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Eclipse Platform
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org.eclipse.swt.widgets
Class Menu

java.lang.Object
  org.eclipse.swt.widgets.Widget
      org.eclipse.swt.widgets.Menu

public class Menu

extends Widget

Instances of this class are user interface objects that contain menu items.

Styles:

BAR, DROP_DOWN, POP_UP, NO_RADIO_GROUP

LEFT_TO_RIGHT, RIGHT_TO_LEFT

Events:

Help, Hide, Show

Note: Only one of BAR, DROP_DOWN and POP_UP may be specified. Only one of LEFT_TO_RIGHT or RIGHT_TO_LEFT may be specified.

IMPORTANT: This class is not intended to be subclassed.

Field Summary

int	handle the handle to the OS resource (Warning: This field is platform dependent)

Constructor Summary

Menu(Control parent)
Constructs a new instance of this class given its parent, and sets the style for the instance so that the instance will be a popup menu on the given parent's shell.

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

Menu(Menu parentMenu)
Constructs a new instance of this class given its parent (which must be a Menu) and sets the style for the instance so that the instance will be a drop-down menu on the given parent's parent.

Menu(MenuItem parentItem)
Constructs a new instance of this class given its parent (which must be a MenuItem) and sets the style for the instance so that the instance will be a drop-down menu on the given parent's parent menu.

Method Summary

void	addHelpListener(HelpListener listener) Adds the listener to the collection of listeners who will be notified when help events are generated for the control, by sending it one of the messages defined in the HelpListener interface.
void	addMenuListener(MenuListener listener) Adds the listener to the collection of listeners who will be notified when menus are hidden or shown, by sending it one of the messages defined in the MenuListener interface.
MenuItem	getDefaultItem() Returns the default menu item or null if none has been previously set.
boolean	getEnabled() Returns true if the receiver is enabled, and false otherwise.
MenuItem	getItem(int index) Returns the item at the given, zero-relative index in the receiver.
int	getItemCount() Returns the number of items contained in the receiver.
MenuItem[]	getItems() Returns an array of MenuItems which are the items in the receiver.
Decorations	getParent() Returns the receiver's parent, which must be a Decorations.
MenuItem	getParentItem() Returns the receiver's parent item, which must be a MenuItem or null when the receiver is a root.
Menu	getParentMenu() Returns the receiver's parent item, which must be a Menu or null when the receiver is a root.
Shell	getShell() Returns the receiver's shell.
boolean	getVisible() Returns true if the receiver is visible, and false otherwise.
int	indexOf(MenuItem item) Searches the receiver's list starting at the first item (index 0) until an item is found that is equal to the argument, and returns the index of that item.
boolean	isEnabled() Returns true if the receiver is enabled and all of the receiver's ancestors are enabled, and false otherwise.
boolean	isVisible() Returns true if the receiver is visible and all of the receiver's ancestors are visible and false otherwise.
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	removeMenuListener(MenuListener listener) Removes the listener from the collection of listeners who will be notified when the menu events are generated for the control.
void	setDefaultItem(MenuItem item) Sets the default menu item to the argument or removes the default emphasis when the argument is null.
void	setEnabled(boolean enabled) Enables the receiver if the argument is true, and disables it otherwise.
void	setLocation(int x, int y) Sets the receiver's location to the point specified by the arguments which are relative to the display.
void	setLocation(Point location) Sets the receiver's location to the point specified by the arguments which are relative to the display.
void	setVisible(boolean visible) Marks the receiver as visible if the argument is true, and marks it invisible otherwise.

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

addDisposeListener, addListener, checkSubclass, 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

Field Detail

handle

public int handle

the handle to the OS resource (Warning: This field is platform dependent)

Constructor Detail

Menu

public Menu(Control parent)

Constructs a new instance of this class given its parent, and sets the style for the instance so that the instance will be a popup menu on the given parent's shell.

Parameters:

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

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.POP_UP, Widget.checkSubclass(), Widget.getStyle()

Menu

public Menu(Decorations parent,
            int style)

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

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 decorations control which will be the parent of the new instance (cannot be null)

style - the style of menu 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.BAR, SWT.DROP_DOWN, SWT.POP_UP, Widget.checkSubclass(), Widget.getStyle()

Menu

public Menu(Menu parentMenu)

Constructs a new instance of this class given its parent (which must be a Menu) and sets the style for the instance so that the instance will be a drop-down menu on the given parent's parent.

