gio:list-model, gobject:object, common-lisp:standard-object, common-lisp:t

gtk:multi-selection, gtk:no-selection, gtk:notebook-pages, gtk:single-selection

The gtk:selection-model interface is an interface that extends the g:list-model interface by adding support for selections. This support is then used by widgets using list models to add the ability to select and unselect various items.

GTK provides default implementations of the most common selection modes such as the gtk:single-selection implementation, so you will only need to implement this interface if you want detailed control about how selections should be handled.

A gtk:selection-model object supports a single boolean per item indicating if an item is selected or not. This can be queried via the gtk:selection-model-is-selected function. When the selected state of one or more items changes, the model will emit the "selection-changed" signal by calling the gtk:selection-model-selection-changed function. The positions given in that signal may have their selection state changed, though that is not a requirement. If new items added to the model via the "items-changed" signal are selected or not is up to the implementation.

Note that items added via the "items-changed" signal may already be selected and no "selection-changed" signal will be emitted for them. So to track which items are selected, it is necessary to listen to both signals.

Additionally, the interface can expose functionality to select and unselect items. If these functions are implemented, list widgets will allow users to select and unselect items. However, the gtk:selection-model implementations are free to only implement them partially or not at all. In that case the widgets will not support the unimplemented operations.

When selecting or unselecting is supported by a model, the return values of the selection functions do not indicate if selection or unselection happened. They are only meant to indicate complete failure, like when this mode of selecting is not supported by the model.

Selections may happen asynchronously, so the only reliable way to find out when an item was selected is to listen to the signals that indicate selection.

The "selection-changed" signal

lambda (model position n-items)    :run-last      

model

The gtk:selection-model object.

position

The unsigned integer with the first item that may have changed.

n-items

The unsigned integer with the number of items with changes.

Emitted when the selection state of some of the items in model changes. Note that this signal does not specify the new selection state of the items, they need to be queried manually. It is also not necessary for a model to change the selection state of any of the items in the selection model, though it would be rather useless to emit such a signal.