JFreeChart-为每个饼定制饼图标签

Question

我试图添加自定义渲染器的每个饼图在我的图表上的基础上，数据的类型是传递（整数vs美元，金额vs百分比）。但是，PieDataSet中的数据似乎只有1个键（然而，当数据集创建为DefaultCategoryDataSet时，它有Rowkey和Columnkey)。

在下面的图片中，我试图实现的是右边的图（“销售总额”）将显示美元金额($#,##0.00)。

我尝试了什么：我尝试创建一个自定义呈现器，并传入datatype的枚举，但这不起作用，因为数据类型是因为我无法确定呈现器中呈现的是哪个馅饼：

    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;
        }
    }

这可能吗？所有jFreeChart多个饼图演示在同一屏幕上显示了所有饼图中的对称数据类型。这需要分成两个单独的图/面板吗？如果是这样，那将是不幸的...

以下是SSCE（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，但似乎很管用。我所做的是将PieDataSet传递给GenerateSectionLabel并找出它在原始CategoryDataSet中的哪个列。根据我的理解，categorytopiedataset#equals(PieDataset)正在比较所有的键和值，看看它们是否匹配。这种方法根本不使用枚举，它只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));
  }
}

除非更熟悉JFree API的人有更好的解决方案，否则只创建单个饼图并将它们抛到x_axisboxlayout中可能会更干净。