How to plot a Line Graph in Java using dataset from a text file?

Question

I have written a Java GUI program which opens a text file and reads the data in the left panel. Now I want to display a graph of the data read from the same file on the righ

Answer 1

Starting from your example, note the following:

• Use a ChartPanel for your graphicsArea; then, your openAction() can simply invoke setChart().

• Parse the chosen file in creatChart(); the title and data lines are shown, but the remaining attributes are left as an exercise.

• Consider using Properties for your file format;

• For greater flexibility, use Action as shown here.

• To change the chart panel's default size, override getPreferredSize() as shown here.

• Swing GUI objects should be constructed and manipulated only on the event dispatch thread.

P.S. The graph should be plotted using AWT/Swing libraries only.

For a single chart, replace ChartPanel with JPanel and override paintComponent() to perform the rendering. You can transform coordinates using the approach is outlined here or here.

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTextArea;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;

//* @see https://stackoverflow.com/a/36764715/230513 */
public class GUI extends JFrame {

    public GUI() {
        super("Data Visualiser");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        final JMenuBar menuBar = new JMenuBar();
        setJMenuBar(menuBar);
        JMenu fileMenu = new JMenu("File");
        JMenu helpMenu = new JMenu("Help");
        menuBar.add(fileMenu);
        menuBar.add(helpMenu);

        final JMenuItem openAction = new JMenuItem("Open", new ImageIcon("images/Open-icon.png"));
        final JMenuItem saveAction = new JMenuItem("Save", new ImageIcon("images/save-file.png"));
        final JMenuItem exitAction = new JMenuItem("Exit", new ImageIcon("images/exit-icon.png"));
        final JMenuItem aboutAction = new JMenuItem("About", new ImageIcon("images/about-us.png"));

        final JTextArea textArea = new JTextArea(8, 16);
        textArea.setFont(new Font("Serif", Font.BOLD, 16));
        textArea.setLineWrap(true);
        textArea.setWrapStyleWord(true);
        textArea.setEditable(false);
        JScrollPane textScrollPane = new JScrollPane(textArea);
        textScrollPane.setBorder(BorderFactory.createCompoundBorder(
            BorderFactory.createTitledBorder("Textual Representation"),
            BorderFactory.createEmptyBorder(5, 5, 5, 5)));

        ChartPanel graphicsArea = new ChartPanel(null);
        graphicsArea.setBorder(BorderFactory.createCompoundBorder(
            BorderFactory.createTitledBorder("Graphical Representation"),
            BorderFactory.createEmptyBorder(5, 5, 5, 5)));

        JSplitPane splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, textScrollPane, graphicsArea);
        splitPane.setOneTouchExpandable(true);
        splitPane.setResizeWeight(0.5);
        add(splitPane, BorderLayout.LINE_END);

        fileMenu.setMnemonic(KeyEvent.VK_F);
        fileMenu.add(openAction);
        openAction.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent arg0) {
                if (arg0.getSource().equals(openAction)) {
                    JFileChooser fileChooser = new JFileChooser(new File("."));
                    if (fileChooser.showOpenDialog(fileChooser) == JFileChooser.APPROVE_OPTION) {
                        File file = fileChooser.getSelectedFile();
                        graphicsArea.setChart(creatChart(file));
                    }
                }
            }

            private JFreeChart creatChart(File file) {
                String title = null;
                String xAxisLabel = null;
                String yAxisLabel = null;
                BufferedReader in = null;
                int start = 0;
                int interval = 0;
                String data = null;
                String line = null;
                try {
                    in = new BufferedReader(new FileReader(file));
                    while ((line = in.readLine()) != null) {
                        textArea.append(line + "\n");
                        if (line.startsWith("Title")) {
                            title = line.split(":")[1].trim();
                        }
                        // parse other lines here
                        if (!line.contains(":")) {
                            data = line;
                        }
                    }
                } catch (IOException ex) {
                    ex.printStackTrace(System.err);
                }
                XYSeries dataset = new XYSeries(file.getName());
                for (String s : data.split(",")) {
                    dataset.add(start, Double.valueOf(s));
                    start += interval;
                }
                return ChartFactory.createXYLineChart(title,
                    xAxisLabel, yAxisLabel, new XYSeriesCollection(dataset));
            }
        });
        fileMenu.add(saveAction);
        fileMenu.add(exitAction);
        exitAction.setMnemonic(KeyEvent.VK_X);
        exitAction.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent arg0) {
                if (arg0.getSource().equals(exitAction)) {
                    System.exit(0);
                }
            }
        });
        fileMenu.addSeparator();
        helpMenu.addSeparator();
        helpMenu.add(aboutAction);
        aboutAction.setMnemonic(KeyEvent.VK_A);
        aboutAction.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                JOptionPane.showMessageDialog(null,
                    "Visualization tool.",
                    "About Us", JOptionPane.PLAIN_MESSAGE);
            }
        });
        pack();
        setLocationRelativeTo(null);
        setVisible(true);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(() -> {
            new GUI();
        });
    }
}