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.
the name of the action to create
the object that has the property to wrap
the name of the property
If action is currently enabled.
If the action is disabled then calls to g_action_activate() and g_action_change_state() have no effect.
If %TRUE, the state of the action will be the negation of the property value, provided the property is boolean.
The name of the action. This is mostly meaningful for identifying the action once it has been added to a #GActionMap.
The object to wrap a property on.
The object must be a non-%NULL #GObject with properties.
The type of the parameter that must be given when activating the action.
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).
The state of the action, or %NULL if the action is stateless.
The #GVariantType of the state that the action has, or %NULL if the action is stateless.
Activates the action.
parameter must be the correct type of parameter for the action (ie:
the parameter type given at construction time). If the parameter
type was %NULL then parameter must also be %NULL.
If the parameter GVariant is floating, it is consumed.
Creates a binding between source_property on source and target_property
on target.
Whenever the source_property is changed the target_property is
updated using the same value. For instance:
g_object_bind_property (action, "active", widget, "sensitive", 0);
Will result in the "sensitive" property of the widget #GObject instance to be updated with the same value of the "active" property of the action #GObject instance.
If flags contains %G_BINDING_BIDIRECTIONAL then the binding will be mutual:
if target_property on target changes then the source_property on source
will be updated as well.
The binding will automatically be removed when either the source or the
target instances are finalized. To remove the binding without affecting the
source and the target you can just call g_object_unref() on the returned
#GBinding instance.
Removing the binding by calling g_object_unref() on it must only be done if
the binding, source and target are only used from a single thread and it
is clear that both source and target outlive the binding. Especially it
is not safe to rely on this if the binding, source or target can be
finalized from different threads. Keep another reference to the binding and
use g_binding_unbind() instead to be on the safe side.
A #GObject can have multiple bindings.
the property on source to bind
the target #GObject
the property on target to bind
flags to pass to #GBinding
Creates a binding between source_property on source and target_property
on target, allowing you to set the transformation functions to be used by
the binding.
This function is the language bindings friendly version of g_object_bind_property_full(), using #GClosures instead of function pointers.
the property on source to bind
the target #GObject
the property on target to bind
flags to pass to #GBinding
a #GClosure wrapping the transformation function from the source to the target, or %NULL to use the default
a #GClosure wrapping the transformation function from the target to the source, or %NULL to use the default
Request for the state of action to be changed to value.
The action must be stateful and value must be of the correct type.
See g_action_get_state_type().
This call merely requests a change. The action may refuse to change
its state or may change its state to something other than value.
See g_action_get_state_hint().
If the value GVariant is floating, it is consumed.
This function is intended for #GObject implementations to re-enforce a [floating][floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling g_object_ref_sink().
Increases the freeze count on object. If the freeze count is
non-zero, the emission of "notify" signals on object is
stopped. The signals are queued until the freeze count is decreased
to zero. Duplicate notifications are squashed so that at most one
#GObject::notify signal is emitted for each property modified while the
object is frozen.
This is necessary for accessors that modify multiple properties to prevent premature notification while the object is still being modified.
Gets a named field from the objects table of associations (see g_object_set_data()).
name of the key for that association
Checks if action is currently enabled.
An action must be enabled in order to be activated or in order to have its state changed from outside callers.
Queries the name of action.
Queries the type of the parameter that must be given when activating
action.
When activating the action using g_action_activate(), the #GVariant given to that function must be of the type returned by this function.
In the case that this function returns %NULL, you must not give any #GVariant, but %NULL instead.
Gets a property of an object.
The value can be:
In general, a copy is made of the property contents and the caller is responsible for freeing the memory by calling g_value_unset().
Note that g_object_get_property() is really intended for language bindings, g_object_get() is much more convenient for C programming.
the name of the property to get
return location for the property value
This function gets back user data pointers stored via g_object_set_qdata().
A #GQuark, naming the user data pointer
Queries the current state of action.
If the action is not stateful then %NULL will be returned. If the action is stateful then the type of the return value is the type given by g_action_get_state_type().
The return value (if non-%NULL) should be freed with g_variant_unref() when it is no longer required.
Requests a hint about the valid range of values for the state of
action.
If %NULL is returned it either means that the action is not stateful or that there is no hint about the valid range of values for the state of the action.
