Error: This dataset already contains a series with the key Object 1

Question

背景： 我正在将 x 和 y 值添加到 XYSeries 数据集，以便我可以呈现 jfreechart。每个 x 和 y 值都是从文本文件中读入的，并且是双精度值。我已将 x 和 y 值设置为等于文本的数组位置并将它们打印出来以检查结果。他们目前正在打印正确的结果。

问题： 但是，我无法将系列添加到我的 XYSeriesCollection。所以我创建了一个名为 series1 的 XYSeries 并添加了两个值。然后当我将该 series1 数据添加到 XYSeriesCollection 时，它会抛出：“此数据集已包含具有键对象 1 的系列”错误。

问题：这个错误是什么意思，我该如何解决？

代码：

    private void renderChartBtnActionPerformed(java.awt.event.ActionEvent evt) {                                               

        String manufacturer = "";
        
        XYSeriesCollection dcd = new XYSeriesCollection();
        
        String[] splitLine = new String[4];
        String[][] twoD_arr = new String[arraySize][4];
        int kount = 0;
        double dnum = 0;
        double dnum2 = 0;
        
         // Checks which radio button is selected and sets equal to manufacturer
        if (audiRB.isSelected()) {
            manufacturer = "Audi";
        }
        else if (volvoRB.isSelected()) {
            manufacturer = "Volvo";       
        }
        
        Iterator<String> itr = carData.iterator();
        while(itr.hasNext()){
            splitLine = itr.next().split(",");
            for(int i=0;i<=3;i++){
                twoD_arr[kount][i] = splitLine[i];
               
            }
            kount = kount + 1;
        }
        // Checks which data type is selected and adds data to series
        for(int i=0; i< twoD_arr.length; i++){
            if (pctShare.isSelected() && (twoD_arr[i][1]).equals(manufacturer)) {
                XYSeries series1 = new XYSeries("Object 1");
                                
                dnum = Double.parseDouble(twoD_arr[i][3]);
                dnum2 = Double.parseDouble(twoD_arr[i][0]);
                series1.add(dnum, dnum2);
                System.out.println(dnum);
                System.out.println(dnum2);
                dcd.addSeries(series1);
            } 
            else if (qtySold.isSelected() && (twoD_arr[i][1]).equals(manufacturer)) {
//                inum = Integer.parseInt(twoD_arr[i][2]);
//                dcd.setValue(inum, "Quantity Sold", twoD_arr[i][0]);
//                dcd.setValue(dnum, dnum, dnum);
//                System.out.println(twoD_arr[i][0] + twoD_arr[i][2]);
                     
            }                
        }
        
         // User selection of chart type        
         if( LineRB.isSelected()){
            jchart = ChartFactory.createXYLineChart("New Car Sales in Norway", "Date", manufacturer, dcd);
        }
        else if(AreaRB.isSelected()){
            jchart = ChartFactory.createXYAreaChart("New Car Sales in Norway", "Date", manufacturer, dcd, PlotOrientation.VERTICAL, true, true, false);
        }
        else if(barRB.isSelected()){
            jchart = ChartFactory.createXYStepAreaChart("New Car Sales in Norway", "Date", manufacturer, dcd, PlotOrientation.VERTICAL, true, true, false);       
        }
        else {
           jchart = null; 
        }
        
        // Add chart to panel
        ChartPanel chartPanel = new ChartPanel(jchart);
        inner_chart_pnl.removeAll();
        inner_chart_pnl.add(chartPanel);
        inner_chart_pnl.updateUI(); 

    }

我的图形界面：

Answer 1

一个XYSeriesCollection根据给每个系列的Comparable键区分它包含的系列。在您的示例中，key 是 String、"Object 1"。将数据添加到系列的循环尝试通过循环每次构造和添加系列。相反，在循环 before 之前创建系列，添加数据，然后 then 添加完整的系列 after已满：

XYSeries series1 = new XYSeries("Object 1");
for(int i=0; i< twoD_arr.length; i++) {
    //XYSeries series1 = new XYSeries("Object 1");
    …
    //dcd.addSeries(series1);
} 
dcd.addSeries(series1);

已显示完整示例 here。

Error: This dataset already contains a series with the key Object 1

Error: This dataset already contains a series with the key Object 1

java

swing

jfreechart

jbutton