Lvgl+NTPClient做一个动态时钟代码

以下是使用Lvgl和ESP32的NTPClient库制作动态时钟的示例代码：

#include <lvgl.h>
#include <WiFi.h>
#include <NTPClient.h>
#include <WiFiUdp.h>

// Set the WiFi credentials
const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";

// Create a WiFiClient instance to connect to the internet
WiFiClient wifiClient;

// Create a UDP instance to send and receive NTP packets
WiFiUDP ntpUDP;

// Create an NTPClient instance to get the time from NTP servers
NTPClient timeClient(ntpUDP, "pool.ntp.org");

// Create a label to display the time
lv_obj_t* label;

void setup() {
  // Initialize LVGL
  lv_init();

  // Initialize the display
  lv_disp_drv_t disp_drv;
  lv_disp_drv_init(&disp_drv);
  disp_drv.disp_flush = my_disp_flush;
  lv_disp_drv_register(&disp_drv);

  // Initialize the touch screen
  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);

  // Connect to the WiFi network
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
  }

  // Start the NTP client
  timeClient.begin();

  // Create the label to display the time
  label = lv_label_create(lv_scr_act(), NULL);
  lv_label_set_text(label, "00:00:00");
  lv_obj_align(label, NULL, LV_ALIGN_CENTER, 0, 0);

  // Set the update callback for the time client
  timeClient.onNTPSyncEvent([](NTPSyncEvent_t event) {
    if (event == timeSyncd) {
      // Update the label with the current time
      char timeStr[9];
      sprintf(timeStr, "%02d:%02d:%02d", timeClient.getHours(), timeClient.getMinutes(), timeClient.getSeconds());
      lv_label_set_text(label, timeStr);
      lv_obj_align(label, NULL, LV_ALIGN_CENTER, 0, 0);
    }
  });
}

void loop() {
  // Update the time client
  timeClient.update();
}

// Implement the display flush function
void my_disp_flush(lv_disp_drv_t* disp_drv, const lv_area_t* area, lv_color_t* color_p) {
  // Write the framebuffer to the display
}

// Implement the touchpad read function
bool my_touchpad_read(lv_indev_drv_t* indev_drv, lv_indev_data_t* data) {
  // Read the touchpad and update the data
}

在此示例代码中，我们首先初始化了LVGL，并为显示器和触摸屏创建了驱动程序。然后，我们连接到WiFi网络，并创建了一个NTPClient实例来获取当前时间。接下来，我们创建了一个标签来显示时间，并将其对齐到屏幕中心。最后，我们设置了一个回调函数，用于更新标签以显示当前时间。在主循环中，我们更新时间客户端，以便它可以更新当前时间。