- java.lang.Object
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- java.awt.Component
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- java.awt.Choice
 
 
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- All Implemented Interfaces:
- ImageObserver,- ItemSelectable,- MenuContainer,- Serializable,- Accessible
 
 public class Choice extends Component implements ItemSelectable, Accessible TheChoiceclass presents a pop-up menu of choices. The current choice is displayed as the title of the menu.The following code example produces a pop-up menu: Choice ColorChooser = new Choice(); ColorChooser.add("Green"); ColorChooser.add("Red"); ColorChooser.add("Blue");
 After this choice menu has been added to a panel, it appears as follows in its normal state:   In the picture, "Green"is the current choice. Pushing the mouse button down on the object causes a menu to appear with the current choice highlighted.Some native platforms do not support arbitrary resizing of Choicecomponents and the behavior ofsetSize()/getSize()is bound by such limitations. Native GUIChoicecomponents' size are often bound by such attributes as font size and length of items contained within theChoice.- Since:
- 1.0
- See Also:
- Serialized Form
 
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Nested Class SummaryNested Classes Modifier and Type Class Description protected classChoice.AccessibleAWTChoiceThis class implements accessibility support for theChoiceclass.- 
Nested classes/interfaces declared in class java.awt.ComponentComponent.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
 
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Field Summary- 
Fields declared in class java.awt.ComponentaccessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
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Fields declared in interface java.awt.image.ImageObserverABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
 
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Constructor SummaryConstructors Constructor Description Choice()Creates a new choice menu.
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Method SummaryAll Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description voidadd(String item)Adds an item to thisChoicemenu.voidaddItem(String item)Obsolete as of Java 2 platform v1.1.voidaddItemListener(ItemListener l)Adds the specified item listener to receive item events from thisChoicemenu.voidaddNotify()Creates theChoice's peer.intcountItems()Deprecated.As of JDK version 1.1, replaced bygetItemCount().AccessibleContextgetAccessibleContext()Gets theAccessibleContextassociated with thisChoice.StringgetItem(int index)Gets the string at the specified index in thisChoicemenu.intgetItemCount()Returns the number of items in thisChoicemenu.ItemListener[]getItemListeners()Returns an array of all the item listeners registered on this choice.<T extends EventListener>
 T[]getListeners(Class<T> listenerType)Returns an array of all the objects currently registered asFooListeners upon thisChoice.intgetSelectedIndex()Returns the index of the currently selected item.StringgetSelectedItem()Gets a representation of the current choice as a string.Object[]getSelectedObjects()Returns an array (length 1) containing the currently selected item.voidinsert(String item, int index)Inserts the item into this choice at the specified position.protected StringparamString()Returns a string representing the state of thisChoicemenu.protected voidprocessEvent(AWTEvent e)Processes events on this choice.protected voidprocessItemEvent(ItemEvent e)Processes item events occurring on thisChoicemenu by dispatching them to any registeredItemListenerobjects.voidremove(int position)Removes an item from the choice menu at the specified position.voidremove(String item)Removes the first occurrence ofitemfrom theChoicemenu.voidremoveAll()Removes all items from the choice menu.voidremoveItemListener(ItemListener l)Removes the specified item listener so that it no longer receives item events from thisChoicemenu.voidselect(int pos)Sets the selected item in thisChoicemenu to be the item at the specified position.voidselect(String str)Sets the selected item in thisChoicemenu to be the item whose name is equal to the specified string.- 
Methods declared in class java.awt.Componentaction, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMinimumSize, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPreferredSize, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, minimumSize, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paint, paintAll, postEvent, preferredSize, prepareImage, prepareImage, print, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, revalidate, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setMixingCutoutShape, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, update, validate
 
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Constructor Detail- 
Choicepublic Choice() throws HeadlessExceptionCreates a new choice menu. The menu initially has no items in it.By default, the first item added to the choice menu becomes the selected item, until a different selection is made by the user by calling one of the selectmethods.- Throws:
- HeadlessException- if GraphicsEnvironment.isHeadless() returns true
- See Also:
- GraphicsEnvironment.isHeadless(),- select(int),- select(java.lang.String)
 
