我有一个JFrame根据您单击的MenuItem显示JPanels。它可以工作,但是现在我需要在将JPanel添加到框架中并显示该方法之后调用一个方法(因为我在该面板内使用JFreeChart,并且当JPanel可见时我必须调用chartPanel.repaint()
):
this.getContentPane().add( myjpanel, BorderLayout.CENTER ); //this = JFrame
this.validate();
myjpanel.methodCalledOnceDisplayed();
看起来还好吗?确实显示了
myjpanel
吗?似乎不是:public void methodCalledOnceDisplayed() {
chartPanel.repaint()
}
这是行不通的(
chartPanel.getChartRenderingInfo().getPlotInfo().getSubplotInfo(0)
抛出IndexOutOfBoundsException)。这意味着在调用repaint时,JPanel不可见,我已经测试了以下内容:public void methodCalledOnceDisplayed() {
JOptionPane.showMessageDialog(null,"You should see myjpanel now");
chartPanel.repaint()
}
现在它可以正常工作了,我在警报后面看到了
myjpanel
,正如预期的那样,chartPanel重新绘制,并且没有发生异常。编辑:SSCCE(需要jfreechart和jcommon:http://www.jfree.org/jfreechart/download.html)
导入java.awt.BorderLayout;
导入java.awt.EventQueue;
导入java.awt.Font;
导入javax.swing.JButton;
导入javax.swing.JFrame;
导入javax.swing.JLabel;
导入javax.swing.JOptionPane;
导入javax.swing.JPanel;
导入javax.swing.border.EmptyBorder;
导入org.jfree.chart.ChartMouseEvent;
导入org.jfree.chart.ChartMouseListener;
导入org.jfree.chart.JFreeChart;
导入org.jfree.chart.plot.CombinedDomainXYPlot;
导入org.jfree.chart.plot.PlotOrientation;
导入org.jfree.chart.plot.XYPlot;
导入org.jfree.chart.ChartPanel;
导入org.jfree.data.time.TimeSeries;
导入org.jfree.data.time.TimeSeriesCollection;
导入org.jfree.data.xy.XYDataset;
导入java.awt.event.ActionListener;
导入java.awt.event.ActionEvent;
公共类Window扩展JFrame {
私人JPanel contentPane;
公共静态void main(String [] args){
EventQueue.invokeLater(new Runnable(){
公共无效run(){
尝试{
窗框= new Window();
frame.setVisible(true);
} catch(Exception e){
e.printStackTrace();
}
}
});
}
公共窗口(){
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100,100,700,500);
contentPane =新的JPanel();
contentPane.setBorder(newEmptyBorder(5,5,5,5));
contentPane.setLayout(new BorderLayout(0,0));
setContentPane(contentPane);
JButton clickme = new JButton(“Click me”);
clickme.addActionListener(new ActionListener(){
公共无效actionPerformed(ActionEvent arg0){
contentPane.removeAll();
MyJPanel mypanel = new MyJPanel();
contentPane.add(mypanel,BorderLayout.CENTER);
validate();
mypanel.methodCalledOnceDisplayed();
}
});
contentPane.add(clickme,BorderLayout.NORTH);
JPanel示例= new JPanel();
example.add(new JLabel(“Example JPanel”));
contentPane.add(例如BorderLayout.CENTER);
}
}
类MyJPanel扩展JPanel实现ChartMouseListener {
私人ChartPanel chartPanel;
私人JFreeChart图表;
私有XYPlot subplotTop;
私有XYPlot subplotBottom;
私人的CombinedDomainXYPlot图;
公共MyJPanel(){
this.add(new JLabel(“此JPanel包含图表”));
createCombinedChart();
chartPanel =新的ChartPanel(图表);
chartPanel.addChartMouseListener(this);
this.add(chartPanel);
}
私人无效createCombinedChart(){
图=新的CombinedDomainXYPlot();
plot.setGap(30);
createSubplots();
plot.add(subplotTop,4);
plot.add(subplotBottom,1);
plot.setOrientation(PlotOrientation.VERTICAL);
chart = new JFreeChart(“Title”,new Font(“Arial”,Font.BOLD,20),plot,true);
}
私人无效createSubplots(){
subplotTop =新的XYPlot();
subplotBottom =新的XYPlot();
subplotTop.setDataset(emptyDataset(“Empty 1”));
subplotBottom.setDataset(emptyDataset(“Empty 2”));;
}
私人XYDataset emptyDataset(字符串标题){
TimeSeries ts = new TimeSeries(title);
TimeSeriesCollection tsc =新的TimeSeriesCollection();
tsc.addSeries(ts);
返回tsc;
}
@Override
public void chartMouseMoved(ChartMouseEvent e){
System.out.println(“鼠标移动!”);
}
@Override
公共无效chartMouseClicked(ChartMouseEvent arg0){}
公共无效methodCalledOnceDisplayed(){
JOptionPane.showMessageDialog(null,“Magic!”); //尝试注释此行并查看控制台
chartPanel.repaint();
