java - jfreechart - 为每个饼图自定义饼图标签

Question

我正在尝试根据传递的数据类型(整数 vs 美元金额 vs 百分比)为图表上的每个饼图添加自定义渲染器。但是，PieDataset 中的数据似乎只有 1 个键(而当数据集创建为 DefaultCategoryDataset 时，它有一个 rowKey 和一个 columnKey )。

在下图中，我想要实现的是右侧的图表(“销售总额”)将显示美元金额( $ #,##0.00 )。



我尝试过的:我尝试创建一个自定义渲染器并传入数据类型的 ENUM，但这不起作用，因为数据类型，因为我无法在渲染器中确定正在渲染哪个馅饼:

    static class CustomLabelGenerator implements PieSectionLabelGenerator {
        public String generateSectionLabel(PieDataset dataset, Comparable key) {
            NumberFormat nf;
            // How do you find out which pie is being rendered? "key" relates to Bob, Sally, George, Tom, etc.
            switch (data_type) {
                case currency:
                    nf = new DecimalFormat("$ #,##0.00");
                    break;
                case integer:
                    nf = new DecimalFormat("#,##0");
                    break;
                case percentage:
                    nf = new DecimalFormat("#,##0.00 %");
                    break;
                default:
                    throw new IllegalStateException("Invalid ENUM. This is impossible");
            }
            return nf.format(dataset.getValue(key));
        }
        public AttributedString generateAttributedSectionLabel(
                PieDataset dataset, Comparable key) {
            return null;
        }
    }

这甚至可能吗？所有 jFreeChart 多饼图演示在同一屏幕上显示所有饼图的对称数据类型。这是否需要分成两个单独的图形/面板？要是这样就太可惜了……

这是 SSCCE(如果您有 jFreeChart 库):

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.text.AttributedString;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import javax.swing.JFrame;
import javax.swing.JPanel;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.labels.PieSectionLabelGenerator;
import org.jfree.chart.plot.MultiplePiePlot;
import org.jfree.chart.plot.PiePlot;
import org.jfree.data.category.CategoryDataset;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.data.general.PieDataset;
import org.jfree.util.TableOrder;

/**
 * This example is similar to {@link MultiplePieChartDemo1}, but slices the
 * dataset by column rather than by row.
 */
public class MultiplePieChart extends JPanel {

    /**
     * Creates a sample dataset.
     *
     * @return A sample dataset.
     */
    private static CategoryDataset createDataset() {
        int bob_quantity = 100;
        int sally_quantity = 115;
        int george_quantity = 112;
        int tom_quantity = 99;
        DefaultCategoryDataset dataset = new DefaultCategoryDataset();
        dataset.addValue(bob_quantity, "Bob", "Sales Quantity");
        dataset.addValue(sally_quantity, "Sally", "Sales Quantity");
        dataset.addValue(george_quantity, "George", "Sales Quantity");
        dataset.addValue(tom_quantity, "Tom", "Sales Quantity");

        double bob_total = 1450.40;
        double sally_total = 1545.12;
        double george_total = 1550.56;
        double tom_total = 1200.90;
        dataset.addValue(bob_total, "Bob", "Sales Total");
        dataset.addValue(sally_total, "Sally", "Sales Total");
        dataset.addValue(george_total, "George", "Sales Total");
        dataset.addValue(tom_total, "Tom", "Sales Total");

        return dataset;
    }

    /**
     * Creates a sample chart with the given dataset.
     *
     * @param dataset  the dataset.
     *
     * @return A sample chart.
     */
    private static JFreeChart createChart(CategoryDataset dataset, String chartTitle, boolean includeLegend, Data_Type data_type) {
        JFreeChart chart = ChartFactory.createMultiplePieChart(
            chartTitle,  // chart title
            dataset,               // dataset
            TableOrder.BY_COLUMN,
            includeLegend,                  // include legend
            true,
            false
        );
        MultiplePiePlot plot = (MultiplePiePlot) chart.getPlot();
        plot.setBackgroundPaint(Color.white);
        plot.setOutlineStroke(new BasicStroke(1.0f));

