Introduction To Greenfoot

What is Greenfoot? Greenfoot: is an Integrated Development Environment. (Remember, an IDE is a program that lets you create other programs) uses the Java Programming Language. is aimed at creating 2D graphical applications.

Greenfoot is great for creating: Games (biomekanoidchicken) Applications Simulations (ants)

In Greenfoot, programs and applications are called “Scenarios.” To open a Scenario: Open Greenfoot Scenario  Open Scenario Find the Greenfoot Folder  Find the Scenario folder  Look for this icon:

Greenfoot uses 2 superclasses: 1. World – The instance of this class becomes the world in which the actor objects do things. 2. Actor – This class contains data properties and methods that allow for actor objects to exist in the instance of the world class. (We will learn more about super and sub classes later…)

The Greenfoot IDE Class Diagrams World Object Actor Object

If a class is striped, it needs to be compiled. Compiling classes: If a class is striped, it needs to be compiled.

You can right-click a class, to see its constructor. Select the constructor, and then you can add an instance of the class to the world. Adding objects to the world: Shift-Click: Another way of adding objects is to click on the class, press shift, and click in the world.

The Run button simply calls the Act method over and over again. Running the World: The Run button simply calls the Act method over and over again. The Act button calls the Act Method. The objects in the world will do whatever they are programmed to do. The speed at which the Run button calls the act method can be altered here.

To see an object’s methods: Right-Click an object in the world. You can also execute those methods. This is great for interactive testing.

To alter the code for a class: Double-click the class. This opens the BluJ editor. Change the code. Save or Compile!

Question: Does the Crab class from the demo have a move( ) method defined in it?

There is no move( ) method in the Crab class There is no move( ) method in the Crab class. So where is that method coming from? Notice how the Crab class from the demo has a class above it named Animal. The Crab class has access to ALL of the Animal class’ methods.

Here is the move( ) method in the code from the Animal class: This Crab class uses the Animal class’ move( ) method to move in the world. We will learn more about this later….

Code that you used today: move( ); //This moves the object forward. turn(-12); //This turns the object -12 degrees if(Greenfoot.isKeyDown(“left”)) { turn(12); } //This code turns the object whenever the left key is pressed down.

Opening Greenfoot Projects from www.classofcrow.com: Mister Crow will be giving you incomplete Greenfoot projects (for now). These will usually be found on the website in a zipped format. “Zipped” means that a folder with files is compressed and zipped into ONE file. You have to have a program like 7-zip to UNZIP those files. 7-Zip is free and it is already loaded on our computers. Download the file  Right-click on it Select “7-Zip”  Select “Extract Here”  The files and folder will be unzipped.

Saving Greenfoot Projects for grading: When you are finished with your project go to: Scenario  “Save a copy as” Name the folder: crow(period)_(ProjectNumber)_(LastNameFirstInitial) For Example: crow3_121_SmithJ This folder will go in the CLASS folder on the due date.