困惑的复选框问题

Question

I have a couple of checkboxes and 2 counters... counter1 counts how many of the checkboxes are checked with the following code

if (isChecked) {
    counter++;
} else {
    counter--;
}

This works like a charm but now i want that counter2 keeps track of the checked checkboxes that belong to the "green" group... for example checkbox 1, 2, 4 and 7 belong to the " green" group and checkbox 3, 5, 6, 8 not.

if (chk1.isChecked() || chk2.isChecked() || chk4.isChecked() || chk7.isChecked()) {
    counter2++;
}

I tried to use another if else to see how much of the "green" group are checked But when I use

System.out.println(counter2);

then I always get the the value of counter1 . Why is this happening? Is it because counter1 checks for all checked boxes and overrules counter2 ?

Answer 1

int counter2 = 0; // reset counter    
for (Checkbox chk : allCheckboxes)  
    {   
       if (chk.isChecked() && isGreen(chk)) {
           counter2++;
       }  
    }   
    //...

and utilily method

private boolean isGreen(Checkbox chk)  
{  
 // return true is checkbox is green  
}

Answer 2

As stated above in a comment, you check once if any of the boxes is checked. If the counter2 always shows the same value as counter1, that could be the result of a simple typo or something. Impossible to say without seeing your code. But a variable can not just overrule another variable.

Are you using Swing and JCheckBox ? If so, you can add an ItemListener to it, if you don't have one already. Then you can dynamically update your counter to reflect the current state of your checkboxes. The code for the itemStateChanged method could look something like this:

public void itemStateChanged(ItemEvent arg0) {
    if (arg0.getStateChange() == ItemEvent.DESELECTED) { 
        counter--;
    } else {
        counter++;
    } 
    // update label or something
}

You can use a different ItemListener for your green group , which additionally sets counter2 .
This frees you from all the iterative checking.