Thread: Switching JFreeCharts on a JPanel using a JComboBox

Okay, so I'm trying to switch between different JFreeChart graphs on a JPanel by using a JComboBox.

In the code below, you will see that I already have already created one such chart, and added as a child to the graphingPanel. This works fine. What I would like to do, is modify the Action Listener to the ComboBox, so that I can change the image on the graphingPanel. In the action listener, you will see my attempt to do so for what I have called "Option 2" in my JComboBox (cbbGraphs), i.e. index1. I thought graphingPanel.add(chartPanel2) might work inside the action listener, but that won't compile because I "Cannot refer to a non-final variable graphingPanel inside an inner class defined in a different method.

import java.util.ArrayList;   
import java.awt.Color;  
import java.awt.Component;  
import java.awt.GridBagConstraints;  
import java.awt.GridBagLayout;  
import java.awt.Insets;  
import java.awt.event.ActionEvent;  
import java.awt.event.ActionListener; 
 
import javax.swing.JComboBox;  
import javax.swing.JFrame;  
import javax.swing.JPanel;    
import javax.swing.border.EmptyBorder;  
 
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;  
import org.jfree.data.category.DefaultCategoryDataset;  
import org.jfree.data.time.TimeSeries;  
import org.jfree.data.time.TimeSeriesCollection;  
import org.jfree.data.time.Day;
 
 
public class Display extends JFrame {
 
	private JPanel panelBackground;  
    private JPanel myPanel;  
 
    private JComboBox cbbGraphs;  
 
    private GridBagConstraints constraints;  
 
     ArrayList<String> categories = new ArrayList<String>();  
 
 
    public Display()   
    {  
        //Frame details  
    super("Title");  
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
    setBounds(100, 100, 1200, 700);  
    setLocationRelativeTo(null);  
    panelBackground = new JPanel();  
    panelBackground.setBorder(new EmptyBorder(5, 5, 5, 5));  
    setContentPane(panelBackground);  
    panelBackground.setBackground(new Color(20,50,75));  
    GridBagLayout gbl_panelBackground = new GridBagLayout();  
    panelBackground.setLayout(gbl_panelBackground);  
 
    //Panel  
    myPanel = new JPanel();  
    myPanel.setBorder(null);  
    myPanel.setBackground(new Color(240, 255, 255));   
    GridBagLayout gbl_myPanel = new GridBagLayout();  
    gbl_myPanel.columnWidths = new int[]{50, 125, 50, 50, 50, 50, 0,50,50,50,50,50,50,50};  
    gbl_myPanel.rowHeights = new int[]{20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20};  
    myPanel.setLayout(gbl_myPanel);  
 
    //Constraints  
    constraints = new GridBagConstraints();  
    constraints.anchor = GridBagConstraints.EAST;  
    constraints.gridx=0;  
    constraints.gridy=0;  
    panelBackground.add(myPanel,constraints);  
 
    //###############################################################################         
 
     GridBagConstraints gbc_lbl = new GridBagConstraints();  
     gbc_lbl.anchor = GridBagConstraints.NORTHWEST;  
     gbc_lbl.gridx = 0;  
     gbc_lbl.gridy = 0;  
 
 
    //Graphing Panel  
 
    JPanel graphingPanel = new JPanel();  
    constraints.anchor = GridBagConstraints.SOUTHWEST;  
    constraints.insets = new Insets(0,0,5,5);  
    constraints.fill = GridBagConstraints.BOTH;  
    addComponent(graphingPanel,6,1,8,13);  
 
