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Chapter 19
java.awt Reference

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Choice

Name

Choice

[Graphic: Figure from the text]

Description

The Choice is a Component that provides a drop-down list of choices to choose from.

Class Definition

public class java.awt.Choice
    extends java.awt.Component
    implements java.awt.ItemSelectable {
  
  // Constructors
  public Choice();
  
  // Instance Methods
  public synchronized void add (String item); 
  public synchronized void addItem (String item); 
  public void addItemListener (ItemListener l); 
  public void addNotify();
  public int countItems();  
  public String getItem (int index);
  public int getItemCount(); 
  public int getSelectedIndex();
  public synchronized String getSelectedItem();
  public synchronized Object[] getSelectedObjects(); 
  public synchronized void insert (String item, int index); 
  public synchronized void remove (int position); 
  public synchronized void remove (String item); 
  public synchronized void removeAll(); 
  public void removeItemListener (ItemListener l); 
  public synchronized void select (int pos);
  public synchronized void select (String str);
  
  // Protected Instance Methods
  protected String paramString();
  protected void processEvent (AWTEvent e);  
  protected void processItemEvent (ItemEvent e); 
}

Constructors

Choice

public Choice()

Description: Constructs a Choice object.

Instance Methods

add

public synchronized void add (String item)

Parameters

item: Text for new entry.

Throws

NullPointerException: If item is null.

Description

Adds a new entry to the available choices.

addItem

public synchronized void addItem (String item)

Parameters

item: Text for new entry.

Throws

NullPointerException: If item is null.

Description

Replaced by add(String).

addItemListener

public void addItemListener (ItemListener l)

Parameters

l: The listener to be added.

Implements

ItemSelectable.addItemListener(ItemListener l)

Description

Adds a listener for the ItemEvent objects this Choice generates.

addNotify

public void addNotify()

Overrides

Component.addNotify()

Description

Creates Choice's peer.

countItems

public int countItems()

Returns

Number of items in the Choice.

Description

Replaced by getItemCount().

getItem

public String getItem (int index)

Parameters

index: Position of entry.

Returns

A string for an entry at a given position.

Throws

ArrayIndexOutOfBoundsException: If index is invalid; indices start at zero.

getItemCount

public int getItemCount()

Returns: Number of items in the Choice.

getSelectedIndex

public int getSelectedIndex()

Returns: Position of currently selected entry.

getSelectedItem

public synchronized String getSelectedItem()

Returns: Currently selected entry as a String.

getSelectedObjects

public synchronized Object[] getSelectedObjects()

Implements

ItemSelectable.getSelectedObjects()

Description

A single-item array containing the current selection.

insert

public synchronized void insert (String item, int index)

Parameters

item

The string to add.

index

The position for the new string.

Throws

IllegalArgumentException: If index is less than zero.

Description

Inserts item in the given position.

remove

public synchronized void remove (int position)

Parameters

position: The index of an entry in the Choice component.

Description

Removes the entry in the given position.

public synchronized void remove (String string)

Parameters

string: Text of an entry within the Choice component.

Throws

IllegalArgumentException: If string is not in the Choice.

Description

Makes the first entry that matches string the selected item.

removeAll

public synchronized void removeAll()

Description: Removes all the entries from the Choice.

removeItemListener

public void removeItemListener (ItemListener l)

Parameters

l: The listener to be removed.

Implements

ItemSelectable.removeItemListener (ItemListener l)

Description

Removes the specified ItemListener so it will not receive ItemEvent objects from this Choice.

select

public synchronized void select (int pos)

Parameters

pos: The index of an entry in the Choice component.

Throws

IllegalArgumentException: If the position is not valid.

Description

Makes the entry in the given position.

public synchronized void select (String str)

Parameters

str: Text of an entry within the Choice component.

Description

Makes the first entry that matches str the selected item for the Choice.

Protected Instance Methods

paramString

protected String paramString()

Returns

A string with current settings of Choice.

Overrides

Component.paramString()

Description

Helper method for toString() to generate string of current settings.

processEvent

protected void processEvent (AWTEvent e)

Parameters

e: The event to process.

Description

Low level AWTEvents are passed to this method for processing.

processItemEvent

protected void processItemEvent (ItemEvent e)

Parameters

e: The item event to process.

Description

Item events are passed to this method for processing. Normally, this method is called by processEvent().

See Also

Component, ItemSelectable, String


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