//现在我们可以获取图表区域
this.chartPanel.getChartRenderingInfo()。getPlotInfo()。getSubplotInfo(0).getDataArea();
this.chartPanel.getChartRenderingInfo()。getPlotInfo()。getSubplotInfo(1).getDataArea();
}
}
查看使用和不使用JOptionPane时发生的情况。
最佳答案
为什么会发生这种情况的解释会很好。
您可以从以下变体中获得一些见解。注意
repaint()
时不需要调用ChartPanel
。 CardLayout
或 JTabbedPane
。 setPreferredSize()
,而是覆盖getPreferredSize()
,如here所述。 附录:您删除了显示问题的两行……。
ChartRenderingInfo
是动态数据,在呈现图表之前不存在。模式图对话框在后台更新图表时处理事件。没有它,您可以通过将方法包装在适合Runnable
的invokeLater()
中来安排方法:EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
myPanel.methodCalledOnceDisplayed();
}
});
更好的方案是在您知道数据有效的侦听器中访问
ChartRenderingInfo
,即由ChartPanel
实现的侦听器。import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Date;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.border.EmptyBorder;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.CombinedDomainXYPlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.PlotRenderingInfo;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.time.Day;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;
import org.jfree.data.xy.XYDataset;
/**
* @see https://stackoverflow.com/a/14894894/230513
*/
public class Test extends JFrame {
private JPanel panel;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
Test frame = new Test();
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public Test() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final MyJPanel myPanel = new MyJPanel();
panel = new JPanel() {
@Override
public Dimension getPreferredSize() {
return myPanel.getPreferredSize();
}
};
panel.setBorder(new EmptyBorder(5, 5, 5, 5));
panel.setLayout(new BorderLayout());
add(panel);
myPanel.start();
JButton clickme = new JButton("Click me");
clickme.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent arg0) {
panel.removeAll();
panel.add(myPanel, BorderLayout.CENTER);
validate();
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
myPanel.methodCalledOnceDisplayed();
}
});
}
});
panel.add(clickme, BorderLayout.NORTH);
JPanel example = new JPanel();
example.add(new JLabel("Example JPanel"));
panel.add(example, BorderLayout.CENTER);
}
private static class MyJPanel extends JPanel {
private static final Random r = new Random();
private ChartPanel chartPanel;
private JFreeChart chart;
private XYPlot subplotTop;
private XYPlot subplotBottom;
private CombinedDomainXYPlot plot;
private Timer timer;
private Day now = new Day(new Date());
public MyJPanel() {
this.add(new JLabel("Chart panel"));
createCombinedChart();
chartPanel = new ChartPanel(chart);
this.add(chartPanel);
timer = new Timer(1000, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
update(subplotTop);
update(subplotBottom);
}
});
timer.start();
}
public void start() {
timer.start();
}
private void update(XYPlot plot) {
TimeSeriesCollection t = (TimeSeriesCollection) plot.getDataset();
for (int i = 0; i < t.getSeriesCount(); i++) {
TimeSeries s = t.getSeries(i);
s.add(now, Math.abs(r.nextGaussian()));
now = (Day) now.next();
}
}
private void createCombinedChart() {
plot = new CombinedDomainXYPlot();
plot.setGap(30);
createSubplots();
plot.add(subplotTop, 4);
plot.add(subplotBottom, 1);
plot.setOrientation(PlotOrientation.VERTICAL);
chart = new JFreeChart("Title",
JFreeChart.DEFAULT_TITLE_FONT, plot, true);
plot.setDomainAxis(new DateAxis("Domain"));
}
private void createSubplots() {
subplotTop = new XYPlot();
subplotBottom = new XYPlot();
subplotTop.setDataset(emptyDataset("Set 1"));