 
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Method Detail- 
addNotifypublic void addNotify() Creates theChoice's peer. This peer allows us to change the look of theChoicewithout changing its functionality.- Overrides:
- addNotifyin class- Component
- See Also:
- Component.getToolkit()
 
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getItemCountpublic int getItemCount() Returns the number of items in thisChoicemenu.- Returns:
- the number of items in this Choicemenu
- Since:
- 1.1
- See Also:
- getItem(int)
 
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countItems@Deprecated public int countItems() Deprecated.As of JDK version 1.1, replaced bygetItemCount().Returns the number of items in thisChoicemenu.- Returns:
- the number of items in this Choicemenu
 
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getItempublic String getItem(int index) Gets the string at the specified index in thisChoicemenu.- Parameters:
- index- the index at which to begin
- Returns:
- the item at the specified index
- See Also:
- getItemCount()
 
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addpublic void add(String item) Adds an item to thisChoicemenu.- Parameters:
- item- the item to be added
- Throws:
- NullPointerException- if the item's value is- null
- Since:
- 1.1
 
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addItempublic void addItem(String item) Obsolete as of Java 2 platform v1.1. Please use theaddmethod instead.Adds an item to this Choicemenu.- Parameters:
- item- the item to be added
- Throws:
- NullPointerException- if the item's value is equal to- null
 
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insertpublic void insert(String item, int index) Inserts the item into this choice at the specified position. Existing items at an index greater than or equal toindexare shifted up by one to accommodate the new item. Ifindexis greater than or equal to the number of items in this choice,itemis added to the end of this choice.If the item is the first one being added to the choice, then the item becomes selected. Otherwise, if the selected item was one of the items shifted, the first item in the choice becomes the selected item. If the selected item was no among those shifted, it remains the selected item. - Parameters:
- item- the non-- nullitem to be inserted
- index- the position at which the item should be inserted
- Throws:
- IllegalArgumentException- if index is less than 0
 
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removepublic void remove(String item) Removes the first occurrence ofitemfrom theChoicemenu. If the item being removed is the currently selected item, then the first item in the choice becomes the selected item. Otherwise, the currently selected item remains selected (and the selected index is updated accordingly).- Parameters:
- item- the item to remove from this- Choicemenu
- Throws:
- IllegalArgumentException- if the item doesn't exist in the choice menu
- Since:
- 1.1
 
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removepublic void remove(int position) Removes an item from the choice menu at the specified position. If the item being removed is the currently selected item, then the first item in the choice becomes the selected item. Otherwise, the currently selected item remains selected (and the selected index is updated accordingly).- Parameters:
- position- the position of the item
- Throws:
- IndexOutOfBoundsException- if the specified position is out of bounds
- Since:
- 1.1
 
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removeAllpublic void removeAll() Removes all items from the choice menu.- Since:
- 1.1
- See Also:
- remove(java.lang.String)
 
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getSelectedItempublic String getSelectedItem() Gets a representation of the current choice as a string.- Returns:
- a string representation of the currently selected item in this choice menu
- See Also:
- getSelectedIndex()
 
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getSelectedObjectspublic Object[] getSelectedObjects() Returns an array (length 1) containing the currently selected item. If this choice has no items, returnsnull.- Specified by:
- getSelectedObjectsin interface- ItemSelectable
- Returns:
- the list of selected objects, or null
- See Also:
- ItemSelectable
 
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getSelectedIndexpublic int getSelectedIndex() Returns the index of the currently selected item. If nothing is selected, returns -1.- Returns:
- the index of the currently selected item, or -1 if nothing is currently selected
- See Also:
- getSelectedItem()
 
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selectpublic void select(int pos) Sets the selected item in thisChoicemenu to be the item at the specified position.Note that this method should be primarily used to initially select an item in this component. Programmatically calling this method will not trigger an ItemEvent. The only way to trigger anItemEventis by user interaction.- Parameters:
- pos- the position of the selected item
- Throws:
- IllegalArgumentException- if the specified position is greater than the number of items or less than zero
- See Also:
- getSelectedItem(),- getSelectedIndex()
 
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selectpublic void select(String str) Sets the selected item in thisChoicemenu to be the item whose name is equal to the specified string. If more than one item matches (is equal to) the specified string, the one with the smallest index is selected.Note that this method should be primarily used to initially select an item in this component. Programmatically calling this method will not trigger an ItemEvent. The only way to trigger anItemEventis by user interaction.- Parameters:
- str- the specified string
- See Also:
- getSelectedItem(),- getSelectedIndex()
 