If a #GVariant array is returned then each item in the array is a possible value for the state. If a #GVariant pair (ie: two-tuple) is returned then the tuple specifies the inclusive lower and upper bound of valid values for the state.
In any case, the information is merely a hint. It may be possible to have a state value outside of the hinted range and setting a value within the range may fail.
The return value (if non-%NULL) should be freed with g_variant_unref() when it is no longer required.
Queries the type of the state of action.
If the action is stateful (e.g. created with g_simple_action_new_stateful()) then this function returns the #GVariantType of the state. This is the type of the initial value given as the state. All calls to g_action_change_state() must give a #GVariant of this type and g_action_get_state() will return a #GVariant of the same type.
If the action is not stateful (e.g. created with g_simple_action_new()) then this function will return %NULL. In that case, g_action_get_state() will return %NULL and you must not call g_action_change_state().
Gets n_properties properties for an object.
Obtained properties will be set to values. All properties must be valid.
Warnings will be emitted and undefined behaviour may result if invalid
properties are passed in.
the names of each property to get
the values of each property to get
Checks whether object has a [floating][floating-ref] reference.
Emits a "notify" signal for the property property_name on object.
When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.
Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.
the name of a property installed on the class of object.
Emits a "notify" signal for the property specified by pspec on object.
This function omits the property name lookup, hence it is faster than g_object_notify().
One way to avoid using g_object_notify() from within the class that registered the properties, and using g_object_notify_by_pspec() instead, is to store the GParamSpec used with g_object_class_install_property() inside a static array, e.g.:
enum
{
PROP_0,
PROP_FOO,
PROP_LAST
};
static GParamSpec *properties[PROP_LAST];
static void
my_object_class_init (MyObjectClass *klass)
{
properties[PROP_FOO] = g_param_spec_int ("foo", "Foo", "The foo",
0, 100,
50,
G_PARAM_READWRITE);
g_object_class_install_property (gobject_class,
PROP_FOO,
properties[PROP_FOO]);
}
and then notify a change on the "foo" property with:
g_object_notify_by_pspec (self, properties[PROP_FOO]);
the #GParamSpec of a property installed on the class of object.
Increase the reference count of object, and possibly remove the
[floating][floating-ref] reference, if object has a floating reference.
In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal reference increasing the reference count by one.
Since GLib 2.56, the type of object will be propagated to the return type
under the same conditions as for g_object_ref().
Releases all references to other objects. This can be used to break reference cycles.
This function should only be called from object system implementations.
Each object carries around a table of associations from strings to pointers. This function lets you set an association.
If the object already had an association with that name, the old association will be destroyed.
Internally, the key is converted to a #GQuark using g_quark_from_string().
This means a copy of key is kept permanently (even after object has been
finalized) — so it is recommended to only use a small, bounded set of values
for key in your program, to avoid the #GQuark storage growing unbounded.
name of the key
data to associate with that key
Sets a property on an object.
the name of the property to set
the value
Remove a specified datum from the object's data associations, without invoking the association's destroy handler.
name of the key
This function gets back user data pointers stored via
g_object_set_qdata() and removes the data from object
without invoking its destroy() function (if any was
set).
Usually, calling this function is only required to update
user data pointers with a destroy notifier, for example:
void
object_add_to_user_list (GObject *object,
const gchar *new_string)
{
// the quark, naming the object data
GQuark quark_string_list = g_quark_from_static_string ("my-string-list");
// retrieve the old string list
GList *list = g_object_steal_qdata (object, quark_string_list);
// prepend new string
list = g_list_prepend (list, g_strdup (new_string));
// this changed 'list', so we need to set it again
g_object_set_qdata_full (object, quark_string_list, list, free_string_list);
}
static void
free_string_list (gpointer data)
{
GList *node, *list = data;
for (node = list; node; node = node->next)
g_free (node->data);
g_list_free (list);
}
Using g_object_get_qdata() in the above example, instead of g_object_steal_qdata() would have left the destroy function set, and thus the partial string list would have been freed upon g_object_set_qdata_full().
A #GQuark, naming the user data pointer
Reverts the effect of a previous call to
g_object_freeze_notify(). The freeze count is decreased on object
and when it reaches zero, queued "notify" signals are emitted.
Duplicate notifications for each property are squashed so that at most one #GObject::notify signal is emitted for each property, in the reverse order in which they have been queued.
It is an error to call this function when the freeze count is zero.
