org.eclipse.swt.widgets

Class MenuItem

java.lang.Object

org.eclipse.swt.widgets.Widget

org.eclipse.swt.widgets.Item

org.eclipse.swt.widgets.MenuItem

All Implemented Interfaces:

Adaptable

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

Constructors

Constructor and Description
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

Modifier and Type	Method and Description
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 menu item is selected, by sending it one of the messages defined in the SelectionListener interface.
int	getAccelerator() Returns the widget accelerator.
<T> T	getAdapter(java.lang.Class<T> adapter) Implementation of the Adaptable interface.
boolean	getEnabled() Returns true if the receiver is enabled, and false otherwise.
int	getID() Gets the identifier associated with the receiver.
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	setID(int id) Sets the identifier associated with the receiver to the argument.
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 selection) Sets the selection state of the receiver.

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

getImage, getText, setText

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

addDisposeListener, addListener, checkSubclass, checkWidget, dispose, getData, getData, getDisplay, getListeners, getStyle, isDisposed, isListening, notifyListeners, removeDisposeListener, removeListener, removeListener, reskin, 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:

java.lang.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 zero-relative index to store the receiver in its parent

Throws:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the parent is null
• ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the parent (inclusive)

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

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

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.

Note: Disposing of a menu item that has a pull down menu will dispose of the menu. To avoid this behavior, set the menu to null before the menu item is disposed.

Parameters:

menu - the new pull down menu

Throws:

java.lang.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

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

setID

public void setID(int id)

Sets the identifier associated with the receiver to the argument.

Parameters:

id - the new identifier. This must be a non-negative value. System-defined identifiers are negative values.

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
• ERROR_INVALID_ARGUMENT - if called with an negative-valued argument.

Since:

1.4

getID

public int getID()

Gets the identifier associated with the receiver.

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

Since:

1.4

setImage

public void setImage(Image image)

Sets the image the receiver will display to the argument.

Note: This operation is a hint and is not supported on platforms that do not have this concept (for example, Windows NT).

Overrides:

setImage in class Item

Parameters:

image - the image to display

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

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.MOD1 | SWT.MOD2 | 'T', SWT.MOD3 | SWT.F2. SWT.CONTROL | SWT.SHIFT | 'T', SWT.ALT | SWT.F2. The default value is zero, indicating that the menu item does not have an accelerator.

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

Since:

2.1

getAccelerator

public int getAccelerator()

Returns 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. The default value is zero, indicating that the menu item does not have an accelerator.

Returns:

the accelerator or 0

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

Since:

2.1

setEnabled

public void setEnabled(boolean enabled)

Enables the receiver if the argument is true, and disables it otherwise. A disabled menu item 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

getEnabled

public boolean getEnabled()

Returns true if the receiver is enabled, and false otherwise. A disabled menu item 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()

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 menu item 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()

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

setSelection

public void setSelection(boolean selection)

Sets the selection state of the receiver.

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

Parameters:

selection - 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

addSelectionListener

public void addSelectionListener(SelectionListener listener)

Adds the listener to the collection of listeners who will be notified when the menu item 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:

java.lang.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

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 no longer be notified

Throws:

java.lang.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)

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:

java.lang.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

Since:

1.3

See Also:

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

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 no longer be notified

Throws:

java.lang.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

Since:

1.3

See Also:

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

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:

java.lang.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

Since:

1.3

See Also:

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

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 no longer be notified

Throws:

java.lang.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

Since:

1.3

See Also:

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

getAdapter

public <T> T getAdapter(java.lang.Class<T> adapter)

Description copied from class: Widget

Implementation of the Adaptable interface.

IMPORTANT: This method is not part of the RWT public API. It is marked public only so that it can be shared within the packages provided by RWT. It should never be accessed from application code.

Specified by:

getAdapter in interface Adaptable

Overrides:

getAdapter in class Widget

Parameters:

adapter - the lookup class

Returns:

an object that can be cast to the given class or null if there is no adapter associated with the given class.