CS 241 – Computer Programming II Lab Kalpa Gunaratna –
Contact Contact by Office hours 376 Joshi Mondays & Wednesday 3:00 pm – 4:00 pm
Container Each GUI component should be a part of the Containment Hierarchy. JFrame & JPanel are two types of containers. Containers are used to hold components. Normally JPanel is placed inside a JFrame and in this way, JPanels could be arranged in any desired way and place components. JFrame has a content pane and menu bar. JPanel is a general purpose container.
Simple Graphics For drawing, Graphics g object reference is used. Each Container has Graphics g object & that reference could be used to draw any shape inside that specific Container. Ex: to draw inside a JPanel, the relevant Graphics g object should be used. It could be parsed to a different class and used outside of the JPanel to draw shapes in JPanle for example. paintComponent method has Graphics reference for drawing in JPanel.
In lab Make "Ball" specific information and details into a separate class called Ball. draw() and move() methods should be implemented in Ball class (you may keep the declaration of these methods in BallPanel and call Ball's methods inside these methods for better coding practices). Values for variables in Ball class should be done in the Ball Constructor (random numbers in ranges mentioned in the assignment). Use Math.random() to generate random number x in the range 0 <= x < 1.
Post lab Make ArraList of Ball objects. Handle each ball object in the list accordingly. paint() & draw() methods for each ball should be invoked accordingly. Get the prefered number of balls from user in the BallPanel constructor using a dialog box. You can use a JoptionPane for this.
Reminders Do not put JavaDocs in multiple line comments. JavaDoc - /** */ Multiple line - /* */ Write test cases for the given format. Ex: input should also be printed. == is checking whether its the same reference. Use compareTo or equalTo. Marks will be deducted if net beans projects are not submitedto WebCT.