lvgl/docs/widgets/core/checkbox.md

.. include:: /header.rst 
:github_url: |github_link_base|/widgets/checkbox.md

Checkbox (lv_checkbox)

Overview

The Checkbox object is created from a "tick box" and a label. When the Chackbox is clicked the tick box is toggled.

Parts and Styles

• LV_PART_MAIN The is the background of the Checkbox and it uses the text and all the typical backround style properties. pad_column adjusts the spacing between the tickbox and the label
• LV_PART_INDICATOR The "tick box" is a square the uses all the typical backround style properties. By deafult its size is equal to the height of the main part's font. Padding properties makes the tick boy larger in the respectiev directions.

The Checkbox is added to the deafult group (if it is set).

Usage

Text

The text can be modified by the lv_checkbox_set_text(cb, "New text") function. It will dynamically allocate the text.

To set a static text, use lv_checkbox_set_static_text(cb, txt). This way, only a pointer of txt will be stored and it shouldn't be deallocated while the checkbox exists.

Check, uncheck, disable

You can manually check, un-check, and disable the Checkbox by using the common state state add/clear function:

lv_obj_add_state(cb, LV_STATE_CHECKED);   /*Make the chekbox checked*/
lv_obj_clear_state(cb, LV_STATE_CHECKED); /*MAke the checkbox unchecked*/
lv_obj_add_state(cb, LV_STATE_CHECKED | LV_STATE_DISABLED); /*Make the checkbox checked and disabled*/

Events

• LV_EVENT_VALUE_CHANGED Sent when the checkbox is toggled.
• LV_EVENT_DRAW_PART_BEGIN and LV_EVENT_DRAW_PART_END are sent for both main and indicator parts to allow hooking the drawing. The for more detail on the main part see the Base object's documentation. For the indicator the following fields are used: clip_area, draw_area, rect_dsc, part.

Learn more about Events.

Keys

The following Keys are processed by the 'Buttons':

• LV_KEY_RIGHT/UP Go to toggled state if toggling is enabled
• LV_KEY_LEFT/DOWN Go to non-toggled state if toggling is enabled
• LV_KEY_ENTER Clicks the checkbox and toggles it

Note that, as usual, the state of LV_KEY_ENTER is translated to LV_EVENT_PRESSED/PRESSING/RELEASED etc.

Learn more about Keys.

Example

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

API

.. doxygenfile:: lv_checkbox.h
  :project: lvgl