        JFreeChart subchart = plot.getPieChart();
        PiePlot p = (PiePlot) subchart.getPlot();

        p.setBackgroundPaint(null);
        p.setOutlineStroke(null);
        p.setStartAngle(0);

//        p.setLabelGenerator(new StandardPieSectionLabelGenerator("{0} ({2})",
//                NumberFormat.getNumberInstance(),
//                NumberFormat.getPercentInstance()));
        p.setMaximumLabelWidth(0.20);

        p.setLabelGenerator(new CustomLabelGenerator(data_type));


        return chart;
    }

    /**
     * Creates a panel for the demo (used by SuperDemo.java).
     *
     * @return A panel.
     */
    public static JPanel createPanel(CategoryDataset dataset, Dimension size, String chartTitle, boolean includeLegend, Data_Type data_type) {
        JFreeChart chart = createChart(dataset, chartTitle, includeLegend, data_type);
        ChartPanel panel = new ChartPanel(chart);
        panel.setMouseWheelEnabled(true);
        if(size != null)
            panel.setPreferredSize(size);
        return panel;
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        JPanel panel = createPanel(createDataset(), new Dimension(800, 500), "Sales", true, Data_Type.integer);
        frame.add(panel);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        frame.setLocationRelativeTo(null);
    }


    enum Data_Type {
        integer,
        percentage,
        currency
    }

    static class CustomLabelGenerator implements PieSectionLabelGenerator {


        private final Data_Type data_type;

        public CustomLabelGenerator(Data_Type data_type) {
            this.data_type = data_type;
        }

        public String generateSectionLabel(PieDataset dataset, Comparable key) {
            NumberFormat nf;
            switch (data_type) {
                case currency:
                    nf = new DecimalFormat("$ #,##0.00");
                    break;
                case integer:
                    nf = new DecimalFormat("#,##0");
                    break;
                case percentage:
                    nf = new DecimalFormat("#,##0.00 %");
                    break;
                default:
                    throw new IllegalStateException("Invalid ENUM. This is impossible");
            }
            return nf.format(dataset.getValue(key));
        }

        public AttributedString generateAttributedSectionLabel(
                PieDataset dataset, Comparable key) {
            return null;
        }

    }
}

Answer 1

这感觉有点笨拙，但似乎有效。我正在做的是带 PieDataset传递给 generateSectionLabel并找出它在原始 CategoryDataset 中的哪一列.据我了解 CategoryToPieDataset#equals(PieDataset)正在比较所有的键和值以查看它们是否匹配。这种方法根本不使用您的枚举，它只是查看它为哪个列生成:

static class CustomLabelGenerator implements PieSectionLabelGenerator {
  private final CategoryDataset catDataset;

  public CustomLabelGenerator(CategoryDataset catDataset) {
    this.catDataset = catDataset;
  }

  public String generateSectionLabel(PieDataset dataset, Comparable key) {
    int column = 0;
    for (int c = 0; c < catDataset.getColumnCount(); c++) {
      CategoryToPieDataset categoryToPieDataset = 
          new CategoryToPieDataset(catDataset, TableOrder.BY_COLUMN, c);
      if (categoryToPieDataset.equals(dataset)) {
        column = c;
        break;
      }
    }
    NumberFormat nf;
    switch (column) {
      case 0: // the 'Sales Quantity' column
        nf = new DecimalFormat("#,##0");
        break;
      case 1: // the 'Sales Total' column
        nf = new DecimalFormat("$ #,##0.00");
        break;
      default:
        throw new IllegalStateException("Invalid column. This is impossible");
    }
    return nf.format(dataset.getValue(key));
  }
}

结果:


除非更熟悉 JFree API 的人有更好的解决方案，否则创建单个饼图并将它们放入 X_AXIS 可能会更清晰。 BoxLayout .