Swing GUI JPanelに表示するカスタムペイントコンポーネントを取得する方法

Java Swing GUIを使用してNetBeansで表示パネルを作成しています。このGUIでJPanelにグラフを描画する必要があります。グラフを描画するために、GraphPanelという別のクラスを作成しました。

package softwaredevelopmentgroupproject;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class GraphPanel extends JPanel
{
    private int[] graphSource;

    public GraphPanel()
    {
        graphSource = new int[] {2, 4, 9, 8, 13, 3, 8};
        //setUpPanel();
    }

    public void setUpPanel() 
    {
        this.setBackground(Color.LIGHT_GRAY);
    }

    @Override
    protected void paintComponent(Graphics currentGraphics)
    {
        super.paintComponent(currentGraphics);

        Graphics2D mainGraphics = (Graphics2D) currentGraphics;

        for(int i = 0; i < graphSource.length; i++)
        {
            int height = this.getHeight()/graphSource.length;
            int width = graphSource[i];
            int xPosition = 0;
            int yPosition = height * i;

            int red = (int)(Math.random() * 256);
            int green = (int)(Math.random() * 256);
            int blue = (int)(Math.random() * 256);
            int alpha = (int)(Math.random() * 255);

            mainGraphics.setColor(new Color(red, green, blue, alpha));
            mainGraphics.fill(new Rectangle(xPosition, yPosition, width, height));
        }
    }
}

問題は、以下のコードをGraphPanelクラスに含めた場合にのみ、このグラフを別のJFrameに表示できることです。

public static void main(String[] args)
    {
        JFrame jp1 = new JFrame();
        GraphPanel graph = new GraphPanel();
        jp1.add(graph, BorderLayout.CENTER);
        jp1.setSize(new Dimension(200,200));
        jp1.setVisible(true);
    }

これが、swing GUIのコードです。

package softwaredevelopmentgroupproject;

import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.util.ArrayList;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.table.DefaultTableModel;

public class AppGUI extends javax.swing.JFrame {

    public AppGUI() 
    {
        initComponents();
        displayProperties();
        //displayBarChart();
    }

    public ArrayList<String> getProperties()
    {
        ArrayList<String> propertiesList = new ArrayList<>();

        try
        {
            String propertyName = "3 bedroom house overlooking seafront";
            String propertyAddress = "139 Archard Street, N69 7GG";
            double price = 957.90;
            String displayPrice = "£" + price + " per month";
            String value = propertyName + System.lineSeparator() + propertyAddress + System.lineSeparator() + displayPrice + System.lineSeparator();
            propertiesList.add(propertyName);
            propertiesList.add(propertyAddress);
            propertiesList.add(displayPrice);
        }
        catch(Exception e)
        {
            JOptionPane.showMessageDialog(null, e);
        }
        return propertiesList;
    }

    public void displayProperties()
    {
        ArrayList<String> list = getProperties();
        //propertyListings.setModel(new PropertyTableModel(td, col));
        DefaultTableModel model = (DefaultTableModel) propertyListings.getModel();
        //propertyListings.setDefaultRenderer(AppGUI.class, model);
        //propertyListings.getColumnModel().getColumn(0).setCellRenderer(model);
        Object[] row = new Object[1]; //list.size()

        for(int i = 0; i < list.size(); i++)
        {
            row[0] = list.get(i);
            model.addRow(row);
        }
    }

    public void displayBarChart()
    {
        GraphPanel graph = new GraphPanel();
        Graphics graphics = graph.getGraphics();
        graphPanel.paint(graphics);
        graphPanel.repaint();
        //graphPanel.add(graph, FlowLayout.CENTER);
        //graphPanel.setSize(new Dimension(200,200));
        //graphPanel.setVisible(true);
    }

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jScrollPane1 = new javax.swing.JScrollPane();
        jTable1 = new javax.swing.JTable();
        topPanel = new javax.swing.JPanel();
        dateTimeDisplay = new javax.swing.JLabel();
        welcomeMessage = new javax.swing.JLabel();
        searchPanel = new javax.swing.JPanel();
        enterPrice1 = new javax.swing.JTextField();
        toLabel = new javax.swing.JLabel();
        enterPrice2 = new javax.swing.JTextField();
        searchPropertiesButton = new javax.swing.JButton();
        jPanel3 = new javax.swing.JPanel();
        jScrollPane2 = new javax.swing.JScrollPane();
        propertyListings = new javax.swing.JTable();
        graphPanel = new java.awt.Panel();

        jTable1.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {
                {null, null, null, null},
                {null, null, null, null},
                {null, null, null, null},
                {null, null, null, null}
            },
            new String [] {
                "Title 1", "Title 2", "Title 3", "Title 4"
            }
        ));
        jScrollPane1.setViewportView(jTable1);

