Checkbox (lv_checkbox)

A tick box with a label. Clicking it toggles the tick on or off.

Overview

A Checkbox is a tick box with a label next to it. Clicking the widget toggles the tick on or off.

Text

The text can be modified with lv_checkbox_set_text(cb, "New text") and will be dynamically allocated.

To set static text, use lv_checkbox_set_text_static(cb, txt). This way, only a pointer to txt will be stored. The provided text buffer must remain available for the lifetime of the Checkbox.

lv_example_checkbox_text.c

Check, uncheck, disable

Toggle programmatically with the generic state helpers:

lv_obj_add_state(cb, LV_STATE_CHECKED);
lv_obj_remove_state(cb, LV_STATE_CHECKED);
lv_obj_add_state(cb, LV_STATE_DISABLED);

Read it back with lv_obj_has_state(cb, LV_STATE_CHECKED).

lv_example_checkbox_states.c

Two parts: LV_PART_MAIN (the label/text area; pad_column controls the gap to the tickbox) and LV_PART_INDICATOR (the tickbox itself — its default size matches the font height; padding scales it).

lv_example_checkbox_styling.c

The headline pattern is state-aware styling on the indicator: one style attached with selector="indicator" for the default look, a second one with selector="indicator|checked" to swap colours when the box is ticked.

Data binding

Data bindings connect a widget property to a piece of global data — a Subject. When the subject's value changes, every widget bound to it updates automatically; and an interactive widget can write back into the subject so other subscribers see the new value.

A Checkbox's checked state is exposed via the generic lv_obj_bind_checked. The link is two-way: flipping the box writes 0/1 into the int subject, and assigning the subject toggles the box. Pair it with bind_flag_if_* / bind_state_if_* on other widgets to react to that flag without writing any event callback.