Class java.awt.Choice





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Class java.awt.Choice


java.lang.Object
|
+----java.awt.Component
|
+----java.awt.Choice



public class Choice
extends Component
implements ItemSelectable

The Choice class 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.









Choice()

Creates a new choice menu.






add(String)
Adds an item to this Choice menu.

addItem(String)
Adds an item to this Choice.

addItemListener(ItemListener)
Adds the specified item listener to receive item events from
this Choice menu.

addNotify()
Creates the Choice's peer.

countItems()

Deprecated.

getItem(int)
Gets the string at the specified index in this
Choice menu.

getItemCount()
Returns the number of items in this Choice menu.

getSelectedIndex()
Returns the index of the currently selected item.

getSelectedItem()
Gets a representation of the current choice as a string.

getSelectedObjects()
Returns an array (length 1) containing the currently selected
item.

insert(String, int)
Inserts the item into this choice at the specified position.

paramString()
Returns the parameter string representing the state of this
choice menu.

processEvent(AWTEvent)
Processes events on this choice.

processItemEvent(ItemEvent)

Processes item events occurring on this Choice
menu by dispatching them to any registered
ItemListener objects.

remove(int)
Removes an item from the choice menu
at the specified position.

remove(String)
Remove the first occurrence of item
from the Choice menu.

removeAll()
Removes all items from the choice menu.

removeItemListener(ItemListener)
Removes the specified item listener so that it no longer receives
item events from this Choice menu.

select(int)
Sets the selected item in this Choice menu to be the
item at the specified position.

select(String)
Sets the selected item in this Choice menu
to be the item whose name is equal to the specified string.







Choice

public Choice()


Creates 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 select methods.


See Also:
select, select







addNotify

public void addNotify()


Creates the Choice's peer. This peer allows us to change the look
of the Choice without changing its functionality.


Overrides:
addNotify in class Component
See Also:
createChoice, getToolkit



getItemCount

public int getItemCount()


Returns the number of items in this Choice menu.


See Also:
getItem



countItems

public int countItems()


Note: countItems() is deprecated.
As of JDK version 1.1,
replaced by getItemCount().



getItem

public String getItem(int index)


Gets the string at the specified index in this
Choice menu.


Parameters:
index - the index at which to begin.
See Also:
getItemCount



add

public void add(String item)


Adds an item to this Choice menu.


Parameters:
item - the item to be added
Throws: NullPointerException
if the item's value is null.



addItem

public synchronized void addItem(String item)


Adds an item to this Choice.


Parameters:
item - the item to be added
Throws: NullPointerException
If the item's value is equal to null.



insert

public synchronized void insert(String item,
int index)


Inserts the item into this choice at the specified position.


Parameters:
item - the item to be inserted
index - the position at which the item should be inserted
Throws: IllegalArgumentException
if index is less than 0.



remove

public synchronized void remove(String item)


Remove the first occurrence of item
from the Choice menu.


Parameters:
item - the item to remove from this Choice menu.
Throws: IllegalArgumentException
if the item doesn't
exist in the choice menu.



remove

public synchronized void remove(int position)


Removes an item from the choice menu
at the specified position.


Parameters:
position - the position of the item.



removeAll

public synchronized void removeAll()


Removes all items from the choice menu.


See Also:
remove



getSelectedItem

public synchronized 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



getSelectedObjects

public synchronized Object[] getSelectedObjects()


Returns an array (length 1) containing the currently selected
item. If this choice has no items, returns null.


See Also:
ItemSelectable



getSelectedIndex

public int getSelectedIndex()


Returns the index of the currently selected item.


See Also:
getSelectedItem



select

public void select(int pos)


Sets the selected item in this Choice menu to be the
item at the specified position.


Parameters:
pos - the positon of the selected item.
Throws: IllegalArgumentException
if the specified
position is invalid.
See Also:
getSelectedItem, getSelectedIndex



select

public synchronized void select(String str)


Sets the selected item in this Choice menu
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.


Parameters:
str - the specified string
See Also:
getSelectedItem, getSelectedIndex



addItemListener

public synchronized void addItemListener(ItemListener l)


Adds the specified item listener to receive item events from
this Choice menu.


Parameters:
l - the item listener.
See Also:
ItemEvent, ItemListener, removeItemListener



removeItemListener

public synchronized void removeItemListener(ItemListener l)


Removes the specified item listener so that it no longer receives
item events from this Choice menu.


Parameters:
l - the item listener.
See Also:
ItemEvent, ItemListener, addItemListener



processEvent

protected void processEvent(AWTEvent e)


Processes events on this choice. If the event is an
instance of ItemEvent, it invokes the
processItemEvent method. Otherwise, it calls its
superclass's processEvent method.


Parameters:
e - the event.
Overrides:
processEvent in class Component
See Also:
ItemEvent, processItemEvent



processItemEvent

protected void processItemEvent(ItemEvent e)


Processes item events occurring on this Choice
menu by dispatching them to any registered
ItemListener objects.

This method is not called unless item events are
enabled for this component. Item events are enabled
when one of the following occurs:

An ItemListener object is registered
via addItemListener.
Item events are enabled via enableEvents.



Parameters:
e - the item event.
See Also:
ItemEvent, ItemListener, addItemListener, enableEvents



paramString

protected String paramString()


Returns the parameter string representing the state of this
choice menu. This string is useful for debugging.


Returns:
the parameter string of this Choice menu.
Overrides:
paramString in class Component




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