Checkbox - One affects all? Need solution

Question

Hello all,
I recently started a small program for the sake of testing out Checkboxes and already I am running into a brick wall.
The problem I am having, as I can best explain it, is that I am testing a very small program that does the following:
- Allows user to check multiple boxes
- As each box is checked, the price is INCREASED based on the value of that box
- As each box is unchecked, the price is DECREASED based on the value of that box
I am finding that if I begin the program with several empty boxes and make just one choice (on one box), all other empty boxes are treated as if they've been UNCHECKED (aka as if they were actually checked before!) Obviously in my case, beginning the program with several checkboxes and selecting only one - something that's supposed to add one dollar amount to the "0.00" beginning balance - instead makes it go into the negatives because the actions for deselecting the checkboxes are taken (those actions which tell the program to SUBTRACT the value from the unchecked boxes . . which is only supposed to occur if they were checked previously and are being unchecked now.)
What I need is some sort of system in which each checkbox is treated independently and so that action is taken only if the box I'm clicking has been selected/deselected, whereas any other boxes within the applet window are not changed at all.
My sample code is as follows:
import java.applet.*;*
*import java.awt.*;
import java.awt.event.*;
public class Sample extends Applet implements ItemListener
          //-------CHECKBOXES------------------------------
          Checkbox priceOneCB = new Checkbox("First Price");
          Checkbox priceTwoCB = new Checkbox("Second Price");
     public void init()
          //-------SET UP INTERFACE--------------------------------
          add(priceOneCB);
                priceOneCB.addItemListener(this);
          add(priceTwoCB);
                priceTwoCB.addItemListener(this);
     public void itemStateChanged(ItemEvent e)
           // price one selected
          if (priceOneCB.getState())
          System.out.println("PRICE ONE SELECTED!");
          // price one NOT selected
          else if (!(priceOneCB.getState()))
          System.out.println("PRICE ONE DESELECTED!");
          // price two selected
          if (priceTwoCB.getState())
             System.out.println("PRICE TWO SELECTED!");
            // price two NOT selected
            else if (!(priceTwoCB.getState()))
            System.out.println("PRICE TWO DESELECTED!");
}Does anyone have any suggestions? Am I just completely missing the mark here with my Checkbox usage? I am a complete "newbie" to this subject and I'm very frustrated, so hopefully someone can lead me down the right path. I also apologize if my explanation wasn't clear enough, but I did the best I could. It's a toughie to explain.
Thanks very much in advance!
- Chubz

Answer 1

Aren't you confusing deselected with unselected?
What your code is doing every time there is an event is going through all the boxes and saying "FOO SELECTED" if it is checked and "FOO DESELECTED" if it is not checked.. But you really want only to respond to changes.
You could do this directly by checking to see what CheckBox caused itemStateChange() to be fired. The ItemEvent class has a couple of methods which look like candidates to return this information. Once you know which check box was selected/deselected, you know how much to change the total by.
Another approach is to work out the total each time there is a click anywhere. Ie go through all of the check boxes and if they are selected multiply by the "value" associated with that box and add them up.
Always use braces - even for one line blocks. It adds greatly to readability
if(foo) {
} else if (bar) {
if(baz) {
}If there is a choice between just two things just use if-else:
if(someCondition) {
    // if true
} else {
    // if not
//if(someCondition) {
//    // if true
//} else if(!someCondition) {
//    // if not
//}This is especially important if someCondition is returned by a method - because it may change between one invocation and the next causing strange results.
Why are you using CheckBox, rather than JCheckBox?