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Animation Revisited

Animation Revisited. The Timer class is in Swing. Animation can be done without using the Timer class. Using threads. Example: Rebound2.java. import java.applet.Applet; import java.awt.*; public class Rebound2 extends Applet implements Runnable {

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Animation Revisited

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  1. Animation Revisited • The Timer class is in Swing. • Animation can be done without using the Timer class. • Using threads

  2. Example: Rebound2.java import java.applet.Applet; import java.awt.*; public class Rebound2 extends Applet implements Runnable { private final int APPLET_WIDTH = 200; private final int APPLET_HEIGHT = 100; private final int IMAGE_SIZE = 35; private final int DELAY = 20; private Thread thread; private int delay = 100; private Image image; private int x, y, moveX, moveY;

  3. Example: Rebound2.java public void init() { x = 0; y = 40; moveX = moveY = 3; image = getImage (getCodeBase(), "happyFace.gif"); setBackground (Color.black); } public void paint (Graphics page) { page.drawImage (image, x, y, this); }

  4. Example: Rebound2.java public void run() { while (Thread.currentThread() == thread) { x += moveX; y += moveY; if (x <= 0 || x >= APPLET_WIDTH-IMAGE_SIZE) moveX = moveX * -1; if (y <= 0 || y >= APPLET_HEIGHT-IMAGE_SIZE) moveY = moveY * -1; repaint(); try { Thread.currentThread().sleep(delay); } catch (InterruptedException e){} } }

  5. Example: Rebound2.java public void start() { thread = new Thread(this); thread.start(); } public void stop() { thread = null; } }

  6. Graphical User Interface (GUI) • Abstract Windows Toolkit (AWT): java.awt • GUI elements: • Primitive • Button, Label, Checkbox, Scrollbar, etc. • Container • Panel, Frame, Dialog, etc. • Layout managers: • FlowLayout, BorderLayout, etc. • Supporting classes

  7. The Component Hierarchy

  8. The Swing Components

  9. Layout Managers • The layout of the elements in a container is handled by the layout managerassociated with the container. • Relative positions of the elements are specified, not their absolute coordinates. • The positions and sizes of the element will be automatically adjusted when the window is resized • .

  10. The Layout Manager Hierarchy

  11. Buttons and Flow Layout width=400 height=50 width=100 height=120

  12. Buttons and Flow Layout Layout elements in horizontal rows. import java.awt.*; import java.applet.Applet; public class Flow extends Applet { public Flow () { setLayout(new FlowLayout()); add(new Button("Java")); add(new Button("C++")); add(new Button("Perl")); add(new Button("Ada")); add(new Button("Smalltalk")); add(new Button("Eiffel")); } }

  13. Border Layout

  14. Border Layout import java.awt.*; import java.applet.Applet; public class Border extends Applet { public Border () { setLayout(new BorderLayout()); add(new Button("North"), BorderLayout.NORTH); add(new Button("South"), BorderLayout.SOUTH); add(new Button("East"), BorderLayout.EAST); add(new Button("West"), BorderLayout.WEST); add(new Button("Center"), BorderLayout.CENTER); } }

  15. Grid Layout row=0 col=1 row=3 col=2 row=1 col=0

  16. Grid Layout import java.awt.*; import java.applet.Applet; public class Grid extends Applet { public void init () { int row = 0, col = 0; String att = getParameter("row"); if (att != null) row = Integer.parseInt(att); att = getParameter("col"); if (att != null) col = Integer.parseInt(att); if (row == 0 && col == 0) { row = 3; col = 2; }

  17. Grid Layout setLayout(new GridLayout(row, col)); add(new Button("Java")); add(new Button("C++")); add(new Button("Perl")); add(new Button("Ada")); add(new Button("Smalltalk")); add(new Button("Eiffel")); } }

