gi-gio-2.0.25: Gio bindings
Copyright Will Thompson Iñaki García Etxebarria and Jonas Platte LGPL-2.1 Iñaki García Etxebarria None Haskell2010

GI.Gio.Interfaces.Action

Description

Action represents a single named action.

The main interface to an action is that it can be activated with actionActivate. This results in the 'activate' signal being emitted. An activation has a GVariant parameter (which may be Nothing). 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 actionChangeState. 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.

Action 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 actionActivate and actionChangeState for type safety and for the state being enabled.

Probably the only useful thing to do with a Action is to put it inside of a SimpleActionGroup.

Synopsis

# Exported types

newtype Action Source #

Memory-managed wrapper type.

Constructors

 Action (ManagedPtr Action)

#### Instances

Instances details
 Source # Instance detailsDefined in GI.Gio.Interfaces.Action Methods(==) :: Action -> Action -> Bool #(/=) :: Action -> Action -> Bool # Source # Instance detailsDefined in GI.Gio.Interfaces.Action Methods Source # Convert Action to and from GValue with toGValue and fromGValue. Instance detailsDefined in GI.Gio.Interfaces.Action Methods Source # Instance detailsDefined in GI.Gio.Interfaces.Action Source # Instance detailsDefined in GI.Gio.Interfaces.Action type ParentTypes Action = '[Object]

A convenience alias for Nothing :: Maybe Action.

class (GObject o, IsDescendantOf Action o) => IsAction o Source #

Type class for types which can be safely cast to Action, for instance with toAction.

#### Instances

Instances details
 (GObject o, IsDescendantOf Action o) => IsAction o Source # Instance detailsDefined in GI.Gio.Interfaces.Action

toAction :: (MonadIO m, IsAction o) => o -> m Action Source #

Cast to Action, for types for which this is known to be safe. For general casts, use castTo.

# Methods

## activate

Arguments

 :: (HasCallStack, MonadIO m, IsAction a) => a action: a Action -> Maybe GVariant parameter: the parameter to the activation -> m ()

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 Nothing then parameter must also be Nothing.

If the parameter GVariant is floating, it is consumed.

Since: 2.28

## changeState

Arguments

 :: (HasCallStack, MonadIO m, IsAction a) => a action: a Action -> GVariant value: the new state -> m ()

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 actionGetStateType.

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 actionGetStateHint.

If the value GVariant is floating, it is consumed.

Since: 2.30

## getEnabled

Arguments

 :: (HasCallStack, MonadIO m, IsAction a) => a action: a Action -> m Bool Returns: whether the action is 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.

Since: 2.28

## getName

Arguments

 :: (HasCallStack, MonadIO m, IsAction a) => a action: a Action -> m Text Returns: the name of the action

Queries the name of action.

Since: 2.28

## getParameterType

Arguments

 :: (HasCallStack, MonadIO m, IsAction a) => a action: a Action -> m (Maybe VariantType) Returns: the parameter type

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

When activating the action using actionActivate, the GVariant given to that function must be of the type returned by this function.

In the case that this function returns Nothing, you must not give any GVariant, but Nothing instead.

Since: 2.28

## getState

Arguments

 :: (HasCallStack, MonadIO m, IsAction a) => a action: a Action -> m GVariant Returns: the current state of the action

Queries the current state of action.

If the action is not stateful then Nothing will be returned. If the action is stateful then the type of the return value is the type given by actionGetStateType.

The return value (if non-Nothing) should be freed with variantUnref when it is no longer required.

Since: 2.28

## getStateHint

Arguments

 :: (HasCallStack, MonadIO m, IsAction a) => a action: a Action -> m (Maybe GVariant) Returns: the state range hint

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

If Nothing 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-Nothing) should be freed with variantUnref when it is no longer required.

Since: 2.28

## getStateType

Arguments

 :: (HasCallStack, MonadIO m, IsAction a) => a action: a Action -> m (Maybe VariantType) Returns: the state type, if the action is stateful

Queries the type of the state of action.

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

If the action is not stateful (e.g. created with simpleActionNew) then this function will return Nothing. In that case, actionGetState will return Nothing and you must not call actionChangeState.

Since: 2.28

## nameIsValid

Arguments

 :: (HasCallStack, MonadIO m) => Text actionName: an potential action name -> m Bool Returns: True if actionName is valid

Checks if actionName is valid.

actionName 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 actionName. actionName must not be Nothing.

Since: 2.38

## parseDetailedName

Arguments

 :: (HasCallStack, MonadIO m) => Text detailedName: a detailed action name -> m (Text, GVariant) (Can throw GError)

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](#signal: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 variantParse. 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 '.'.

Since: 2.38

## printDetailedName

Arguments

 :: (HasCallStack, MonadIO m) => Text actionName: a valid action name -> Maybe GVariant targetValue: a GVariant target value, or Nothing -> m Text Returns: a detailed format string

Formats a detailed action name from actionName and targetValue.

It is an error to call this function with an invalid action name.

This function is the opposite of actionParseDetailedName. It will produce a string that can be parsed back to the actionName and targetValue by that function.

See that function for the types of strings that will be printed by this function.

Since: 2.38

# Properties

## enabled

If action is currently enabled.

If the action is disabled then calls to actionActivate and actionChangeState have no effect.

Since: 2.28

getActionEnabled :: (MonadIO m, IsAction o) => o -> m Bool Source #

Get the value of the “enabled” property. When overloading is enabled, this is equivalent to

get action #enabled


## 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.

Since: 2.28

getActionName :: (MonadIO m, IsAction o) => o -> m Text Source #

Get the value of the “name” property. When overloading is enabled, this is equivalent to

get action #name


## parameterType

The type of the parameter that must be given when activating the action. This is immutable, and may be Nothing if no parameter is needed when activating the action.

Since: 2.28

getActionParameterType :: (MonadIO m, IsAction o) => o -> m (Maybe VariantType) Source #

Get the value of the “parameter-type” property. When overloading is enabled, this is equivalent to

get action #parameterType


## state

The state of the action, or Nothing if the action is stateless.

Since: 2.28

getActionState :: (MonadIO m, IsAction o) => o -> m (Maybe GVariant) Source #

Get the value of the “state” property. When overloading is enabled, this is equivalent to

get action #state


## stateType

The VariantType of the state that the action has, or Nothing if the action is stateless. This is immutable.

Since: 2.28

getActionStateType :: (MonadIO m, IsAction o) => o -> m (Maybe VariantType) Source #

Get the value of the “state-type” property. When overloading is enabled, this is equivalent to

get action #stateType