The check widget is similar to the radio widget, except that it does not work as a group. It toggles the value of a boolean between true and false.

This widget inherits from the layout widget. All layout functions can be used on the check widget.

• Adding a Check
• Modifying Check Styles
• Using Check Widget
• Using Check Callbacks

• Check Widget API
• A Check Example

This is how to create a check widget.

Evas_Object *check;
check = elm_check_add(parent);

Check widget style can be set with the elm_object_style_set() function. The following styles are available:

• “default”
• “toggle”

elm_object_style_get() allows to get the current style.

After having created a check object, it is possible to set its boolean value to EINA_TRUE.

elm_check_state_set(check, EINA_TRUE);

We can also retrieve the current value of the check object.

Eina_Bool value = elm_check_state_get(check);

As with the radio object, an icon and a label can be set.

Default content parts of the check widget that you can use for are:

• “icon” - An icon of the check

Default text parts of the check widget that you can use for are:

• “default” - A label of the check
• “on” - On state label of the check (only valid for “toggle” style.)
• “off” - Off state label of the check (only valid for “toggle” style.)

// Create a Home icon
Evas_Object *icon;
 
icon = elm_icon_add(parent);
elm_icon_standard_set(icon, "home");
 
// Set it to the check object
elm_object_part_content_set(check, "icon", icon);
 
// Set the check label
elm_object_text_set(check, "Check label");

We can also modify the “on” and “off” labels (only valid for '“toggle” style).

elm_object_part_text_set(check, "on", "True");
elm_object_part_text_set(check, "off", "False");

The get functions of the elementary object API can be used to retrieve the content set to the check object.

// Get the current set text of the check label
char *text = elm_object_text_get(check);
 
// Get the content set in the icon part
Evas_Object *icon = elm_object_part_content_get(check, "icon");

This widget emits the following signals, besides the ones sent from Layout:

• “changed” - This is called whenever the user changes the state of the check objects (event_info is always NULL).
• “focused” - When the check has received focus. (since 1.8)
• “unfocused” - When the check has lost focus. (since 1.8)
• “language,changed” - the program's language changed (since 1.9)

When the value is changed by the user, the changed signal is emitted. event_info parameter is NULL.

This example shows how to register a callback on this signal.

evas_object_smart_callback_add(check, "changed", _changed_cb, data);
 
// Callback function for the "changed" signal
// This callback is called when the check value changes
static void
_changed_cb(void *data, Evas_Object *obj, void *event_info)
{
   printf("The value has changed\n");
}

A Check Example