Java Module java.desktop Package java.awt Class MenuItem（JDK11）

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java.lang.Object
- java.awt.MenuComponent
- - java.awt.MenuItem

All Implemented Interfaces:

Serializable, Accessible

Direct Known Subclasses:

CheckboxMenuItem, Menu
```
public class MenuItem
extends MenuComponent
implements Accessible
```
All items in a menu must belong to the class MenuItem, or one of its subclasses.
The default MenuItem object embodies a simple labeled menu item.

This picture of a menu bar shows five menu items:
The first two items are simple menu items, labeled "Basic" and "Simple". Following these two items is a separator, which is itself a menu item, created with the label "-". Next is an instance of CheckboxMenuItem labeled "Check". The final menu item is a submenu labeled "More Examples", and this submenu is an instance of Menu.

When a menu item is selected, AWT sends an action event to the menu item. Since the event is an instance of ActionEvent, the processEvent method examines the event and passes it along to processActionEvent. The latter method redirects the event to any ActionListener objects that have registered an interest in action events generated by this menu item.

Note that the subclass Menu overrides this behavior and does not send any event to the frame until one of its subitems is selected.

See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`protected class`	`MenuItem.AccessibleAWTMenuItem`	Inner class of MenuItem used to provide default support for accessibility.

Nested classes/interfaces declared in class java.awt.MenuComponent
MenuComponent.AccessibleAWTMenuComponent

Constructor Summary

Constructors
Constructor	Description
`MenuItem()`	Constructs a new MenuItem with an empty label and no keyboard shortcut.
`MenuItem(String label)`	Constructs a new MenuItem with the specified label and no keyboard shortcut.
`MenuItem(String label, MenuShortcut s)`	Create a menu item with an associated keyboard shortcut.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`void`	`addActionListener(ActionListener l)`	Adds the specified action listener to receive action events from this menu item.
`void`	`addNotify()`	Creates the menu item's peer.
`void`	`deleteShortcut()`	Delete any `MenuShortcut` object associated with this menu item.
`void`	`disable()`	Deprecated. As of JDK version 1.1, replaced by `setEnabled(boolean)`.
`protected void`	`disableEvents(long eventsToDisable)`	Disables event delivery to this menu item for events defined by the specified event mask parameter.
`void`	`enable()`	Deprecated. As of JDK version 1.1, replaced by `setEnabled(boolean)`.
`void`	`enable(boolean b)`	Deprecated. As of JDK version 1.1, replaced by `setEnabled(boolean)`.
`protected void`	`enableEvents(long eventsToEnable)`	Enables event delivery to this menu item for events to be defined by the specified event mask parameter
`AccessibleContext`	`getAccessibleContext()`	Gets the AccessibleContext associated with this MenuItem.
`String`	`getActionCommand()`	Gets the command name of the action event that is fired by this menu item.
`ActionListener[]`	`getActionListeners()`	Returns an array of all the action listeners registered on this menu item.
`String`	`getLabel()`	Gets the label for this menu item.
`<T extends EventListener> T[]`	`getListeners(Class<T> listenerType)`	Returns an array of all the objects currently registered as `FooListener`s upon this `MenuItem`.
`MenuShortcut`	`getShortcut()`	Get the `MenuShortcut` object associated with this menu item,
`boolean`	`isEnabled()`	Checks whether this menu item is enabled.
`String`	`paramString()`	Returns a string representing the state of this `MenuItem`.
`protected void`	`processActionEvent(ActionEvent e)`	Processes action events occurring on this menu item, by dispatching them to any registered `ActionListener` objects.
`protected void`	`processEvent(AWTEvent e)`	Processes events on this menu item.
`void`	`removeActionListener(ActionListener l)`	Removes the specified action listener so it no longer receives action events from this menu item.
`void`	`setActionCommand(String command)`	Sets the command name of the action event that is fired by this menu item.
`void`	`setEnabled(boolean b)`	Sets whether or not this menu item can be chosen.
`void`	`setLabel(String label)`	Sets the label for this menu item to the specified label.
`void`	`setShortcut(MenuShortcut s)`	Set the `MenuShortcut` object associated with this menu item.

Methods declared in class java.awt.MenuComponent
dispatchEvent, getFont, getName, getParent, getTreeLock, postEvent, removeNotify, setFont, setName, toString

Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - MenuItem
```
public MenuItem()
         throws HeadlessException
```
    Constructs a new MenuItem with an empty label and no keyboard shortcut.
    
    Throws:
    
    HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
    
    Since:
    
    1.1
    
    See Also:
    
    GraphicsEnvironment.isHeadless()
  - MenuItem
```
public MenuItem(String label)
         throws HeadlessException
```
    Constructs a new MenuItem with the specified label and no keyboard shortcut. Note that use of "-" in a label is reserved to indicate a separator between menu items. By default, all menu items except for separators are enabled.
    
    Parameters:
    
    label - the label for this menu item.
    
