Next: , Previous: GtkCheckButton, Up: Top

17 GtkRadioButton

A choice from multiple check buttons

17.1 Overview

A single radio button performs the same basic function as a <gtk-check-button>, as its position in the object hierarchy reflects. It is only when multiple radio buttons are grouped together that they become a different user interface component in their own right.

Every radio button is a member of some group of radio buttons. When one is selected, all other radio buttons in the same group are deselected. A <gtk-radio-button> is one way of giving the user a choice from many options.

Radio button widgets are created with gtk-radio-button-new, passing NULL as the argument if this is the first radio button in a group. In subsequent calls, the group you wish to add this button to should be passed as an argument. Optionally, gtk-radio-button-new-with-label can be used if you want a text label on the radio button.

Alternatively, when adding widgets to an existing group of radio buttons, use gtk-radio-button-new-from-widget with a <gtk-radio-button> that already has a group assigned to it. The convenience function gtk-radio-button-new-with-label-from-widget is also provided.

To retrieve the group a <gtk-radio-button> is assigned to, use gtk-radio-button-get-group.

To remove a <gtk-radio-button> from one group and make it part of a new one, use gtk-radio-button-set-group.

The group list does not need to be freed, as each <gtk-radio-button> will remove itself and its list item when it is destroyed.

     void create_radio_buttons (void) {
        GtkWidget *window, *radio1, *radio2, *box, *entry;
        window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
        box = gtk_vbox_new (TRUE, 2);
        /* Create a radio button with a GtkEntry widget */
        radio1 = gtk_radio_button_new (NULL);
        entry = gtk_entry_new ();
        gtk_container_add (GTK_CONTAINER (radio1), entry);
        /* Create a radio button with a label */
        radio2 = gtk_radio_button_new_with_label_from_widget (GTK_RADIO_BUTTON (radio1),
     							"I'm the second radio button.");
        /* Pack them into a box, then show all the widgets */
        gtk_box_pack_start (GTK_BOX (box), radio1, TRUE, TRUE, 2);
        gtk_box_pack_start (GTK_BOX (box), radio2, TRUE, TRUE, 2);
        gtk_container_add (GTK_CONTAINER (window), box);
        gtk_widget_show_all (window);

When an unselected button in the group is clicked the clicked button receives the "toggled" signal, as does the previously selected button. Inside the "toggled" handler, gtk-toggle-button-get-active can be used to determine if the button has been selected or deselected.

17.2 Usage

— Class: <gtk-radio-button>

Derives from <gtk-check-button>.

This class defines the following slots:

The radio button whose group this widget belongs to.
— Signal on <gtk-radio-button>: group-changed

Emitted when the group of radio buttons that a radio button belongs to changes. This is emitted when a radio button switches from being alone to being part of a group of 2 or more buttons, or vice-versa, and when a buttton is moved from one group of 2 or more buttons to a different one, but not when the composition of the group that a button belongs to changes.

Since 2.4

— Function: gtk-radio-button-new (group <gtk-radio-group*>) ⇒  (ret <gtk-widget>)

Creates a new <gtk-radio-button>. To be of any practical value, a widget should then be packed into the radio button.

an existing radio button group, or ‘#f’ if you are creating a new group.
a new radio button.
— Function: gtk-radio-button-new-from-widget (group <gtk-radio-button>) ⇒  (ret <gtk-widget>)

Creates a new <gtk-radio-button>, adding it to the same group as group. As with gtk-radio-button-new, a widget should be packed into the radio button.

an existing <gtk-radio-button>.
a new radio button.
— Function: gtk-radio-button-new-with-label (group <gtk-radio-group*>) (label mchars) ⇒  (ret <gtk-widget>)

Creates a new <gtk-radio-button> with a text label.

an existing radio button group, or ‘#f’ if you are creating a new group.
the text label to display next to the radio button.
a new radio button.
— Function: gtk-radio-button-new-with-mnemonic (group <gtk-radio-group*>) (label mchars) ⇒  (ret <gtk-widget>)

Creates a new <gtk-radio-button> containing a label, adding it to the same group as group. The label will be created using gtk-label-new-with-mnemonic, so underscores in label indicate the mnemonic for the button.

the radio button group
the text of the button, with an underscore in front of the mnemonic character
a new <gtk-radio-button>
— Function: gtk-radio-button-set-group (self <gtk-radio-button>) (group <gtk-radio-group*>)
— Method: set-group

Sets a <gtk-radio-button>'s group. It should be noted that this does not change the layout of your interface in any way, so if you are changing the group, it is likely you will need to re-arrange the user interface to reflect these changes.

a <gtk-radio-button>.
an existing radio button group, such as one returned from gtk-radio-button-get-group.
— Function: gtk-radio-button-get-group (self <gtk-radio-button>) ⇒  (ret <gtk-radio-group*>)
— Method: get-group

Retrieves the group assigned to a radio button.

a <gtk-radio-button>.
a linked list containing all the radio buttons in the same group as radio-button.