将 ChartPanel 添加到 JPanel

我这里有一些不起作用的代码：

    XYSeriesCollection dataset = new XYSeriesCollection();
    dataset.addSeries(series);
    JFreeChart chart = ChartFactory.createXYLineChart(null, null, null, dataset, PlotOrientation.HORIZONTAL, true, true, true);
    ChartPanel chartpanel = new ChartPanel(chart);

    chartpanel.setDomainZoomable(true);
    jPanel4.setLayout(new BorderLayout());
    jPanel4.add(chartpanel, BorderLayout.NORTH);

所以问题是带有图表的jPanel4不可见。当我将图表面板添加到框架并使其可见时，它就可以工作。

谁知道我的错误是什么？

这对我来说非常有效：

import java.awt.BorderLayout;

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.plot.PlotOrientation;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;

public class Main {
    public static void main(String[] args) {
        XYSeries series = new XYSeries("asdf");
        for (int i = 0; i < 100; i++)
            series.add(i, Math.random());
        XYSeriesCollection dataset = new XYSeriesCollection(series);
        JFreeChart chart = ChartFactory.createXYLineChart(null, null, null, dataset, PlotOrientation.HORIZONTAL, true, true, true);
        ChartPanel chartpanel = new ChartPanel(chart);
        chartpanel.setDomainZoomable(true);

        JPanel jPanel4 = new JPanel();
        jPanel4.setLayout(new BorderLayout());
        jPanel4.add(chartpanel, BorderLayout.NORTH);

        JFrame frame = new JFrame();
        frame.add(jPanel4);
        frame.pack();
        frame.setVisible(true);
    }
}

您能为我们提供更多代码吗？你是否放入了其他东西jPanel4？每个位置不能有超过一个组件（NORTH, SOUTH, WEST, EAST, CENTER）。您是否将面板放入框架中？