    TimeSeries pop = new TimeSeries("Sales", Day.class);
	 TimeSeries pop2 = new TimeSeries("Purchases", Day.class);
	 pop2.add(new Day(20, 1, 2004), 200);
	 pop2.add(new Day(20, 2, 2004), 250);
	 pop2.add(new Day(20, 3, 2004), 450);
	 pop2.add(new Day(20, 4, 2004), 475);
	 pop2.add(new Day(20, 5, 2004), 125);
	 pop2.add(new Day(20, 6, 2004), 100);
	 pop2.add(new Day(20, 7, 2004), 400);
	 pop2.add(new Day(20, 8, 2004), 125);
	 pop2.add(new Day(20, 9, 2004), 300);
	 pop2.add(new Day(20, 10, 2004), 223);
	 pop2.add(new Day(20, 11, 2004), 125);
	 pop2.add(new Day(20, 12, 2004), 125);
 
	 pop.add(new Day(10, 1, 2004), 100);
	 pop.add(new Day(10, 2, 2004), 150);
	 pop.add(new Day(10, 3, 2004), 250);
	 pop.add(new Day(10, 4, 2004), 275);
	 pop.add(new Day(10, 5, 2004), 325);
	 pop.add(new Day(20, 6, 2004), 57);
	 pop.add(new Day(20, 7, 2004), 125);
	 pop.add(new Day(20, 8, 2004), 98);
	 pop.add(new Day(20, 9, 2004), 200);
	 pop.add(new Day(20, 10, 2004), 100);
	 pop.add(new Day(20, 11, 2004), 200);
	 pop.add(new Day(20, 12, 2004), 100);
 
 
	 TimeSeriesCollection dataset = new TimeSeriesCollection();
	 dataset.addSeries(pop2);
	 dataset.addSeries(pop);
	 JFreeChart chart = ChartFactory.createTimeSeriesChart(
	 "Sales and Purchases",
	 "Date", 
	 "Quantity",
	 dataset,
	 true,
	 true,
	 false);
 
 
 
	ChartPanel chartPanel = new ChartPanel(chart); 	
	graphingPanel.add(chartPanel);
 
    String [] graphOptions ={"Option 1","Option 2","Option 3"};
 
    cbbGraphs = new JComboBox(graphOptions);  
    constraints.fill = GridBagConstraints.HORIZONTAL;  
    constraints.anchor = GridBagConstraints.EAST;  
    constraints.insets = new Insets(0, 0, 5, 5);  
    addComponent(cbbGraphs, 3, 4,2,1);  
 
 
    cbbGraphs.addActionListener(new ActionListener(){  
        public void actionPerformed(ActionEvent e){  
        	int selection =cbbGraphs.getSelectedIndex();
        	if(selection ==1){ 
        		//Create bar chart
        	    DefaultCategoryDataset data = new DefaultCategoryDataset();
        	    data.setValue(6, "Profit1", "Jane");
        	    data.setValue(3, "Profit2", "Jane");
        	    data.setValue(7, "Profit1", "Tom");
        	    data.setValue(10, "Profit2", "Tom");
        	    data.setValue(8, "Profit1", "Jill");
        	    data.setValue(8, "Profit2", "Jill");
        	    data.setValue(5, "Profit1", "John");
        	    data.setValue(6, "Profit2", "John");
        	    data.setValue(12, "Profit1", "Fred");
        	    data.setValue(5, "Profit2", "Fred");
 
        	 	JFreeChart chart = ChartFactory.createBarChart3D("Comparison between Salesman", 
        	 			 "Salesman", "Value ($)", data, PlotOrientation.VERTICAL, true, true, false );
        		ChartPanel chartPanel2 = new ChartPanel(chart);
 
        	}
 
 
              }  
 
 
            });  
 
    setContentPane(panelBackground);  
    panelBackground.add(myPanel);  
 
    setVisible(true);  
}  
 
    //###############################################################################         
 
    //Main Method  
 
    public static void main (String[]args)  
    {  
        Display a = new Display();  
    }  
 
    //###############################################################################         
 
 
    public void addComponent(Component component, int row, int column, int width,int height ){  
        constraints.gridx=column;  
        constraints.gridy=row;  
        constraints.gridwidth=width;  
        constraints.gridheight=height;  
        myPanel.add(component,constraints);  
 
 
 
 
 
    }  
 
 
}

So, how would I make it, so that the JComboBox will allow me to switch the chart displayed on the panel. Can it be done?

Without spending too much time looking at your code, what you describe sounds like a job for CardLayout. I'll spend more time looking at your code and let you know if I have other ideas.

