */, 14 /* R4 */,
      5 /* G0 */, 6 /* G1 */, 7 /* G2 */, 15 /* G3 */, 16 /* G4 */, 4 /* G5 */,
      8 /* B0 */, 3 /* B1 */, 46 /* B2 */, 9 /* B3 */, 1 /* B4 */
  );
  
  
  #ifdef SCREEN_NORMAL
  Arduino_RPi_DPI_RGBPanel *gfx = new Arduino_RPi_DPI_RGBPanel(
      bus,
      800 /* width */, 0 /* hsync_polarity */, 210 /* hsync_front_porch */, 30 /* hsync_pulse_width */, 16 /* hsync_back_porch */,
      480 /* height */, 0 /* vsync_polarity */, 22 /* vsync_front_porch */, 13 /* vsync_pulse_width */, 10 /* vsync_back_porch */,
      1 /* pclk_active_neg */, 16000000 /* prefer_speed */, true /* auto_flush */);
  #endif
  
  
  #ifdef SCREEN_HD
  Arduino_RPi_DPI_RGBPanel *gfx = new Arduino_RPi_DPI_RGBPanel(
      bus,
      SCREEN_W /* width */, 1 /* hsync_polarity */, 40 /* hsync_front_porch */, 48 /* hsync_pulse_width */, 128 /* hsync_back_porch */,
      SCREEN_H /* height */, 1 /* vsync_polarity */, 13 /* vsync_front_porch */, 3 /* vsync_pulse_width */, 45 /* vsync_back_porch */,
      1 /* pclk_active_neg */, 16000000 /* prefer_speed */, true /* auto_flush */);

The more detail you can click Add LVGL into your project.

The raw code.