creating a GUI to display a previously created array of objects

[sammyboy78]

I'm trying to display my array of objects in a GUI. How do I get JLabel to refer to the data in my objects? I've read my textbook and some tutorials online I just cannot get this. Plus all the examples I've seen are creating the information that will be displayed from scratch, while I have to use my previously created classes and add a GUI to it. I'm trying to do this GUI using JLabels but it won't let me refer to my CD class methods that display the information. I keep getting this error when I try to compile my CDinventory2.java file :

C:\Documents and Settings\Sam\CDInventory2.java:33: 'void' type not allowed here
JLabel cDObjects1 = new JLabel(CD.displayTotalInventory( completeCDInventory ), JLabel.LEFT);
^
C:\Documents and Settings\Sam\CDInventory2.java:39: 'void' type not allowed here
JLabel cDObjects2 = new JLabel( CD.sortedCDInventory( completeCDInventory ), JLabel.LEFT);
^
2 errors


Heres the code:

// CDInventory2.java
// uses CD class
 
import java.awt.*;
import javax.swing.*;
 
public class CDInventory2 extends JFrame
{
 
    public static void main( String args[] )
    {
    new CDInventory2();
 
    }//end main
 
    public CDInventory2()//constructor
    {
    super( "Compact Disc Inventory" );
 
    CD completeCDInventory[] = new CD2[ 5 ]; // creates a new 5 element array
 
    // populates array with objects that implement CD
    completeCDInventory[ 0 ] = new CD2( "Sixpence None the Richer" , "D121401" , 12 , 11.99, 1990 );
    completeCDInventory[ 1 ] = new CD2( "Clear" , "D126413" , 10 , 10.99, 1998 );
    completeCDInventory[ 2 ] = new CD2( "NewsBoys: Love Liberty Disco" , "2438-51720-2" , 10 , 12.99, 1999 );
    completeCDInventory[ 3 ] = new CD2( "Skillet: Hey You, I Love Your Soul" , "D122966" , 9 , 9.99, 1998 );
    completeCDInventory[ 4 ] = new CD2( "Michael Sweet: Real" , "020831-1376-204" , 15 , 12.99, 1995 );
 
    double totalInventoryValue = CD.calculateTotalInventory( completeCDInventory ); //declares totalInventoryValue variable
 
    Container content = getContentPane();
 
    JLabel cDObjects1 = new JLabel(CD.displayTotalInventory( completeCDInventory ), JLabel.LEFT);
    content.add(cDObjects1);
 
    JLabel invVal1 = new JLabel("Total Inventory value is:" + totalInventoryValue , JLabel.LEFT);
    content.add(invVal1);
 
    JLabel cDObjects2 = new JLabel( CD.sortedCDInventory( completeCDInventory ), JLabel.LEFT);
    content.add(cDObjects2);
 
    JLabel invVal2 = new JLabel("Total Inventory value is:" + totalInventoryValue , JLabel.LEFT);
    content.add(invVal2);
 
    pack();
    setVisible( true );
 
    }//end constructor
 
} //end class

// CD2.java
// subclass of CD
 
public class CD2 extends CD
{
    protected int copyrightDate; // CDs copyright date variable declaration
    private double price2;
 
    // constructor
    public CD2( String title, String prodNumber, double numStock, double price, int copyrightDate )
    {
        // explicit call to superclass CD constructor
        super( title, prodNumber, numStock, price );
 
        this.copyrightDate = copyrightDate;
 
    }// end constructor
 
    public double getInventoryValue() // modified subclass method to add restocking fee
    {
        price2 = price + price * 0.05;
        return numStock * price2;
 
    } //end getInventoryValue
 
    public void displayInventory() // modified subclass display method
        {
 
            System.out.printf( "\n%-22s%s\n%-22s%d\n%-22s%s\n%-22s%.2f\n%-22s%s%.2f\n%-22s%s%.2f\n%-22s%s%.2f\n  \n" , "CD Title:", title, "Copyright Date:", copyrightDate, "Product Number:", prodNumber , "Number in Stock:", numStock , "CD Price:" , "$" , price , "Restocking fee (5%):", "$", price*0.05, "Inventory Value:" , "$" , getInventoryValue() );
 