So, after experimenting, I have done it in two different ways. The first is through the use of CardLayout, which you recommended. It is mostly a result of playing around with the first demo on the Javadocs.

import java.awt.*;
import java.awt.event.*;
 
import javax.swing.*;
 
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PiePlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.data.general.DefaultPieDataset;
import org.jfree.data.time.Day;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;
 
public class Display implements ItemListener {
    JPanel cards; 
 
    final static String LINEGRAPHPANEL = "Line graph";
    final static String BARCHARTPANEL = "Bar chart";
    final static String PIECHARTPANEL ="Pie chart";
 
    public void addComponentToPane(Container pane) {
        //Put the JComboBox in a JPanel to get a nicer look.
        JPanel comboBoxPane = new JPanel(); //use FlowLayout
        String comboBoxItems[] = { LINEGRAPHPANEL, BARCHARTPANEL, PIECHARTPANEL};
        JComboBox cb = new JComboBox(comboBoxItems);
        cb.setEditable(false);
        cb.addItemListener(this);
        comboBoxPane.add(cb);
 
        //############################Build first chart###################################
        TimeSeries pop = new TimeSeries("Sales", Day.class);
   	 TimeSeries pop2 = new TimeSeries("Purchases", Day.class);
   	 pop2.add(new Day(20, 1, 2004), 200);
   	 pop2.add(new Day(20, 2, 2004), 250);
   	 pop2.add(new Day(20, 3, 2004), 450);
   	 pop2.add(new Day(20, 4, 2004), 475);
   	 pop2.add(new Day(20, 5, 2004), 125);
   	 pop2.add(new Day(20, 6, 2004), 100);
   	 pop2.add(new Day(20, 7, 2004), 400);
   	 pop2.add(new Day(20, 8, 2004), 125);
   	 pop2.add(new Day(20, 9, 2004), 300);
   	 pop2.add(new Day(20, 10, 2004), 223);
   	 pop2.add(new Day(20, 11, 2004), 125);
   	 pop2.add(new Day(20, 12, 2004), 125);
 
   	 pop.add(new Day(10, 1, 2004), 100);
   	 pop.add(new Day(10, 2, 2004), 150);
   	 pop.add(new Day(10, 3, 2004), 250);
   	 pop.add(new Day(10, 4, 2004), 275);
   	 pop.add(new Day(10, 5, 2004), 325);
   	 pop.add(new Day(20, 6, 2004), 57);
   	 pop.add(new Day(20, 7, 2004), 125);
   	 pop.add(new Day(20, 8, 2004), 98);
   	 pop.add(new Day(20, 9, 2004), 200);
   	 pop.add(new Day(20, 10, 2004), 100);
   	 pop.add(new Day(20, 11, 2004), 200);
   	 pop.add(new Day(20, 12, 2004), 100);
 
 
   	 TimeSeriesCollection dataset = new TimeSeriesCollection();
   	 dataset.addSeries(pop2);
   	 dataset.addSeries(pop);
   	 JFreeChart chart = ChartFactory.createTimeSeriesChart(
   	 "Sales and Purchases",
   	 "Date", 
   	 "Quantity",
   	 dataset,
   	 true,
   	 true,
   	 false);
 
 
 
   	ChartPanel firstChartPanel = new ChartPanel(chart); 	
 
 
      //#############################Build second chart##################################
 
        DefaultCategoryDataset profitAndLossData = new DefaultCategoryDataset();
		profitAndLossData.setValue(123, "Purchases", "January");
		profitAndLossData.setValue(213, "Sales", "January");
		profitAndLossData.setValue(321, "Purchases", "February");
		profitAndLossData.setValue(23, "Sales", "February");
		profitAndLossData.setValue(322, "Purchases", "March");
		profitAndLossData.setValue(232, "Sales", "March");
		profitAndLossData.setValue(222, "Purchases", "April");
		profitAndLossData.setValue(222, "Sales", "April");
		profitAndLossData.setValue(111, "Purchases", "May");
		profitAndLossData.setValue(222, "Sales", "May");
 
 
		// create a chart...
		JFreeChart secondChart = ChartFactory.createBarChart(
				"Purchases and Sales", "Key", "Amount (€)",
				profitAndLossData, PlotOrientation.VERTICAL, true, true, false);
		ChartPanel secondChartPanel = new ChartPanel (secondChart);
 
 
	     //#############################Build third chart##################################
 
		DefaultPieDataset categoryData = new DefaultPieDataset();
		categoryData.setValue("capacitors", new Double(100));
		categoryData.setValue("Resistors", new Double(100));
		categoryData.setValue("Interface Devices", new Double(
				40));
		categoryData
				.setValue("Transformers", new Double(100));
		categoryData.setValue("Monitors", new Double(100));
		categoryData.setValue("Other", new Double(100));
 
		// create a pie chart
		secondChart = ChartFactory.createPieChart(
				"Stock Distribution by category", categoryData, true, true,
				true);
		PiePlot categoryPlot = (PiePlot) secondChart.getPlot();
		categoryPlot.setSimpleLabels(true);
 
		ChartPanel thirdChartPanel = new ChartPanel(secondChart);
 
 
		//#####################################################################################
 
        //Create the "cards".
        JPanel card1 = new JPanel();
        JPanel card2 = new JPanel();
        JPanel card3 = new JPanel();
 
        card1.add(firstChartPanel);
        card2.add(secondChartPanel);
        card3.add(thirdChartPanel);
 
 
 
        //Create the panel that contains the "cards".
        cards = new JPanel(new CardLayout());
        cards.add(card1, LINEGRAPHPANEL);
        cards.add(card2, BARCHARTPANEL);
        cards.add(card3,PIECHARTPANEL);
 
        pane.add(comboBoxPane, BorderLayout.PAGE_START);
        pane.add(cards, BorderLayout.CENTER);
    }
 
    public void itemStateChanged(ItemEvent evt) {
        CardLayout cl = (CardLayout)(cards.getLayout());
        cl.show(cards, (String)evt.getItem());
    }
 
 
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("CardLayoutDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
        //Create and set up the content pane.
        Display demo = new Display();
        demo.addComponentToPane(frame.getContentPane());
 
        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }
 
    public static void main(String[] args) {
        /* Use an appropriate Look and Feel */
        try {
            //UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
            UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
        } catch (UnsupportedLookAndFeelException ex) {
            ex.printStackTrace();
        } catch (IllegalAccessException ex) {
            ex.printStackTrace();
        } catch (InstantiationException ex) {
            ex.printStackTrace();
        } catch (ClassNotFoundException ex) {
            ex.printStackTrace();
        }
        /* Turn off metal's use of bold fonts */
        UIManager.put("swing.boldMetal", Boolean.FALSE);
 
        //Schedule a job for the event dispatch thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

However, I also discovered a way of doing it while keeping the original GridBagLayout, thus allowing me to keep any JButtons or JLabels in the exact same position (and there were some in the real program, though I've removed them from any of my SSCCEs for the sake of simplicity.

import java.util.ArrayList;   
import java.awt.Color;  
import java.awt.Component;  
import java.awt.Font;
import java.awt.GridBagConstraints;  
import java.awt.GridBagLayout;  
import java.awt.Insets;  
import java.awt.event.ActionEvent;  
import java.awt.event.ActionListener; 
 
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
 
import javax.swing.JComboBox;  
import javax.swing.JFrame;  
import javax.swing.JPanel;    
import javax.swing.border.EmptyBorder;  
 
 
 
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PiePlot;
import org.jfree.chart.plot.PlotOrientation;  
import org.jfree.data.category.DefaultCategoryDataset;  
import org.jfree.data.general.DefaultPieDataset;
import org.jfree.data.time.TimeSeries;  
import org.jfree.data.time.TimeSeriesCollection;  
import org.jfree.data.time.Day;
 
 
public class Display extends JFrame {
 
	public static JPanel graphingPanel;
	public static ChartPanel chartPanel;
 
	public static JFreeChart firstChart;
	public static JFreeChart secondChart;
	public static JFreeChart thirdChart;
 
	private JPanel panelBackground;  
    private JPanel myPanel;  
 
    private JComboBox cbbGraphs;  
 
    private GridBagConstraints constraints;  
 