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        topPanel.setBackground(new java.awt.Color(67, 38, 126));
        topPanel.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.RAISED));

        dateTimeDisplay.setText("Date/Time");

        welcomeMessage.setText("Welcome back, blah");

        javax.swing.GroupLayout topPanelLayout = new javax.swing.GroupLayout(topPanel);
        topPanel.setLayout(topPanelLayout);
        topPanelLayout.setHorizontalGroup(
            topPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(topPanelLayout.createSequentialGroup()
                .addGap(65, 65, 65)
                .addComponent(dateTimeDisplay)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addComponent(welcomeMessage)
                .addGap(182, 182, 182))
        );
        topPanelLayout.setVerticalGroup(
            topPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(topPanelLayout.createSequentialGroup()
                .addGap(8, 8, 8)
                .addGroup(topPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(dateTimeDisplay)
                    .addComponent(welcomeMessage))
                .addGap(0, 16, Short.MAX_VALUE))
        );

        enterPrice1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                enterPrice1ActionPerformed(evt);
            }
        });

        toLabel.setText("to");

        enterPrice2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                enterPrice2ActionPerformed(evt);
            }
        });

        searchPropertiesButton.setBackground(new java.awt.Color(67, 38, 126));
        searchPropertiesButton.setText("Search for a property");
        searchPropertiesButton.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                searchPropertiesButtonActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout searchPanelLayout = new javax.swing.GroupLayout(searchPanel);
        searchPanel.setLayout(searchPanelLayout);
        searchPanelLayout.setHorizontalGroup(
            searchPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(searchPanelLayout.createSequentialGroup()
                .addGap(28, 28, 28)
                .addComponent(enterPrice1, javax.swing.GroupLayout.PREFERRED_SIZE, 77, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(toLabel)
                .addGap(18, 18, 18)
                .addComponent(enterPrice2, javax.swing.GroupLayout.PREFERRED_SIZE, 79, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(47, 47, 47)
                .addComponent(searchPropertiesButton)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        searchPanelLayout.setVerticalGroup(
            searchPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(searchPanelLayout.createSequentialGroup()
                .addGap(30, 30, 30)
                .addGroup(searchPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(enterPrice1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(toLabel)
                    .addComponent(enterPrice2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(searchPropertiesButton))
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );

        javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3);
        jPanel3.setLayout(jPanel3Layout);
        jPanel3Layout.setHorizontalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 467, Short.MAX_VALUE)
        );
        jPanel3Layout.setVerticalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 7, Short.MAX_VALUE)
        );

        propertyListings.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {

            },
            new String [] {
                "Property Listings in Oslo"
            }
        ));
        jScrollPane2.setViewportView(propertyListings);

        graphPanel.addContainerListener(new java.awt.event.ContainerAdapter() {
            public void componentAdded(java.awt.event.ContainerEvent evt) {
                graphPanelComponentAdded(evt);
            }
        });
        graphPanel.addComponentListener(new java.awt.event.ComponentAdapter() {
            public void componentShown(java.awt.event.ComponentEvent evt) {
                graphPanelComponentShown(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(topPanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addComponent(searchPanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jPanel3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(0, 0, Short.MAX_VALUE))
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addGap(0, 0, Short.MAX_VALUE)
                        .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 444, javax.swing.GroupLayout.PREFERRED_SIZE)))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(graphPanel, javax.swing.GroupLayout.PREFERRED_SIZE, 410, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(38, 38, 38))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addComponent(topPanel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(1, 1, 1)
                .addComponent(searchPanel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(36, 36, 36)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(graphPanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jScrollPane2, javax.swing.GroupLayout.DEFAULT_SIZE, 391, Short.MAX_VALUE))
                .addGap(28, 28, 28)
                .addComponent(jPanel3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        

    private void enterPrice1ActionPerformed(java.awt.event.ActionEvent evt) {                                            
        // TODO add your handling code here:
    }                                           

    private void searchPropertiesButtonActionPerformed(java.awt.event.ActionEvent evt) {                                                       
        // TODO add your handling code here:
    }                                                      

    private void enterPrice2ActionPerformed(java.awt.event.ActionEvent evt) {                                            
        // TODO add your handling code here:
    }                                           

    private void graphPanelComponentShown(java.awt.event.ComponentEvent evt) {                                          

    }                                         

    private void graphPanelComponentAdded(java.awt.event.ContainerEvent evt) {                                          
        // TODO add your handling code here:
    }                                         


    public static void main(String args[]) 
    {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(AppGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(AppGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(AppGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(AppGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() 
        {
            public void run() 
            {
                new AppGUI().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JLabel dateTimeDisplay;
    private javax.swing.JTextField enterPrice1;
    private javax.swing.JTextField enterPrice2;
    public java.awt.Panel graphPanel;
    private javax.swing.JPanel jPanel3;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JScrollPane jScrollPane2;
    private javax.swing.JTable jTable1;
    private javax.swing.JTable propertyListings;
    private javax.swing.JPanel searchPanel;
    private javax.swing.JButton searchPropertiesButton;
    private javax.swing.JLabel toLabel;
    private javax.swing.JPanel topPanel;
    private javax.swing.JLabel welcomeMessage;
    // End of variables declaration                   

}

グラフを表示するためにさまざまなメソッドをテストしていたので、コードはかなり面倒で、うまくいけばそれは読みやすいでしょう。私のdisplayBarChartメソッドは、それをGUIに表示する試みですが、何らかの理由でまったく表示されません。