Thread: Custom Table using AbstractTableModel

You made this more complicated than necessary. Regardless, where do you call the drawInbox() method that creates the JTable?

I am sort of confused about how your code actually works and why you did it this way.

Found something.

Look at this code:

void populateTable(){
		InboxTable dataStruc = new InboxTable() ;
		MailDescriptor [] mArray = new MailDescriptor[mailList.size()] ;
		mArray = mailList.toArray(mArray) ;
 
		dataStruc.data = new Object [mArray.length][4] ;
		for (int i = 0 ; i < mArray.length ; i++){
			dataStruc.data[i][0] = new Boolean(false) ;
			dataStruc.data[i][1] = mArray[i].mailFrom ;
			dataStruc.data[i][2] = mArray[i].mailSub ;
			dataStruc.data[i][3] = mArray[i].mailDate ;
			/*
			dataStruc.setValueAt(new Boolean(false), i, 0) ;
			dataStruc.setValueAt(mArray[i].mailFrom, i, 1) ;
			dataStruc.setValueAt(mArray[i].mailSub, i, 2) ;
			dataStruc.setValueAt(mArray[i].mailDate, i, 3) ;
			*/
		}
		System.out.println(dataStruc.data.length) ;
	}
 
	void drawInbox(){
		inbox = new Inbox( wClient, 200, 100, 500, 500, dataStruc) ;
		inbox.tableDraw() ;
	}

In your drawInbox() method, you send dataStruc. In your populateTable() method, you have this: InboxTable dataStruc = new InboxTable() ;. Based on the code, I can only assume the dataStruc variable being used in your drawInbox() method is global. When you make changes to the dataStruc variable in your populateTable() method, you create a new Object named dataStruc but you do not alter the dataStruc variable that your drawInbox() method will use.

Sort of confusing. Does that make sense?

Sorry for late reply, had a long sleep. @aussiemcgr : obeservation of a veteran. I think i am learning and implementing in a wrong way. Could u help regarding implementation of a custom table which will be populated by large data ?? Fixed this now getting an Exception like this:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException and painting later only when taken mouse over.
at InboxTable.getColumnClass(Inbox.java:35)
at javax.swing.JTable.getColumnClass(Unknown Source)
at javax.swing.JTable.getCellRenderer(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI.paintCell(Unkn own Source)
at javax.swing.plaf.basic.BasicTableUI.paintCells(Unk nown Source)
at javax.swing.plaf.basic.BasicTableUI.paint(Unknown Source)
at javax.swing.plaf.ComponentUI.update(Unknown Source)
at javax.swing.JComponent.paintComponent(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JLayeredPane.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.BufferStrategyPaintManager.paint(Unkno wn Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at java.awt.GraphicsCallback$PaintCallback.run(Unknow n Source)
at sun.awt.SunGraphicsCallback.runOneComponent(Unknow n Source)
at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)
at java.awt.Container.paint(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unkno wn Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unkno wn Source)
at javax.swing.RepaintManager.seqPaintDirtyRegions(Un known Source)
at javax.swing.SystemEventQueueUtilities$ComponentWor kRequest.run(Unknow
n Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(U nknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

I threw this together as a simple example of how to create a JTable the easiest way I have found.

Main:

import javax.swing.JFrame;
 
public class Table 
{
 
    public static void main(String[] args) 
    {
    	JFrame mainFrame = new JFrame("JTable Test");
 
    	mainFrame.setContentPane(new TableJAVA());
 
    	mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    	mainFrame.setSize(500,400);
 		mainFrame.setVisible(true);
    }
 
}

TableJAVA (extends JPanel and contains JTable code):

import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import java.util.Vector;
import java.awt.Dimension;
 
public class TableJAVA extends JPanel
{
	//Create Table Elements
	/* There are a few important things when creating a JTable.
	 * 1) The Data Array. This is a 2D array that holds the row
	 *    and column data.
	 * 2) The Column Names Array. This is a 1D array that holds
	 *    the column names.
	 * 3) The JTable Object itself.
	 * 4) A Table Model, in this case a DefaultTableModel.
	 * 5) A JScrollPane to allow the table to be viewable 
	 *    completely. 
	 */
	Object[][] data;
	String[] columnNames;
	JTable table;
	DefaultTableModel model;
	JScrollPane tableScroller;
 
	/* To create a table of dynamic size, we need a dynamic data
	 * structure to hold a list of Object that will be represented
	 * in the table. For this example, it is Person Objects.
	 */
	Vector<Person> personList;
 
    public TableJAVA() 
    {
    	super();
 
    	//Initialize Person List
    	personList = new Vector<Person>();
    	personList.add(new Person("First1", "Last1", 23, "Male"));
    	personList.add(new Person("First2", "Last2", 58, "Female"));
    	personList.add(new Person("First3", "Last3", 94, "Male"));
    	personList.add(new Person("First4", "Last4", 34, "Female"));
    	personList.add(new Person("First5", "Last5", 20, "Male"));
    	personList.add(new Person("First6", "Last6", 71, "Female"));
    	personList.add(new Person("First7", "Last7", 13, "Male"));
    	personList.add(new Person("First8", "Last8", 43, "Female"));
 
    	//Initialize Column Names Array
    	columnNames = new String[]{"First Name","Last Name","Age","Gender"	};
    	//Initialize Data Array
    	data = new Object[personList.size()][columnNames.length];
 
    	//Fill Data Array
    	for(int i=0;i<personList.size();i++)
    	{
    		data[i][0] = personList.get(i).firstName;
    		data[i][1] = personList.get(i).lastName;
    		data[i][2] = personList.get(i).age;
    		data[i][3] = personList.get(i).gender;
    	}
 
    	//Initialize DefaultTableModel
    	model = new DefaultTableModel(data,columnNames);
 
    	//Initialize JTable
    	table = new JTable(model);
 
    	//Initialize Table Scroll Pane and set size
    	tableScroller = new JScrollPane(table);
		tableScroller.setPreferredSize(new Dimension(450, 250));
 
		//Remember to add the Table Scroller, not the JTable to the container
		super.add(tableScroller);
 
		// ----- Now let's add a new person -----
		Person newPerson = new Person("First9", "Last9", 18, "Female");
		//Remember to add to Person List for consistency
		personList.add(newPerson);
		//Now we add to the JTable
		model.addRow(new Object[]{newPerson.firstName,newPerson.lastName,newPerson.age,newPerson.gender});
    }
}

Person Class:

public class Person 
{
	String firstName;
	String lastName;
	int age;
	String gender;
 
    public Person(String fn, String ln, int a, String gen) 
    {
    	firstName = fn;
    	lastName = ln;
    	age = a;
    	gender = gen;
    }    
}

Tell me if anything is confusing. JTables can be hard to learn how to properly use.