        } // end method
 
 
}//end class CD2

// CD.java
// Represents a compact disc object
import java.util.Arrays;
 
class CD implements Comparable
{
    protected String title; // CD title (name of product)
    protected String prodNumber; // CD product number
    protected double numStock; // CD stock number
    protected double price; // price of CD
    protected double inventoryValue; //number of units in stock times price of each unit
 
 
    // constructor initializes CD information
    public CD( String title, String prodNumber, double numStock, double price )
    {
        this.title = title; // Artist: album name
        this.prodNumber = prodNumber; //product number
        this.numStock = numStock; // number of CDs in stock
        this.price = price; //price per CD
 
    } // end constructor
 
    public double getInventoryValue()
    {
        return numStock * price;
 
    } //end getInventoryValue
 
    public void displayInventory()
    {
 
        System.out.printf( "\n%s%35s\n%s%12s\n%s%9.2f\n%s%12s%.2f\n%s%.2f\n%s%5s%.2f\n  \n" , "CD Title:", title, "Product Number:", prodNumber , "Number in Stock:", numStock , "CD Price:" , "$" , price , "Restocking fee (5%):", price*0.05, "Inventory Value:" , "$" , getInventoryValue() );
 
    } // end method
 
    public static double calculateTotalInventory( CD completeCDInventory[] )
    {
        double totalInventoryValue = 0;
 
        for ( int count = 0; count < completeCDInventory.length; count++ )
        {
             totalInventoryValue += completeCDInventory[count].getInventoryValue();
 
        } // end for
 
        return totalInventoryValue;
 
    } // end calculateTotalInventory
 
 
    public static void displayTotalInventory( CD completeCDInventory[] )
    {
        System.out.printf( "\n%s\n" ,"Inventory of CDs (unsorted):" );
 
        for ( int count = 0; count < completeCDInventory.length; count++ )
        {
            System.out.printf( "%s%d", "Item# ", count + 1 );
 
            completeCDInventory[count].displayInventory();
 
        }// end for
 
    }// end displayTotalInventory
 
    public int compareTo( Object obj ) //overlaod compareTo method
    {
        CD tmp = ( CD )obj;
 
        if( this.title.compareTo( tmp.title ) < 0 )
        {
            return -1; //instance lt received
        }
        else if( this.title.compareTo( tmp.title ) > 0 )
        {
            return 1; //instance gt received
        }
 
        return 0; //instance == received
 
        }// end compareTo method
 
    public static void sortedCDInventory( CD completeCDInventory[] )
    {
           System.out.printf( "\n%s\n" ,"Inventory of CDs (sorted by title):" );
 
           Arrays.sort( completeCDInventory ); // sort array
 
           for( int count = 0; count < completeCDInventory.length; count++ )
           {
                System.out.printf( "%s%d", "Item# ", count + 1 );
 
                   completeCDInventory[count].displayInventory();}
           }
 
 
} // end class CD

[JosAH]

Did you ever take a peek at the JTable component?

kind regards,

Jos

[sammyboy78]

Did you ever take a peek at the JTable component?

kind regards,

Jos

I don't think that'll work for me, the information isn't really set up to be displayed in a table. I have an example of what I need here using DVDs (I only need one of the two displays, preferrably the easiest!):

[sammyboy78]

Is that top one possibly using JLabels and the bottom example using a JTextArea?

[JosAH]

Is that top one possibly using JLabels and the bottom example using a JTextArea?

Yep, you can even put html text in JLabels; something like this:

String text= "<html><center>Hello<br>world></center></html>";
JLabel lab= new JLabel(text);
...
 

All it takes is a bit of String fiddling to 'html-ize' your text. Adding text to a
JTextArea is even easier, i.e. add text to the area using the append() method.

kind regards,

Jos

ps. Your table rotated 90 degrees with the column headers on top make it very
well suited for a JTable display.

[sammyboy78]

so how would I get my CDobjects to display on a JLabel?

[JosAH]

so how would I get my CDobjects to display on a JLabel?

Simply concatenate the text representations of all the CDs and htlm-ize the
result a bit; something like this:

String html= "<html><center>";
 
for (CD cd : CDCollection)
   html+= cd+"<br>";
 
html+="</center></html>";
 
// html is the text for your label
 

kind regards,

Jos