12.7 實例2 · Java 開源項目中文文檔

## 12.7 實例2 ### 12.7.1 概述在本實例中，目的是在每個系列的標簽上顯示出值和百分比值（這個百分比值，這個系列在某一部分的條形直方圖或全部條形直方圖的總值中的比值）。如下圖12.4所示。 ![](img/jfc80114.png) 圖12.4 帶有比值的直方圖該實現中，標簽產生器計算出百分比。如果傳入構造函數的是一個種類索引，那么這個百分比的基數就是指定種類的當前系列的值。如果種類索引是無效的，那么這個基數就是指定種類的全部系列總和。標簽產生器會默認創建一個百分比格式——一種比較成熟的格式，提供格式化能力。 ### 12.7.2 源代碼 ``` package demo; import java.awt.Color; import java.awt.Dimension; import java.text.NumberFormat; import javax.swing.JPanel; import org.jfree.chart.ChartFactory; import org.jfree.chart.ChartPanel; import org.jfree.chart.JFreeChart; import org.jfree.chart.axis.AxisLocation; import org.jfree.chart.axis.NumberAxis; import org.jfree.chart.labels.AbstractCategoryItemLabelGenerator; import org.jfree.chart.labels.CategoryItemLabelGenerator; import org.jfree.chart.plot.CategoryPlot; import org.jfree.chart.plot.PlotOrientation; import org.jfree.chart.renderer.category.CategoryItemRenderer; import org.jfree.data.category.CategoryDataset; import org.jfree.data.category.DefaultCategoryDataset; import org.jfree.ui.ApplicationFrame; import org.jfree.ui.RefineryUtilities; public class ItemLabelDemo2 extends ApplicationFrame { static class LabelGenerator extends AbstractCategoryItemLabelGenerator implements CategoryItemLabelGenerator { private Integer category; private NumberFormat formatter = NumberFormat.getPercentInstance(); public LabelGenerator(int i) { this(new Integer(i)); } public LabelGenerator(Integer integer) { super("", NumberFormat.getInstance()); category = integer; } public String generateLabel(CategoryDataset categorydataset, int i, int i_0_) { String string = null; double d = 0.0; if (category != null) { Number number = categorydataset .getValue(i, category.intValue()); d = number.doubleValue(); } else d = calculateSeriesTotal(categorydataset, i); Number number = categorydataset.getValue(i, i_0_); if (number != null) { double d_1_ = number.doubleValue(); string = (number.toString() + " (" + formatter.format(d_1_ / d) + ")"); } return string; } private double calculateSeriesTotal(CategoryDataset categorydataset, int i) { double d = 0.0; for (int i_2_ = 0; i_2_ < categorydataset.getColumnCount(); i_2_++) { Number number = categorydataset.getValue(i, i_2_); if (number != null) d += number.doubleValue(); } return d; } } public ItemLabelDemo2(String string) { super(string); CategoryDataset categorydataset = createDataset(); JFreeChart jfreechart = createChart(categorydataset); ChartPanel chartpanel = new ChartPanel(jfreechart); chartpanel.setPreferredSize(new Dimension(500, 270)); setContentPane(chartpanel); } private static CategoryDataset createDataset() { DefaultCategoryDataset defaultcategorydataset = new DefaultCategoryDataset(); defaultcategorydataset.addValue(100.0, "S1", "C1"); defaultcategorydataset.addValue(44.3, "S1", "C2"); defaultcategorydataset.addValue(93.0, "S1", "C3"); defaultcategorydataset.addValue(80.0, "S2", "C1"); defaultcategorydataset.addValue(75.1, "S2", "C2"); defaultcategorydataset.addValue(15.1, "S2", "C3"); return defaultcategorydataset; } private static JFreeChart createChart(CategoryDataset categorydataset) { JFreeChart jfreechart = ChartFactory.createBarChart( "Item Label Demo 2", "Category", "Value", categorydataset, PlotOrientation.HORIZONTAL, true, true, false); jfreechart.setBackgroundPaint(Color.white); CategoryPlot categoryplot = (CategoryPlot) jfreechart.getPlot(); categoryplot.setBackgroundPaint(Color.lightGray); categoryplot.setDomainGridlinePaint(Color.white); categoryplot.setRangeGridlinePaint(Color.white); categoryplot.setRangeAxisLocation(AxisLocation.BOTTOM_OR_LEFT); NumberAxis numberaxis = (NumberAxis) categoryplot.getRangeAxis(); numberaxis.setUpperMargin(0.25); CategoryItemRenderer categoryitemrenderer = categoryplot.getRenderer(); categoryitemrenderer.setBaseItemLabelsVisible(true); categoryitemrenderer.setBaseItemLabelGenerator(new LabelGenerator( (Integer) null)); return jfreechart; } public static JPanel createDemoPanel() { JFreeChart jfreechart = createChart(createDataset()); return new ChartPanel(jfreechart); } public static void main(String[] strings) { ItemLabelDemo2 itemlabeldemo2 = new ItemLabelDemo2("Item Label Demo 2"); itemlabeldemo2.pack(); RefineryUtilities.centerFrameOnScreen(itemlabeldemo2); itemlabeldemo2.setVisible(true); } } ```