## GSimpleAction

GSimpleAction — A simple GAction implementation

## Synopsis

                        GSimpleAction;

    GSimpleAction *     g_simple_action_new                 (const gchar *name,
                                                             const GVariantType *parameter_type);
    GSimpleAction *     g_simple_action_new_stateful        (const gchar *name,
                                                             const GVariantType *parameter_type,
                                                             GVariant *state);

    void                g_simple_action_set_enabled         (GSimpleAction *simple,
                                                             gboolean enabled);
    void                g_simple_action_set_state           (GSimpleAction *simple,
                                                             GVariant *value);

## Object Hierarchy

      GObject
       +----GSimpleAction

## Implemented Interfaces

GSimpleAction implements GAction.

## Properties

      "enabled"                  gboolean              : Read / Write
      "name"                     gchar*                : Read / Write / Construct Only
      "parameter-type"           GVariantType*         : Read / Write / Construct Only
      "state"                    GVariant*             : Read / Write
      "state-type"               GVariantType*         : Read

## Signals

      "activate"                                       : Run Last
      "change-state"                                   : Run Last

## Description

A GSimpleAction is the obvious simple implementation of the GAction interface. This is the easiest way to create an action for purposes of adding it to a GSimpleActionGroup.

See also GtkAction.

## Details

### GSimpleAction

    typedef struct _GSimpleAction GSimpleAction;

### g_simple_action_new ()

    GSimpleAction *     g_simple_action_new                 (const gchar *name,
                                                             const GVariantType *parameter_type);

Creates a new action.

The created action is stateless. See `g_simple_action_new_stateful()`.

`name` : | the name of the action
`parameter_type` : | the type of parameter to the activate function. [allow-none]
Returns : | a new GSimpleAction

Since 2.28

### g_simple_action_new_stateful ()

    GSimpleAction *     g_simple_action_new_stateful        (const gchar *name,
                                                             const GVariantType *parameter_type,
                                                             GVariant *state);

Creates a new stateful action.

`state` is the initial state of the action. All future state values must have the same GVariantType as the initial state.

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

`name` : | the name of the action
`parameter_type` : | the type of the parameter to the activate function. [allow-none]
`state` : | the initial state of the action
Returns : | a new GSimpleAction

Since 2.28

### g_simple_action_set_enabled ()

    void                g_simple_action_set_enabled         (GSimpleAction *simple,
                                                             gboolean enabled);

Sets the action as enabled or not.

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

This should only be called by the implementor of the action. Users of the action should not attempt to modify its enabled flag.

`simple` : | a GSimpleAction
`enabled` : | whether the action is enabled

Since 2.28

### g_simple_action_set_state ()

    void                g_simple_action_set_state           (GSimpleAction *simple,
                                                             GVariant *value);

Sets the state of the action.

This directly updates the 'state' property to the given value.

This should only be called by the implementor of the action. Users of the action should not attempt to directly modify the 'state' property. Instead, they should call `g_action_change_state()` to request the change.

`simple` : | a GSimpleAction
`value` : | the new GVariant for the state

Since 2.30

## Property Details

### The `"enabled"` property

      "enabled"                  gboolean              : Read / Write

If `action` is currently enabled.

If the action is disabled then calls to `g_action_activate()` and `g_action_change_state()` have no effect.

Default value: TRUE

Since 2.28

### The `"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 GSimpleActionGroup.

Default value: NULL

Since 2.28

### The `"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

### The `"state"` property

      "state"                    GVariant*             : Read / Write

The state of the action, or `NULL` if the action is stateless.

Allowed values: GVariant<*>

Default value: NULL

Since 2.28

### The `"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

## Signal Details

### The `"activate"` signal

    void                user_function                      (GSimpleAction *simple,
                                                            GVariant      *parameter,
                                                            gpointer       user_data)      : Run Last

Indicates that the action was just activated.

`parameter` will always be of the expected type. In the event that an incorrect type was given, no signal will be emitted.

`simple` : | the GSimpleAction
`parameter` : | the parameter to the activation. [allow-none]
`user_data` : | user data set when the signal handler was connected.

Since 2.28

### The `"change-state"` signal

    void                user_function                      (GSimpleAction *simple,
                                                            GVariant      *value,
                                                            gpointer       user_data)      : Run Last

Indicates that the action just received a request to change its state.

`value` will always be of the correct state type. In the event that an incorrect type was given, no signal will be emitted.

If no handler is connected to this signal then the default behaviour is to call `g_simple_action_set_state()` to set the state to the requested value. If you connect a signal handler then no default action is taken. If the state should change then you must call `g_simple_action_set_state()` from the handler.

Example 26. Example 'change-state' handler

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13

    static void
    change_volume_state (GSimpleAction *action,
                         GVariant      *value,
                         gpointer       user_data)
    {
      gint requested;

      requested = g_variant_get_int32 (value);

      // Volume only goes from 0 to 10
      if (0 <= requested && requested <= 10)
        g_simple_action_set_state (action, value);
    }

The handler need not set the state to the requested value. It could set it to any value at all, or take some other action.

`simple` : | the GSimpleAction
`value` : | the requested value for the state. [allow-none]
`user_data` : | user data set when the signal handler was connected.

Since 2.30