Parameters:

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

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.DROP_DOWN, Widget.checkSubclass(), Widget.getStyle()

Menu

public Menu(MenuItem parentItem)

Constructs a new instance of this class given its parent (which must be a MenuItem) and sets the style for the instance so that the instance will be a drop-down menu on the given parent's parent menu.

Parameters:

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

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.DROP_DOWN, Widget.checkSubclass(), Widget.getStyle()

Method Detail

addHelpListener

public void addHelpListener(HelpListener listener)

Adds the listener to the collection of listeners who will be notified when 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)

addMenuListener

public void addMenuListener(MenuListener listener)

Adds the listener to the collection of listeners who will be notified when menus are hidden or shown, by sending it one of the messages defined in the MenuListener 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:

MenuListener, removeMenuListener(org.eclipse.swt.events.MenuListener)

getDefaultItem

public MenuItem getDefaultItem()

Returns the default menu item or null if none has been previously set.

Returns:

the default menu item.

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 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()

getItem

public MenuItem getItem(int index)

Returns the item at the given, zero-relative index in the receiver. Throws an exception if the index is out of range.

Parameters:

index - the index of the item to return

Returns:

the item at the given index

Throws:

IllegalArgumentException -

• ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)

SWTException -

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

getItemCount

public int getItemCount()

Returns the number of items contained in the receiver.

Returns:

the number of items

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

getItems

public MenuItem[] getItems()

Returns an array of MenuItems which are the items in the receiver.

Note: This is not the actual structure used by the receiver to maintain its list of items, so modifying the array will not affect the receiver.

Returns:

the items in 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

getParent

public Decorations getParent()

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

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

getParentItem

public MenuItem getParentItem()

Returns the receiver's parent item, which must be a MenuItem or null when the receiver is a root.

Returns:

the receiver's parent item

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

getParentMenu

public Menu getParentMenu()

Returns the receiver's parent item, which must be a Menu or null when the receiver is a root.

Returns:

the receiver's parent item

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

getShell

public Shell getShell()

Returns the receiver's shell. For all controls other than shells, this simply returns the control's nearest ancestor shell. Shells return themselves, even if they are children of other shells.

Returns:

the receiver's shell

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:

getParent()

getVisible

public boolean getVisible()

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

If one of the receiver's ancestors is not visible or some other condition makes the receiver not visible, this method may still indicate that it is considered visible even though it may not actually be showing.

Returns:

the receiver's visibility 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

indexOf

public int indexOf(MenuItem item)

Searches the receiver's list starting at the first item (index 0) until an item is found that is equal to the argument, and returns the index of that item. If no item is found, returns -1.

Parameters:

item - the search item

Returns:

the index of the item

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string 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

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()

isVisible

public boolean isVisible()

Returns true if the receiver is visible and all of the receiver's ancestors are visible and false otherwise.

Returns:

the receiver's visibility 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:

getVisible()

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)

removeMenuListener

public void removeMenuListener(MenuListener listener)

Removes the listener from the collection of listeners who will be notified when the menu 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:

MenuListener, addMenuListener(org.eclipse.swt.events.MenuListener)

setDefaultItem

public void setDefaultItem(MenuItem item)

Sets the default menu item to the argument or removes the default emphasis when the argument is null.

Parameters:

item - the default menu item or null

Throws:

IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the menu item has been disposed

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

setLocation

public void setLocation(int x,
                        int y)

Sets the receiver's location to the point specified by the arguments which are relative to the display.

Note: This is different from most widgets where the location of the widget is relative to the parent.

Parameters:

x - the new x coordinate for the receiver

y - the new y coordinate for 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

setLocation

public void setLocation(Point location)

Sets the receiver's location to the point specified by the arguments which are relative to the display.

Note: This is different from most widgets where the location of the widget is relative to the parent.

Parameters:

location - the new location for the receiver

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the point 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:

2.1

setVisible

public void setVisible(boolean visible)

Marks the receiver as visible if the argument is true, and marks it invisible otherwise.

If one of the receiver's ancestors is not visible or some other condition makes the receiver not visible, marking it visible may not actually cause it to be displayed.

Parameters:

visible - the new visibility 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