Question

我正在尝试根据传递的数据类型为我的图表上的每个饼图添加自定义渲染器（整数与美元金额与百分比）。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rowKey和columnKey。< / p>

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

enter image description here

我尝试了什么：我尝试创建自定义渲染器并传入数据类型的ENUM，但由于数据类型不起作用，因为我无法在渲染器中确定正在渲染哪个饼：

    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多个饼图演示都在同一屏幕上的所有饼图中显示对称数据类型。这是否需要分成两个单独的图/面板？如果是这样那将是不幸的......

这是SSCCE（如果你有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kludgy，但它似乎工作。我正在做的是将PieDataset传递给generateSectionLabel并确定原始CategoryDataset中的哪一列。据我所知，CategoryToPieDataset#equals(PieDataset)正在比较所有键和值，以确定它们是否匹配。这种方法根本不使用你的枚举，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： result

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其放入X_AXIS BoxLayout可能会更清晰。

jfreechart - 自定义每个饼图的饼图标签

1 个答案: