Java examples for Swing:JCheckBox
Handle State change event in JCheckBox
import java.awt.*; import java.awt.event.*; import javax.swing.*; /*// w ww . j a v a 2s . c o m * CheckBoxDemo.java requires 16 image files in the images/geek * directory: * geek-----.gif, geek-c---.gif, geek--g--.gif, geek---h-.gif, geek----t.gif, * geek-cg--.gif, ..., geek-cght.gif. */ public class CheckBoxDemo extends JPanel implements ItemListener { JCheckBox chinButton; JCheckBox glassesButton; JCheckBox hairButton; JCheckBox teethButton; /* * Four accessory choices provide for 16 different * combinations. The image for each combination is * contained in a separate image file whose name indicates * the accessories. The filenames are "geek-XXXX.gif" * where XXXX can be one of the following 16 choices. * The "choices" StringBuffer contains the string that * indicates the current selection and is used to generate * the file name of the image to display. ---- //zero accessories c--- //one accessory -g-- --h- ---t cg-- //two accessories c-h- c--t -gh- -g-t --ht -ght //three accessories c-ht cg-t cgh- cght //all accessories */ StringBuffer choices; JLabel pictureLabel; public CheckBoxDemo() { super(new BorderLayout()); //Create the check boxes. chinButton = new JCheckBox("Chin"); chinButton.setMnemonic(KeyEvent.VK_C); chinButton.setSelected(true); glassesButton = new JCheckBox("Glasses"); glassesButton.setMnemonic(KeyEvent.VK_G); glassesButton.setSelected(true); hairButton = new JCheckBox("Hair"); hairButton.setMnemonic(KeyEvent.VK_H); hairButton.setSelected(true); teethButton = new JCheckBox("Teeth"); teethButton.setMnemonic(KeyEvent.VK_T); teethButton.setSelected(true); //Register a listener for the check boxes. chinButton.addItemListener(this); glassesButton.addItemListener(this); hairButton.addItemListener(this); teethButton.addItemListener(this); //Indicates what's on the geek. choices = new StringBuffer("cght"); //Set up the picture label pictureLabel = new JLabel(); pictureLabel .setFont(pictureLabel.getFont().deriveFont(Font.ITALIC)); updatePicture(); //Put the check boxes in a column in a panel JPanel checkPanel = new JPanel(new GridLayout(0, 1)); checkPanel.add(chinButton); checkPanel.add(glassesButton); checkPanel.add(hairButton); checkPanel.add(teethButton); add(checkPanel, BorderLayout.LINE_START); add(pictureLabel, BorderLayout.CENTER); setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20)); } /** Listens to the check boxes. */ public void itemStateChanged(ItemEvent e) { int index = 0; char c = '-'; Object source = e.getItemSelectable(); if (source == chinButton) { index = 0; c = 'c'; } else if (source == glassesButton) { index = 1; c = 'g'; } else if (source == hairButton) { index = 2; c = 'h'; } else if (source == teethButton) { index = 3; c = 't'; } //Now that we know which button was pushed, find out //whether it was selected or deselected. if (e.getStateChange() == ItemEvent.DESELECTED) { c = '-'; } //Apply the change to the string. choices.setCharAt(index, c); updatePicture(); } protected void updatePicture() { //Get the icon corresponding to the image. ImageIcon icon = createImageIcon("images/geek/geek-" + choices.toString() + ".gif"); pictureLabel.setIcon(icon); pictureLabel.setToolTipText(choices.toString()); if (icon == null) { pictureLabel.setText("Missing Image"); } else { pictureLabel.setText(null); } } /** Returns an ImageIcon, or null if the path was invalid. */ protected static ImageIcon createImageIcon(String path) { java.net.URL imgURL = CheckBoxDemo.class.getResource(path); if (imgURL != null) { return new ImageIcon(imgURL); } else { System.err.println("Couldn't find file: " + path); return null; } } /** * Create the GUI and show it. For thread safety, * this method should be invoked from the * event-dispatching thread. */ private static void createAndShowGUI() { //Create and set up the window. JFrame frame = new JFrame("CheckBoxDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and set up the content pane. JComponent newContentPane = new CheckBoxDemo(); newContentPane.setOpaque(true); //content panes must be opaque frame.setContentPane(newContentPane); //Display the window. frame.pack(); frame.setVisible(true); } public static void main(String[] args) { //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } } /* * Copyright (c) 1995, 2008, Oracle and/or its affiliates. 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