Introduzione. GreenFoot è uno strumento software progettato per permettere ai principianti di fare esperienza con laprogrammazione orientata. The Greenfoot Programmers’ Manual is licensed under a. Creative Commons Attribution-Non-Commercial UK: England & Wales License. Contents 1. 2. 3. 4. Opening the Code editor for a class displays all of the programming instructions for the class. Programming instructions are organized into methods in the class.
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Greenfoot provides four important classes that you should know about: Enter a title for your scenario, a short description and a full description. The image can be made partially transparent by using the setTransparancy method. Then we can use the two image objects to change the image repeatedly.
You can change the image of a class, which will change the default image for all objects of that class. This code assumes that we have a hasEaten method in our code, and then sets the image accordingly. This method is usually only called from the constructor of your subclass of World, such as in the ants scenaro:.
The image selector in the dialogue shows two groups of images: Each scenario on the gallery has an icon, which is part of a sceenshot of the scenario. All actors will be delayed when the delay method is called; if you want some actors to continue moving, or may in the future want to add an actor that continues moving during that time, then it would be better to have a boolean field or method that is false when you want to delay and true the rest of the time.
For scenarios which use some sort of Graphical User Interface such as buttons, dialogs, sliders and other application-like input. GreenfootImage is used to work with images, and Greenfoot provides access to the Greenfoot framework itself. If any errors are displayed, fix them and compile again. However, while the scenario is stopped the user can call methods of the actors in the world form their popup menus.
The Publish page of the export dialog box provides you with fields to enter information to be published with your scenario.
Tags should usually be one word long, or a small number of words connected by hyphens, and each tag should be typed on a new line in the textbox. Utilizzare classi di supporto Ci sono un certo numero di classi riutilizzabili che sono disponibili per i tuoi progetti.
The Greenfoot Programmers’ Manual « Programmare con Java
progtammer The parameter can also be the world object, which finds out if the mouse action was over an area where there were no actors, or null which finds out if that mouse action happened at all irrespective of what actor it was over.
The method takes the string to be drawn, and the x and y position of the baseline of the first character.
If we write no special image handling code, this is the image that will be used to display objects of this class. The order of events is:. Calling the stop method programmet equivalent to the user pressing the Pause button. Enter a number — say: This example illustrates a second version of the setImage method: Please visit the progdammer web page for more information about this new edition.
Generating random numbers in Greenfoot is fairly easy.
The image will then be stretched or made smaller to fit that size. If you want to paint the background programmatically you can manuzl do so instead of using an image file. Control-click the Wombat class in the class display.
Even if you don’t purchase the textbook, you can download and experiment with the textbook programs here.
Change the behaviour of an object. AP Computer Science with Greenfoot. Ci sono un certo numero di classi riutilizzabili che sono disponibili per i tuoi progetti. Close the editor, compile and test create an object.
The Lock scenario option allows you to prevent users of your scenario from changing the speed of execution and dragging objects around the world before the scenario progarmmer run. Three attributes of each actor become automatically and immediately visible on screen when you change them.
This allows you to look inside the pdogrammer and inspect the value of its fields.
If you added the following manuxl to the pop method then the scenario would re-start as soon as a user tried to pop a balloon through the popup menu. The possible names are: The Greenfoot software can be downloaded from www. There are two ways how you can change the image of objects: It loops through all the pieces of food left in the pile, and for each one draws four pixels onto the image next to each other in a random position.
Cell based In some scenarios, like Wombats, objects are always entirely contained within a cell, and you are only interested in the location of the object in the grid. greenfoot
The co-ordinates start at 0,0 at the top-left of an image, and are measured in pixels. Installing on Mac OS X. All positioning of actors in the world is in terms of cells.
The image will be completely programmer. Or an object may change its image programmatically, which will change only the individual object. There are two versions of the setImage method: A third option is to combine the two: Create a new world.
New Kinect with Greenfoot. Let us have a closer look at the code inside the new world class. This method is automatically called when the actor has been added to the world. This class has a method called getRandomNumber. This section discusses some of the characteristics of actor classes, and what to consider when writing them.
Towards the right side of the window is the class display.