KAction Class Reference

from PyKDE4.kdeui import *

Inherits: QWidgetAction → QAction → QObject
Subclasses: KActionMenu, KPasteTextAction, KSelectAction, KToggleAction, KToolBarLabelAction, KToolBarPopupAction, KToolBarSpacerAction

Detailed Description

Class to encapsulate user-driven action or event

The KAction class (and derived and super classes) extends QAction, which provides a way to easily encapsulate a "real" user-selected action or event in your program.

For instance, a user may want to paste the contents of the clipboard, scroll down a document, or quit the application. These are all actions -- events that the user causes to happen. The KAction class allows the developer to deal with these actions in an easy and intuitive manner, and conforms to KDE's extended functionality requirements - including supporting multiple user-configurable shortcuts, and KDE named icons. Actions also improve accessibility.

Specifically, QAction (and thus KAction) encapsulates the various attributes of an event/action. For instance, an action might have an icon() that provides a visual representation (a clipboard for a "paste" action or scissors for a "cut" action). The action should also be described by some text(). It will certainly be connected to a method that actually executes the action! All these attributes are contained within the action object.

The advantage of dealing with actions is that you can manipulate the Action without regard to the GUI representation of it. For instance, in the "normal" way of dealing with actions like "cut", you would manually insert a item for Cut into a menu and a button into a toolbar. If you want to disable the cut action for a moment (maybe nothing is selected), you would have to hunt down the pointer to the menu item and the toolbar button and disable both individually. Setting the menu item and toolbar item up uses very similar code - but has to be done twice!

With the action concept, you simply add the action to whatever GUI element you want. The KAction class will then take care of correctly defining the menu item (with icons, accelerators, text, etc), toolbar button, or other. From then on, if you manipulate the action at all, the effect will propagate through all GUI representations of it. Back to the "cut" example: if you want to disable the Cut Action, you would simply call 'cutAction->setEnabled(false)' and both the menuitem and button would instantly be disabled!

This is the biggest advantage to the action concept -- there is a one-to-one relationship between the "real" action and all GUI representations of it.

KAction emits the hovered() signal on mouseover, and the triggered(bool checked) signal on activation of a corresponding GUI element ( menu item, toolbar button, etc. )

If you are in the situation of wanting to map the triggered() signal of multiple action objects to one slot, with a special argument bound to each action, you have several options:

Using QActionGroup:

Create a QActionGroup and assign it to each of the actions with setActionGroup(), then

Connect the QActionGroup.triggered(QAction*) signal to your slot.

Using QSignalMapper:

 QSignalMapper *desktopNumberMapper = new QSignalMapper( this );
 connect( desktopNumberMapper, SIGNAL( mapped( int ) ),
          this, SLOT( moveWindowToDesktop( int ) ) );

 for ( uint i = 0; i < numberOfDesktops; ++i ) {
     KAction *desktopAction = new KAction( i18n( "Move Window to Desktop %i" ).arg( i ), ... );
     connect( desktopAction, SIGNAL( triggered(bool) ), desktopNumberMapper, SLOT( map() ) );
     desktopNumberMapper->setMapping( desktopAction, i );
 }

General Usage

The steps to using actions are roughly as follows:

Decide which attributes you want to associate with a given

action (icons, text, keyboard shortcut, etc)

Create the action using KAction (or derived or super class).

Add the action into whatever GUI element you want. Typically,

this will be a menu or toolbar.

The kinds of shortcuts

Local shortcuts are active in their context, global shortcus are active everywhere, usually even if another program has focus.

Active shortcuts trigger a KAction if activated.

Default shortcuts are what the active shortcuts revert to if the user chooses

to reset shortcuts to default.

Detailed Example

Here is an example of enabling a "New [document]" action

 KAction *newAct = actionCollection()->addAction(
              KStandardAction.New,   //< see KStandardAction
              this,                   //< Receiver
              SLOT(fileNew())  );     //< SLOT

This section creates our action. Text, Icon and Shortcut will be set from KStandardAction. KStandardAction ensures your application complies to the platform standards. When triggered the fileNew() slot will be called.

See also:: KStandardAction for more information.

