TTGO_TWatch_Library/examples/lvgl_button/lvgl_button.ino

#include <TTGO.h>

TTGOClass *ttgo;

static void event_handler(lv_obj_t *obj, lv_event_t event)
{
    if (event == LV_EVENT_CLICKED) {
        Serial.printf("Clicked\n");
    } else if (event == LV_EVENT_VALUE_CHANGED) {
        Serial.printf("Toggled\n");
    }
}

void setup()
{
    Serial.begin(115200);
    ttgo = TTGOClass::getWatch();
    ttgo->begin();
    ttgo->openBL();
    ttgo->lvgl_begin();

    lv_obj_t *label;
    lv_obj_t *btn1 = lv_btn_create(lv_scr_act(), NULL);
    lv_obj_set_event_cb(btn1, event_handler);
    lv_obj_align(btn1, NULL, LV_ALIGN_CENTER, 0, -40);

    label = lv_label_create(btn1, NULL);
    lv_label_set_text(label, "Button");

    lv_obj_t *btn2 = lv_btn_create(lv_scr_act(), NULL);
    lv_obj_set_event_cb(btn2, event_handler);
    lv_obj_align(btn2, NULL, LV_ALIGN_CENTER, 0, 40);
    lv_btn_set_toggle(btn2, true);
    lv_btn_toggle(btn2);
    lv_btn_set_fit2(btn2, LV_FIT_NONE, LV_FIT_TIGHT);

    label = lv_label_create(btn2, NULL);
    lv_label_set_text(label, "Toggled");

}

void loop()
{
    lv_task_handler();
    delay(5);
}