2D graph in jPanel in Netbeans

Question

I have a question concerning some primitive graphics. I am new to java graphics and gui building in general, so I get a lot of questions.
I am using Netbeans 6.9.1. Basically, there is a Main frame and a panel inside it. I want to draw a graph inside the panel. Well, the question is to do that? Below is code for three of the class (mostly auto-generated):

   package graphics;

import org.jdesktop.application.Action;
import org.jdesktop.application.ResourceMap;
import org.jdesktop.application.SingleFrameApplication;
import org.jdesktop.application.FrameView;
import org.jdesktop.application.TaskMonitor;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.Timer;
import javax.swing.Icon;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JPanel;
/**
 * The application's main frame.
 */
public class GraphicsView extends FrameView {

public GraphicsView(SingleFrameApplication app) {
    super(app);

    initComponents();

    jPanel1.add(new Graph());

    // status bar initialization - message timeout, idle icon and busy animation, etc
    ResourceMap resourceMap = getResourceMap();
    int messageTimeout = resourceMap.getInteger("StatusBar.messageTimeout");
    messageTimer = new Timer(messageTimeout, new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            statusMessageLabel.setText("");
        }
    });
    messageTimer.setRepeats(false);
    int busyAnimationRate = resourceMap.getInteger("StatusBar.busyAnimationRate");
    for (int i = 0; i < busyIcons.length; i++) {
        busyIcons[i] = resourceMap.getIcon("StatusBar.busyIcons[" + i + "]");
    }
    busyIconTimer = new Timer(busyAnimationRate, new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            busyIconIndex = (busyIconIndex + 1) % busyIcons.length;
            statusAnimationLabel.setIcon(busyIcons[busyIconIndex]);
        }
    });
    idleIcon = resourceMap.getIcon("StatusBar.idleIcon");
    statusAnimationLabel.setIcon(idleIcon);
    progressBar.setVisible(false);

    // connecting action tasks to status bar via TaskMonitor
    TaskMonitor taskMonitor = new TaskMonitor(getApplication().getContext());
    taskMonitor.addPropertyChangeListener(new java.beans.PropertyChangeListener() {
        public void propertyChange(java.beans.PropertyChangeEvent evt) {
            String propertyName = evt.getPropertyName();
            if ("started".equals(propertyName)) {
                if (!busyIconTimer.isRunning()) {
                    statusAnimationLabel.setIcon(busyIcons[0]);
                    busyIconIndex = 0;
                    busyIconTimer.start();
                }
                progressBar.setVisible(true);
                progressBar.setIndeterminate(true);
            } else if ("done".equals(propertyName)) {
                busyIconTimer.stop();
                statusAnimationLabel.setIcon(idleIcon);
                progressBar.setVisible(false);
                progressBar.setValue(0);
            } else if ("message".equals(propertyName)) {
                String text = (String)(evt.getNewValue());
                statusMessageLabel.setText((text == null) ? "" : text);
                messageTimer.restart();
            } else if ("progress".equals(propertyName)) {
                int value = (Integer)(evt.getNewValue());
                progressBar.setVisible(true);
                progressBar.setIndeterminate(false);
                progressBar.setValue(value);
            }
        }
    });
}

@Action
public void showAboutBox() {
    if (aboutBox == null) {
        JFrame mainFrame = GraphicsApp.getApplication().getMainFrame();
        aboutBox = new GraphicsAboutBox(mainFrame);
        aboutBox.setLocationRelativeTo(mainFrame);
    }
    GraphicsApp.getApplication().show(aboutBox);
}

