Computer Science 120
Introduction to Programming
Spring 2012, Siena College
ColorEvents Demo
A working demo of ColorEvents will appear below. Click inside the applet to interact with it.
ColorEvents BlueJ Project
Click here to download a BlueJ project for ColorEvents.
ColorEvents Source Code
The Java source code for ColorEvents is below. Click on a file name to download it.
import objectdraw.*;
import java.awt.*;
/*
* An example demonstrating the use of more event handling methods
* and setting the color of a graphical object.
*
* Jim Teresco, CSIS 120, Siena College, Spring 2011
*
* $Id: ColorEvents.java 1487 2011-01-13 21:20:10Z terescoj $
*/
public class ColorEvents extends WindowController {
/* Define some names (instance variables) to remember
the objects we're drawing so we can change their colors
later
*/
private FilledOval oval;
private FramedRect rect;
private Line line;
/* Draw a few objects on the canvas to play with later */
public void begin() {
/* assignment statements: note how we construct the object on
the right hand side of the assignment and put the name
where we wish to remember the object on the left. */
oval = new FilledOval(50, 50, 100, 200, canvas);
rect = new FramedRect(200, 10, 50, 100, canvas);
line = new Line(20, 300, 300, 20, canvas);
}
/* This method will execute when someone clicks the mouse in the window.
*/
public void onMouseClick(Location point) {
oval.setColor(Color.red);
}
/* This method will execute when the mouse is moved in the window.
*/
public void onMouseMove(Location point) {
rect.setColor(Color.blue);
}
/* This method will execute when someone drags the mouse in the window.
*/
public void onMouseDrag(Location point) {
line.setColor(Color.green);
}
/* This method will execute when the mouse enters the window.
*/
public void onMouseEnter(Location point) {
oval.setColor(Color.black);
rect.setColor(Color.black);
line.setColor(Color.black);
}
/* This method will execute when the mouse exits the window.
*/
public void onMouseExit(Location point) {
oval.setColor(Color.white);
rect.setColor(Color.white);
line.setColor(Color.white);
}
}