     ArrayList<String> categories = new ArrayList<String>();  
 
 
 
    public Display()   
    {  
        //Frame details  
    super("Title");  
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
    setBounds(100, 100, 1200, 700);  
    setLocationRelativeTo(null);  
    panelBackground = new JPanel();  
    panelBackground.setBorder(new EmptyBorder(5, 5, 5, 5));  
    setContentPane(panelBackground);  
    panelBackground.setBackground(new Color(20,50,75));  
    GridBagLayout gbl_panelBackground = new GridBagLayout();  
    panelBackground.setLayout(gbl_panelBackground);  
 
    //Panel  
    myPanel = new JPanel();  
    myPanel.setBorder(null);  
    myPanel.setBackground(new Color(240, 255, 255));   
    GridBagLayout gbl_myPanel = new GridBagLayout();  
    gbl_myPanel.columnWidths = new int[]{50, 125, 50, 50, 50, 50, 0,50,50,50,50,50,50,50};  
    gbl_myPanel.rowHeights = new int[]{20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20};  
    myPanel.setLayout(gbl_myPanel);  
 
    //Constraints  
    constraints = new GridBagConstraints();  
    constraints.anchor = GridBagConstraints.EAST;  
    constraints.gridx=0;  
    constraints.gridy=0;  
    panelBackground.add(myPanel,constraints);  
 
    //###############################################################################         
 
     GridBagConstraints gbc_lbl = new GridBagConstraints();  
     gbc_lbl.anchor = GridBagConstraints.NORTHWEST;  
     gbc_lbl.gridx = 0;  
     gbc_lbl.gridy = 0;  
 
 
    //Graphing Panel  
 
    graphingPanel = new JPanel();  
    constraints.anchor = GridBagConstraints.SOUTHWEST;  
    constraints.insets = new Insets(0,0,5,5);  
    constraints.fill = GridBagConstraints.BOTH;  
    addComponent(graphingPanel,6,1,8,13);  
 
    //###############################################Construct first chart####################################################
 
    TimeSeries pop = new TimeSeries("Sales", Day.class);
	 TimeSeries pop2 = new TimeSeries("Purchases", Day.class);
	 pop2.add(new Day(20, 1, 2004), 200);
	 pop2.add(new Day(20, 2, 2004), 250);
	 pop2.add(new Day(20, 3, 2004), 450);
	 pop2.add(new Day(20, 4, 2004), 475);
	 pop2.add(new Day(20, 5, 2004), 125);
	 pop2.add(new Day(20, 6, 2004), 100);
	 pop2.add(new Day(20, 7, 2004), 400);
	 pop2.add(new Day(20, 8, 2004), 125);
	 pop2.add(new Day(20, 9, 2004), 300);
	 pop2.add(new Day(20, 10, 2004), 223);
	 pop2.add(new Day(20, 11, 2004), 125);
	 pop2.add(new Day(20, 12, 2004), 125);
 
	 pop.add(new Day(10, 1, 2004), 100);
	 pop.add(new Day(10, 2, 2004), 150);
	 pop.add(new Day(10, 3, 2004), 250);
	 pop.add(new Day(10, 4, 2004), 275);
	 pop.add(new Day(10, 5, 2004), 325);
	 pop.add(new Day(20, 6, 2004), 57);
	 pop.add(new Day(20, 7, 2004), 125);
	 pop.add(new Day(20, 8, 2004), 98);
	 pop.add(new Day(20, 9, 2004), 200);
	 pop.add(new Day(20, 10, 2004), 100);
	 pop.add(new Day(20, 11, 2004), 200);
	 pop.add(new Day(20, 12, 2004), 100);
 
 
	 TimeSeriesCollection dataset = new TimeSeriesCollection();
	 dataset.addSeries(pop2);
	 dataset.addSeries(pop);
	 firstChart = ChartFactory.createTimeSeriesChart(
	 "Sales and Purchases",
	 "Date", 
	 "Quantity",
	 dataset,
	 true,
	 true,
	 false);
 
	 chartPanel=new ChartPanel(firstChart);
 