If you want to create your own non standard action use

 KAction *newAct = actionCollection()->addAction("quick-connect");
 newAct->setText(i18n("Quick Connect"))
 newAct->setIcon(KIcon("quick-connect"));
 newAct->setShortcut(Qt.Key_F6);
 connect(newAct, SIGNAL(triggered()), this, SLOT(quickConnect()));

This section creates our action. It will display the text "Quick Connect" and use the Icon "quick-connect". F6 will trigger the action. It further says that whenever this action is invoked, it will use the quickConnect() slot to execute it.

 QMenu *file = new QMenu;
 file->addAction(newAct);

That just inserted the action into the File menu. The point is, it's not important in which menu it is: all manipulation of the item is done through the newAct object.

 toolBar()->addAction(newAct);

And this added the action into the main toolbar as a button.

That's it!

If you want to disable that action sometime later, you can do so with

 newAct->setEnabled(false)

and both the menuitem in File and the toolbar button will instantly be disabled.

Unlike with previous versions of KDE, the action can simply be deleted when you have finished with it - the destructor takes care of all of the cleanup.

Note:: calling QAction.setShortcut() on a KAction may lead to unexpected behavior. There is nothing we can do about it because QAction.setShortcut() is not virtual.

Note:: if you are using a "standard" action like "new", "paste", "quit", or any other action described in the KDE UI Standards, please use the methods in the KStandardAction class rather than defining your own.

Usage Within the XML Framework

If you are using KAction within the context of the XML menu and toolbar building framework, you do not ever have to add your actions to containers manually. The framework does that for you.

See also:: KStandardAction

Enumerations
GlobalShortcutLoading	{ Autoloading, NoAutoloading }
ShortcutType	{ ActiveShortcut, DefaultShortcut } Typesafe wrapper: ShortcutTypes
Signals
	triggered (Qt.MouseButtons buttons, Qt.KeyboardModifiers modifiers)
Methods
	__init__ (self, QObject parent)
	__init__ (self, QString text, QObject parent)
	__init__ (self, KIcon icon, QString text, QObject parent)
	forgetGlobalShortcut (self)
KShortcut	globalShortcut (self, KAction.ShortcutTypes type=KAction.ActiveShortcut)
bool	globalShortcutAllowed (self)
bool	isGlobalShortcutEnabled (self)
bool	isShortcutConfigurable (self)
KRockerGesture	rockerGesture (self, KAction.ShortcutTypes type=KAction.ActiveShortcut)
	setGlobalShortcut (self, KShortcut shortcut, KAction.ShortcutTypes type=KAction.ShortcutTypes(KAction.ActiveShortcut\|KAction.DefaultShortcut), KAction.GlobalShortcutLoading loading=KAction.Autoloading)
	setGlobalShortcutAllowed (self, bool allowed, KAction.GlobalShortcutLoading loading=KAction.Autoloading)
	setRockerGesture (self, KRockerGesture gest, KAction.ShortcutTypes type=KAction.ShortcutTypes(KAction.ActiveShortcut\|KAction.DefaultShortcut))
	setShapeGesture (self, KShapeGesture gest, KAction.ShortcutTypes type=KAction.ShortcutTypes(KAction.ActiveShortcut\|KAction.DefaultShortcut))
	setShortcut (self, KShortcut shortcut, KAction.ShortcutTypes type=KAction.ShortcutTypes(KAction.ActiveShortcut\|KAction.DefaultShortcut))
	setShortcut (self, QKeySequence shortcut, KAction.ShortcutTypes type=KAction.ShortcutTypes(KAction.ActiveShortcut\|KAction.DefaultShortcut))
	setShortcutConfigurable (self, bool configurable)
	setShortcuts (self, [QKeySequence] shortcuts, KAction.ShortcutTypes type=KAction.ShortcutTypes(KAction.ActiveShortcut\|KAction.DefaultShortcut))
KShapeGesture	shapeGesture (self, KAction.ShortcutTypes type=KAction.ActiveShortcut)
KShortcut	shortcut (self, KAction.ShortcutTypes types=KAction.ActiveShortcut)
	triggered (self, Qt.MouseButtons buttons, Qt.KeyboardModifiers modifiers)

Method Documentation

__init__	(	self,
		QObject	parent
	)

Constructs an action.

__init__	(	self,
		QString	text,
		QObject	parent
	)

Constructs an action with the specified parent and visible text.

