1. WJEC GCSE Computer Science
Unit 2
Greenfoot

2. Learning Intentions and Outcomes
Use the Greenfoot programming environment to design, write, and test Java programs.
Skills Checklist
Adding new and existing Actors to the World
Editing Actors to add methods (making them move!)
Using the random number generation function
Removing objects from the world (isTouching)
Playing Sounds
Adding a Counter and Score System

3. Opening an Existing Scenario

4. Adding to the World
Adding Actors addObject(new actorname(), X, Y); e.g. addObject(new WaterDrop(), 1,1); Adding Counters Counter Score = new Counter(); addObject(Score, 0,0);

5. Moving Actors: Using Keys
Check if the button is down:
if(Greenfoot.isKeyDown(“button”))
Add curly braces { }
Set Rotation:
Right = 0
Down = 90
Left = 180
Up = 270
setRotation(X);
Move 1
move(1);

6. Moving Actors Randomly
Turn a random amount between 0 and 360 degrees
turn(Greenfoot.getRandomNumber(360));
Move 1
move(1);

7. Making Actors Remove Inside the Actor you move
Check if it is touching:
if(isTouching(actor.class)) { }
Remove Touching
removeTouching(actor.class);

8. Changing the Score Set up a Counter Variable Find the Counter
Counter Score =
Find the Counter
(Counter)getWorld().getObjects(Counter.class).get(0);
On a new line.. Bump the Counter!
Score.bumpCount(1);
Score.bumpCount(-1);

9. Playing a Sound Right Click the Actor Open Editor Code
if (isTouching(Bee.class)) {
removeTouching(Bee.class);
Greenfoot.playSound(“file.wav”); }

10. Workbook
Complete section 11