Gio.Action¶
interface
GAction represents a single named action.
The main interface to an action is that it can be activated with
Action.activate. This results in the 'activate' signal being
emitted. An activation has a GVariant parameter (which may be
NULL). The correct type for the parameter is determined by a static
parameter type (which is given at construction time).
An action may optionally have a state, in which case the state may be
set with Action.change_state. This call takes a GLib.Variant. The
correct type for the state is determined by a static state type
(which is given at construction time).
The state may have a hint associated with it, specifying its valid range.
GAction is merely the interface to the concept of an action, as
described above. Various implementations of actions exist, including
SimpleAction.
In all cases, the implementing class is responsible for storing the
name of the action, the parameter type, the enabled state, the optional
state type and the state and emitting the appropriate signals when these
change. The implementor is responsible for filtering calls to
Action.activate and Action.change_state
for type safety and for the state being enabled.
Probably the only useful thing to do with a GAction is to put it
inside of a SimpleActionGroup.
Methods¶
activate¶
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 GLib.Variant is floating, it is consumed.
Parameters:
parameter— the parameter to the activation
change_state¶
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 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 Action.get_state_hint.
If the value GLib.Variant is floating, it is consumed.
Parameters:
value— the new state
get_enabled¶
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.
get_name¶
Queries the name of action.
get_parameter_type¶
Queries the type of the parameter that must be given when activating
action.
When activating the action using Action.activate, the
GLib.Variant 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
GLib.Variant, but NULL instead.
get_state¶
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 Action.get_state_type.
The return value (if non-NULL) should be freed with
GLib.Variant.unref when it is no longer required.
get_state_hint¶
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 GLib.Variant array is returned then each item in the array is a
possible value for the state. If a GLib.Variant 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
GLib.Variant.unref when it is no longer required.
get_state_type¶
Queries the type of the state of action.
If the action is stateful (e.g. created with
SimpleAction.new_stateful) then this function returns the
GLib.VariantType of the state. This is the type of the initial value
given as the state. All calls to Action.change_state must give a
GLib.Variant of this type and Action.get_state will return a
GLib.Variant of the same type.
If the action is not stateful (e.g. created with SimpleAction.new)
then this function will return NULL. In that case, Action.get_state
will return NULL and you must not call Action.change_state.
Static functions¶
name_is_valid¶
Checks if action_name is valid.
action_name is valid if it consists only of alphanumeric characters,
plus - and .. The empty string is not a valid action name.
It is an error to call this function with a non-UTF-8 action_name.
action_name must not be NULL.
Parameters:
action_name— a potential action name
parse_detailed_name¶
Parses a detailed action name into its separate name and target components.
Detailed action names can have three formats.
The first format is used to represent an action name with no target
value and consists of just an action name containing no whitespace
nor the characters :, ( or ). For example: app.action.
The second format is used to represent an action with a target value
that is a non-empty string consisting only of alphanumerics, plus -
and .. In that case, the action name and target value are
separated by a double colon (::). For example:
app.action::target.
The third format is used to represent an action with any type of
target value, including strings. The target value follows the action
name, surrounded in parens. For example: app.action(42). The
target value is parsed using GLib.Variant.parse. If a tuple-typed
value is desired, it must be specified in the same way, resulting in
two sets of parens, for example: app.action((1,2,3)). A string
target can be specified this way as well: app.action('target').
For strings, this third format must be used if target value is
empty or contains characters other than alphanumerics, - and ..
If this function returns TRUE, a non-NULL value is guaranteed to be returned
in action_name (if a pointer is passed in). A NULL value may still be
returned in target_value, as the detailed_name may not contain a target.
If returned, the GLib.Variant in target_value is guaranteed to not be floating.
Parameters:
detailed_name— a detailed action name
print_detailed_name¶
@staticmethod
def print_detailed_name(action_name: str, target_value: GLib.Variant | None = ...) -> str
Formats a detailed action name from action_name and target_value.
It is an error to call this function with an invalid action name.
This function is the opposite of Action.parse_detailed_name.
It will produce a string that can be parsed back to the action_name
and target_value by that function.
See that function for the types of strings that will be printed by this function.
Parameters:
action_name— a valid action nametarget_value— aGLib.Varianttarget value, orNULL
Virtual methods¶
do_activate¶
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 GLib.Variant is floating, it is consumed.
Parameters:
parameter— the parameter to the activation
do_change_state¶
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 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 Action.get_state_hint.
If the value GLib.Variant is floating, it is consumed.
Parameters:
value— the new state
do_get_enabled¶
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.
do_get_name¶
Queries the name of action.
do_get_parameter_type¶
Queries the type of the parameter that must be given when activating
action.
When activating the action using Action.activate, the
GLib.Variant 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
GLib.Variant, but NULL instead.
do_get_state¶
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 Action.get_state_type.
The return value (if non-NULL) should be freed with
GLib.Variant.unref when it is no longer required.
do_get_state_hint¶
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 GLib.Variant array is returned then each item in the array is a
possible value for the state. If a GLib.Variant 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
GLib.Variant.unref when it is no longer required.
do_get_state_type¶
Queries the type of the state of action.
If the action is stateful (e.g. created with
SimpleAction.new_stateful) then this function returns the
GLib.VariantType of the state. This is the type of the initial value
given as the state. All calls to Action.change_state must give a
GLib.Variant of this type and Action.get_state will return a
GLib.Variant of the same type.
If the action is not stateful (e.g. created with SimpleAction.new)
then this function will return NULL. In that case, Action.get_state
will return NULL and you must not call Action.change_state.
Properties¶
enabled¶
If action is currently enabled.
If the action is disabled then calls to Action.activate and
Action.change_state have no effect.
name¶
The name of the action. This is mostly meaningful for identifying
the action once it has been added to a ActionGroup. It is immutable.
parameter_type¶
The type of the parameter that must be given when activating the
action. This is immutable, and may be NULL if no parameter is needed when
activating the action.
state¶
The state of the action, or NULL if the action is stateless.
state_type¶
The GLib.VariantType of the state that the action has, or NULL if the
action is stateless. This is immutable.