Calendar (lv_calendar)

A classic month calendar that can show day names, highlight today, and mark any user-defined dates.

Overview

Calendar is a classic month calendar. It can:

• show the days of any month in a 7x7 grid,
• show the name of each day,
• highlight today, and
• highlight any user-defined dates.

Calendar is added to the default group (if one is set). It is an editable widget — dates can be picked with a pointer, an encoder, or a keyboard.

To stay flexible, Calendar does not show the current year or month by default. Optional "headers" can be attached to add this.

Styling

The calendar Widget uses the Button Matrix Widget under the hood to arrange the days into a matrix.

• LV_PART_MAIN Calendar background. Uses the typical background style properties.

• LV_PART_ITEMS Refers to dates and day names. Button matrix control flags are set to differentiate the buttons and a custom drawer event is added to modify the properties of the buttons as follows:

  • day names have no border, no background and are drawn with a gray color
  • days of the previous and next month have the LV_BUTTONMATRIX_CTRL_DISABLED flag
  • today has a thicker border with the theme's primary color - highlighted days have some opacity with the theme's primary color.

Some functions use the lv_calendar_date_t type which is a structure with year, month and day fields.

Current date

To set the current date (today), use the lv_calendar_set_today_date(calendar, year, month, day) function. month needs to be in 1..12 range and day in 1..31 range.

Month shown

To set the shown date, use

Highlighted days

The list of highlighted dates should be stored in a lv_calendar_date_t array and applied to the Calendar by calling lv_calendar_set_highlighted_dates(calendar, highlighted_dates, date_num). Only the array's pointer will be saved so the array should be have static or global scope.

Highlighted dates aren't yet exposed through XML attributes (the dates need a static array that outlives the widget). This C example also wires an LV_EVENT_VALUE_CHANGED callback that logs the tapped date — the typical pattern for picking a day:

Names of days

The names of the days can be adjusted with lv_calendar_set_day_names(calendar, day_names) where day_names looks like const char * day_names[7] = {"Su", "Mo", ...}; Only the pointer of the day names is saved so the array should have static or global scope.

static const char * day_names[7] = {"Su", "Mo", "Tu", "We", "Th", "Fr", "Sa"};
lv_calendar_set_day_names(calendar, day_names);

Custom year list

Set a custom year list with lv_calendar_header_dropdown_set_year_list(calendar, years_list) where years_list is a pointer to the custom years list. It can be a constant string like static const char * years = "2023\n2022\n2021\n2020\n2019";, or can be generated dynamically into a buffer as well. Calendar stores these in a Drop-Down List Widget via lv_dropdown_set_options so the passed string pointer can be supplied by a local variable or buffer and does not need to persist beyond the call.

lv_calendar_header_dropdown_set_year_list(calendar, "2026\n2025\n2024\n2023");

Chinese calendar

lv_calendar_set_chinese_mode(calendar, true) adds lunar-date and solar-term annotations alongside each Gregorian day. Requires LV_USE_CALENDAR_CHINESE and a CJK font.

Events

• LV_EVENT_VALUE_CHANGED Sent if a date is clicked. lv_calendar_get_pressed_date(calendar, &date) to set date to the date currently being pressed. Returns LV_RESULT_OK if there is a valid pressed date; otherwise it returns LV_RESULT_INVALID.

Learn more about Events emitted by all Widgets.

Keys

• LV_KEY_DOWN/UP/LEFT/RIGHT To navigate among the buttons to dates
• LV_KEY_ENTER To press/release the selected date

Learn more about Keys.

Headers

From LVGL v8.1 onward, the header is added directly into the Calendar Widget and the API of the headers has been changed.

Arrow buttons

lv_calendar_add_header_arrow(calendar) creates a header that contains a left and right arrow on the sides and text between the arrows showing the current year and month.

Drop-down

lv_calendar_add_header_dropdown(calendar) creates a header that contains 2 Drop-Drown List Widgets for the year and month.