org.eclipse.swt.widgets
Class MenuItem

java.lang.Object
  |
  +--org.eclipse.swt.widgets.Widget
        |
        +--org.eclipse.swt.widgets.Item
              |
              +--org.eclipse.swt.widgets.MenuItem

public class MenuItem

extends Item

Instances of this class represent a selectable user interface object that issues notification when pressed and released.

Styles:

CHECK, CASCADE, PUSH, RADIO, SEPARATOR

Events:

Arm, Help, Selection

Note: Only one of the styles CHECK, CASCADE, PUSH, RADIO and SEPARATOR may be specified.

IMPORTANT: This class is not intended to be subclassed.

Constructor Summary

MenuItem(Menu parent, int style)
Constructs a new instance of this class given its parent (which must be a Menu) and a style value describing its behavior and appearance.

MenuItem(Menu parent, int style, int index)
Constructs a new instance of this class given its parent (which must be a Menu), a style value describing its behavior and appearance, and the index at which to place it in the items maintained by its parent.

Method Summary

void	addArmListener(ArmListener listener) Adds the listener to the collection of listeners who will be notified when the arm events are generated for the control, by sending it one of the messages defined in the ArmListener interface.
void	addHelpListener(HelpListener listener) Adds the listener to the collection of listeners who will be notified when the help events are generated for the control, by sending it one of the messages defined in the HelpListener interface.
void	addSelectionListener(SelectionListener listener) Adds the listener to the collection of listeners who will be notified when the control is selected, by sending it one of the messages defined in the SelectionListener interface.
protected void	checkSubclass() Checks that this class can be subclassed.
int	getAccelerator() Return the widget accelerator.
Display	getDisplay() Returns the Display that is associated with the receiver.
boolean	getEnabled() Returns true if the receiver is enabled, and false otherwise.
Menu	getMenu() Returns the receiver's cascade menu if it has one or null if it does not.
Menu	getParent() Returns the receiver's parent, which must be a Menu.
boolean	getSelection() Returns true if the receiver is selected, and false otherwise.
boolean	isEnabled() Returns true if the receiver is enabled and all of the receiver's ancestors are enabled, and false otherwise.
void	removeArmListener(ArmListener listener) Removes the listener from the collection of listeners who will be notified when the arm events are generated for the control.
void	removeHelpListener(HelpListener listener) Removes the listener from the collection of listeners who will be notified when the help events are generated for the control.
void	removeSelectionListener(SelectionListener listener) Removes the listener from the collection of listeners who will be notified when the control is selected.
void	setAccelerator(int accelerator) Sets the widget accelerator.
void	setEnabled(boolean enabled) Enables the receiver if the argument is true, and disables it otherwise.
void	setImage(Image image) Sets the image the receiver will display to the argument.
void	setMenu(Menu menu) Sets the receiver's pull down menu to the argument.
void	setSelection(boolean selected) Sets the selection state of the receiver.
void	setText(String string) Sets the receiver's text.

Methods inherited from class org.eclipse.swt.widgets.Item

getImage, getText

Methods inherited from class org.eclipse.swt.widgets.Widget

addDisposeListener, addListener, checkWidget, dispose, getData, getData, getStyle, isDisposed, isListening, notifyListeners, removeDisposeListener, removeListener, removeListener, setData, setData, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

MenuItem

public MenuItem(Menu parent,
                int style)

Constructs a new instance of this class given its parent (which must be a Menu) and a style value describing its behavior and appearance. The item is added to the end of the items maintained by its parent.

The style value is either one of the style constants defined in class SWT which is applicable to instances of this class, or must be built by bitwise OR'ing together (that is, using the int "|" operator) two or more of those SWT style constants. The class description lists the style constants that are applicable to the class. Style bits are also inherited from superclasses.

Parameters:

parent - a menu control which will be the parent of the new instance (cannot be null)

style - the style of control to construct

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the parent is null

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
• ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass

See Also:

SWT.CHECK, SWT.CASCADE, SWT.PUSH, SWT.RADIO, SWT.SEPARATOR, Widget.checkSubclass(), Widget.getStyle()

MenuItem

public MenuItem(Menu parent,
                int style,
                int index)

Constructs a new instance of this class given its parent (which must be a Menu), a style value describing its behavior and appearance, and the index at which to place it in the items maintained by its parent.

The style value is either one of the style constants defined in class SWT which is applicable to instances of this class, or must be built by bitwise OR'ing together (that is, using the int "|" operator) two or more of those SWT style constants. The class description lists the style constants that are applicable to the class. Style bits are also inherited from superclasses.

Parameters:

parent - a menu control which will be the parent of the new instance (cannot be null)

style - the style of control to construct

index - the index to store the receiver in its parent

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the parent is null

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
• ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass

See Also:

SWT.CHECK, SWT.CASCADE, SWT.PUSH, SWT.RADIO, SWT.SEPARATOR, Widget.checkSubclass(), Widget.getStyle()

Method Detail

addArmListener

public void addArmListener(ArmListener listener)

Adds the listener to the collection of listeners who will be notified when the arm events are generated for the control, by sending it one of the messages defined in the ArmListener interface.

Parameters:

listener - the listener which should be notified

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the listener is null

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

See Also:

ArmListener, removeArmListener(org.eclipse.swt.events.ArmListener)

addHelpListener

public void addHelpListener(HelpListener listener)

Adds the listener to the collection of listeners who will be notified when the help events are generated for the control, by sending it one of the messages defined in the HelpListener interface.

Parameters:

listener - the listener which should be notified

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the listener is null

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

See Also:

HelpListener, removeHelpListener(org.eclipse.swt.events.HelpListener)

addSelectionListener

public void addSelectionListener(SelectionListener listener)

Adds the listener to the collection of listeners who will be notified when the control is selected, by sending it one of the messages defined in the SelectionListener interface.

