Java Class subclass variable reference

Question

I keep running into the 'cannot find symbol' error on my class. The variable is clearly declared in the super class, yet the subclass can not see it. I receive no errors except on the new constructor of JLabel in the subclass RecordViewer.

 class RecordViewer extends JDialog{
     private JButton next;
     private JButton prev;
     private JLabel label;
     private int current;

     public RecordViewer(CDinventoryItem [] array){
         super();
         current = 0;
         final CDinventoryItem [] items = array;

         label = new JLabel(items[getCurrent()]);

Predefined toString from my CDinventoryItem class...

        @Override public String toString(){

        //  Decimal foramting for the inventory values
        NumberFormat dformat = new DecimalFormat("#0.00");

        //  Formatting for the inventory output
        StringBuilder ouput  = new StringBuilder();
        String New_Line = System.getProperty("line.separator");

            ouput.append("The product number of my CD is: ").append(iPitemNumber).append (New_Line);
            ouput.append("The title of the CD is: ").append(sPtitle).append (New_Line);
            ouput.append("I have ").append(iPnumberofUnits).append(" units in stock.").append (New_Line);
            ouput.append("The total value of my inventory on this product is: ").append(dformat.format(stockValue())).append (New_Line);
            return ouput.toString();
        }

Please provide the whole error message.

adamax
– adamax

2011-01-24 20:39:10 +00:00
Commented Jan 24, 2011 at 20:39 — adamax
– adamax, Commented Jan 24, 2011 at 20:39

Jems · Accepted Answer · 2011-01-24 20:41:17Z

3

Is that the standard Java JLabel? You are trying to pass an object of type CDinventoryItem, and the JLabel won't have a constructor to handle that kind of argument, unless it is extending the String or Icon classes.

answered Jan 24, 2011 at 20:41

Jems

11.6k1 gold badge31 silver badges35 bronze badges

Sign up to request clarification or add additional context in comments.

12 Comments

user569127 Over a year ago

Yes just the standard JLabel. CDinventory class is an array of String, int, int, double

Jems Over a year ago

So it doesn't extend the String or Icon class? Then the constructor isn't going to work. extend doesn't mean it contains a String variable/array of Strings as a member field, it means you used the keyword extend in your class declaration; CDinventory would then be a subclass of String. That probably isn't what you are trying to do though- maybe you want to do something like items[getCurrent()].getName() as your argument, where getName would be some method returning a String.

user569127 Over a year ago

OK a label = this.setLabel(items[Current()]); removed the error. I let NetBeans create a method for the setLabel.

user569127 Over a year ago

Thank you. But I still am running into another error. You are referring to the other problem I am having as well. getLabel().setText(items[getCurrent()]); returns a 'cannot be applied to given types'. I just want it to display the array in the JLabel, but tells me I cannot because it is of String type.

Jems Over a year ago

Again, this is because a CDinventoryItem isn't a String. That method expects a String as an argument. You need to make a method for the CDinventoryItem class that returns a String containing whatever text you need for the JLabel, and then have that method called as the argument for setText

|

Bozho · Accepted Answer · 2011-01-24 20:47:38Z

2

organize your imports, so that JLabel is imported properly
JLabel does not define a constructor taking your custom type. You need to pass a string there.

edited Jan 24, 2011 at 20:47

answered Jan 24, 2011 at 20:32

Bozho

599k147 gold badges1.1k silver badges1.2k bronze badges

2 Comments

user569127 Over a year ago

Yes i have the import javax.swing.*; at the top. I just added the import javax.swing.JLabel; as you suggested. Still no change.

Bozho Over a year ago

@user569127 are you using an IDE?

Michael Berry · Accepted Answer · 2011-01-24 20:37:23Z

0

Just a guess, but your question wording implies you're trying to use a private field directly from a subclass? private fields can't be seen anywhere other than the class that they're declared in, including classes in the same inheritance hierarchy. You could make it protected, but this is frowned upon - better to either provide a mutator method to label or better still, initialise it in the superclass constructor.

answered Jan 24, 2011 at 20:37

Michael Berry

72.8k23 gold badges165 silver badges227 bronze badges

2 Comments

user569127 Over a year ago

Yes even if I initialize it in the superclass it doesn't see it. Was one of the first things I tried.

user569127 Over a year ago

OK a label = this.setLabel(items[Current()]); removed the error. I let NetBeans create a method for the setLabel.

Collectives™ on Stack Overflow

Java Class subclass variable reference

3 Answers 3

12 Comments

2 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

12 Comments

2 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related