 
	 //###############################################Construct second chart####################################################
 
	 DefaultPieDataset categoryData = new DefaultPieDataset();
		categoryData.setValue("capacitors", new Double(100));
		categoryData.setValue("Resistors", new Double(100));
		categoryData.setValue("Interface Devices", new Double(
				40));
		categoryData
				.setValue("Transformers", new Double(100));
		categoryData.setValue("Monitors", new Double(100));
		categoryData.setValue("Other", new Double(100));
 
		// create a pie chart
		secondChart = ChartFactory.createPieChart(
				"Stock Distribution by category", categoryData, true, true,
				true);
		PiePlot categoryPlot = (PiePlot) secondChart.getPlot();
		categoryPlot.setSimpleLabels(true);
 
 
	//###############################################Construct third chart####################################################
 
		DefaultCategoryDataset profitAndLossData = new DefaultCategoryDataset();
		profitAndLossData.setValue(123, "Purchases", "January");
		profitAndLossData.setValue(213, "Sales", "January");
		profitAndLossData.setValue(321, "Purchases", "February");
		profitAndLossData.setValue(23, "Sales", "February");
		profitAndLossData.setValue(322, "Purchases", "March");
		profitAndLossData.setValue(232, "Sales", "March");
		profitAndLossData.setValue(222, "Purchases", "April");
		profitAndLossData.setValue(222, "Sales", "April");
		profitAndLossData.setValue(111, "Purchases", "May");
		profitAndLossData.setValue(222, "Sales", "May");
 
 
		// create a chart...
		thirdChart = ChartFactory.createBarChart(
				"Purchases and Sales", "Key", "Amount (€)",
				profitAndLossData, PlotOrientation.VERTICAL, true, true, false);
 
		// ######################################################################################################
 
 
 
	graphingPanel.add(chartPanel);
 
    String [] graphOptions ={"Option 1","Option 2","Option 3"};
 
    cbbGraphs = new JComboBox(graphOptions);  
    constraints.fill = GridBagConstraints.HORIZONTAL;  
    constraints.anchor = GridBagConstraints.EAST;  
    constraints.insets = new Insets(0, 0, 5, 5);  
    addComponent(cbbGraphs, 3, 4,2,1);  
 
 
    cbbGraphs.addItemListener(new ItemListener() {
		@Override
		public void itemStateChanged(ItemEvent e) {
			int item = cbbGraphs.getSelectedIndex();
 
			switch (item) {
			case 0:
				graphingPanel.removeAll();
				graphingPanel.setVisible(false);
				chartPanel = new ChartPanel(firstChart);
				graphingPanel.add(chartPanel);
				graphingPanel.setVisible(true);
				break;
			case 1:
				graphingPanel.removeAll();
				graphingPanel.setVisible(false);
				chartPanel = new ChartPanel(secondChart);
				graphingPanel.add(chartPanel);
				graphingPanel.setVisible(true);
				break;
			case 2:
				graphingPanel.removeAll();
				graphingPanel.setVisible(false);
				chartPanel = new ChartPanel(thirdChart);
				graphingPanel.add(chartPanel);
				graphingPanel.setVisible(true);
				break;
 
			default:
				graphingPanel.removeAll();
				graphingPanel.setVisible(false);
				//chartPanel = new ChartPanel(salesAndPurchasesChart);
				graphingPanel.add(chartPanel);
				graphingPanel.setVisible(true);
				break;
			}
 
		}
	});
 
    setContentPane(panelBackground);  
    panelBackground.add(myPanel);  
 
    setVisible(true);  
}  
 
    //###############################################################################         
 
    //Main Method  
 
    public static void main (String[]args)  
    {  
        Display a = new Display();  
    }  
 
    //###############################################################################         
 
 
    public void addComponent(Component component, int row, int column, int width,int height ){  
        constraints.gridx=column;  
        constraints.gridy=row;  
        constraints.gridwidth=width;  
        constraints.gridheight=height;  
        myPanel.add(component,constraints);  
 
 
 
 
 
    }  
 
 
}