Item Events in Java
Introduction
In this section, you will learn about handling item events in java. This
demonstrates that the event generated when you select an item from the group of
the items.
This program demonstrates how the item events is handled. You can perform
several operations according to the
selecting of items from the item group.
Here, you will see the handling item event through the given program in
which, a combo box and a text area have been taken. Items of the combo box are
as follows : Red, Green, Blue. If you select an item from the combo box then the
message with the item name will be displayed in the text area.
Choice() :
This is the constructor of the Choice
class which creates combo box.
ItemEvent :
This is the ItemEvent class which indicates an
event on selecting or deselecting items from the item group. This event is passed
by
ItemListener
object. The generated event is passed to all ItemListener objects which is
registered to receive such types of event. This is done using the
addItemListener()
method of the object.
getItem() :
This is the method of the ItemEvent
class which returns the value of the selected or deselected item.
Here is the code of program :
import java.awt.*;
import java.awt.event.*;
public class AwtItemEvent extends Frame{
TextArea txtArea;
public AwtItemEvent(String title){
super(title);
txtArea = new TextArea();
add(txtArea, BorderLayout.CENTER);
Choice choice = new Choice();
choice.addItem("red");
choice.addItem("green");
choice.addItem("blue");
choice.addItemListener(new ItemListener(){
public void itemStateChanged(ItemEvent e){
txtArea.setText("This is the " + e.getItem() + " color.\n");
}
});
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
add(choice, BorderLayout.NORTH);
setSize(400,400);
setVisible(true);
setResizable(false);
}
public static void main(String[] args){
AwtItemEvent f = new AwtItemEvent("AWT Demo");
}
}
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