Assignment 2:
Jumping Button
This assignment handles topics of events and
GUI-elements. It's a little game. The task: create a window with a button that
randomly relocates to a different position on the screen each time it is hit.
The player has to hit the button 10 times, the score is the time needed to
finish this task. That's it. short and simple.
HELP:
It will be helpful to follow these steps:
1. import packages: you will need three packages: javax.swing.*, java.awt.*, java.awt.event.* (if you are using netbeans,
it is interesting NOT to import the packages, because netbeans
will do so for you, reminding you at the time they are needed!)
2. Create a class "JumpingButton",
which extends JFrame.
3. Do all the necessary things a JFrame
needs (setDefaultCloseOperation etc).
4. Set the layout (for example: getContentPane().setLayout(new GridLayout(1,1));
5. Create a button, add it to your frame's content pane
6. make the frame visible.
So far you only set up the GUI for the game,
no functionality is provided. But, at least, there's a button on the screen!
Let's add functionality:
7. prepare to register your program to the event-source,
which is the button. You can only register to a button, when you guarantee that
you are an ActionListener object. Currently, you are
only a JFrame object. To implement and guarantee the
functionality of an Actionlistener, you have to
implement the interface "ActionListener".
So: change your class declaration from "class JumpingButton
extends JFrame" to "class JumpingButton extends JFrame
implements ActionListener", which immediately
makes netbeans complain that you didn't implement the
method "actionPerformed" yet. Hence: do so.
This is the method the button calls every time it is clicked! BUT: so far we
didn't register. We only prepared to register.
8. register! now that you are an ActionListener,
you may register yourself to the button. Do so!
9. The method actionPerformed"
is the place to insert the code to let the button jump, see below.
10. Test if the button jumps.
11. Add the scoring logic: you need a counter, that
increases every time your button is pressed. If it reaches 10, the time has to
be measured.
12. Measuring time: you can get the current time in
milliseconds using the method "System.currentTimeMillis()".
It returns a long-integer (primitive type "long"). If you call this
method at the very beginning and after 15 clicks, the difference in the results
is the time in milliseconds. Divide by 1000 to get the seconds, print, exit,
ready.
The following method relocates a JFrame on the screen to a random position (Toolkit and
Dimension are in package java.awt):
public void relocate(JFrame
f){
/*If this function is called, it will relocate the window to a new random
position on the screen */
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
Dimension windowSize = f.getSize();
int x = rand.nextInt(screenSize.width - windowSize.width);
int y = rand.nextInt(screenSize.height - windowSize.height);
f.setLocation(x,y);
}
BONUS (2 points): Surround the button with 8
other buttons (=>grid 3x3) which the user is not allowed to hit!
Enjoy! Bonus points will be given for any
extensions to the game idea. Be creative! Buttons can contain images etc...
The basic assignment is 10 points. Due date:
Sunday 2/5 (10 points), Sunday 2/12 (6 points), 0 points thereafter.