March 16, 2000

Details

Title	Applets
Time Allotment	3 hrs

Reading / References

Java Programming Introductory - Chapter 6, Section A & B
ftp://ftp.talltech.com/student/shared/java/Java-CH6SecAandB.ppt

Additional Resources

http://www.javapowered.com/werks.html (JavaPowered)
http://metalab.unc.edu/javafaq/javatutorial.html (Tutorial)
http://rummelplatz.uni-mannheim.de/~skoch/javatut/kneedeep.htm (Knee Deep in Java)
http://www.stars.com/Authoring/Java/Intro/ (Your first applet)
http://users.neca.com/vmis/java.html (Learning Java)

Objectives

Write an HTML Doc to host an applet
Write a simple applet using a label
Basic methods used in an applet
Change label's font

Exercises (For Hand In)

Assignment #: JA03
Assignment: Applets
Due: Mar 21/2000
Marks: 20 marks

Exercise 2 (pg 290) and exercise 3 (pg 310).

Demo

HTML Code <APPLET CODE="" WIDTH=# HEIGHT=#> (pg 270 - 271)
Creating a simple applet using a label (pg. 273)

Import - applet base classes

Import - Abstract Windows Toolkit (AWT)

Methods that are basic part of every applet (pg 272)

Order that the methods are called (pg 292)

Change a label's font - using the font object (pg 276)
Text fields

Constructors (pg 277)

setText (pg 277)

getText (pg 277)

requestFocus (pg 277)

setEditable (pg 278)

Button

Constructors (pg 278)

getLabel (pg 278)

setLabel (pg 278)

Event driven programming (pg 279-281)
addActionListener (pg 280)
actionPerformed (pg 281)
Using a label for output (pg 283)
Screen redraw (pg 284)

FOR DEMO

Greet.htm

Greet.java

import java.applet.*;
import java.awt.*;

public class Greet extends Applet
{
      Label greeting = new Label("Hello World!");

      public void init()
      {
            add(greeting);
      }
}

Greet.java - with font

import java.applet.*;
import java.awt.*;

public class Greet extends Applet
{
      Label greeting = new Label("Hello World!");
      Font bigFont = new Font("Arial", Font.ITALIC,24);

      public void init()
      {
            greeting.setFont(bigFont);
            add(greeting);
      }
}

Greet.java - with button & text box

import java.applet.*;
import java.awt.*;

public class Greet extends Applet
{
       Label greeting = new Label("Hello World!");
       Font bigFont = new Font("Arial", Font.ITALIC,24);

       Button pressMe = new Button("Press Me");
       TextField answer = new TextField("",10);

       public void init()
       {
              greeting.setFont(bigFont);
              add(greeting);
              add(answer);
              add(pressMe);
              answer.requestFocus();
       }
}

Greet.java - with a very basic event handler

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class Greet extends Applet implements ActionListener
{
       Label greeting = new Label("Hello World!");
       Font bigFont = new Font("Arial", Font.ITALIC,24);

       Button pressMe = new Button("Press Me");
       TextField answer = new TextField("",10);

       public void init()
       {
              greeting.setFont(bigFont);
              add(greeting);
              add(answer);
              add(pressMe);
              pressMe.addActionListener(this);

              answer.requestFocus();
              answer.addActionListener(this);
       }

       public void actionPerformed(ActionEvent thisEvent)
       {
              String name = answer.getText();

              Label personalGreeting = new Label("");
              personalGreeting.setText("Hi " + name);
              add(personalGreeting);

              invalidate();
              validate();
       }
}