class Gtk::ListItemFactory

Overview

A Gtk::ListItemFactory creates widgets for the items taken from a GListModel.

This is one of the core concepts of handling list widgets such as Gtk::ListView or Gtk::GridView.

The Gtk::ListItemFactory is tasked with creating widgets for items taken from the model when the views need them and updating them as the items displayed by the view change.

A view is usually only able to display anything after both a factory and a model have been set on the view. So it is important that you do not skip this step when setting up your first view.

Because views do not display the whole list at once but only a few items, they only need to maintain a few widgets at a time. They will instruct the Gtk::ListItemFactory to create these widgets and bind them to the items that are currently displayed.

As the list model changes or the user scrolls to the list, the items will change and the view will instruct the factory to bind the widgets to those new items.

The actual widgets used for displaying those widgets is provided by you.

When the factory needs widgets created, it will create a Gtk::ListItem and hand it to your code to set up a widget for. This list item will provide various properties with information about what item to display and provide you with some opportunities to configure its behavior. See the Gtk::ListItem documentation for further details.

Various implementations of Gtk::ListItemFactory exist to allow you different ways to provide those widgets. The most common implementations are Gtk::BuilderListItemFactory which takes a Gtk::Builder .ui file and then creates widgets and manages everything automatically from the information in that file and Gtk::SignalListItemFactory which allows you to connect to signals with your own code and retain full control over how the widgets are setup and managed.

A Gtk::ListItemFactory is supposed to be final - that means its behavior should not change and the first widget created from it should behave the same way as the last widget created from it. If you intend to do changes to the behavior, it is recommended that you create a new Gtk::ListItemFactory which will allow the views to recreate its widgets.

Once you have chosen your factory and created it, you need to set it on the view widget you want to use it with, such as via Gtk::ListView#factory=. Reusing factories across different views is allowed, but very uncommon.

Direct Known Subclasses

Defined in:

lib/gi-crystal/src/auto/gtk-4.0/list_item_factory.cr

Constructors

Class Method Summary

Instance methods inherited from class GObject::Object

bind_property(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags) : GObject::Binding bind_property, bind_property_full(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags, transform_to : GObject::Closure, transform_from : GObject::Closure) : GObject::Binding bind_property_full, data(key : String) : Pointer(Void)? data, finalize finalize, freeze_notify : Nil freeze_notify, getv(names : Enumerable(String), values : Enumerable(_)) : Nil getv, notify(property_name : String) : Nil notify, notify_by_pspec(pspec : GObject::ParamSpec) : Nil notify_by_pspec, notify_signal notify_signal, property(property_name : String, value : _) : Nil property, qdata(quark : UInt32) : Pointer(Void)? qdata, ref_count : UInt32 ref_count, run_dispose : Nil run_dispose, set_data(key : String, data : Pointer(Void)?) : Nil set_data, set_property(property_name : String, value : _) : Nil set_property, steal_data(key : String) : Pointer(Void)? steal_data, steal_qdata(quark : UInt32) : Pointer(Void)? steal_qdata, thaw_notify : Nil thaw_notify, to_unsafe : Pointer(Void) to_unsafe, watch_closure(closure : GObject::Closure) : Nil watch_closure

Constructor methods inherited from class GObject::Object

cast(obj : GObject::Object) : self cast, cast?(obj : GObject::Object) : self? cast?, new(pointer : Pointer(Void), transfer : GICrystal::Transfer)
new new, newv(object_type : UInt64, parameters : Enumerable(GObject::Parameter)) : self newv

Class methods inherited from class GObject::Object

compat_control(what : UInt64, data : Pointer(Void)?) : UInt64 compat_control, g_type : UInt64 g_type, interface_find_property(g_iface : GObject::TypeInterface, property_name : String) : GObject::ParamSpec interface_find_property, interface_list_properties(g_iface : GObject::TypeInterface) : Enumerable(GObject::ParamSpec) interface_list_properties

Constructor Detail

def self.new #

Initialize a new ListItemFactory.


Class Method Detail

def self.g_type : UInt64 #

Returns the type id (GType) registered in GLib type system.