Java tutorial
/* * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of Oracle or the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package components; import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.event.*; /* * SliderDemo.java requires all the files in the images/doggy * directory. */ public class SliderDemo extends JPanel implements ActionListener, WindowListener, ChangeListener { //Set up animation parameters. static final int FPS_MIN = 0; static final int FPS_MAX = 30; static final int FPS_INIT = 15; //initial frames per second int frameNumber = 0; int NUM_FRAMES = 14; ImageIcon[] images = new ImageIcon[NUM_FRAMES]; int delay; Timer timer; boolean frozen = false; //This label uses ImageIcon to show the doggy pictures. JLabel picture; public SliderDemo() { setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS)); delay = 1000 / FPS_INIT; //Create the label. JLabel sliderLabel = new JLabel("Frames Per Second", JLabel.CENTER); sliderLabel.setAlignmentX(Component.CENTER_ALIGNMENT); //Create the slider. JSlider framesPerSecond = new JSlider(JSlider.HORIZONTAL, FPS_MIN, FPS_MAX, FPS_INIT); framesPerSecond.addChangeListener(this); //Turn on labels at major tick marks. framesPerSecond.setMajorTickSpacing(10); framesPerSecond.setMinorTickSpacing(1); framesPerSecond.setPaintTicks(true); framesPerSecond.setPaintLabels(true); framesPerSecond.setBorder(BorderFactory.createEmptyBorder(0, 0, 10, 0)); Font font = new Font("Serif", Font.ITALIC, 15); framesPerSecond.setFont(font); //Create the label that displays the animation. picture = new JLabel(); picture.setHorizontalAlignment(JLabel.CENTER); picture.setAlignmentX(Component.CENTER_ALIGNMENT); picture.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createLoweredBevelBorder(), BorderFactory.createEmptyBorder(10, 10, 10, 10))); updatePicture(0); //display first frame //Put everything together. add(sliderLabel); add(framesPerSecond); add(picture); setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10)); //Set up a timer that calls this object's action handler. timer = new Timer(delay, this); timer.setInitialDelay(delay * 7); //We pause animation twice per cycle //by restarting the timer timer.setCoalesce(true); } /** Add a listener for window events. */ void addWindowListener(Window w) { w.addWindowListener(this); } //React to window events. public void windowIconified(WindowEvent e) { stopAnimation(); } public void windowDeiconified(WindowEvent e) { startAnimation(); } public void windowOpened(WindowEvent e) { } public void windowClosing(WindowEvent e) { } public void windowClosed(WindowEvent e) { } public void windowActivated(WindowEvent e) { } public void windowDeactivated(WindowEvent e) { } /** Listen to the slider. */ public void stateChanged(ChangeEvent e) { JSlider source = (JSlider) e.getSource(); if (!source.getValueIsAdjusting()) { int fps = (int) source.getValue(); if (fps == 0) { if (!frozen) stopAnimation(); } else { delay = 1000 / fps; timer.setDelay(delay); timer.setInitialDelay(delay * 10); if (frozen) startAnimation(); } } } public void startAnimation() { //Start (or restart) animating! timer.start(); frozen = false; } public void stopAnimation() { //Stop the animating thread. timer.stop(); frozen = true; } //Called when the Timer fires. public void actionPerformed(ActionEvent e) { //Advance the animation frame. if (frameNumber == (NUM_FRAMES - 1)) { frameNumber = 0; } else { frameNumber++; } updatePicture(frameNumber); //display the next picture if (frameNumber == (NUM_FRAMES - 1) || frameNumber == (NUM_FRAMES / 2 - 1)) { timer.restart(); } } /** Update the label to display the image for the current frame. */ protected void updatePicture(int frameNum) { //Get the image if we haven't already. if (images[frameNumber] == null) { images[frameNumber] = createImageIcon("images/doggy/T" + frameNumber + ".gif"); } //Set the image. if (images[frameNumber] != null) { picture.setIcon(images[frameNumber]); } else { //image not found picture.setText("image #" + frameNumber + " not found"); } } /** Returns an ImageIcon, or null if the path was invalid. */ protected static ImageIcon createImageIcon(String path) { java.net.URL imgURL = SliderDemo.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("SliderDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); SliderDemo animator = new SliderDemo(); //Add content to the window. frame.add(animator, BorderLayout.CENTER); //Display the window. frame.pack(); frame.setVisible(true); animator.startAnimation(); } public static void main(String[] args) { /* 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(); } }); } }