Action

class Action(*args, **kwargs)

Implementations: PropertyAction, SimpleAction

GAction represents a single named action.

The main interface to an action is that it can be activated with 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 change_state. This call takes a 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 activate and 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

class Action

activate(parameter: Variant | None = None) → None

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 None then parameter must also be None.

If the parameter GVariant is floating, it is consumed.

Added in version 2.28.

Parameters:: parameter – the parameter to the activation

change_state(value: Variant) → None

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 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 get_state_hint().

If the value GVariant is floating, it is consumed.

Added in version 2.30.

Parameters:: value – the new state

get_enabled() → bool

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.

Added in version 2.28.

get_name() → str: Queries the name of action.

Added in version 2.28.

get_parameter_type() → VariantType | None

Queries the type of the parameter that must be given when activating action.

When activating the action using activate(), the Variant given to that function must be of the type returned by this function.

In the case that this function returns None, you must not give any Variant, but None instead.

Added in version 2.28.

get_state() → Variant | None

Queries the current state of action.

If the action is not stateful then None will be returned. If the action is stateful then the type of the return value is the type given by get_state_type().

The return value (if non-None) should be freed with unref() when it is no longer required.

Added in version 2.28.

get_state_hint() → Variant | None

Requests a hint about the valid range of values for the state of action.

If None 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 Variant array is returned then each item in the array is a possible value for the state. If a 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-None) should be freed with unref() when it is no longer required.

Added in version 2.28.

get_state_type() → VariantType | None

Queries the type of the state of action.

If the action is stateful (e.g. created with new_stateful()) then this function returns the VariantType of the state. This is the type of the initial value given as the state. All calls to change_state() must give a Variant of this type and get_state() will return a Variant of the same type.

If the action is not stateful (e.g. created with new()) then this function will return None. In that case, get_state() will return None and you must not call change_state().

Added in version 2.28.

name_is_valid(action_name: str) → bool

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-utf8 action_name. action_name must not be None.

Added in version 2.38.

Parameters:: action_name – a potential action name

parse_detailed_name(detailed_name: str) → tuple[bool, str, Variant]

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 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-None value is guaranteed to be returned in action_name (if a pointer is passed in). A None value may still be returned in target_value, as the detailed_name may not contain a target.

If returned, the Variant in target_value is guaranteed to not be floating.

Added in version 2.38.

Parameters:: detailed_name – a detailed action name

print_detailed_name(action_name: str, target_value: Variant | None = 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 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.

Added in version 2.38.

Parameters:

action_name – a valid action name
target_value – a Variant target value, or None

Properties

class Action

props.enabled: bool

If action is currently enabled.

If the action is disabled then calls to activate() and change_state() have no effect.

Added in version 2.28.

props.name: str: The name of the action. This is mostly meaningful for identifying the action once it has been added to a ActionGroup. It is immutable.

Added in version 2.28.

props.parameter_type: VariantType: The type of the parameter that must be given when activating the action. This is immutable, and may be None if no parameter is needed when activating the action.

Added in version 2.28.

props.state: Variant: The state of the action, or None if the action is stateless.

Added in version 2.28.

props.state_type: VariantType: The VariantType of the state that the action has, or None if the action is stateless. This is immutable.

Added in version 2.28.

Virtual Methods

class Action

do_activate(parameter: Variant | None = None) → None

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 None then parameter must also be None.

If the parameter GVariant is floating, it is consumed.

Added in version 2.28.

Parameters:: parameter – the parameter to the activation

do_change_state(value: Variant) → None

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 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 get_state_hint().

If the value GVariant is floating, it is consumed.

Added in version 2.30.

Parameters:: value – the new state

do_get_enabled() → bool

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.

Added in version 2.28.

do_get_name() → str: Queries the name of action.

Added in version 2.28.

do_get_parameter_type() → VariantType | None

Queries the type of the parameter that must be given when activating action.

When activating the action using activate(), the Variant given to that function must be of the type returned by this function.

In the case that this function returns None, you must not give any Variant, but None instead.

Added in version 2.28.

do_get_state() → Variant | None

Queries the current state of action.

If the action is not stateful then None will be returned. If the action is stateful then the type of the return value is the type given by get_state_type().

The return value (if non-None) should be freed with unref() when it is no longer required.

Added in version 2.28.

do_get_state_hint() → Variant | None

Requests a hint about the valid range of values for the state of action.

If None 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.

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-None) should be freed with unref() when it is no longer required.

Added in version 2.28.

do_get_state_type() → VariantType | None

Queries the type of the state of action.

If the action is not stateful (e.g. created with new()) then this function will return None. In that case, get_state() will return None and you must not call change_state().

Added in version 2.28.