Java examples for Swing:Focus Event
Track focus with KeyboardFocusManager
/*/*from w w w . j a v a2 s. com*/ * TrackFocusDemo.java requires the following files: * Picture.java * images/Maya.jpg * images/Anya.jpg * images/Laine.jpg * images/Cosmo.jpg * images/Adele.jpg * images/Alexi.jpg */ import javax.swing.*; import java.beans.*; //Property change stuff import java.awt.*; import java.awt.event.*; import javax.swing.InputMap; import javax.swing.KeyStroke; import javax.swing.Action; import javax.swing.JComponent; import javax.accessibility.Accessible; import java.beans.*; import java.awt.*; import java.awt.event.*; class Picture extends JComponent implements MouseListener, FocusListener, Accessible { Image image; public Picture(Image image) { this.image = image; setFocusable(true); addMouseListener(this); addFocusListener(this); } public void mouseClicked(MouseEvent e) { //Since the user clicked on us, let's get focus! requestFocusInWindow(); } public void mouseEntered(MouseEvent e) { } public void mouseExited(MouseEvent e) { } public void mousePressed(MouseEvent e) { } public void mouseReleased(MouseEvent e) { } public void focusGained(FocusEvent e) { //Draw the component with a red border //indicating that it has focus. this.repaint(); } public void focusLost(FocusEvent e) { //Draw the component with a black border //indicating that it doesn't have focus. this.repaint(); } protected void paintComponent(Graphics graphics) { Graphics g = graphics.create(); //Draw in our entire space, even if isOpaque is false. g.setColor(Color.WHITE); g.fillRect(0, 0, image == null ? 125 : image.getWidth(this), image == null ? 125 : image.getHeight(this)); if (image != null) { //Draw image at its natural size of 125x125. g.drawImage(image, 0, 0, this); } //Add a border, red if picture currently has focus if (isFocusOwner()) { g.setColor(Color.RED); } else { g.setColor(Color.BLACK); } g.drawRect(0, 0, image == null ? 125 : image.getWidth(this), image == null ? 125 : image.getHeight(this)); g.dispose(); } } public class TrackFocusDemo extends JPanel { Picture pic1, pic2, pic3, pic4, pic5, pic6; JLabel info; static String mayaString = "Maya"; static String anyaString = "Anya"; static String laineString = "Laine"; static String cosmoString = "Cosmo"; static String adeleString = "Adele"; static String alexiString = "Alexi"; String[] comments = { "Oops. What is this?", "This is Maya", "This is Anya", "This is Laine", "This is Cosmo", "This is Adele", "This is Alexi" }; public TrackFocusDemo() { super(new BorderLayout()); JPanel mugshots = new JPanel(new GridLayout(2, 3)); pic1 = new Picture(createImageIcon("images/" + mayaString + ".jpg", mayaString).getImage()); pic1.setName("1"); mugshots.add(pic1); pic2 = new Picture(createImageIcon("images/" + anyaString + ".jpg", anyaString).getImage()); pic2.setName("2"); mugshots.add(pic2); pic3 = new Picture(createImageIcon( "images/" + laineString + ".jpg", laineString).getImage()); pic3.setName("3"); mugshots.add(pic3); pic4 = new Picture(createImageIcon( "images/" + cosmoString + ".jpg", cosmoString).getImage()); pic4.setName("4"); mugshots.add(pic4); pic5 = new Picture(createImageIcon( "images/" + adeleString + ".jpg", adeleString).getImage()); pic5.setName("5"); mugshots.add(pic5); pic6 = new Picture(createImageIcon( "images/" + alexiString + ".jpg", alexiString).getImage()); pic6.setName("6"); mugshots.add(pic6); info = new JLabel("Nothing selected"); setPreferredSize(new Dimension(450, 350)); add(mugshots, BorderLayout.CENTER); add(info, BorderLayout.PAGE_END); setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20)); KeyboardFocusManager focusManager = KeyboardFocusManager .getCurrentKeyboardFocusManager(); focusManager .addPropertyChangeListener(new PropertyChangeListener() { public void propertyChange(PropertyChangeEvent e) { String prop = e.getPropertyName(); if (("focusOwner".equals(prop)) && ((e.getNewValue()) instanceof Picture)) { Component comp = (Component) e.getNewValue(); String name = comp.getName(); Integer num = new Integer(name); int index = num.intValue(); if (index < 0 || index > comments.length) { index = 0; } info.setText(comments[index]); } } }); } /** Returns an ImageIcon, or null if the path was invalid. */ protected static ImageIcon createImageIcon(String path, String description) { java.net.URL imageURL = TrackFocusDemo.class.getResource(path); if (imageURL == null) { System.err.println("Resource not found: " + path); return null; } else { return new ImageIcon(imageURL, description); } } /** * 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("TrackFocusDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JComponent newContentPane = new TrackFocusDemo(); 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) { /* Use an appropriate Look and Feel */ try { //UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); //UIManager.setLookAndFeel("com.sun.java.swing.plaf.gtk.GTKLookAndFeel"); UIManager .setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel"); } catch (UnsupportedLookAndFeelException ex) { ex.printStackTrace(); } catch (IllegalAccessException ex) { ex.printStackTrace(); } catch (InstantiationException ex) { ex.printStackTrace(); } catch (ClassNotFoundException ex) { ex.printStackTrace(); } /* Turn off metal's use of bold fonts */ UIManager.put("swing.boldMetal", Boolean.FALSE); //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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