JFreeChart：使用ChartMouseEvent在散点图上显示数据

Question

我的目标是用JFreeChart XY散点图显示一些数据，以便在按下jButton时显示该散点图，并且还可以单击该散点图上的数据点并查看有关它们的一些附加信息。在按下jButton之后，从外部数据文件导入数据点，并创建散点图。绘图按预期工作，但情节对鼠标单击没有反应。

我试图在包含散点图的图表面板中添加一个ChartMouseListener，但它似乎没有注册鼠标单击，或者对单击没有反应。

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();

在该部分之上创建散点图。所有这些代码都位于jButtonActionPerformed方法中，并被try和catch块包围（用于捕获处理图表数据所必需的BiffException、IOException和SQLEException）。

当单击散点图上的数据点时，应该会出现一个消息窗口，其中包含包含该数据点的XY系列的索引，该索引也应该由System.out.println传递，但单击数据点时实际上不会发生任何事情。代码有什么问题？谢谢你的帮助。

Answer 1

我设法找到了解决办法。代码很好，有一个更简单的错误--程序包含许多生成散点图的jButtons，但并不是每个jButton都创建一个带有ChartmouseListener的图表。当运行程序时，一个这样的jButton被推到了正确的jButton上，所以散点图不会对点击做出反应，因为它没有ChartmouseListener...

在寻找解决方案并尝试不同的选项时，我用同样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，并打印出点击数据点的x坐标。我把它贴在这里，也许它可以作为某人的一个例子（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;               

}