JFreeChart：使用ChartMouseEvent在散点图上显示数据

Question

我的目标是使用JFreeChart XY散点图显示一些数据，以便在按下jButton时显示该图，还应该可以单击该图上的数据点并查看有关它们的一些其他信息。按下jButton之后，将从外部数据文件中导入数据点，并创建散点图。绘图按预期方式工作，但是该绘图对鼠标单击没有反应。

我试图向包含散点图的图表面板添加一个ChartMouseListener，但是似乎它没有记录鼠标单击或对单击没有反应。

这是代码的一部分：

    ChartPanel chapa = new ChartPanel(scatterchart);

    chapa.addChartMouseListener(new ChartMouseListener(){

          @Override
          public void chartMouseClicked(ChartMouseEvent event){

                ChartEntity entity = event.getEntity();

                if (entity != null && entity instanceof XYItemEntity) {
                        XYItemEntity ent = (XYItemEntity) entity;

                        int serindex = ent.getSeriesIndex();
                        int itemindex = ent.getItem();

                        JOptionPane.showMessageDialog(null, serindex);
                        System.out.println(serindex);
                }
         }
         @Override
         public void chartMouseMoved(ChartMouseEvent cme) {}
    });

    jPanel2.setLayout(new java.awt.BorderLayout());
    jPanel2.add(chapa, BorderLayout.CENTER);
    jPanel2.validate();

在该部分上方创建了散点图。所有这些代码都位于jButtonActionPerformed方法内部，并由try and catch块包围（用于捕获处理图表数据所必需的BiffException，IOException和SQLException）。

在散点图上单击数据点时，将出现一个消息窗口，其中包含包含该数据点的XY系列索引，并且该索引也应由System.out.println传递，但实际上，当单击一个数据点。代码有什么问题？感谢您的帮助。

Answer 1

我设法找到了解决方案。代码很好，有一个简单的错误-程序包含许多生成散点图的jButton，但是并非每个jButton都使用chartMouseListener创建图表。运行该程序时，按下了一个这样的jButton而不是右边的jButton，因此散点图对点击没有反应，因为它只是没有chartMouseListener ...

当寻找解决方案并尝试不同的选项时，我以相同的想法编写了一个更简单的代码（只有一个jButton和一个jPanel）。它创建一个简单的散点图，并打印出单击的数据点的x坐标。我将其发布在这里，也许它可以作为某人的示例（将其复制并保存为“ graphclick”）：

import java.awt.BorderLayout;
import javax.swing.JOptionPane;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartMouseEvent;
import org.jfree.chart.ChartMouseListener;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.entity.ChartEntity;
import org.jfree.chart.entity.XYItemEntity;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;

public class graphclick extends javax.swing.JFrame {

    public graphclick() {
        initComponents();
    }

    private void initComponents() {

        jPanel1 = new javax.swing.JPanel();
        jButton1 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 0, Short.MAX_VALUE)
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 421, Short.MAX_VALUE)
        );

        jButton1.setText("jButton1");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addContainerGap())
            .addGroup(layout.createSequentialGroup()
                .addGap(365, 365, 365)
                .addComponent(jButton1)
                .addContainerGap(383, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(jButton1)
                .addContainerGap(59, Short.MAX_VALUE))
        );

        pack();
    }

    // HERE IS THE MAIN ACTION TAKING PLACE
    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         

        XYSeriesCollection impser = new XYSeriesCollection();
        try {
        XYSeries series1 = new XYSeries("Series1");
        series1.add(1.0, 2.0);
        series1.add(2.0, 2.5);
        series1.add(3.0, 2.0);

        impser.addSeries(series1);
        JFreeChart scatterchart = ChartFactory.createScatterPlot("", "X", "Y", impser);

        XYPlot xyplot = scatterchart.getXYPlot();
        ValueAxis domainAxis = xyplot.getDomainAxis(); // x-axis
        ValueAxis rangeAxis = xyplot.getRangeAxis();

        domainAxis.setRange(0.0, impser.getDomainUpperBound(false) + 1.0);
        rangeAxis.setRange(0.0, impser.getRangeUpperBound(true) + 1.0);

        jPanel1.removeAll();
        ChartPanel chapa = new ChartPanel(scatterchart);

        chapa.addChartMouseListener(new ChartMouseListener(){
            @Override
            public void chartMouseClicked(ChartMouseEvent event){

                ChartEntity entity = event.getEntity();

                if (entity != null && entity instanceof XYItemEntity) {
                    XYItemEntity ent = (XYItemEntity) entity;

                    int sindex = ent.getSeriesIndex();
                    int iindex = ent.getItem();

                    XYSeries ser = impser.getSeries(sindex);

                    System.out.println(impser.getX(sindex, iindex));

                }
            }
            @Override
            public void chartMouseMoved(ChartMouseEvent cme) {}
        });

        jPanel1.setLayout(new java.awt.BorderLayout());
        jPanel1.add(chapa, BorderLayout.CENTER);
        jPanel1.validate();

        } catch (Exception e) {
            JOptionPane.showMessageDialog(null, "Error: " + e.getMessage());
        }
    }                                        

    public static void main(String args[]) {

        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(graphclick.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(graphclick.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(graphclick.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(graphclick.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }

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

    private javax.swing.JButton jButton1;
    private javax.swing.JPanel jPanel1;               

}