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GIO Reference Manual | |
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| Top | Description | Object Hierarchy | Prerequisites | Known Implementations | Properties | ||||
GAction; const gchar * g_action_get_name (GAction *action); const GVariantType * g_action_get_parameter_type (GAction *action); const GVariantType * g_action_get_state_type (GAction *action); GVariant * g_action_get_state_hint (GAction *action); gboolean g_action_get_enabled (GAction *action); GVariant * g_action_get_state (GAction *action); void g_action_set_state (GAction *action,GVariant *value); void g_action_activate (GAction *action,GVariant *parameter);
"enabled" gboolean : Read / Write / Construct "name" gchar* : Read / Write / Construct Only "parameter-type" GVariantType* : Read / Write / Construct Only "state" GVariant* : Read / Write / Construct "state-type" GVariantType* : Read
GAction represents a single named action.
The main interface to an action is that it can be activated with
g_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 g_action_set_state(). This call takes a GVariant. 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 GSimpleAction and GtkAction.
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 responsible for filtering
calls to g_action_activate() and g_action_set_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 GSimpleActionGroup.
const gchar * g_action_get_name (GAction *action);
Queries the name of action.
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a GAction |
Returns : |
the name of the action |
Since 2.28
const GVariantType * g_action_get_parameter_type (GAction *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.
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a GAction |
Returns : |
the parameter type. [allow-none] |
Since 2.28
const GVariantType * g_action_get_state_type (GAction *action);
Queries the type of the state of action.
If the action is stateful (ie: was created with
g_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_set_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 (ie: created with g_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_set_state().
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a GAction |
Returns : |
the state type, if the action is stateful. [allow-none] |
Since 2.28
GVariant * g_action_get_state_hint (GAction *action);
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.
|
a GAction |
Returns : |
the state range hint. [transfer full] |
Since 2.28
gboolean g_action_get_enabled (GAction *action);
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.
|
a GAction |
Returns : |
whether the action is enabled |
Since 2.28
GVariant * g_action_get_state (GAction *action);
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.
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a GAction |
Returns : |
the current state of the action. [transfer full] |
Since 2.28
void g_action_set_state (GAction *action,GVariant *value);
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.
|
a GAction |
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the new state |
Since 2.28
void g_action_activate (GAction *action,GVariant *parameter);
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.
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a GAction |
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the parameter to the activation. [allow-none] |
Since 2.28
"enabled" property"enabled" gboolean : Read / Write / Construct
If action is currently enabled.
If the action is disabled then calls to g_action_activate() and
g_action_set_state() have no effect.
Default value: TRUE
Since 2.28
"name" property"name" gchar* : Read / Write / Construct Only
The name of the action. This is mostly meaningful for identifying the action once it has been added to a GActionGroup.
Default value: NULL
Since 2.28
"parameter-type" property"parameter-type" GVariantType* : Read / Write / Construct Only
The type of the parameter that must be given when activating the action.
Since 2.28
"state" property"state" GVariant* : Read / Write / Construct
The state of the action, or NULL if the action is stateless.
Allowed values: GVariant<*>
Default value: NULL
Since 2.28
"state-type" property"state-type" GVariantType* : Read
The GVariantType of the state that the action has, or NULL if the
action is stateless.
Since 2.28