7.SWING AND EVENT HANDLING IN JAVA

 

import java.awt.*; import java.awt.event.*; import javax.swing.*; public class SwingDemo { private JFrame mainFrame; private JLabel headerLabel; private JLabel statusLabel; private JPanel controlPanel; public SwingDemo() { prepareGUI(); } public static void main(String[] args) { SwingDemo swingControlDemo = new SwingDemo(); swingControlDemo.showEventDemo(); } 

private void prepareGUI() { mainFrame = new JFrame("Java SWING Examples"); mainFrame.setSize(400,400); mainFrame.setLayout(new GridLayout(3, 1)); headerLabel = new JLabel("",JLabel.CENTER ); statusLabel = new JLabel("",JLabel.CENTER); statusLabel.setSize(350,100); mainFrame.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent windowEvent) { System.exit(0); } }); controlPanel = new JPanel(); controlPanel.setLayout(new FlowLayout()); mainFrame.add(headerLabel); mainFrame.add(controlPanel); mainFrame.add(statusLabel); mainFrame.setVisible(true); } private void showEventDemo() { headerLabel.setText("Control in action: Button"); JButton okButton = new JButton("OK"); JButton submitButton = new JButton("Submit"); JButton cancelButton = new JButton("Cancel"); okButton.setActionCommand("OK"); submitButton.setActionCommand("Submit"); cancelButton.setActionCommand("Cancel"); okButton.addActionListener(new ButtonClickListener()); submitButton.addActionListener(new ButtonClickListener()); cancelButton.addActionListener(new ButtonClickListener()); controlPanel.add(okButton); controlPanel.add(submitButton); controlPanel.add(cancelButton); mainFrame.setVisible(true); } private class ButtonClickListener implements ActionListener { public void actionPerformed(ActionEvent e) { String command = e.getActionCommand(); if( command.equals( "OK" )) { statusLabel.setText("Ok Button clicked."); } else if( command.equals( "Submit" ) ){statusLabel.setText("Submit Button clicked."); } else { statusLabel.setText("Cancel Button clicked."); }} } }