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

Calendar (lv_calendar)

From v8.1 the header is added directly into the Calendar widget and the API of the headers has been changed.

Overview

The Calendar object is a classic calendar which can:

• show the days of any month in a 7x7 matrix
• Show the name of the days
• highlight the current day (today)
• highlight any user-defined dates

The Calendar is added to the default group (if it is set). Calendar is an editable object which allow selecting and clicking the dates with encoder navigation too.

To make the Calendar flexible, by default it doesn't show the current year or month. Instead, there are optional "headers" that can be attached to the calendar.

Parts and Styles

The Calendar is composed of 3 widegets

• Container: A rectangle which is a container for the Header and the Days. Uses only LV_PART_MAIN where all the background related style properties are working.
• Days: It's a Button matrix object under the hood to arrange the days into a matrix. lv_calendar_get_btnmatrix(calendar) can be used to get it.
  • LV_PART_MAIN The background of the calendar. Uses all the background related style properties.
  • LV_PART_ITEMS Refers to the dates and day names. Button matrix control flags are set to differentiate the buttons and a custom drawer event is added modify the properties of the buttons as follows:
    • day names have no border, no background and drawn with a gray color
    • days of the previous and next month have LV_BTNMATRIX_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.
• Header: Not created by default, the details are up to the given header.

Usage

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.

Shown date

To set the shown date, use lv_calendar_set_shown_date(calendar, year, month);

Highlighted days

The list of highlighted dates should be stored in a lv_calendar_date_t array loaded by lv_calendar_set_highlighted_dates(calendar, highlighted_dates, date_num). Only the array's pointer will be saved so the array should be a static or global variable.

Name of the days

The name 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 elements should be static, global or constant variables.

Events

• LV_EVENT_VALUE_CHANGED Sent if a date is clicked. lv_calendar_get_pressed_date(calendar, &date) set date to the date currently being pressed. Returns LV_RES_OK if there is a valid pressed date, else LV_RES_INV.

Learn more about Events.

Keys

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

Learn more about Keys.

Headers

Arrow buttons

lv_calendar_header_arrow_create(calendar) creates a header that contains a left and right arrow on the sides and a text with the current year and month between them.

Drop-down

lv_calendar_header_dropdown_create(calendar) creates a header that contains 2 drop-drown lists: one for the year and another for the month.

Example

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

API

.. doxygenfile:: lv_calendar.h
  :project: lvgl