feat(examples) add event examples

examples/event/lv_example_event_1.c

@@ -0,0 +1,30 @@
+#include "../lv_examples.h"
+#if LV_BUILD_EXAMPLES && LV_USE_SWITCH
+
+static void event_cb(lv_event_t * e)
+{
+    LV_LOG_USER("Clicked");
+
+    static uint32_t cnt = 1;
+    lv_obj_t * btn = lv_event_get_target(e);
+    lv_obj_t * label = lv_obj_get_child(btn, 0);
+    lv_label_set_text_fmt(label, "%d", cnt);
+    cnt++;
+}
+
+/**
+ * Add click event to a button
+ */
+void lv_example_event_1(void)
+{
+    lv_obj_t * btn = lv_btn_create(lv_scr_act());
+    lv_obj_set_size(btn, 100, 50);
+    lv_obj_center(btn);
+    lv_obj_add_event_cb(btn, event_cb, LV_EVENT_CLICKED, NULL);
+
+    lv_obj_t * label = lv_label_create(btn);
+    lv_label_set_text(label, "Click me!");
+    lv_obj_center(label);
+}
+
+#endif