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addItemListenerpublic void addItemListener(ItemListener l) Adds the specified item listener to receive item events from thisChoicemenu. Item events are sent in response to user input, but not in response to calls toselect. If l isnull, no exception is thrown and no action is performed.Refer to AWT Threading Issues for details on AWT's threading model. - Specified by:
- addItemListenerin interface- ItemSelectable
- Parameters:
- l- the item listener
- Since:
- 1.1
- See Also:
- removeItemListener(java.awt.event.ItemListener),- getItemListeners(),- select(int),- ItemEvent,- ItemListener
 
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removeItemListenerpublic void removeItemListener(ItemListener l) Removes the specified item listener so that it no longer receives item events from thisChoicemenu. If l isnull, no exception is thrown and no action is performed.Refer to AWT Threading Issues for details on AWT's threading model. - Specified by:
- removeItemListenerin interface- ItemSelectable
- Parameters:
- l- the item listener
- Since:
- 1.1
- See Also:
- addItemListener(java.awt.event.ItemListener),- getItemListeners(),- ItemEvent,- ItemListener
 
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getItemListenerspublic ItemListener[] getItemListeners() Returns an array of all the item listeners registered on this choice.- Returns:
- all of this choice's ItemListeners or an empty array if no item listeners are currently registered
- Since:
- 1.4
- See Also:
- addItemListener(java.awt.event.ItemListener),- removeItemListener(java.awt.event.ItemListener),- ItemEvent,- ItemListener
 
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getListenerspublic <T extends EventListener> T[] getListeners(Class<T> listenerType) Returns an array of all the objects currently registered asFooListeners upon thisChoice.FooListeners are registered using theaddFooListenermethod.You can specify the listenerTypeargument with a class literal, such asFooListener.class. For example, you can query aChoice cfor its item listeners with the following code:ItemListener[] ils = (ItemListener[])(c.getListeners(ItemListener.class)); If no such listeners exist, this method returns an empty array.- Overrides:
- getListenersin class- Component
- 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 choice, or an empty array if no such listeners have been added
- Throws:
- ClassCastException- if- listenerTypedoesn't specify a class or interface that implements- java.util.EventListener
- Since:
- 1.3
- See Also:
- getItemListeners()
 
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processEventprotected void processEvent(AWTEvent e) Processes events on this choice. If the event is an instance ofItemEvent, it invokes theprocessItemEventmethod. Otherwise, it calls its superclass'sprocessEventmethod.Note that if the event parameter is nullthe behavior is unspecified and may result in an exception.- Overrides:
- processEventin class- Component
- Parameters:
- e- the event
- Since:
- 1.1
- See Also:
- ItemEvent,- processItemEvent(java.awt.event.ItemEvent)
 
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processItemEventprotected void processItemEvent(ItemEvent e) Processes item events occurring on thisChoicemenu by dispatching them to any registeredItemListenerobjects.This method is not called unless item events are enabled for this component. Item events are enabled when one of the following occurs: - An ItemListenerobject is registered viaaddItemListener.
- Item events are enabled via enableEvents.
 Note that if the event parameter is nullthe behavior is unspecified and may result in an exception.- Parameters:
- e- the item event
- Since:
- 1.1
- See Also:
- ItemEvent,- ItemListener,- addItemListener(ItemListener),- Component.enableEvents(long)
 
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paramStringprotected String paramString() Returns a string representing the state of thisChoicemenu. 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 benull.- Overrides:
- paramStringin class- Component
- Returns:
- the parameter string of this Choicemenu
 
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getAccessibleContextpublic AccessibleContext getAccessibleContext() Gets theAccessibleContextassociated with thisChoice. ForChoicecomponents, theAccessibleContexttakes the form of anAccessibleAWTChoice. A newAccessibleAWTChoiceinstance is created if necessary.- Specified by:
- getAccessibleContextin interface- Accessible
- Overrides:
- getAccessibleContextin class- Component
- Returns:
- an AccessibleAWTChoicethat serves as theAccessibleContextof thisChoice
- Since:
- 1.3
 
 
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