Class g-property-action

Package: gio

Superclasses

g-action, g-object, common-lisp:standard-object, common-lisp:t

Documented Subclasses

None

Direct Slots

enabled

The enabled property of type :boolean (Read)
If the action is currently enabled. If the action is disabled then calls to the functions g-action-activate and g-action-change-state have no effect.
Default value: true

invert-boolean

The invert-boolean property of type :boolean (Read / Write / Construct Only)
If true, the state of the action will be the negation of the property value, provided the property is boolean.
Default value: false

name

The name property of type g-string (Read / Write / Construct Only)
The name of the action. This is mostly meaningful for identifying the action once it has been added to a g-action-map object.
Default value: nil

object

The object property of type g-object (Write / Construct Only)
The object to wrap a property on. The object must be a GObject with properties.
Note: In the Lisp binding this property is not readable and not writeable.

parameter-type

The parameter-type property of type g-variant-type (Read)
The type of the parameter that must be given when activating the action.

property-name

The property-name property of type g-string (Write / Construct only)
The name of the property to wrap on the object. The property must exist on the passed-in object and it must be readable and writable and not construct-only.
Note: In the Lisp binding this property is not readable und not writeable.

state

The state property of type g-variant (Read)
The state of the action, or nil if the action is stateless.
Default value: nil

state-type

The state-type property of type g-variant-type (Read)
The variant type of the state that the action has, or nil if the action is stateless.

Details

A g-property-action is a way to get a g-action 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. g-property-action 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 g-action 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-combo-box. 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 g-action to control a setting stored in GSettings, see g_settings_create_action() instead, and possibly combine its use with g_settings_bind().