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:

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	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.
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	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(java.lang.String string) Sets the receiver's text.

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

checkSubclass, getImage, getText

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

addDisposeListener, addListener, checkWidget, dispose, getData, getData, getDisplay, 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:

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 index to store the receiver in its parent

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()

Method Detail

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

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

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()

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 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()

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)

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

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

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

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:

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

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(java.lang.String string)

Sets the receiver's text. The string may include the mnemonic character and accelerator text.

Mnemonics are indicated by an '&' that causes the next character to be the mnemonic. When the user presses a key sequence that matches the mnemonic, a selection event occurs. On most platforms, the mnemonic appears underlined but may be emphasised in a platform specific manner. The mnemonic indicator character '&' can be escaped by doubling it in the string, causing a single '&' to be displayed.

Accelerator text is indicated by the '\t' character. On platforms that support accelerator text, the text that follows the '\t' character is displayed to the user, typically indicating the key stroke that will cause the item to become selected. On most platforms, the accelerator text appears right aligned in the menu. Setting the accelerator text does not install the accelerator key sequence. The accelerator key sequence is installed using #setAccelerator.

Overrides:

setText in class Item

Parameters:

string - the new text

Throws:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the text 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:

setAccelerator(int)