/** This method is called from within the constructor to
 * initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is
 * always regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

    mainPanel = new javax.swing.JPanel();
    jPanel1 = new javax.swing.JPanel();
    menuBar = new javax.swing.JMenuBar();
    javax.swing.JMenu fileMenu = new javax.swing.JMenu();
    javax.swing.JMenuItem exitMenuItem = new javax.swing.JMenuItem();
    javax.swing.JMenu helpMenu = new javax.swing.JMenu();
    javax.swing.JMenuItem aboutMenuItem = new javax.swing.JMenuItem();
    statusPanel = new javax.swing.JPanel();
    javax.swing.JSeparator statusPanelSeparator = new javax.swing.JSeparator();
    statusMessageLabel = new javax.swing.JLabel();
    statusAnimationLabel = new javax.swing.JLabel();
    progressBar = new javax.swing.JProgressBar();

    mainPanel.setName("mainPanel"); // NOI18N

    jPanel1.setName("jPanel1"); // NOI18N

    javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 380, Short.MAX_VALUE)
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 229, Short.MAX_VALUE)
    );

    javax.swing.GroupLayout mainPanelLayout = new javax.swing.GroupLayout(mainPanel);
    mainPanel.setLayout(mainPanelLayout);
    mainPanelLayout.setHorizontalGroup(
        mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(mainPanelLayout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addContainerGap())
    );
    mainPanelLayout.setVerticalGroup(
        mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(mainPanelLayout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addContainerGap())
    );

    menuBar.setName("menuBar"); // NOI18N

    org.jdesktop.application.ResourceMap resourceMap = org.jdesktop.application.Application.getInstance(graphics.GraphicsApp.class).getContext().getResourceMap(GraphicsView.class);
    fileMenu.setText(resourceMap.getString("fileMenu.text")); // NOI18N
    fileMenu.setName("fileMenu"); // NOI18N

    javax.swing.ActionMap actionMap = org.jdesktop.application.Application.getInstance(graphics.GraphicsApp.class).getContext().getActionMap(GraphicsView.class, this);
    exitMenuItem.setAction(actionMap.get("quit")); // NOI18N
    exitMenuItem.setName("exitMenuItem"); // NOI18N
    fileMenu.add(exitMenuItem);

    menuBar.add(fileMenu);

    helpMenu.setText(resourceMap.getString("helpMenu.text")); // NOI18N
    helpMenu.setName("helpMenu"); // NOI18N

    aboutMenuItem.setAction(actionMap.get("showAboutBox")); // NOI18N
    aboutMenuItem.setName("aboutMenuItem"); // NOI18N
    helpMenu.add(aboutMenuItem);

    menuBar.add(helpMenu);

    statusPanel.setName("statusPanel"); // NOI18N

    statusPanelSeparator.setName("statusPanelSeparator"); // NOI18N

    statusMessageLabel.setName("statusMessageLabel"); // NOI18N

    statusAnimationLabel.setHorizontalAlignment(javax.swing.SwingConstants.LEFT);
    statusAnimationLabel.setName("statusAnimationLabel"); // NOI18N

    progressBar.setName("progressBar"); // NOI18N

    javax.swing.GroupLayout statusPanelLayout = new javax.swing.GroupLayout(statusPanel);
    statusPanel.setLayout(statusPanelLayout);
    statusPanelLayout.setHorizontalGroup(
        statusPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(statusPanelSeparator, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE)
        .addGroup(statusPanelLayout.createSequentialGroup()
            .addContainerGap()
            .addComponent(statusMessageLabel)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 230, Short.MAX_VALUE)
            .addComponent(progressBar, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addComponent(statusAnimationLabel)
            .addContainerGap())
    );
    statusPanelLayout.setVerticalGroup(
        statusPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(statusPanelLayout.createSequentialGroup()
            .addComponent(statusPanelSeparator, javax.swing.GroupLayout.PREFERRED_SIZE, 2, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addGroup(statusPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(statusMessageLabel)
                .addComponent(statusAnimationLabel)
                .addComponent(progressBar, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(3, 3, 3))
    );

    setComponent(mainPanel);
    setMenuBar(menuBar);
    setStatusBar(statusPanel);
}// </editor-fold>

