## GActionGroup

GActionGroup — A group of actions

## Synopsis

                        GActionGroup;

    gboolean            g_action_group_has_action           (GActionGroup *action_group,
                                                             const gchar *action_name);
    gchar **            g_action_group_list_actions         (GActionGroup *action_group);

    gboolean            g_action_group_get_action_enabled   (GActionGroup *action_group,
                                                             const gchar *action_name);
    const GVariantType * g_action_group_get_action_parameter_type
                                                            (GActionGroup *action_group,
                                                             const gchar *action_name);
    const GVariantType * g_action_group_get_action_state_type
                                                            (GActionGroup *action_group,
                                                             const gchar *action_name);
    GVariant *          g_action_group_get_action_state_hint
                                                            (GActionGroup *action_group,
                                                             const gchar *action_name);

    GVariant *          g_action_group_get_action_state     (GActionGroup *action_group,
                                                             const gchar *action_name);
    void                g_action_group_change_action_state  (GActionGroup *action_group,
                                                             const gchar *action_name,
                                                             GVariant *value);

    void                g_action_group_activate_action      (GActionGroup *action_group,
                                                             const gchar *action_name,
                                                             GVariant *parameter);

    void                g_action_group_action_added         (GActionGroup *action_group,
                                                             const gchar *action_name);
    void                g_action_group_action_removed       (GActionGroup *action_group,
                                                             const gchar *action_name);
    void                g_action_group_action_enabled_changed
                                                            (GActionGroup *action_group,
                                                             const gchar *action_name,
                                                             gboolean enabled);
    void                g_action_group_action_state_changed (GActionGroup *action_group,
                                                             const gchar *action_name,
                                                             GVariant *state);

## Object Hierarchy

      GInterface
       +----GActionGroup

## Prerequisites

GActionGroup requires GObject.

## Known Implementations

GActionGroup is implemented by GApplication and GSimpleActionGroup.

## Signals

      "action-added"                                   : Has Details
      "action-enabled-changed"                         : Has Details
      "action-removed"                                 : Has Details
      "action-state-changed"                           : Has Details

## Description

GActionGroup represents a group of actions.

Each action in the group has a unique name (which is a string). All method calls, except `g_action_group_list_actions()` take the name of an action as an argument.

The GActionGroup API is meant to be the 'public' API to the action group. The calls here are exactly the interaction that 'external forces' (eg: UI, incoming D-Bus messages, etc.) are supposed to have with actions. 'Internal' APIs (ie: ones meant only to be accessed by the action group implementation) are found on subclasses. This is why you will find -- for example -- `g_action_group_get_action_enabled()` but not an equivalent ``set()`` call.

Signals are emitted on the action group in response to state changes on individual actions.

## Details

### GActionGroup

    typedef struct _GActionGroup GActionGroup;

### g_action_group_has_action ()

    gboolean            g_action_group_has_action           (GActionGroup *action_group,
                                                             const gchar *action_name);

Checks if the named action exists within `action_group`.

`action_group` : | a GActionGroup
`action_name` : | the name of the action to check for
Returns : | whether the named action exists

Since 2.28

### g_action_group_list_actions ()

    gchar **            g_action_group_list_actions         (GActionGroup *action_group);

Lists the actions contained within `action_group`.

The caller is responsible for freeing the list with `g_strfreev()` when it is no longer required.

`action_group` : | a GActionGroup
Returns : | a `NULL`-terminated array of the names of the actions in the groupb. [transfer full]

Since 2.28

### g_action_group_get_action_enabled ()

    gboolean            g_action_group_get_action_enabled   (GActionGroup *action_group,
                                                             const gchar *action_name);

Checks if the named action within `action_group` is currently enabled.

An action must be enabled in order to be activated or in order to have its state changed from outside callers.

`action_group` : | a GActionGroup
`action_name` : | the name of the action to query
Returns : | whether or not the action is currently enabled

Since 2.28

### g_action_group_get_action_parameter_type ()

    const GVariantType * g_action_group_get_action_parameter_type
                                                            (GActionGroup *action_group,
                                                             const gchar *action_name);

Queries the type of the parameter that must be given when activating the named action within `action_group`.

When activating the action using `g_action_group_activate_action()`, 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.

The parameter type of a particular action will never change but it is possible for an action to be removed and for a new action to be added with the same name but a different parameter type.

`action_group` : | a GActionGroup
`action_name` : | the name of the action to query
Returns : | the parameter type

Since 2.28

### g_action_group_get_action_state_type ()

    const GVariantType * g_action_group_get_action_state_type
                                                            (GActionGroup *action_group,
                                                             const gchar *action_name);

Queries the type of the state of the named action within `action_group`.

If the action is stateful then this function returns the GVariantType of the state. All calls to `g_action_group_change_action_state()` must give a GVariant of this type and `g_action_group_get_action_state()` will return a GVariant of the same type.

If the action is not stateful then this function will return `NULL`. In that case, `g_action_group_get_action_state()` will return `NULL` and you must not call `g_action_group_change_action_state()`.

The state type of a particular action will never change but it is possible for an action to be removed and for a new action to be added with the same name but a different state type.