Parameters:

	text	The visible text for this action.
	parent	The parent for this action.

__init__	(	self,
		KIcon	icon,
		QString	text,
		QObject	parent
	)

Constructs an action with text and icon; a shortcut may be specified by the ampersand character (e.g. \"&Option\" creates a shortcut with key O )

This is the other common KAction constructor used. Use it when you do have a corresponding icon.

Parameters:

	icon	The icon to display.
	text	The text that will be displayed.
	parent	The parent for this action.

forgetGlobalShortcut ( self )

Sets the globalShortcutEnabled property to false and sets the global shortcut to an empty shortcut. This will also wipe out knowlegde about the existence of this action's global shorctut so it will not be considered anymore for shortcut conflict resolution. It will also not be visible anymore in the shortcuts KControl module. This method should not be used unless these effects are explicitly desired. @since: 4.1

KShortcut globalShortcut	(	self,
		KAction.ShortcutTypes	type=KAction.ActiveShortcut
	)

Get the global shortcut for this action, if one exists. Global shortcuts allow your actions to respond to accellerators independently of the focused window. Unlike regular shortcuts, the application's window does not need focus for them to be activated.

Parameters:

type

the type of shortcut to be returned. Should both be specified, only the active shortcut will be returned. Defaults to the active shortcut, if one exists.

\sa KGlobalAccel \sa setGlobalShortcut()

bool globalShortcutAllowed ( self )

Returns true if this action is permitted to have a global shortcut. Defaults to false. Use isGlobalShortcutEnabled() instead.

bool isGlobalShortcutEnabled ( self )

Returns true if this action is enabled to have a global shortcut. This will be respected by \class KGlobalShortcutsEditor. Defaults to false.

bool isShortcutConfigurable ( self )

Returns true if this action's shortcut is configurable.

KRockerGesture rockerGesture	(	self,
		KAction.ShortcutTypes	type=KAction.ActiveShortcut
	)

setGlobalShortcut	(	self,
		KShortcut	shortcut,
		KAction.ShortcutTypes	type=KAction.ShortcutTypes(KAction.ActiveShortcut\|KAction.DefaultShortcut),
		KAction.GlobalShortcutLoading	loading=KAction.Autoloading
	)

Assign a global shortcut for this action. Global shortcuts allow an action to respond to key shortcuts independently of the focused window, i.e. the action will trigger if the keys were pressed no matter where in the X session.

The action must have a per main component unique objectName() to enable cross-application bookeeping. If the objectName() is empty this method will do nothing, otherwise the isGlobalShortcutEnabled() property will be set to true and the shortcut will be enabled. It is mandatory that the objectName() doesn't change once isGlobalshortcutEnabled() has become true.

Note:: KActionCollection.insert(name, action) will set action's objectName to name so you often don't have to set an objectName explicitly.

When an action, identified by main component name and objectName(), is assigned a global shortcut for the first time on a KDE installation the assignment will be saved. The shortcut will then be restored every time setGlobalShortcut() is called with loading == Autoloading.

If you actually want to change the global shortcut you have to set loading to NoAutoloading. The new shortcut will be automatically saved again.

Parameters:

shortcut

global shortcut(s) to assign. Will be ignored unless loading is set to NoAutoloading or this is the first time ever you call this method (see above).

Parameters:

type

the type of shortcut to be set, whether the active shortcut, the default shortcut, or both (the default).

Parameters:

loading

if Autoloading, assign the global shortcut this action has previously had if any. That way user preferences and changes made to avoid clashes will be conserved. if NoAutoloading the given shortcut will be assigned without looking up old values. You should only do this if the user wants to change the shortcut or if you have another very good reason. Key combinations that clash with other shortcuts will be dropped.

Note:: the default shortcut will never be influenced by autoloading - it will be set as given.

\sa globalShortcut()

setGlobalShortcutAllowed	(	self,
		bool	allowed,
		KAction.GlobalShortcutLoading	loading=KAction.Autoloading
	)

Indicate whether the programmer and/or user may define a global shortcut for this action. Defaults to false. Note that calling setGlobalShortcut() turns this on automatically.

Parameters:

allowed

set to true if this action may have a global shortcut, otherwise false.

