class Gio::PropertyAction

Overview

A #GPropertyAction is a way to get a #GAction with a state value reflecting and controlling the value of a #GObject property.

The state of the action will correspond to the value of the property. Changing it will change the property (assuming the requested value matches the requirements as specified in the #GParamSpec).

Only the most common types are presently supported. Booleans are mapped to booleans, strings to strings, signed/unsigned integers to int32/uint32 and floats and doubles to doubles.

If the property is an enum then the state will be string-typed and conversion will automatically be performed between the enum value and "nick" string as per the #GEnumValue table.

Flags types are not currently supported.

Properties of object types, boxed types and pointer types are not supported and probably never will be.

Properties of #GVariant types are not currently supported.

If the property is boolean-valued then the action will have a NULL parameter type, and activating the action (with no parameter) will toggle the value of the property.

In all other cases, the parameter type will correspond to the type of the property.

The general idea here is to reduce the number of locations where a particular piece of state is kept (and therefore has to be synchronised between). #GPropertyAction does not have a separate state that is kept in sync with the property value -- its state is the property value.

For example, it might be useful to create a #GAction corresponding to the "visible-child-name" property of a #Gtk::Stack so that the current page can be switched from a menu. The active radio indication in the menu is then directly determined from the active page of the #Gtk::Stack.

An anti-example would be binding the "active-id" property on a #Gtk::ComboBox. This is because the state of the combobox itself is probably uninteresting and is actually being used to control something else.

Another anti-example would be to bind to the "visible-child-name" property of a #Gtk::Stack if this value is actually stored in #GSettings. In that case, the real source of the value is #GSettings. If you want a #GAction to control a setting stored in #GSettings, see g_settings_create_action() instead, and possibly combine its use with g_settings_bind().

Included Modules

Defined in:

lib/gi-crystal/src/auto/gio-2.0/property_action.cr

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from module Gio::Action

activate(parameter : _?) : Nil activate, change_state(value : _) : Nil change_state, enabled : Bool enabled, enabled? : Bool enabled?, name : String name, parameter_type : GLib::VariantType? parameter_type, parse_detailed_name(detailed_name : String, action_name : String, target_value : _) : Bool parse_detailed_name, state : GLib::Variant? state, state_hint : GLib::Variant? state_hint, state_type : GLib::VariantType? state_type, to_unsafe to_unsafe

Class methods inherited from module Gio::Action

g_type : UInt64 g_type, name_is_valid(action_name : String) : Bool name_is_valid, print_detailed_name(action_name : String, target_value : _?) : String print_detailed_name

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(name : String, object : GObject::Object, property_name : String) : self #

Creates a #GAction corresponding to the value of property @property_name on @object.

The property must be existent and readable and writable (and not construct-only).

This function takes a reference on @object and doesn't release it until the action is destroyed.


def self.new #

Initialize a new PropertyAction.


def self.new(*, enabled : Bool? = nil, invert_boolean : Bool? = nil, name : String? = nil, object : GObject::Object? = nil, parameter_type : GLib::VariantType? = nil, property_name : String? = nil, state : GLib::Variant? = nil, state_type : GLib::VariantType? = nil) #

Class Method Detail

def self.g_type : UInt64 #

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


Instance Method Detail

def enabled? : Bool #

def invert_boolean=(value : Bool) : Bool #

def invert_boolean? : Bool #

def name : String #

def name=(value : String) : String #

def object=(value : GObject::Object?) : GObject::Object? #

def parameter_type : GLib::VariantType? #

def property_name=(value : String) : String #

def state : GLib::Variant? #

def state_type : GLib::VariantType? #