Computer Science 120
Introduction to Programming
Spring 2011, 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); } }