Trait gio::prelude::ListModelExt

pub trait ListModelExt: 'static {
    // Required methods
    fn item_type(&self) -> Type;
    fn n_items(&self) -> u32;
    fn item(&self, position: u32) -> Option<Object>;
    fn items_changed(&self, position: u32, removed: u32, added: u32);
    fn connect_items_changed<F: Fn(&Self, u32, u32, u32) + 'static>(
        &self,
        f: F
    ) -> SignalHandlerId;
}

Trait containing all ListModel methods.

Implementors

ListModel, ListStore

Required Methods

fn item_type(&self) -> Type

Gets the type of the items in self.

All items returned from g_list_model_get_item() are of the type returned by this function, or a subtype, or if the type is an interface, they are an implementation of that interface.

The item type of a ListModel can not change during the life of the model.

Returns

the GType of the items contained in self.

fn n_items(&self) -> u32

Gets the number of items in self.

Depending on the model implementation, calling this function may be less efficient than iterating the list with increasing values for position until g_list_model_get_item() returns None.

Returns

the number of items in self.

fn item(&self, position: u32) -> Option<Object>

Get the item at position.

If position is greater than the number of items in self, None is returned.

None is never returned for an index that is smaller than the length of the list.

This function is meant to be used by language bindings in place of g_list_model_get_item().

See also: n_items()

position

the position of the item to fetch

Returns

the object at position.

fn items_changed(&self, position: u32, removed: u32, added: u32)

Emits the items-changed signal on self.

This function should only be called by classes implementing ListModel. It has to be called after the internal representation of self has been updated, because handlers connected to this signal might query the new state of the list.

Implementations must only make changes to the model (as visible to its consumer) in places that will not cause problems for that consumer. For models that are driven directly by a write API (such as ListStore), changes can be reported in response to uses of that API. For models that represent remote data, changes should only be made from a fresh mainloop dispatch. It is particularly not permitted to make changes in response to a call to the ListModel consumer API.

Stated another way: in general, it is assumed that code making a series of accesses to the model via the API, without returning to the mainloop, and without calling other code, will continue to view the same contents of the model.

position

the position at which self changed

removed

the number of items removed

added

the number of items added

fn connect_items_changed<F: Fn(&Self, u32, u32, u32) + 'static>( &self, f: F ) -> SignalHandlerId

This signal is emitted whenever items were added to or removed from list. At position, removed items were removed and added items were added in their place.

Note: If removed != added, the positions of all later items in the model change.

position

the position at which list changed

removed

the number of items removed

added

the number of items added

Implementors

impl<O: IsA<ListModel>> ListModelExt for O