`action_group` : | a GActionGroup
`action_name` : | the name of the action to query
Returns : | the state type, if the action is stateful. [transfer full]

Since 2.28

### g_action_group_get_action_state_hint ()

    GVariant *          g_action_group_get_action_state_hint
                                                            (GActionGroup *action_group,
                                                             const gchar *action_name);

Requests a hint about the valid range of values for the state of the named action within `action_group`.

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.

`action_group` : | a GActionGroup
`action_name` : | the name of the action to query
Returns : | the state range hint. [transfer full]

Since 2.28

### g_action_group_get_action_state ()

    GVariant *          g_action_group_get_action_state     (GActionGroup *action_group,
                                                             const gchar *action_name);

Queries the current state of the named action within `action_group`.

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_group_get_action_state_type()`.

The return value (if non-`NULL`) should be freed with `g_variant_unref()` when it is no longer required.

`action_group` : | a GActionGroup
`action_name` : | the name of the action to query
Returns : | the current state of the action. [allow-none]

Since 2.28

### g_action_group_change_action_state ()

    void                g_action_group_change_action_state  (GActionGroup *action_group,
                                                             const gchar *action_name,
                                                             GVariant *value);

Request for the state of the named action within `action_group` to be changed to `value`.

The action must be stateful and `value` must be of the correct type. See `g_action_group_get_action_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_group_get_action_state_hint()`.

If the `value` GVariant is floating, it is consumed.

`action_group` : | a GActionGroup
`action_name` : | the name of the action to request the change on
`value` : | the new state

Since 2.28

### g_action_group_activate_action ()

    void                g_action_group_activate_action      (GActionGroup *action_group,
                                                             const gchar *action_name,
                                                             GVariant *parameter);

Activate the named action within `action_group`.

If the action is expecting a parameter, then the correct type of parameter must be given as `parameter`. If the action is expecting no parameters then `parameter` must be `NULL`. See `g_action_group_get_action_parameter_type()`.

`action_group` : | a GActionGroup
`action_name` : | the name of the action to activate
`parameter` : | parameters to the activation. [allow-none]

Since 2.28

### g_action_group_action_added ()

    void                g_action_group_action_added         (GActionGroup *action_group,
                                                             const gchar *action_name);

Emits the "action-added" signal on `action_group`.

This function should only be called by GActionGroup implementations.

`action_group` : | a GActionGroup
`action_name` : | the name of an action in the group

Since 2.28

### g_action_group_action_removed ()

    void                g_action_group_action_removed       (GActionGroup *action_group,
                                                             const gchar *action_name);

Emits the "action-removed" signal on `action_group`.

This function should only be called by GActionGroup implementations.

`action_group` : | a GActionGroup
`action_name` : | the name of an action in the group

Since 2.28

### g_action_group_action_enabled_changed ()

    void                g_action_group_action_enabled_changed
                                                            (GActionGroup *action_group,
                                                             const gchar *action_name,
                                                             gboolean enabled);

Emits the "action-enabled-changed" signal on `action_group`.

This function should only be called by GActionGroup implementations.

`action_group` : | a GActionGroup
`action_name` : | the name of an action in the group
`enabled` : | whether or not the action is now enabled

Since 2.28

### g_action_group_action_state_changed ()

    void                g_action_group_action_state_changed (GActionGroup *action_group,
                                                             const gchar *action_name,
                                                             GVariant *state);

Emits the "action-state-changed" signal on `action_group`.

This function should only be called by GActionGroup implementations.

`action_group` : | a GActionGroup
`action_name` : | the name of an action in the group
`state` : | the new state of the named action

Since 2.28

## Signal Details

### The `"action-added"` signal

    void                user_function                      (GActionGroup *action_group,
                                                            gchar        *action_name,
                                                            gpointer      user_data)         : Has Details

Signals that a new action was just added to the group. This signal is emitted after the action has been added and is now visible.

`action_group` : | the GActionGroup that changed
`action_name` : | the name of the action in `action_group`
`user_data` : | user data set when the signal handler was connected.

Since 2.28

### The `"action-enabled-changed"` signal

    void                user_function                      (GActionGroup *action_group,
                                                            gchar        *action_name,
                                                            gboolean      enabled,
                                                            gpointer      user_data)         : Has Details

Signals that the enabled status of the named action has changed.

`action_group` : | the GActionGroup that changed
`action_name` : | the name of the action in `action_group`
`enabled` : | whether the action is enabled or not
`user_data` : | user data set when the signal handler was connected.

Since 2.28

### The `"action-removed"` signal

    void                user_function                      (GActionGroup *action_group,
                                                            gchar        *action_name,
                                                            gpointer      user_data)         : Has Details

Signals that an action is just about to be removed from the group. This signal is emitted before the action is removed, so the action is still visible and can be queried from the signal handler.

`action_group` : | the GActionGroup that changed
`action_name` : | the name of the action in `action_group`
`user_data` : | user data set when the signal handler was connected.

Since 2.28

### The `"action-state-changed"` signal

    void                user_function                      (GActionGroup *action_group,
                                                            gchar        *action_name,
                                                            GVariant     *value,
                                                            gpointer      user_data)         : Has Details

Signals that the state of the named action has changed.

`action_group` : | the GActionGroup that changed
`action_name` : | the name of the action in `action_group`
`value` : | the new value of the state
`user_data` : | user data set when the signal handler was connected.

Since 2.28