    Throws:
    
    HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
    
    Since:
    
    1.0
    
    See Also:
    
    GraphicsEnvironment.isHeadless()
  - MenuItem
```
public MenuItem(String label,
                MenuShortcut s)
         throws HeadlessException
```
    Create a menu item with an associated keyboard shortcut. Note that use of "-" in a label is reserved to indicate a separator between menu items. By default, all menu items except for separators are enabled.
    
    Parameters:
    
    label - the label for this menu item.
    
    s - the instance of MenuShortcut associated with this menu item.
    
    Throws:
    
    HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
    
    Since:
    
    1.1
    
    See Also:
    
    GraphicsEnvironment.isHeadless()
- Method Detail
  - addNotify
```
public void addNotify()
```
    Creates the menu item's peer. The peer allows us to modify the appearance of the menu item without changing its functionality.
  - getLabel
```
public String getLabel()
```
    Gets the label for this menu item.
    
    Returns:
    
    the label of this menu item, or null if this menu item has no label.
    
    Since:
    
    1.0
    
    See Also:
    
    setLabel(java.lang.String)
  - setLabel
```
public void setLabel(String label)
```
    Sets the label for this menu item to the specified label.
    
    Parameters:
    
    label - the new label, or null for no label.
    
    Since:
    
    1.0
    
    See Also:
    
    getLabel()
  - isEnabled
```
public boolean isEnabled()
```
    Checks whether this menu item is enabled.
    
    Returns:
    
    true if the item is enabled; otherwise false
    
    Since:
    
    1.0
    
    See Also:
    
    setEnabled(boolean)
  - setEnabled
```
public void setEnabled(boolean b)
```
    Sets whether or not this menu item can be chosen.
    
    Parameters:
    
    b - if true, enables this menu item; if false, disables it.
    
    Since:
    
    1.1
    
    See Also:
    
    isEnabled()
  - enable
```
@Deprecated
public void enable()
```
    Deprecated.
    As of JDK version 1.1, replaced by setEnabled(boolean).
  - enable
```
@Deprecated
public void enable(boolean b)
```
    Deprecated.
    As of JDK version 1.1, replaced by setEnabled(boolean).
    
    Sets whether or not this menu item can be chosen.
    
    Parameters:
    
    b - if true, enables this menu item; otherwise disables
  - disable
```
@Deprecated
public void disable()
```
    Deprecated.
    As of JDK version 1.1, replaced by setEnabled(boolean).
  - getShortcut
```
public MenuShortcut getShortcut()
```
    Get the MenuShortcut object associated with this menu item,
    
    Returns:
    
    the menu shortcut associated with this menu item, or null if none has been specified.
    
    Since:
    
    1.1
    
    See Also:
    
    setShortcut(java.awt.MenuShortcut)
  - setShortcut
```
public void setShortcut(MenuShortcut s)
```
    Set the MenuShortcut object associated with this menu item. If a menu shortcut is already associated with this menu item, it is replaced.
    
    Parameters:
    
    s - the menu shortcut to associate with this menu item.
    
    Since:
    
    1.1
    
    See Also:
    
    getShortcut()
  - deleteShortcut
```
public void deleteShortcut()
```
    Delete any MenuShortcut object associated with this menu item.
    
    Since:
    
    1.1
  - enableEvents
```
protected final void enableEvents(long eventsToEnable)
```
    Enables event delivery to this menu item for events to be defined by the specified event mask parameter
    Since event types are automatically enabled when a listener for that type is added to the menu item, this method only needs to be invoked by subclasses of MenuItem which desire to have the specified event types delivered to processEvent regardless of whether a listener is registered.
    
    Parameters:
    
    eventsToEnable - the event mask defining the event types
    
    Since:
    
    1.1
    
    See Also:
    
    processEvent(java.awt.AWTEvent), disableEvents(long), Component.enableEvents(long)
  - disableEvents
```
protected final void disableEvents(long eventsToDisable)
```
    Disables event delivery to this menu item for events defined by the specified event mask parameter.
    
    Parameters:
    
    eventsToDisable - the event mask defining the event types
    
    Since:
    
    1.1
    
    See Also:
    
    processEvent(java.awt.AWTEvent), enableEvents(long), Component.disableEvents(long)
  - setActionCommand
```
public void setActionCommand(String command)
```
    Sets the command name of the action event that is fired by this menu item.
    By default, the action command is set to the label of the menu item.
    
    Parameters:
    
    command - the action command to be set for this menu item.
    
    Since:
    
    1.1
    
    See Also:
    
    getActionCommand()
  - getActionCommand
```
public String getActionCommand()
```
    Gets the command name of the action event that is fired by this menu item.
    
    Returns:
    
    the action command name
    
    Since:
    
    1.1
    
    See Also:
    
    setActionCommand(java.lang.String)
  - addActionListener
```
public void addActionListener(ActionListener l)
```
    Adds the specified action listener to receive action events from this menu item. If l is null, no exception is thrown and no action is performed.
    Refer to AWT Threading Issues for details on AWT's threading model.
    
