Developing User Interfaces DUI

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Developing User Interfaces(DUI)

• Chris North
• cs3724 HCI

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GUI Development Goals

• Learn general GUI programming concepts
• GUI components
• Layout
• Event-based programming
• Graphics
• Animation
• Learn Java
• Swing
• Layout managers
• Listerners
• 2D graphics
• Threads
• Then can learn other languages quickly
• VB, C, Xwin, Java 49

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Intro to Java
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Why Java?
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Java materials

• Java 2 sdk 1.2 or better
• http//java.sun.com/j2se/
• Documentation
• http//java.sun.com/docs/
• Tutorials, reference, API
• Borland JBuilder 6
• http//www.borland.com/jbuilder/personal/
• Free! Cross between VB and VC

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Java differences

• Basic statements identical to C
• Object-oriented only!
• No .h files
• main() is inside a class
• No global variables
• No pointers (object references only)
• No delete automatic garbage collection
• Single inheritance only, interfaces
• Applet/application
• GUI AWT, Swing
• Packaging
• Error Handling, exceptions (try, catch)
• E.g. Array bounds checking
• Security
• Components beans

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Java compiling

• Code
• hello.java (text file)
• Compile
• javac hello.java
• Creates hello.class (byte code)
• Run
• java hello
• Java virtual machine, interpets/compiles
  (machine code)
• Packaging jar
• Or use JBuilder, like VC

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Java Applications

• Run from command line
• hello.java
• class hello
• public static void main(String args)
• System.out.println(Hello World!)
• javac hello.java
• java hello
• Hello World!

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Typically create objects

• hello.java
• class hello
• public static void main(String args)
• // Create and use objects
• hello h new hello()
• public hello() // Constructor

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Many Classes

• Compile each separately
• Can be main( ) in any/all classes
• hello.java
• class hello
• goodbye g
• public static void main(String args)
• goodbye.java
• class goodbye
• public static void main(String args)

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Hmmm

• dir
• hello.class
• goodbye.class
• blah.class
• foo.class
• bar.class
• areyouawakein.class
• Java ???
• RunMe.bat
• java hello

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JBuilder
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Java Applets

• Run in a web browser
• hello.java
• import javax.swing.
• class hello extends JApplet
• public void init()
• getContentPane().add(
• new JLabel(Hello World!) )
• javac hello.java
• appletviewer hello

Hello World!
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Java Applets in HTML

• hello.html
• height100 width200
• Need java.
• Put hello.html and hello.class on website
• Java plug-in

hello.html
Hello World!
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Applet Methods

• init( ) - initialization
• start( ) - resume processing (e.g. animations)
• stop( ) - pause
• destroy( ) - cleanup
• paint( ) - redraw stuff (expose event)

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Applet Security

• No read/write on client machine
• Cant execute programs on client machine
• Communicate only with server
• Java applet window Warning
• Certificates

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Upcoming Java Topics

• GUIs Swing, AWT, MVC
• Event handling, listeners
• Graphics
• Animation, threads
• Components, JavaBeans
• Databases, JDBC