Decreases the reference count of object. When its reference count
drops to 0, the object is finalized (i.e. its memory is freed).
If the pointer to the #GObject may be reused in future (for example, if it is an instance variable of another object), it is recommended to clear the pointer to %NULL rather than retain a dangling pointer to a potentially invalid #GObject instance. Use g_clear_object() for this.
Activates the action.
parameter must be the correct type of parameter for the action (ie:
the parameter type given at construction time). If the parameter
type was %NULL then parameter must also be %NULL.
If the parameter GVariant is floating, it is consumed.
Request for the state of action to be changed to value.
The action must be stateful and value must be of the correct type.
See g_action_get_state_type().
This call merely requests a change. The action may refuse to change
its state or may change its state to something other than value.
See g_action_get_state_hint().
If the value GVariant is floating, it is consumed.
Checks if action is currently enabled.
An action must be enabled in order to be activated or in order to have its state changed from outside callers.
Queries the name of action.
Queries the type of the parameter that must be given when activating
action.
When activating the action using g_action_activate(), the #GVariant given to that function must be of the type returned by this function.
In the case that this function returns %NULL, you must not give any #GVariant, but %NULL instead.
Queries the current state of action.
If the action is not stateful then %NULL will be returned. If the action is stateful then the type of the return value is the type given by g_action_get_state_type().
The return value (if non-%NULL) should be freed with g_variant_unref() when it is no longer required.
Requests a hint about the valid range of values for the state of
action.
If %NULL is returned it either means that the action is not stateful or that there is no hint about the valid range of values for the state of the action.
If a #GVariant array is returned then each item in the array is a possible value for the state. If a #GVariant pair (ie: two-tuple) is returned then the tuple specifies the inclusive lower and upper bound of valid values for the state.
In any case, the information is merely a hint. It may be possible to have a state value outside of the hinted range and setting a value within the range may fail.
The return value (if non-%NULL) should be freed with g_variant_unref() when it is no longer required.
Queries the type of the state of action.
If the action is stateful (e.g. created with g_simple_action_new_stateful()) then this function returns the #GVariantType of the state. This is the type of the initial value given as the state. All calls to g_action_change_state() must give a #GVariant of this type and g_action_get_state() will return a #GVariant of the same type.
If the action is not stateful (e.g. created with g_simple_action_new()) then this function will return %NULL. In that case, g_action_get_state() will return %NULL and you must not call g_action_change_state().
Emits a "notify" signal for the property property_name on object.
When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.
Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.
This function essentially limits the life time of the closure to
the life time of the object. That is, when the object is finalized,
the closure is invalidated by calling g_closure_invalidate() on
it, in order to prevent invocations of the closure with a finalized
(nonexisting) object. Also, g_object_ref() and g_object_unref() are
added as marshal guards to the closure, to ensure that an extra
reference count is held on object during invocation of the
closure. Usually, this function will be called on closures that
use this object as closure data.
#GClosure to watch
Find the #GParamSpec with the given name for an
interface. Generally, the interface vtable passed in as g_iface
will be the default vtable from g_type_default_interface_ref(), or,
if you know the interface has already been loaded,
g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
name of a property to look up.
Add a property to an interface; this is only useful for interfaces that are added to GObject-derived types. Adding a property to an interface forces all objects classes with that interface to have a compatible property. The compatible property could be a newly created #GParamSpec, but normally g_object_class_override_property() will be used so that the object class only needs to provide an implementation and inherits the property description, default value, bounds, and so forth from the interface property.
This function is meant to be called from the interface's default
vtable initialization function (the class_init member of
#GTypeInfo.) It must not be called after after class_init has
been called for any object types implementing this interface.
If pspec is a floating reference, it will be consumed.
any interface vtable for the interface, or the default vtable for the interface.
the #GParamSpec for the new property
Lists the properties of an interface.Generally, the interface
vtable passed in as g_iface will be the default vtable from
g_type_default_interface_ref(), or, if you know the interface has
already been loaded, g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
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.
the name of the action to create
the object that has the property to wrap
the name of the property
Creates a new instance of a #GObject subtype and sets its properties.
Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY) which are not explicitly specified are set to their default values.
the type id of the #GObject subtype to instantiate
an array of #GParameter
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 #GtkStack 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 #GtkStack.
An anti-example would be binding the "active-id" property on a #GtkComboBox. 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 #GtkStack 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().