    Parameters:
    
    l - the action listener.
    
    Since:
    
    1.1
    
    See Also:
    
    removeActionListener(java.awt.event.ActionListener), getActionListeners(), ActionEvent, ActionListener
  - removeActionListener
```
public void removeActionListener(ActionListener l)
```
    Removes the specified action listener so it no longer receives action events from this menu item. If l is null, no exception is thrown and no action is performed.
    Refer to AWT Threading Issues for details on AWT's threading model.
    
    Parameters:
    
    l - the action listener.
    
    Since:
    
    1.1
    
    See Also:
    
    addActionListener(java.awt.event.ActionListener), getActionListeners(), ActionEvent, ActionListener
  - getActionListeners
```
public ActionListener[] getActionListeners()
```
    Returns an array of all the action listeners registered on this menu item.
    
    Returns:
    
    all of this menu item's ActionListeners or an empty array if no action listeners are currently registered
    
    Since:
    
    1.4
    
    See Also:
    
    addActionListener(java.awt.event.ActionListener), removeActionListener(java.awt.event.ActionListener), ActionEvent, ActionListener
  - getListeners
```
public <T extends EventListener> T[] getListeners(Class<T> listenerType)
```
    Returns an array of all the objects currently registered as FooListeners upon this MenuItem. FooListeners are registered using the addFooListener method.
    You can specify the listenerType argument with a class literal, such as FooListener.class. For example, you can query a MenuItem m for its action listeners with the following code:
    
    ActionListener[] als = (ActionListener[])(m.getListeners(ActionListener.class));
    If no such listeners exist, this method returns an empty array.
    Type Parameters:
    
    T - the type of the listeners
    
    Parameters:
    
    listenerType - the type of listeners requested; this parameter should specify an interface that descends from java.util.EventListener
    
    Returns:
    
    an array of all objects registered as FooListeners on this menu item, or an empty array if no such listeners have been added
    
    Throws:
    
    ClassCastException - if listenerType doesn't specify a class or interface that implements java.util.EventListener
    
    Since:
    
    1.3
    
    See Also:
    
    getActionListeners()
  - processEvent
```
protected void processEvent(AWTEvent e)
```
    Processes events on this menu item. If the event is an instance of ActionEvent, it invokes processActionEvent, another method defined by MenuItem.
    Currently, menu items only support action events.
    
    Note that if the event parameter is null the behavior is unspecified and may result in an exception.
    
    Overrides:
    
    processEvent in class MenuComponent
    
    Parameters:
    
    e - the event
    
    Since:
    
    1.1
    
    See Also:
    
    processActionEvent(java.awt.event.ActionEvent)
  - processActionEvent
```
protected void processActionEvent(ActionEvent e)
```
    Processes action events occurring on this menu item, by dispatching them to any registered ActionListener objects. This method is not called unless action events are enabled for this component. Action events are enabled when one of the following occurs:
    
    An ActionListener object is registered via addActionListener.
    
    Action events are enabled via enableEvents.
    
    Note that if the event parameter is null the behavior is unspecified and may result in an exception.
    Parameters:
    
    e - the action event
    
    Since:
    
    1.1
    
    See Also:
    
    ActionEvent, ActionListener, enableEvents(long)
  - paramString
```
public String paramString()
```
    Returns a string representing the state of this MenuItem. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null.
    
    Overrides:
    
    paramString in class MenuComponent
    
    Returns:
    
    the parameter string of this menu item
  - getAccessibleContext
```
public AccessibleContext getAccessibleContext()
```
    Gets the AccessibleContext associated with this MenuItem. For menu items, the AccessibleContext takes the form of an AccessibleAWTMenuItem. A new AccessibleAWTMenuItem instance is created if necessary.
    
    Specified by:
    
    getAccessibleContext in interface Accessible
    
    Overrides:
    
    getAccessibleContext in class MenuComponent
    
    Returns:
    
    an AccessibleAWTMenuItem that serves as the AccessibleContext of this MenuItem
    
    Since:
    
    1.3

Java Module java.desktop Package java.awt Class MenuItem（JDK11）

Class MenuItem

Nested Class Summary

Nested classes/interfaces declared in class java.awt.MenuComponent

Constructor Summary

Method Summary

Methods declared in class java.awt.MenuComponent

Methods declared in class java.lang.Object

Constructor Detail

MenuItem

MenuItem

MenuItem

Method Detail

addNotify

getLabel

setLabel

isEnabled

setEnabled

enable

enable

disable

getShortcut

setShortcut

deleteShortcut

enableEvents

disableEvents

setActionCommand

getActionCommand

addActionListener

removeActionListener

getActionListeners

getListeners

processEvent

processActionEvent

paramString

getAccessibleContext