ndg/lib/lvgl/docs/widgets/extra/menu.md

Menu (lv_menu)

Overview

The menu widget can be used to easily create multi-level menus. It handles the traversal between pages automatically.

Parts and Styles

The menu widget is built from the following objects:

• Main container: lv_menu_main_cont
  • Main header: lv_menu_main_header_cont
    • Back btn: lv_btn
      • Back btn icon: lv_img
  • Main page: lv_menu_page
• Sidebar container: lv_menu_sidebar_cont
  • Sidebar header: lv_menu_sidebar_header_cont
    • Back btn: lv_btn
      • Back btn icon: lv_img
  • Sidebar page: lv_menu_page

Usage

Create a menu

lv_menu_create(parent) creates a new empty menu.

Header mode

The following header modes exist:

• LV_MENU_HEADER_TOP_FIXED Header is positioned at the top.
• LV_MENU_HEADER_TOP_UNFIXED Header is positioned at the top and can be scrolled out of view.
• LV_MENU_HEADER_BOTTOM_FIXED Header is positioned at the bottom.

You can set header modes with lv_menu_set_mode_header(menu, LV_MENU_HEADER...).

Root back button mode

The following root back button modes exist:

• LV_MENU_ROOT_BACK_BTN_DISABLED
• LV_MENU_ROOT_BACK_BTN_ENABLED

You can set root back button modes with lv_menu_set_mode_root_back_btn(menu, LV_MENU_ROOT_BACK_BTN...).

Create a menu page

lv_menu_page_create(menu, title) creates a new empty menu page. You can add any widgets to the page.

Set a menu page in the main area

Once a menu page has been created, you can set it to the main area with lv_menu_set_page(menu, page). NULL to clear main and clear menu history.

Set a menu page in the sidebar

Once a menu page has been created, you can set it to the sidebar with lv_menu_set_sidebar_page(menu, page). NULL to clear sidebar.

Linking between menu pages

For instance, you have created a btn obj in the main page. When you click the btn obj, you want it to open up a new page, use lv_menu_set_load_page_event(menu, obj, new page).

Create a menu container, section, separator

The following objects can be created so that it is easier to style the menu:

lv_menu_cont_create(parent page) creates a new empty container.

lv_menu_section_create(parent page) creates a new empty section.

lv_menu_separator_create(parent page) creates a separator.

Events

• LV_EVENT_VALUE_CHANGED Sent when a page is shown.
  • lv_menu_get_cur_main_page(menu) returns a pointer to menu page that is currently displayed in main.
  • lv_menu_get_cur_sidebar_page(menu) returns a pointer to menu page that is currently displayed in sidebar.
• LV_EVENT_CLICKED Sent when a back btn in a header from either main or sidebar is clicked. LV_OBJ_FLAG_EVENT_BUBBLE is enabled on the buttons so you can add events to the menu itself.
  • lv_menu_back_btn_is_root(menu, btn) to check if btn is root back btn

See the events of the Base object too.

Learn more about Events.

Keys

No keys are handled by the menu widget.

Learn more about Keys.

Example

.. include:: ../../../examples/widgets/menu/index.rst

API

.. doxygenfile:: lv_menu.h
  :project: lvgl