Lecture Summary 8

Animation Revisited

• The Timer class is in Swing.
• Animation can be done without using the Timer class.
• Using threads
• Another version of rebound: Rebound2.java [Rebound2.html]

GUI Development

• 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:
• Event handling
• java.awt.event package
• Graphics
• Color, Font, Graphics, etc.
• Geometry
• Point, Rectangle, Dimension, etc.
• Imaging
• Image class and java.awt.image package
• Swing: javax.swing.*
• Component hierarchy
• Layout manager
• The layout of the elements in a container is handled by the layout manager associated 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
• FlowLayout
• Example: Flow.java
• BorderLayout
• Example: Border.java
• GridLayout
• Example: Grid.java
• Nesting components
• Example: NestedPanels.java
• Swing Frame Demo


• Source code: FrameDemo.java, NestedPanels2.java

Selected Advanced Topics

• 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
• Package declaration
• package name;
• Example:


package cs1;

public class Keyboard {
  // ...
}
 

package edu.depaul.csc224;

public class MyProject {
  // ...
  public static void main(String[] args) {
    // ...
  }
}
 

• The directory structure must match the package structure
 

Package	Directory
default package	. (current working directory)
cs1	.\cs1\
edu.depaul.csc224	.\edu\depaul\csc224\

• 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
• 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
• 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\
• Example: Using cs1.Keyboard class in MyProg.java in the default package
1. MyProg.java and cs1 are in the same directory
C:\
  +-- csc224
        |-- MyProg.java
        +-- cs1
             +-- Keyboard.class
• javac MyProg.java
• java MyProg
2. 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
3. Pack cs.Keyboard in a JAR file.
C:\
  |-- csc224
  |     +-- MyProg.java
  |
  +-- book
        +-- kb.jar
• 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
• For more info: J2SDK documentation, tools documentation