refactor: minor refactoring and widget docs update

examples/widgets/button/lv_example_button_1.c

@@ -0,0 +1,40 @@
+#include "../../lv_examples.h"
+#if LV_USE_BTN && LV_BUILD_EXAMPLES
+
+static void event_handler(lv_event_t * e)
+{
+    lv_event_code_t code = lv_event_get_code(e);
+
+    if(code == LV_EVENT_CLICKED) {
+        LV_LOG_USER("Clicked");
+    }
+    else if(code == LV_EVENT_VALUE_CHANGED) {
+        LV_LOG_USER("Toggled");
+    }
+}
+
+void lv_example_button_1(void)
+{
+    lv_obj_t * label;
+
+    lv_obj_t * btn1 = lv_button_create(lv_screen_active());
+    lv_obj_add_event_cb(btn1, event_handler, LV_EVENT_ALL, NULL);
+    lv_obj_align(btn1, LV_ALIGN_CENTER, 0, -40);
+    lv_obj_remove_flag(btn1, LV_OBJ_FLAG_PRESS_LOCK);
+
+    label = lv_label_create(btn1);
+    lv_label_set_text(label, "Button");
+    lv_obj_center(label);
+
+    lv_obj_t * btn2 = lv_button_create(lv_screen_active());
+    lv_obj_add_event_cb(btn2, event_handler, LV_EVENT_ALL, NULL);
+    lv_obj_align(btn2, LV_ALIGN_CENTER, 0, 40);
+    lv_obj_add_flag(btn2, LV_OBJ_FLAG_CHECKABLE);
+    lv_obj_set_height(btn2, LV_SIZE_CONTENT);
+
+    label = lv_label_create(btn2);
+    lv_label_set_text(label, "Toggle");
+    lv_obj_center(label);
+
+}
+#endif