Java On The Web

Session 15

Memory Upload

• JAVA Applets• Colors• Fonts• Drawing Methods• Posting your Applet

Applets

• An applet is a program that runs embedded in HTML code

• They must be viewed either in Web Browser Appletviewer

GUI Elements

• Applets can display GUI elements Graphical User Interface

• Colors• Fonts• Text-Fields, Button , Labels, etc.Butt

on

Skeletonimport java.awt.*;import java.applet;public class MyApplet extends Applet { public void init( ){ } public void paint(Graphics g){ //instructions go here }}

Skeletonimport java.awt.*;import java.applet;public class MyApplet extends Applet { public void init( ){ } public void paint(Graphics g){ //instructions go here }}

Colors

• Colors are made out of 3 values• Each value goes from 0 to 255

REDRED GREENGREEN BLUEBLUE

ColorsBlack Color.black 0,0,0Blue Color.blue 0,0,255Cyan Color.cyan 0,255,255Gray Color.gray 128,128,128Green Color.green 0,255,0Magenta Color.magenta 255,0,255Orange Color.orange 255,200,0Pink Color.pink 255,175,175Red Color.red 255,0,0White Color.white 255,255,255Yellow Color.yellow 255,255,0

Colorsimport java.awt.*;import java.applet;public class MyApplet extends Applet { public void init( ){ } public void paint(Graphics g){ //Your Own

Color MyColor = new Color(50, 200,150);g.setColor(MyColor);

}}

.setColor(Color)

g.setColor(Color.yellow);

g.setColor(Color.red);

g.setColor(MyColor);

Fonts• The constructor

Font f = new Font(Type, Style, Size);import java.awt.*;import java.applet;public class MyApplet extends Applet { public void init( ){a } public void paint(Graphics g){

Font f=new Font(“Tahoma”,Font.PLAIN, 10);

g.setFont(f); }}

Methodsvoid drawLine(int x1, int y1, int x1, int y2)void drawRect(int x, int y, int w, int h)void fillRect((int x, int y, int w, int h)void drawOval(int x, int y, int w, int h)void fillOval(int x, int y, int w, int h)void drawString(String, int x, int y)void drawArc(int x, int y, int w, int h, int start angle, int arcAngle)void fillArc(int x, int y, int w, int h, int start angle, int arcAngle)

The coordinates0,0

xx

yy

0,0

drawLine

g.drawLine(10,10,18,24);

10

10

24

18

0,0

drawRect

810

10

10

g.setColor(Color.green); g.drawRect(10,10,8,10);

0,0

810

10

10

fillRect

g.setColor(Color.green); g.fillRect(10,10,8,10);

0,0

810

10

10

drawOval

g.setColor(Color.red);g.drawOval(10,10,8,10);

0,0

810

10

10

fillOval

g.setColor(Color.red);g.fillOval(10,10,8,10);

0,0

810

10

10

drawArc

g.setColor(Color.blue);g.drawArc(10,10,8,10,0,45);

0,0

810

10

10

fillArc

g.setColor(Color.blue);g.fillArc(10,10,8,10,0,45);

0,0

drawString

g.setColor(Color.Magenta);g.setFont(“Arial”,Font.PLAIN, 30);g.drawString(“Blanca”,10,10);

10

10

Blanca

Posting Your Applet

• Write your  JAVA code• Compile your code• Make it available

The Applet Tag<applet

CODE="YourClass.class"WIDTH=www HEIGHT=hhhIGNORE=""></applet>

•Substitute www and hhh for your own width and height.

•Substitute YourClass.class with the name of your own class.

•The Applet tag should be regarded as any other html tag inside your HTML page.

Time to Try it Out

Appletson the

Web

• Drawing Applet Skeleton• Drawing Methods• Colors• Fonts• Posting Applets in the Web• E-mail any questions to

blanca@hawaii.edu

Memory Defragmenter

Task Manager

• Post the sample applet from webct on the web, in your website.

• Read your e-mail• Visit WebCT, webct.hawaii.edu

Task Manager

• Post the sample applet from webct on the web, in your website.

• Read your e-mail• Visit WebCT, webct.hawaii.edu