APPLET LIFE CYCLE METHODS - JAVA APPLETS

JAVA APPLETS

• Introduction Applest

▫Java programs that can be embedded in Hypertext Markup Language (HTML) documents.

▫The browser that executes an applet is generically known as the applet container

import java.awt.*;

import java.applet.*;

/*

<applet code=applet1 width=200 height=400>

</applet>

*/

public class applet1 extends Applet

{

 public void paint(Graphics g)

 {

  g.drawString("Hello Welcome to java", 40,100);

  }

 }

APPLET LIFE CYCLE

•public void init() 

 This method is used to initialize

 variables of applet. Called only once.

•public void start()

▫ Called immediately after init and can be called

 repeatedly.

▫ Used to start animation threads

•public void paint(Graphics g)

▫This method is called automatically after 

start() method when applet begins its 

execution.

•public void stop()

▫ Called when the browser leaves the page

▫ Used to stop animation threads

•public void destroy()

▫Called automatically by applet when it ends up

 its activity. It releases the resources used by 

applet.

/*

<applet code=app width=500 height=500>

</applet>

*/

public class app extends Applet

{

  String str; 

  public void init()

  {

    str +=" init";

}

public void start()

{

 str +=" start";

 }

public void stop()

{

 str +=" stop";

 } 

 public void paint(Graphics g)

 {

   g.drawString(str,10,20);  

   }

 }

GRAPHICS IN APPLETS

Drawing Lines

public void drawLine(int x1,int y1,int x2,int y2);

Drawing Rectangles

public void drawRect(int x,int y , int width , int height);

public void drawRoundRect(int x,int y , int width , int height,int arcw ,int arch);

public void draw3DRect(int x, int y , int width , int height , boolean raised);

public void fillRect(int x,int y , int width , int height);

public void fillRoundRect(int x,int y , int width , int height,int arcw ,int arch);

public void fill3DRect(int x, int y , int width , int height , boolean raised);

public void clearRect(int x, int y, int width , int height);

 {clears the rectangle and fills it with background color }

Drawing Ovals & Circles

public void drawOval(int x,int y , int width , int height);

public void fillOval(int x,int y , int width , int height);

Drawing Ovals & Circles

public void drawArc(int x ,int y , int width , int height ,int startangle , int arcangle);

public void fillArc(int x , int y , int width , int height ,int startangle , int arcangle);

Drawing Polygons

public void drawPolygon(int xpoints[ ] ,int ypoints[ ] , int nPoints);

public void fillPolygon(int xpoints[ ] ,int ypoints[ ] , int nPoints);

Public void drawPolygon(Polygon P); {Draw outline}

 Drawing PolyLines

To draw open-Ended polylines

public void drawPolyline(int xpoints[ ] ,int ypoints[ ] , int nPoints);

Colors In Graphics

•Belongs to java.awt.color;

• Some common color constants…..

•Color.black

•Color.blue

•Color.cyan

•Color.darkGray

•Color.gray

•Color.green

•Color.lightGray

•Color.magenta

•Color.orange

•Color.pink

•Color.red

•Color.white

•Color.yellow

•We can also generate colors by combination of

RGB [red , green & blue].

•We can also generate colors by combination of

HSB [hue , saturation & brightness].