When widgetSelected is called, the stateMask field of the event object is valid. widgetDefaultSelected is not called.

Parameters:

listener - the listener which should be notified

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the listener is null

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

See Also:

SelectionListener, removeSelectionListener(org.eclipse.swt.events.SelectionListener), SelectionEvent

checkSubclass

protected void checkSubclass()

Description copied from class: Widget

Checks that this class can be subclassed.

The SWT class library is intended to be subclassed only at specific, controlled points (most notably, Composite and Canvas when implementing new widgets). This method enforces this rule unless it is overridden.

IMPORTANT: By providing an implementation of this method that allows a subclass of a class which does not normally allow subclassing to be created, the implementer agrees to be fully responsible for the fact that any such subclass will likely fail between SWT releases and will be strongly platform specific. No support is provided for user-written classes which are implemented in this fashion.

The ability to subclass outside of the allowed SWT classes is intended purely to enable those not on the SWT development team to implement patches in order to get around specific limitations in advance of when those limitations can be addressed by the team. Subclassing should not be attempted without an intimate and detailed understanding of the hierarchy.

Overrides:

checkSubclass in class Item

getAccelerator

public int getAccelerator()

Return the widget accelerator. An accelerator is the bit-wise OR of zero or more modifier masks and a key. Examples: SWT.CONTROL | SWT.SHIFT | 'T', SWT.ALT | SWT.F2.

Returns:

the accelerator

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

getDisplay

public Display getDisplay()

Description copied from class: Widget

Returns the Display that is associated with the receiver.

A widget's display is either provided when it is created (for example, top level Shells) or is the same as its parent's display.

Specified by:

getDisplay in class Widget

Returns:

the receiver's display

getEnabled

public boolean getEnabled()

Returns true if the receiver is enabled, and false otherwise. A disabled control is typically not selectable from the user interface and draws with an inactive or "grayed" look.

Returns:

the receiver's enabled state

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

See Also:

isEnabled()

getMenu

public Menu getMenu()

Returns the receiver's cascade menu if it has one or null if it does not. Only CASCADE menu items can have a pull down menu. The sequence of key strokes, button presses and/or button releases that are used to request a pull down menu is platform specific.

Returns:

the receiver's menu

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

getParent

public Menu getParent()

Returns the receiver's parent, which must be a Menu.

Returns:

the receiver's parent

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

getSelection

public boolean getSelection()

Returns true if the receiver is selected, and false otherwise.

When the receiver is of type CHECK or RADIO, it is selected when it is checked.

Returns:

the selection state

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

isEnabled

public boolean isEnabled()

Returns true if the receiver is enabled and all of the receiver's ancestors are enabled, and false otherwise. A disabled control is typically not selectable from the user interface and draws with an inactive or "grayed" look.

Returns:

the receiver's enabled state

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

See Also:

getEnabled()

removeArmListener

public void removeArmListener(ArmListener listener)

Removes the listener from the collection of listeners who will be notified when the arm events are generated for the control.

Parameters:

listener - the listener which should be notified

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the listener is null

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

See Also:

ArmListener, addArmListener(org.eclipse.swt.events.ArmListener)

removeHelpListener

public void removeHelpListener(HelpListener listener)

Removes the listener from the collection of listeners who will be notified when the help events are generated for the control.

Parameters:

listener - the listener which should be notified

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the listener is null

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

See Also:

HelpListener, addHelpListener(org.eclipse.swt.events.HelpListener)

removeSelectionListener

public void removeSelectionListener(SelectionListener listener)

Removes the listener from the collection of listeners who will be notified when the control is selected.

Parameters:

listener - the listener which should be notified

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the listener is null

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

See Also:

SelectionListener, addSelectionListener(org.eclipse.swt.events.SelectionListener)

setAccelerator

public void setAccelerator(int accelerator)

Sets the widget accelerator. An accelerator is the bit-wise OR of zero or more modifier masks and a key. Examples: SWT.CONTROL | SWT.SHIFT | 'T', SWT.ALT | SWT.F2.

Parameters:

accelerator - an integer that is the bit-wise OR of masks and a key

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

setEnabled

public void setEnabled(boolean enabled)

Enables the receiver if the argument is true, and disables it otherwise. A disabled control is typically not selectable from the user interface and draws with an inactive or "grayed" look.

Parameters:

enabled - the new enabled state

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

setImage

public void setImage(Image image)

Sets the image the receiver will display to the argument.

Note: This feature is not available on all window systems (for example, Window NT), in which case, calling this method will silently do nothing.

Overrides:

setImage in class Item

Parameters:

image - the image to display on the receiver (may be null)

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

setMenu

public void setMenu(Menu menu)

Sets the receiver's pull down menu to the argument. Only CASCADE menu items can have a pull down menu. The sequence of key strokes, button presses and/or button releases that are used to request a pull down menu is platform specific.

Parameters:

menu - the new pull down menu

Throws:

IllegalArgumentException -

• ERROR_MENU_NOT_DROP_DOWN - if the menu is not a drop down menu
• ERROR_MENUITEM_NOT_CASCADE - if the menu item is not a CASCADE
• ERROR_INVALID_ARGUMENT - if the menu has been disposed
• ERROR_INVALID_PARENT - if the menu is not in the same widget tree

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

setSelection

public void setSelection(boolean selected)

Sets the selection state of the receiver.

When the receiver is of type CHECK or RADIO, it is selected when it is checked.

Parameters:

selected - the new selection state

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

setText

public void setText(String string)

Description copied from class: Item

Sets the receiver's text.

Overrides:

setText in class Item

Parameters:

string - the new text