我从DynamicTimeSeriesCollection显示的JFreeCharts获得了源代码。
当我将它作为一个简单的Java应用程序运行时，它工作正常，但后来我想把它作为applet。
所以我制作了Applet代码，并在start（），paint（）和init（）函数中插入了所有代码。
当我执行“运行文件”时运行良好，但是当我尝试在Web浏览器上打开生成的HTML页面（启用Java SE 6）时，它会显示一个空白屏幕。我使用的是Netbeans 7.0。
代码如下，
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JApplet;
import javax.swing.JButton;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.time.DynamicTimeSeriesCollection;
import org.jfree.data.time.Second;
import org.jfree.data.xy.XYDataset;
import javax.swing.JComboBox;
import javax.swing.JPanel;
import javax.swing.Timer;
public class GraphTest extends JApplet {
private static final String TITLE = "ECG of the Patient";
private static final String START = "Start";
private static final String STOP = "Stop";
private static final float MINMAX = 100;
private static final int COUNT = 2 * 60;
private static final int FAST = 100;
private static final int SLOW = FAST * 5;
private Timer timer;
// private Object random;
//private static final Random random = new Random();
ReadAFile file_reader = new ReadAFile();
byte[] values = file_reader.Readfile();
float[] temp = new float[120];
public GraphTest() {
//super(title);
final DynamicTimeSeriesCollection dataset =
new DynamicTimeSeriesCollection(1, COUNT, new Second());
dataset.setTimeBase(new Second(0, 0, 0, 1, 1, 2011));
dataset.addSeries(temp, 0, "ECG Plot");
JFreeChart chart = createChart(dataset);
final JButton run = new JButton(STOP);
run.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
String cmd = e.getActionCommand();
if (STOP.equals(cmd)) {
timer.stop();
run.setText(START);
} else {
timer.start();
run.setText(STOP);
}
}
});
final JComboBox combo = new JComboBox();
combo.addItem("Fast");
combo.addItem("Slow");
combo.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if ("Fast".equals(combo.getSelectedItem())) {
timer.setDelay(FAST);
} else {
timer.setDelay(SLOW);
}
}
});
this.add(new ChartPanel(chart), BorderLayout.CENTER);
JPanel btnPanel = new JPanel(new FlowLayout());
btnPanel.add(run);
btnPanel.add(combo);
this.add(btnPanel, BorderLayout.SOUTH);
timer = new Timer(FAST, new ActionListener() {
float[] newData = new float[1];
int i = 0;
@Override
public void actionPerformed(ActionEvent e) {
newData[0] = values[i];
dataset.advanceTime();
dataset.appendData(newData);
i++;
}
});
}
/**
* Initialization method that will be called after the applet is loaded
* into the browser.
*/
@Override
public void init() {
EventQueue.invokeLater(new Runnable() {
private String TITLE;
// this.setLayout(new FlowLayout());
@Override
public void run() {
//DTSCTest demo = new DTSCTest(TITLE);
// DTSCTest demo = new DTSCTest(TITLE);
// pack();
//RefineryUtilities.centerFrameOnScreen();
//RefineryUtilities.centerFrameOnScreen(demo);
setVisible(true);
//demo.start();
}
});
// TODO start asynchronous download of heavy resources
}
@Override
public void paint(Graphics g) {
}
private JFreeChart createChart(final XYDataset dataset) {
final JFreeChart result = ChartFactory.createTimeSeriesChart(
TITLE, "hh:mm:ss", "Magnitude", dataset, true, true, false);
final XYPlot plot = result.getXYPlot();
ValueAxis domain = plot.getDomainAxis();
domain.setAutoRange(true);
ValueAxis range = plot.getRangeAxis();
range.setRange(-MINMAX, MINMAX);
return result;
}
@Override
public void start() {
timer.start();
}
}
这是另一个由此类调用的java文件
import java.io.*;
public class ReadAFile {
float[] datavalues = new float[300];
/**
* @param args the command line arguments
*/
public byte[] Readfile() {
StringBuilder contents = new StringBuilder();
try {
// use buffering, reading one line at a time
// FileReader always assumes default encoding is OK!
BufferedReader input = new BufferedReader(new FileReader("Desktop/Mytest.txt"));
try {
String line = null; // not declared within while loop
/*
* readLine is a bit quirky : it returns the content of a line
* MINUS the newline. it returns null only for the END of the
* stream. it returns an empty String if two newlines appear in
* a row.
*/
while ((line = input.readLine()) != null) {
contents.append(line);
}
} finally {
input.close();
}
} catch (IOException ex) { System.out.println("Exception coming ");
}
byte[] finalarray = new byte[contents.length()];
for (int ch = 0; ch < contents.length(); ++ch) {
char co = contents.charAt(ch);
int j = (int) co;
finalarray[ch] = (byte) j;
}
return finalarray;
}
}
答案 0 :(得分：0)
我可能看起来像是在重复自己（如果你看看我的其他答案），但是：永远不要覆盖Swing中的paint()方法！
如果你真的需要画一些东西，请覆盖paintComponent()。但在你的情况下，你应该简单地将一个JFreeChart的组件放在applet中（你在构造函数中做了什么），然后完成。
（只是为了完整性：所有GUI相关的东西都应该在AWT事件调度线程中完成，比如使用EventQueue.invokeLater（或者SwingUtilities.invokeLater）。在这个线程中不会调用Applet的构造函数，这意味着你不应该在构造函数中进行GUI初始化。最好将它放在从init方法调用的invokeLater中。）