Download public void paint(Graphics g)

Life Cycle of an Applet,
along with response to mouse
events and other simple
features.
(ps:only two possible examples for life circle of
an Applet)
Demonstrating the Life Cycle
of an Applet: Simple0
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class Simple0 extends Applet {
StringBuffer buffer;
public void init() {
buffer = new StringBuffer();
addItem("initializing... "); }
public void start() {
addItem ("starting... ");
}
public void stop() {
addItem("stopping... "); }
public void destroy() {
addItem("preparing for unloading...");
void addItem(String newWord) {
System.out.println(newWord);
buffer.append(newWord);
repaint() }
}
public void paint(Graphics g)
{
g.setColor(new Color(200, 1, 200));
g.drawRect(0, 0, getSize().width - 1, getSize().height - 1);
//Draw the current string inside the rectangle
g.setColor(Color.blue);
g.drawString(buffer.toString(), 5, 15);
}
}
Demonstrates Life Cycle of
an Applet + Mouse Events:
Simple1
import java.awt.*;
import java.awt.event.*;
public class Simple1 extends Applet {
StringBuffer buffer;
public void init() {
addMouseListener(new Bob());
buffer = new StringBuffer();
addItem("initializing... ");
}
public void start() {
addItem("starting... ") ; }
public void stop() {
addItem("stopping... "); }
public void destroy() {
addItem("preparing for unloading...");
void addItem(String newWord) {
System.out.println(newWord);
buffer.append(newWord);
repaint(); }
}
public void paint(Graphics g) {
g.setColor(new Color(200, 1, 200));
g.drawRect(0, 0, getSize().width - 1, getSize().height - 1);
g.setColor(Color.blue);
g.drawString(buffer.toString(), 5, 15);
}
private class Bob implements MouseListener {
public void mouseEntered(MouseEvent event) { }
public void mouseExited(MouseEvent event) { }
public void mousePressed(MouseEvent event) { }
public void mouseReleased(MouseEvent event) { }
public void mouseClicked(MouseEvent event) {
addItem("click!... ");
}
}
}
Three simple applet examples
A method which returns the volume of a cube
import java.awt.*;
import java.applet.Applet;
public class volume extends Applet {
public void paint(Graphics g) {
float answer = areaCube(7,4,2);
g.drawString("Area of cube is " +answer, 100, 100); }
private float areaCube(float height, float width, float depth) {
float area = height*width*depth; return area;
}
}
Draws a circle based on a given center position and
radius
import java.awt.*;
import java.applet.Applet;
public class DrawCircle extends Applet {
public void paint(Graphics g) {
circle(g, 150, 135, 120);
//call circle function
}
//end function
//function draws a circle
private void circle(Graphics g, int xCentre, int yCentre, int radius)
{
int horiz = xCentre - radius; //finds starting horizon. position
int vert = yCentre - radius; //finds starting vertical position
int diameter = radius * 2; //finds diameter
g.drawOval(horiz, vert, diameter, diameter);
}
//end function
}
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
Drawing Houses
public class drawHouse extends Applet {
public void paint(Graphics g) {
int wall=50;
//allows you to change the size of the house and have them still be 10 pixels apart
drawStreet(g,wall,20,100);
drawStreet(g,wall,20+wall+10,100);
drawStreet(g,wall,20+wall*2+20,100);
drawStreet(g,wall,20+wall*3+30,100);
}
private void drawStreet(Graphics g, int wallHeight, int bottomX, int bottomY)
{
g.drawRect(bottomX, bottomY, wallHeight, wallHeight);
g.drawLine(bottomX+wallHeight, bottomY, bottomX+wallHeight/2,
bottomY-wallHeight/2);
g.drawLine(bottomX+wallHeight/2, bottomY-wallHeight/2, bottomX,
bottomY);
} }
A more complex applet example
Converts temperature Celsius to Fahrenheit within 100
degrees with a scrollbar
import java.awt.*;
import java.applet.Applet;
import java.awt.event.*;
public class Temp extends Applet implements AdjustmentListener {
private Scrollbar ConvertCelc;
//scrollbar named arbitrarily as ConvertCelc
private float ConvertCelcValue = 0;
//ConvertCelcValue is a float because of the transformation formula
public void init() {
Label title1;
title1 = new Label("degrees C . . . to . . . degrees F");
//label scrollbar
add(title1);
ConvertCelc= new Scrollbar (Scrollbar.HORIZONTAL, 0, 1, 0, 101);
add(ConvertCelc);
ConvertCelc.addAdjustmentListener (this);
} //end init
public void paint(Graphics g) {
float cCF;
cCF = ((ConvertCelcValue*1.8f) +32);
//calculate the conversion
g.drawString("Celcius = “ +ConvertCelctValue + “ Fahrenheit =“ +cCF
, 0,
75);
//draw text
}
//end paint
public void adjustmentValueChanged(AdjustmentEvent e) {
ConvertCelcValue = (float) ConvertCelc.getValue();
//slider gets value of conversion and placement of bar
repaint();
}
//end adujustmentValueChanged
} //end all