这是基于@trashgod 的代码example https://stackoverflow.com/a/21307289/230513关于实时绘图:
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.SimpleDateFormat;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.time.DynamicTimeSeriesCollection;
import org.jfree.data.time.Second;
/**
* @see https://stackoverflow.com/a/21307289/230513
*/
public class DynamicTimeSeriesChart extends JPanel {
private static final long serialVersionUID = 5128935838291298041L;
private final DynamicTimeSeriesCollection dataset;
private final JFreeChart chart;
public DynamicTimeSeriesChart(final String title) {
dataset = new DynamicTimeSeriesCollection(1, 1000, new Second());
dataset.setTimeBase(new Second(0, 0, 0, 1, 1, 2014));
dataset.addSeries(new float[1], 0, title);
chart = ChartFactory.createTimeSeriesChart(
title, "Time", title, dataset, true, true, false);
final XYPlot plot = chart.getXYPlot();
DateAxis axis = (DateAxis) plot.getDomainAxis();
axis.setFixedAutoRange(10000);
axis.setDateFormatOverride(new SimpleDateFormat("ss.SS"));
final ChartPanel chartPanel = new ChartPanel(chart);
add(chartPanel);
}
public void update(float value) {
float[] newData = new float[1];
newData[0] = value;
dataset.advanceTime();
dataset.appendData(newData);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame = new JFrame("testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final DynamicTimeSeriesChart chart
= new DynamicTimeSeriesChart("Alternating data");
frame.add(chart);
frame.pack();
Timer timer = new Timer(1000, new ActionListener() {
private boolean b;
@Override
public void actionPerformed(ActionEvent e) {
chart.update(b ? 1 : 0);
b = !b;
}
});
timer.start();
frame.setVisible(true);
}
});
}
}
运行Java后,我仍然不明白为什么图表从40秒开始,尽管new Seconds
从0开始?
运行代码;找不到任何 40 秒启动的设置。
另外,如何向后滚动图表以查看以前的数据。
该图表从用于构建该日期的午夜后 16 分 40 秒开始Second
传递给setTimeBase()
。这与 1000 个间隔相同,每个间隔一秒,在nMoments
构造函数参数。如果时间设置为午夜,则可以使用一些可能的替代方案来获得从零开始的显示。
-
Make nMoments
的倍数60
.
dataset = new DynamicTimeSeriesCollection(1, 960, new Second());
dataset.setTimeBase(new Second(0, 0, 0, 1, 1, 2014));
-
减去nMoments
从名义基准日算起。
int nMoments = 1000;
dataset = new DynamicTimeSeriesCollection(1, nMoments, new Second());
Calendar c = Calendar.getInstance();
c.setTime(new Date(0));
c.add(Calendar.SECOND, -nMoments);
dataset.setTimeBase(new Second(c.getTime()));
两种方法都会产生相同的显示。
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