JButton

Java Swing Tutorial Explaining the JButton Component. The abstract class AbstractButton extends class JComponent and provides a foundation for a family of button classes, including JButton. A button is a component the user clicks to trigger a specific action.

 

 

There are several types of buttons in Java, all are subclasses of AbstractButton.

•     command buttons: is created with class JButton. It generates ActionEvent.

•     toggle buttons: have on/off or true/false values.

•     check boxes: a group of buttons. It generates ItemEvent.

•     radio buttons: a group of buttons in which only one can be selected. It generates ItemEvent.

JButton Source Code

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.net.URL;

import javax.swing.AbstractButton;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;


public class JButtonDemo extends JPanel implements ActionListener {
    protected static JButton jbnLeft, jbnMiddle, jbnRight;

    public JButtonDemo() {
    	
    	//Create Icons that can be used with the jButtons
        ImageIcon leftButtonIcon = createImageIcon("rightarrow.JPG");
        ImageIcon middleButtonIcon = createImageIcon("java-swing-tutorial.JPG");
        ImageIcon rightButtonIcon = createImageIcon("leftarrow.JPG");

        jbnLeft = new JButton("Disable centre button", leftButtonIcon);
        jbnLeft.setVerticalTextPosition(AbstractButton.CENTER);
        jbnLeft.setHorizontalTextPosition(AbstractButton.LEADING); 
        jbnLeft.setMnemonic(KeyEvent.VK_D);				

	// Alt-D clicks the button
        jbnLeft.setActionCommand("disable");
        jbnLeft.setToolTipText("disable the Centre button."); //Adding Tool tips
        
        jbnMiddle = new JButton("Centre button", middleButtonIcon);
        jbnMiddle.setVerticalTextPosition(AbstractButton.BOTTOM);
        jbnMiddle.setHorizontalTextPosition(AbstractButton.CENTER);
        jbnMiddle.setMnemonic(KeyEvent.VK_M);				

	// Alt-M clicks the button
        jbnMiddle.setToolTipText("Centre button");

        jbnRight = new JButton("Enable centre button", rightButtonIcon);
        //Use the default text position of CENTER, TRAILING (RIGHT).
        jbnRight.setMnemonic(KeyEvent.VK_E);				

	// Alt-E clicks the button
        jbnRight.setActionCommand("enable");
        jbnRight.setEnabled(false);				

	// Disable the Button at creation time

        //Listen for actions on Left and Roght Buttons
        jbnLeft.addActionListener(this);
        jbnRight.addActionListener(this);
        jbnRight.setToolTipText("Enable the Centre button.");
        

        //Add Components to the frame, using the default FlowLayout.
        add(jbnLeft);
        add(jbnMiddle);
        add(jbnRight);
    }

    public void actionPerformed(ActionEvent e) {
        if ("disable".equals(e.getActionCommand())) {
            jbnMiddle.setEnabled(false);
            jbnLeft.setEnabled(false);
            jbnRight.setEnabled(true);
        } else {
            jbnMiddle.setEnabled(true);
            jbnLeft.setEnabled(true);
            jbnRight.setEnabled(false);
        }
    }

    // Returns an ImageIcon, or null if the path was invalid. 
    protected static ImageIcon createImageIcon(String path) {
        URL imgURL = JButtonDemo.class.getResource(path);	
        if (imgURL != null) {
            return new ImageIcon(imgURL);
        } else {
            System.err.println("Couldn't find image in system: " + path);
            return null;
        }
    }

    //Create the GUI and show it.  
    private static void createGUI() {

        JFrame.setDefaultLookAndFeelDecorated(true);	    

        //Create and set up the frame.
        JFrame frame = new JFrame("jButton usage demo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        JButtonDemo buttonContentPane = new JButtonDemo();
        
        buttonContentPane.setOpaque(true); //content panes must be opaque
        frame.getRootPane().setDefaultButton(jbnLeft);  
        
        frame.setContentPane(buttonContentPane); 
       
        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {

        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createGUI(); 
            }
        });
    }
}

Output

Download jButton Source Code

Another Example: JButton Source Code

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;


    public class JButtonDemo2 {
    	JFrame jtfMainFrame;
    	JButton jbnButton1, jbnButton2;
    	JTextField jtfInput; 
    	JPanel jplPanel;
    	
    	public JButtonDemo2() {
        		
        	jtfMainFrame = new JFrame("Which Button Demo"); 
        	jtfMainFrame.setSize(50, 50);
    		jbnButton1 = new JButton("Button 1"); 
    		jbnButton2 = new JButton("Button 2");
    		jtfInput = new JTextField(20);
    		jplPanel = new JPanel();
    		
    		jbnButton1.setMnemonic(KeyEvent.VK_I);	//Set ShortCut Keys

            jbnButton1.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                	jtfInput.setText("Button 1!");
                }

            });

        	jbnButton2.setMnemonic(KeyEvent.VK_I);
            jbnButton2.addActionListener(new ActionListener() {
            	public void actionPerformed(ActionEvent e) {
            		jtfInput.setText("Button 2!");
            	}
            });

    		jplPanel.setLayout(new FlowLayout());
    		jplPanel.add(jtfInput);
    		jplPanel.add(jbnButton1); 
    		jplPanel.add(jbnButton2);
        		
        	jtfMainFrame.getContentPane().add(jplPanel, BorderLayout.CENTER);

        	jtfMainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
        	jtfMainFrame.pack();
        	jtfMainFrame.setVisible(true);
    }


        public static void main(String[] args) {
        	// Set the look and feel to Java Swing Look
            	try {
            		UIManager.setLookAndFeel(
            				UIManager.getCrossPlatformLookAndFeelClassName()); 
            	} catch(Exception e) {}
            	JButtonDemo2 application = new JButtonDemo2(); 
        }

    }

Output

Download jButton Source Code