In this tutorial we are going to see how you can use an ActionListener, a ChangeListener and an ItemListener with the JCheckBox component to construct a CheckBox listener. This is very useful because it gives a generic way to construct you own custom listeners based on the build in ones, in your own components.
Basically all you have to do to create a CheckBox listener is:
- Create a new
ActionListenerinstance. - Override the
actionPerformedmethod in order to customize the handling of a specific event. Using this you can monitor the ticking actions of the checkbox. - Create a new
ChangeListenerinstance. - Override the
stateChangedmethod. Using this you can monitor the state of the checkboxes e.g if its pressed, selected, armed etc. - Create a new
ItemListenerinstance. - Override the
itemStateChangedmethod in order to customize the handling of state changes in the checkboxes. - Create a new
JCheckBoxcomponent and useaddActionListener,addChangeListener,addItemListenerto add the above event listeners to your checkbox component.
Let’s take a look at the code snippets that follow:
package com.javacodegeeks.snippets.desktop;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.KeyEvent;
import javax.swing.AbstractButton;
import javax.swing.ButtonModel;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class Main {
private static String label1 = "Unckecked";
private static String label2 = "Checked";
public static void main(String args[]) {
JFrame jFrame = new JFrame("Selecting CheckBox");
jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JCheckBox tickBox = new JCheckBox(label1);
ActionListener actionListener = new ActionListener() {
@Override
public void actionPerformed(ActionEvent actionEvent) {
AbstractButton absB = (AbstractButton) actionEvent.getSource();
boolean slct = absB.getModel().isSelected();
String nL = (slct ? label2 : label1);
absB.setText(nL);
}
};
ChangeListener chListener = new ChangeListener() {
@Override
public void stateChanged(ChangeEvent changeEvent) {
AbstractButton absB = (AbstractButton) changeEvent.getSource();
ButtonModel bMod = absB.getModel();
boolean armed = bMod.isArmed();
boolean pressed = bMod.isPressed();
boolean selected = bMod.isSelected();
System.out.println("Changed: " + armed + "/" + pressed + "/" + selected);
}
};
ItemListener itemlistener = new ItemListener() {
@Override
public void itemStateChanged(ItemEvent itemE) {
AbstractButton absB = (AbstractButton) itemE.getSource();
Color fgrnd = absB.getForeground();
Color bgrnd = absB.getBackground();
int st = itemE.getStateChange();
if (st == ItemEvent.SELECTED) {
absB.setForeground(bgrnd);
absB.setBackground(fgrnd);
}
}
};
tickBox.addActionListener(actionListener);
tickBox.addChangeListener(chListener);
tickBox.addItemListener(itemlistener);
tickBox.setMnemonic(KeyEvent.VK_S);
Container contentPane = jFrame.getContentPane();
contentPane.add(tickBox, BorderLayout.NORTH);
jFrame.setSize(200, 80);
jFrame.setVisible(true);
}
}
This was an example on how to create a CheckBox Listener in Java.
