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§1.8 Class Choice

public  class  java.awt.Choice
    extends  java.awt.Component  (II-§1.10)
{
        // Constructors
    public Choice();	§1.8.1

        // Methods
    public void addItem(String  item);	§1.8.2
    public void addNotify();	§1.8.3
    public int countItems();	§1.8.4
    public String getItem(int  index);	§1.8.5
    public int getSelectedIndex();	§1.8.6
    public String getSelectedItem();	§1.8.7
    protected String paramString();	§1.8.8
    public void select(int  pos);	§1.8.9
    public void select(String  str);	§1.8.10
}

The Choice class presents a pop-up menu of choices. The current choice is displayed as the title of the menu.

For example, the code:


Choice ColorChooser = new Choice();
ColorChooser.addItem("Green");
ColorChooser.addItem("Red");
ColorChooser.addItem("Blue");

produces the following pop-up menu, after it has been added to a panel:

In the picture, "Green" is the current choice. Pushing the mouse button down on on causes a menu to appear with the current choice highlighted.

After any choice is made,¹ AWT sends an action event (II-§1.14.11) to the choice menu. The event's target is the choice menu, and its object is the string label of the currently selected item. An application should override the action method (II-§1.10.1) of the choice menu or of one of its parent containers in order to cause some action to occur.

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 or by calling one of the select methods (§1.8.9, §1.8.10).

addItem

public void addItem(String  item)

Adds an item to this choice menu.

Parameters:: item -the item to be added
Throws: NullPointerException (I-§1.40); If the item's value is equal to null.

addNotify

public void addNotify()

This method calls the createChoice method (II-§1.41.7) of this object's toolkit (II-§1.10.20) in order to create a ChoicePeer (II-§3.5) for this button. This peer allows the application to change the look of a choice mneu without changing its functionality.

Most applications do not call this method directly.

Overrides:: addNotify in class Component (II-§1.10.2).

countItems

public int countItems()

Returns:: the number of menu items in this choice menu.
See Also:: getItem (II-§1.8.5).

getItem

public String getItem(int  index)

Parameters:: index -the index
Returns:: the string at the specified index in this choice menu
See Also:: countItems (II-§1.8.4).

getSelectedIndex

public int getSelectedIndex()

Returns:: the index of the currently selected item in this choice menu.
See Also:: getSelectedItem (II-§1.8.7).

getSelectedItem

public String getSelectedItem()

Returns:: a string representation of the currently selected item in this choice menu.
See Also:: getSelectedIndex (II-§1.8.6).

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 (II-§1.10.51).

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 selected item position
Throws: IllegalArgumentException (I-§1.32); If the choice item position is invalid.
See Also:: getSelectedItem (II-§1.8.7)
getSelectedIndex (II-§1.8.6).

select

public void select(String  str)

Sets the selected item in this choice menu to be the choice whose name is equal (I-§1.16.14) to the specified string. If more than one choice is equal to the specified string, the one with the smallest index whose name matches is selected.

Parameters:: str -the string to select
See Also:: getSelectedItem (II-§1.8.7)
getSelectedIndex (II-§1.8.6).

¹ In Java 1.0, the AWT does not send mouse or focus events to a choice menu. In Java 1.1, the AWT sends the cheoice menu all mouse, keyboard, and focus events that occur over it.

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