menu.rst

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: :cpp:type:`lv_menu_main_cont`
• Main header: :cpp:type:`lv_menu_main_header_cont`
• Back button: :ref:`lv_button`
• Back button icon: :ref:`lv_image`
• Main page: :cpp:type:`lv_menu_page`
• Sidebar container: :cpp:type:`lv_menu_sidebar_cont`
• Sidebar header: :cpp:type:`lv_menu_sidebar_header_cont`
• Back button: :ref:`lv_button`
• Back button icon: :ref:`lv_image`
• Sidebar page: :cpp:type:`lv_menu_page`

Usage

Create a menu

:cpp:expr:`lv_menu_create(parent)` creates a new empty menu.

Header mode

The following header modes exist:

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

You can set header modes with :cpp:expr:`lv_menu_set_mode_header(menu, LV_MENU_HEADER...)`.

Root back button mode

The following root back button modes exist:

• :cpp:enumerator:`LV_MENU_ROOT_BACK_BTN_DISABLED`
• :cpp:enumerator:`LV_MENU_ROOT_BACK_BTN_ENABLED`

You can set root back button modes with :cpp:expr:`lv_menu_set_mode_root_back_button(menu, LV_MENU_ROOT_BACK_BTN...)`.

Create a menu page

:cpp:expr:`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 :cpp:expr:`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 :cpp:expr:`lv_menu_set_sidebar_page(menu, page)`. NULL to clear sidebar.

Linking between menu pages

For instance, you have created a button obj in the main page. When you click the button obj, you want it to open up a new page, use :cpp:expr:`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:

• :cpp:expr:`lv_menu_cont_create(parent page)` creates a new empty container.
• :cpp:expr:`lv_menu_section_create(parent page)` creates a new empty section.
• :cpp:expr:`lv_menu_separator_create(parent page)` creates a separator.

Events

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

See the events of the :ref:`Base object <lv_obj>` too.

Learn more about :ref:`events`.

Keys

No keys are handled by the menu widget.

Learn more about :ref:`indev_keys`.

Example

API