我正在制作一个显示后台计算结果的 GUI。但在此之前，我想测试更改数据集。这是我的代码:

 DefaultXYDataset dataset = new DefaultXYDataset();
@Override
        public void run() {
                // TODO Auto-generated method stub
                for (int i = 0; i < periods; i++) {
                        series[0][i] = (double) i;
                        series[1][i] = 0;
                }
                dataset.addSeries("Series0", series);
                for (int it = 0; it < 10; it++) {
                        series[1][random.nextInt(periods)] =  random.nextInt(100) / 2;
                        double[][] d = new double[2][periods];
                        for (int i = 0; i < periods; i++) {
                                d[0][i] = series[0][i];
                                d[1][i] = series[1][i];
                        }
                        dataset.removeSeries("Series0");
                        dataset.addSeries("Series0", series);
//                      try {
//                              Thread.sleep(100);
//                      } catch (java.lang.InterruptedException ex) {
//                      }
                }

如您所见，我想更改图表上的点(每次它完成“一些复杂的计算”)——此更改在我在另一个类中调用的线程中进行。我的问题是整个概念都行不通。它抛出'系列索引越界'-IllegalArgumentException，'索引越界'-一些库内部数组列表等。我没有使用 DynamicTimeSeriesCollection 因为我需要 X 轴是我的内部迭代次数而不是时间期间，并且在“某些计算”完成时也不是每隔一段时间更新一次。你能告诉我我做错了什么吗？或者是否有更好的方法来更新/刷新图形？

最佳答案

您的代码段未正确同步；你应该从 SwingWorker 的 process() 方法更新你的 dataset ，如图here .因为您的域是“我的内部迭代次数”，所以不要使用 DateAxis；相反，使用 NumberAxis，如 ChartFactory.createXYLineChart() 中所示.

附录:example 的变体在折线图上绘制 worker 的进度。请注意，createXYLineChart() 对域和范围都使用了 NumberAxis。给定折线图数据集中的 series，还要注意 process() 的实现如何在新数据到达时安全地更新数据集；收听图表将自行更新以做出响应。

private XYSeries series = new XYSeries("Result");
…
@Override
protected void process(List<Double> chunks) {
    for (double d : chunks) {
        label.setText(df.format(d));
        series.add(++n, d);
    }
}

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.beans.PropertyChangeEvent;
import java.text.DecimalFormat;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JProgressBar;
import javax.swing.SwingWorker;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.xy.XYDataset;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;

/**
 * @see https://stackoverflow.com/a/13205322/230513
 * @see https://stackoverflow.com/questions/4637215
 */
public final class ChartWorker {

    private static final String S = "0.000000000000000";
    private final JProgressBar progressBar = new JProgressBar();
    private final JLabel label = new JLabel(S, JLabel.CENTER);
    private final XYSeries series = new XYSeries("Result");
    private final XYDataset dataset = new XYSeriesCollection(series);

    private void create() {
        JFrame f = new JFrame("√2");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(progressBar, BorderLayout.NORTH);
        JFreeChart chart = ChartFactory.createXYLineChart(
            "Newton's Method", "X", "Y", dataset,
            PlotOrientation.VERTICAL, false, true, false);
        XYPlot plot = (XYPlot) chart.getPlot();
        plot.getRangeAxis().setRange(1.4, 1.51);
        plot.getDomainAxis().setStandardTickUnits(
            NumberAxis.createIntegerTickUnits());
        XYLineAndShapeRenderer renderer
            = (XYLineAndShapeRenderer) plot.getRenderer();
        renderer.setSeriesShapesVisible(0, true);
        f.add(new ChartPanel(chart) {
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(640, 480);
            }
        }, BorderLayout.CENTER);
        f.add(label, BorderLayout.SOUTH);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
        runCalc();
    }

    private void runCalc() {
        progressBar.setIndeterminate(true);
        TwoWorker task = new TwoWorker();
        task.addPropertyChangeListener((PropertyChangeEvent e) -> {
            if ("progress".equals(e.getPropertyName())) {
                progressBar.setIndeterminate(false);
                progressBar.setValue((Integer) e.getNewValue());
            }
        });
        task.execute();
    }

    private class TwoWorker extends SwingWorker<Double, Double> {

        private static final int N = 5;
        private final DecimalFormat df = new DecimalFormat(S);
        double x = 1;
        private int n;

        @Override
        protected Double doInBackground() throws Exception {
            for (int i = 1; i <= N; i++) {
                x = x - (((x * x - 2) / (2 * x)));
                setProgress(i * (100 / N));
                publish(x);
                Thread.sleep(1000); // simulate latency
            }
            return x;
        }

        @Override
        protected void process(List<Double> chunks) {
            for (double d : chunks) {
                label.setText(df.format(d));
                series.add(++n, d);
            }
        }
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new ChartWorker()::create);
    }
}

关于java - 使用 JFreeChart 更改系列时出现随机错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/13205251/