Parameters:

loading

if Autoloading, assign to this action the global shortcut it has previously had if any.

setRockerGesture	(	self,
		KRockerGesture	gest,
		KAction.ShortcutTypes	type=KAction.ShortcutTypes(KAction.ActiveShortcut\|KAction.DefaultShortcut)
	)

setShapeGesture	(	self,
		KShapeGesture	gest,
		KAction.ShortcutTypes	type=KAction.ShortcutTypes(KAction.ActiveShortcut\|KAction.DefaultShortcut)
	)

setShortcut	(	self,
		KShortcut	shortcut,
		KAction.ShortcutTypes	type=KAction.ShortcutTypes(KAction.ActiveShortcut\|KAction.DefaultShortcut)
	)

Set the shortcut for this action.

This is preferred over QAction.setShortcut(), as it allows for multiple shortcuts per action.

Parameters:

shortcut

shortcut(s) to use for this action in its specified shortcutContext()

Parameters:

type

type of shortcut to be set: active shortcut, default shortcut, or both (the default).

setShortcut	(	self,
		QKeySequence	shortcut,
		KAction.ShortcutTypes	type=KAction.ShortcutTypes(KAction.ActiveShortcut\|KAction.DefaultShortcut)
	)

void setShortcut(const KShortcut& shortcut)

Set the primary shortcut only for this action.

This function is there to explicitly override QAction.setShortcut(const QKeySequence&). QAction.setShortcut() will bypass everything in KAction and may lead to unexpected behavior.

Parameters:

shortcut

shortcut(s) to use for this action in its specified shortcutContext()

Parameters:

type

type of shortcut to be set: active shortcut, default shortcut, or both (default argument value).

setShortcutConfigurable	(	self,
		bool	configurable
	)

Indicate whether the user may configure the action's shortcut.

Parameters:

configurable

set to true if this shortcut may be configured by the user, otherwise false.

setShortcuts	(	self,
		[QKeySequence]	shortcuts,
		KAction.ShortcutTypes	type=KAction.ShortcutTypes(KAction.ActiveShortcut\|KAction.DefaultShortcut)
	)

void setShortcuts(const QList<QKeySequence>& shortcuts).

Set the shortcuts for this action.

This function is there to explicitly override QAction.setShortcut(const QList<QKeySequence>&). QAction.setShortcuts() will bypass everything in KAction and may lead to unexpected behavior.

Parameters:

shortcut

shortcut(s) to use for this action in its specified shortcutContext()

Parameters:

type

type of shortcut to be set: active shortcut, default shortcut, or both (default argument value).

KShapeGesture shapeGesture	(	self,
		KAction.ShortcutTypes	type=KAction.ActiveShortcut
	)

KShortcut shortcut	(	self,
		KAction.ShortcutTypes	types=KAction.ActiveShortcut
	)

Get the shortcut for this action.

This is preferred over QAction.shortcut(), as it allows for multiple shortcuts per action. The first and second shortcut as reported by shortcuts() will be the primary and alternate shortcut of the shortcut returned.

Parameters:

types

the type of shortcut to return. Should both be specified, only the active shortcut will be returned. Defaults to the active shortcut, if one exists.

\sa shortcuts()

triggered	(	self,
		Qt.MouseButtons	buttons,
		Qt.KeyboardModifiers	modifiers
	)

Emitted when the action is triggered. Also provides the state of the keyboard modifiers and mouse buttons at the time.

Signal syntax:: QObject.connect(source, SIGNAL("triggered(MouseButtons, KeyboardModifiers)"), target_slot)

Enumeration Documentation

GlobalShortcutLoading

Look up the action in global settings (using its main component's name and text()) and set the shortcut as saved there.

See also:: setGlobalShortcut()

Enumerator:

Autoloading = 0x0
NoAutoloading = 0x4

ShortcutType

The shortcut will immediately become active but may be reset to "default".

Note:: It is necessary to wrap members of this enumeration in a ShortcutTypes instance when passing them to a method as group of flags. For example: ShortcutTypes( ActiveShortcut | DefaultShortcut)

Enumerator:

ActiveShortcut = 0x1
DefaultShortcut = 0x2

KAction Class Reference

Detailed Description

Enumerations

Signals

Methods

Method Documentation

Enumeration Documentation

Modules