我试图在按下 NetBeans 中的 JButton
时使用 JFreeChart
进行拨号。问题是,虽然代码在 JButton
外部看起来没问题,但当我将其放入内部时,它会在程序中出现错误。
private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here
}
public class DemoChartProblem {
private final DefaultValueDataset dataset = new DefaultValueDataset(50);
private final JFrame frame = new JFrame();
public void main(String[] args) throws Exception {
new DemoChartProblem();
}
public DemoChartProblem() {
frame.setPreferredSize(new Dimension(300, 300));
frame.add(buildDialPlot(0, 30, 5));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
frame.setVisible(true);
}
});
}
private ChartPanel buildDialPlot(int minimumValue, int maximumValue,
int majorTickGap) {
DialPlot plot = new DialPlot(dataset);
plot.setDialFrame(new StandardDialFrame());
plot.addLayer(new DialValueIndicator(0));
plot.addLayer(new DialPointer.Pointer());
StandardDialScale scale = new StandardDialScale(minimumValue,
maximumValue, -120, -300, majorTickGap, majorTickGap - 1);
scale.setTickRadius(0.88);
scale.setTickLabelOffset(0.20);
plot.addScale(0, scale);
return new ChartPanel(new JFreeChart(plot));
}
}
我想这是显而易见的事情,但我似乎没有发现问题;如有任何帮助,我们将不胜感激。
最佳答案
您的示例中有几个问题值得关注:
使用
Action
封装功能;此示例会在每次调用时递增dataset
值。frame.add(new JButton(new AbstractAction("Update") { @Override public void actionPerformed(ActionEvent e) { dataset.setValue(dataset.getValue().intValue() + 1); } }), BorderLayout.SOUTH);
main()
方法必须是静态
。Swing GUI 对象应该仅在 event dispatch thread 上构建和操作。 .
考虑这些 alternate ways控制初始图表大小。
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.dial.DialPlot;
import org.jfree.chart.plot.dial.DialPointer;
import org.jfree.chart.plot.dial.DialValueIndicator;
import org.jfree.chart.plot.dial.StandardDialFrame;
import org.jfree.chart.plot.dial.StandardDialScale;
import org.jfree.data.general.DefaultValueDataset;
public class DemoChartProblem {
private final DefaultValueDataset dataset = new DefaultValueDataset(41);
private final JFrame frame = new JFrame();
public static void main(String[] args) throws Exception {
EventQueue.invokeLater(() -> {
new DemoChartProblem();
});
}
public DemoChartProblem() {
frame.add(buildDialPlot(0, 30, 5));
frame.add(new JButton(new AbstractAction("Update") {
@Override
public void actionPerformed(ActionEvent e) {
dataset.setValue(dataset.getValue().intValue() + 1);
}
}), BorderLayout.SOUTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setVisible(true);
}
private ChartPanel buildDialPlot(int minimumValue, int maximumValue,
int majorTickGap) {
DialPlot plot = new DialPlot(dataset);
plot.setDialFrame(new StandardDialFrame());
plot.addLayer(new DialValueIndicator(0));
plot.addLayer(new DialPointer.Pointer());
StandardDialScale scale = new StandardDialScale(minimumValue,
maximumValue, -120, -300, majorTickGap, majorTickGap - 1);
scale.setTickRadius(0.88);
scale.setTickLabelOffset(0.20);
plot.addScale(0, scale);
return new ChartPanel(new JFreeChart(plot)) {
@Override
public Dimension getPreferredSize() {
return new Dimension(300, 300);
}
};
}
}
关于java - NetBeans JButton 中的 JFreeChart 拨号,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30678969/