Java Swing Tutorials - Herong's Tutorial Examples - v4.32, by Herong Yang
AWT Button Action Handler at the Frame Level
This section provides a tutorial example on how to create an AWT button to handle actions by adding the ActionListener interface to the frame that contains the button component.
In the previous section, we extended the button to handle its own action. That works fine, if the action only requires modifying the behavior of the same button.
But if the action requires modifying the behavior of other components, you need to implement the action listener as a higher level. The following program shows you how to use the action handler to modify the text of a label component:
/* ButtonAction2.java * Copyright (c) 1997-2024 HerongYang.com. All Rights Reserved. */ import java.awt.Frame; import java.awt.Button; import java.awt.Label; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; public class ButtonAction2 implements ActionListener { Button myButton = null; Label myLabel = null; String text = null; public static void main(String[] a) { ButtonAction2 myTest = new ButtonAction2(); myTest.createFrame(); } public void createFrame() { Frame f = new Frame("My Switch Button"); f.setLayout(new GridLayout(2,1)); text = "On"; myButton = new Button(text); myButton.addActionListener(this); f.add(myButton); myLabel = new Label(text); f.add(myLabel); f.pack(); f.setVisible(true); } public void actionPerformed(ActionEvent e) { if (text.equals("On")) text = "Off"; else text = "On"; myButton.setLabel(text); myLabel.setText(text); } }
If you run this example, you will get:
The button works nicely. If you click the button, the button label text will change from "On" to "Off", and the text of the label component will also change.
Table of Contents
Introduction of Java Swing Package
Graphics Environment of the Local System
JCheckBox - Swing Check Box Class
JRadioButton - Swing Radio Button Class
JTextField - Swing Text Field Class
JComboBox - Swing Combo Box Class
Menu Bar, Menus, Menu Items and Listeners
Creating Internal Frames inside the Main Frame
Layout of Components in a Container
JEditorPane - The Editor Pane Class
SwingWorker - The Background Task Worker
►AWT (Abstract Windows Toolkit)
What Is AWT (Abstract Windows Toolkit)
HelloAWT.java - My First AWT Program
Closing AWT Frame and Terminating Application
Drawing Graphics - Using paint() on Frame or Component
Creating Labels with java.awt.Label Class
Creating Buttons with java.awt.Button Class
AWT Button Action Handler at the Component Level
►AWT Button Action Handler at the Frame Level
AWT Button Mouse Click Handler at the Frame Level
AWT TextField and ActionListener
MenuBarTest.java - AWT Menu Bar Test Program
MenuTest.java - AWT Menu Test Program
MenuItemTest.java - AWT Menu Item Test Program
MenuItemActionListenerTest.java - AWT Menu Item Action Listener