// Variables declaration - do not modify
private javax.swing.JPanel jPanel1;
private javax.swing.JPanel mainPanel;
private javax.swing.JMenuBar menuBar;
private javax.swing.JProgressBar progressBar;
private javax.swing.JLabel statusAnimationLabel;
private javax.swing.JLabel statusMessageLabel;
private javax.swing.JPanel statusPanel;
// End of variables declaration

private final Timer messageTimer;
private final Timer busyIconTimer;
private final Icon idleIcon;
private final Icon[] busyIcons = new Icon[15];
private int busyIconIndex = 0;

private JDialog aboutBox;
}

So, here I have added only

jPanel1.add(new Graph());

The next is main class:

package graphics;

import org.jdesktop.application.Application;
import org.jdesktop.application.SingleFrameApplication;

/**
* The main class of the application.
*/
public class GraphicsApp extends SingleFrameApplication {

/**
 * At startup create and show the main frame of the application.
 */
@Override protected void startup() {
    show(new GraphicsView(this));
}

/**
 * This method is to initialize the specified window by injecting resources.
 * Windows shown in our application come fully initialized from the GUI
 * builder, so this additional configuration is not needed.
 */
@Override protected void configureWindow(java.awt.Window root) {
}

/**
 * A convenient static getter for the application instance.
 * @return the instance of GraphicsApp
 */
public static GraphicsApp getApplication() {
    return Application.getInstance(GraphicsApp.class);
}

/**
 * Main method launching the application.
 */
public static void main(String[] args) {
    launch(GraphicsApp.class, args);
}
}

At the last class is with graphics itself:

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
*/

package graphics;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import javax.swing.JPanel;

public class Graph extends JPanel{

int[] data = {
    21, 14, 18, 03, 86, 88, 74, 87, 54, 77,
    61, 55, 48, 60, 49, 36, 38, 27, 20, 18
};
final int PAD = 20;

 protected void paintComponent(Graphics g) {
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D)g;
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                        RenderingHints.VALUE_ANTIALIAS_ON);
    int w = getWidth();
    int h = getHeight();
    // Draw ordinate.
    g2.draw(new Line2D.Double(PAD, PAD, PAD, h-PAD));
    // Draw abcissa.
    g2.draw(new Line2D.Double(PAD, h-PAD, w-PAD, h-PAD));
    double xInc = (double)(w - 2*PAD)/(data.length-1);
    double scale = (double)(h - 2*PAD)/getMax();
    // Mark data points.
    g2.setPaint(Color.red);
    for(int i = 0; i < data.length; i++) {
        double x = PAD + i*xInc;
        double y = h - PAD - scale*data[i];
        g2.fill(new Ellipse2D.Double(x-2, y-2, 4, 4));
    }
}

private int getMax() {
    int max = -Integer.MAX_VALUE;
    for(int i = 0; i < data.length; i++) {
        if(data[i] > max)
            max = data[i];
    }
    return max;
}
}

I have several questions:
(a) How to I make graph appear in jPanel1?
(b) What are good practices in initialization graphical components? I mean, where is the best place to call for graph()?
(c) For a different application I have used jfreechart to draw graphs and then dump them to a .jpeg file. Can I use jfreechart to build graphs and to show it directly in a pagel?

Thank you very much in advance!

Answer 1

Some answers:

(a) Have jPanel1 use BorderLayout for its layout manager and add the graph JPanel to jPanel1 in the BorderLayout.CENTER position.
(b) I'm not clear what you're asking here. You construct an object when you need it.
(c) Yes. JFreeChart's graph components extend Swing components, I believe JPanel (either that or JComponent), so you should be able to directly add them to your GUI as a component, as long as (and this is key), your component acting as a container, that is the one holding the chart, uses the right layout manager. If you haven't already done so, you should read the Swing tutorial on "Laying out Components in a Container" because it's information is key for this to succeed.

My final recommendation (for now) is to ditch the NetBeans code generation and create your Swing code by hand. It's really the best way to learn Swing.

Luck!