如何在条形图中显示每个栏的栏值？ [英] How to display bar value for each bar in a bar graph?

问题描述

有必要查看条形图中条形的精确值，而不是Y轴的近似值。可能是做了什么？

感谢您的阅读！ 3.7.6您可以在BarPlot属性下选中显示标签框。

在之前的版本（3.1.4）中，我不得不创建一个ChartCustomizer类。

如果你需要格式化标签中的数字（例如，百分比，添加千位分隔符等），那么您肯定需要ChartCustomizer，即使在新版本中也是如此。

简单例如：

  import java.text.NumberFormat; 
 
导入net.sf.jasperreports.engine.JRChart; 
导入net.sf.jasperreports.engine.JRChartCustomizer; 
 
导入org.jfree.chart.JFreeChart; 
 import org.jfree.chart.labels.AbstractCategoryItemLabelGenerator; 
 import org.jfree.chart.labels.CategoryItemLabelGenerator; 
 import org.jfree.chart.plot.CategoryPlot; 
 import org.jfree.chart.renderer.category.BarRenderer; 
 import org.jfree.chart.renderer.category.CategoryItemRenderer; 
 import org.jfree.data.category.CategoryDataset; 
 
 
 public class SimpleBarChartCustomizer实现JRChartCustomizer {
 $ b $ public void customize（JFreeChart chart，JRChart jasperChart）{
 CategoryPlot plot = chart.getCategoryPlot（）; 
 BarRenderer渲染器=（BarRenderer）plot.getRenderer（）; 
 
 CategoryItemRenderer catRenderer =（（CategoryItemRenderer）renderer）; 
 catRenderer.setBaseItemLabelGenerator（new NumberLabelGenerator（，NumberFormat.getInstance（）））; 
 
 
 
 
 
静态类NumberLabelGenerator extends AbstractCategoryItemLabelGenerator实现CategoryItemLabelGenerator {
 public NumberLabelGenerator（String labelFormat，
 NumberFormat formatter，NumberFormat percentFormatter）{
 super（labelFormat，formatter，percentFormatter）; 
 
 
保护NumberLabelGenerator（字符串labelFormat，NumberFormat格式化程序）{
 super（labelFormat，formatter）; 
} 
 
 private NumberFormat formatter = NumberFormat.getInstance（）; 
 
 public String generateLabel（CategoryDataset dataset，int series，int category）{
 Number b = dataset.getValue（series，category）; 
 formatter.setMaximumFractionDigits（2）; 
返回formatter.format（b）; 
} 
 
} 
} 
  

There is a need to see the exact value that a bar in a bar graph represents, as opposed to the approximate value in the Y axis.

How can that be possibly done?

Thanks for reading!

解决方案

In iReport 3.7.6 you can just check "Show Labels" box under BarPlot properties.

In a prior version (3.1.4), I had to create a ChartCustomizer class.

If you need to format the number in the label (e.g. to Percentage, add thousands separator, etc), then you definitely need a ChartCustomizer, even in the new version.

A simple example:

import java.text.NumberFormat;

import net.sf.jasperreports.engine.JRChart;
import net.sf.jasperreports.engine.JRChartCustomizer;

import org.jfree.chart.JFreeChart;
import org.jfree.chart.labels.AbstractCategoryItemLabelGenerator;
import org.jfree.chart.labels.CategoryItemLabelGenerator;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.renderer.category.BarRenderer;
import org.jfree.chart.renderer.category.CategoryItemRenderer;
import org.jfree.data.category.CategoryDataset;


public class SimpleBarChartCustomizer implements JRChartCustomizer {

    public void customize(JFreeChart chart, JRChart jasperChart) {
        CategoryPlot plot = chart.getCategoryPlot();
        BarRenderer renderer = (BarRenderer) plot.getRenderer();

        CategoryItemRenderer catRenderer = ((CategoryItemRenderer)renderer);
        catRenderer.setBaseItemLabelGenerator(new NumberLabelGenerator("", NumberFormat.getInstance()));

    }

    static class NumberLabelGenerator extends AbstractCategoryItemLabelGenerator implements CategoryItemLabelGenerator {
        public NumberLabelGenerator(String labelFormat,
                NumberFormat formatter, NumberFormat percentFormatter) {
            super(labelFormat, formatter, percentFormatter);
        }

        protected NumberLabelGenerator(String labelFormat,  NumberFormat formatter) {
            super(labelFormat, formatter);
        }

        private NumberFormat formatter = NumberFormat.getInstance();

        public String generateLabel(CategoryDataset dataset, int series, int category) {
            Number b = dataset.getValue(series, category);
            formatter.setMaximumFractionDigits(2);
            return formatter.format(b);
        }

    }
}

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