  18. Nested Panels

  19. Nested Panels public class NestedPanels extends Applet { protected Label messageBar; protected Choice choice; public NestedPanels () { // set up the center panel Panel center = new Panel(); center.setLayout(new BorderLayout()); center.add(new Button("south"), BorderLayout.SOUTH); center.add(new Button("north"), BorderLayout.NORTH); center.add(new Button("east"), BorderLayout.EAST); center.add(new Button("west"), BorderLayout.WEST); center.add(new Button("center"), BorderLayout.CENTER);

  20. Nested Panels // set up the south panel Panel south = new Panel(); south.setLayout(new FlowLayout()); south.add(new Button("Help")); choice = new Choice(); choice.addItem("one"); choice.addItem("two"); choice.addItem("three"); choice.addItem("four"); choice.addItem("five"); south.add(choice); messageBar = new Label("This is a message bar."); south.add(messageBar);

  21. Nested Panels // set up the outer panel setLayout(new BorderLayout()); add(new Button("North"), BorderLayout.NORTH); add(new Button("East"), BorderLayout.EAST); add(new Button("West"), BorderLayout.WEST); add(south, BorderLayout.SOUTH); add(center, BorderLayout.CENTER); } }

  22. Swing Frame Demo

  23. Example: FrameDemo.java import java.awt.*; import javax.swing.*; public class FrameDemo extends JFrame { public FrameDemo() { super("Swing Frame Demo"); setDefaultCloseOperation(EXIT_ON_CLOSE); setSize(400, 200); } public static void main(String[] args) { FrameDemo frame = new FrameDemo(); frame.getContentPane().setLayout(new BorderLayout()); frame.getContentPane().add(new NestedPanels2(), BorderLayout.CENTER); frame.show(); } }

  24. Example: NestedPanels2.java import java.awt.*; import javax.swing.*; import java.awt.event.*; public class NestedPanels2 extends JPanel { JLabel message_bar; JComboBox choice; JButton southButton1 = new JButton("south"); JButton northButton1 = new JButton("north"); JButton eastButton1 = new JButton("east"); JButton westButton1 = new JButton("west"); JButton centerButton1 = new JButton("center"); JButton northButton2 = new JButton("North"); JButton eastButton2 = new JButton("East"); JButton westButton2 = new JButton("West"); JButton helpButton = new JButton("Help");

  25. Example: NestedPanels2.java public NestedPanels2 () { JPanel center = new JPanel(); center.setLayout(new BorderLayout()); center.add(southButton1, BorderLayout.SOUTH); center.add(northButton1, BorderLayout.NORTH); center.add(eastButton1, BorderLayout.EAST); center.add(westButton1, BorderLayout.WEST); center.add(centerButton1, BorderLayout.CENTER); JPanel south = new JPanel(); south.setLayout(new FlowLayout()); south.add(helpButton);

  26. Example: NestedPanels2.java choice = new JComboBox(); choice.addItem("one"); choice.addItem("two"); choice.addItem("three"); choice.addItem("four"); choice.addItem("five"); south.add(choice); message_bar = new JLabel("This is a message bar."); south.add(message_bar); setLayout(new BorderLayout()); add(northButton2, BorderLayout.NORTH); add(eastButton2, BorderLayout.EAST); add(westButton2, BorderLayout.WEST); add(south, BorderLayout.SOUTH); add(center, BorderLayout.CENTER);

  27. Example: NestedPanels2.java ChoiceEventHandler chandler = new ChoiceEventHandler(); choice.addItemListener(chandler); ButtonEventHandler bhandler = new ButtonEventHandler(); southButton1.addActionListener(bhandler); northButton1.addActionListener(bhandler); eastButton1.addActionListener(bhandler); westButton1.addActionListener(bhandler); centerButton1.addActionListener(bhandler); DialogButtonEventHandler dhandler = new DialogButtonEventHandler(); northButton2.addActionListener(dhandler); eastButton2.addActionListener(dhandler); westButton2.addActionListener(dhandler); helpButton.addActionListener(bhandler); }

  28. Example: NestedPanels2.java class ChoiceEventHandler implements ItemListener { public void itemStateChanged(ItemEvent event) { JComboBox choice = (JComboBox) event.getSource(); if (choice != null) message_bar.setText("Choice selected: " + event.getItem()); } } class ButtonEventHandler implements ActionListener { public void actionPerformed(ActionEvent event) { JButton source = (JButton) event.getSource(); if (source != null) message_bar.setText("Button pushed: " + source.getText()); } }

  29. Example: NestedPanels2.java class DialogButtonEventHandler implements ActionListener { public void actionPerformed(ActionEvent event) { JButton source = (JButton) event.getSource(); if (source != null) JOptionPane.showMessageDialog(null, "Button pushed: " + source.getText()); } } }

  30. Using Packages • A package contains classes and other packages. Packages form a hierarchy. • Package names: • pkg1, pkg1.pag2, pkg1.pkg2.pkg3, ... • Convention: use the reverse of the internet domain of your company/organization • e.g., edu.depaul.csc224

  31. Package Declaration • packagename; • Example: package cs1; public class Keyboard {   // ... } package edu.depaul.csc224; public class MyProject {   // ...   public static void main(String[] args) {     // ...   } }

  32. Package Directory default package . (current working directory) cs1  .\cs1\ edu.depaul.csc224 .\edu\depaul\csc224\ Package and Directory Structure • The directory structure must match the package structure

  33. Using Packages: Examples • Example: cs1.Keyboard • Source code: .\cs1\Keyboard.java • Compile: in the current working directory javac cs1\Keyboard.java • Byte code file: .\Keyboard.class • Example: edu.depaul.csc224.MyProject • Source code: .\edu\depaul\csc224\MyProject.java • Compile: in the current working directory javac edu\depaul\csc224\*.java • Byte code file: .\edu\depaul\csc224\*.class • Run: in the current working directory java edu.depaul.csc224.MyProject

  34. Jar Files and Jar Tool • To pack files and directories into a single file for the purpose of distribution, deployment, etc. • Pack: jar cvf filename.jar files-or-dirs • Unpack: jar xvf filename.jar • Examples: • pack all the classes in the default package jar cvf hw.jar *.class • pack all the classes in the cs1 package jar cvf kb.jar cs1\Keyboard.class • pack all the classes in the edu.depaul.csc224 package jar cvf csc224.jar edu\depaul\csc224\*.class • pack all the classes in the edu package jar cvf edu.jar edu

  35. Class Path • where the Java compiler and virtual machine look for the source or byte code files. • consists of a list directories and/or jar files, separated by • ;  (on Windows) • :  (on Unix/Linux) • default: all the J2SDK standard classes and the current directory • classpath switch of javac and java • CLASSPATH environment variable • extension mechanism: place JAR file in C:\jdk1.3\jre\lib\ext\

  36. Class Path Examples • Example: Using cs1.Keyboard class in MyProg.java in the default package • MyProg.java and cs1 are in the same directory C:\   +-- csc224         |-- MyProg.java         +-- cs1              +-- Keyboard.class javac MyProg.java java MyProg

  37. Class Path Examples • MyProg.java and cs1 are in different directory C:\   |-- csc224   |     +-- MyProg.java   |   +-- book         +-- cs1              +-- Keyboard.class In csc224 • javac -classpath C:\book MyProg.java • java -classpath C:\book MyProg Or • set CLASSPATH=C:\book • javac MyProg.java • java MyProg

  38. Class Path Examples • Pack cs.Keyboard in a JAR file. C:\   |-- csc224   |     +-- MyProg.java   |   +-- book         +-- kb.jar

  39. Class Path Examples In C:\csc224 • javac -classpath C:\book\kb.jar MyProg.java • java -classpath C:\book\kb.jar MyProg Or • set CLASSPATH=C:\book\kb.jar • javac MyProg.java • java MyProg Or • copy kb.jar to C:\jdk1.3\jre\lib\ext\ • javac MyProg.java • java MyProg

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