subplotTop.setRenderer(new XYLineAndShapeRenderer());
subplotTop.setRangeAxis(new NumberAxis("Range"));
subplotBottom.setDataset(emptyDataset("Set 2"));
subplotBottom.setRenderer(new XYLineAndShapeRenderer());
subplotBottom.setRangeAxis(new NumberAxis("Range"));
}
private XYDataset emptyDataset(String title) {
TimeSeriesCollection tsc = new TimeSeriesCollection();
TimeSeries ts = new TimeSeries(title);
tsc.addSeries(ts);
return tsc;
}
public void methodCalledOnceDisplayed() {
PlotRenderingInfo plotInfo =
this.chartPanel.getChartRenderingInfo().getPlotInfo();
for (int i = 0; i < plotInfo.getSubplotCount(); i++) {
System.out.println(plotInfo.getSubplotInfo(i).getDataArea());
}
JOptionPane.showMessageDialog(null, "Magic!");
}
}
}
附录:进行一次额外的迭代来说明
ChartMouseListener
并清除一些松散的结局。import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Date;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import org.jfree.chart.ChartMouseEvent;
import org.jfree.chart.ChartMouseListener;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.entity.ChartEntity;
import org.jfree.chart.plot.CombinedDomainXYPlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.time.Day;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;
import org.jfree.data.xy.XYDataset;
/**
* @see https://stackoverflow.com/a/14894894/230513
*/
public class Test {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
Test t = new Test();
}
});
}
public Test() {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final MyJPanel myPanel = new MyJPanel();
f.add(myPanel, BorderLayout.CENTER);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
myPanel.start();
}
private static class MyJPanel extends JPanel {
private static final Random r = new Random();
private ChartPanel chartPanel;
private JFreeChart chart;
private XYPlot subplotTop;
private XYPlot subplotBottom;
private CombinedDomainXYPlot plot;
private Timer timer;
private Day now = new Day(new Date());
public MyJPanel() {
createCombinedChart();
chartPanel = new ChartPanel(chart);
this.add(chartPanel);
timer = new Timer(1000, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
update(subplotTop);
update(subplotBottom);
now = (Day) now.next();
}
});
chartPanel.addChartMouseListener(new ChartMouseListener() {
@Override
public void chartMouseClicked(ChartMouseEvent e) {
final ChartEntity entity = e.getEntity();
System.out.println(entity + " " + entity.getArea());
}
@Override
public void chartMouseMoved(ChartMouseEvent e) {
}
});
}
public void start() {
timer.start();
}
private void update(XYPlot plot) {
TimeSeriesCollection t = (TimeSeriesCollection) plot.getDataset();
for (int i = 0; i < t.getSeriesCount(); i++) {
TimeSeries s = t.getSeries(i);
s.add(now, Math.abs(r.nextGaussian()));
}
}
private void createCombinedChart() {
plot = new CombinedDomainXYPlot();
createSubplots();
plot.add(subplotTop, 4);
plot.add(subplotBottom, 1);
plot.setOrientation(PlotOrientation.VERTICAL);
chart = new JFreeChart("Title",
JFreeChart.DEFAULT_TITLE_FONT, plot, true);
plot.setDomainAxis(new DateAxis("Domain"));
}
private void createSubplots() {
subplotTop = new XYPlot();
subplotBottom = new XYPlot();
subplotTop.setDataset(emptyDataset("Set 1"));
subplotTop.setRenderer(new XYLineAndShapeRenderer());
subplotTop.setRangeAxis(new NumberAxis("Range"));
subplotBottom.setDataset(emptyDataset("Set 2"));
subplotBottom.setRenderer(new XYLineAndShapeRenderer());
subplotBottom.setRangeAxis(new NumberAxis("Range"));
}
private XYDataset emptyDataset(String title) {
TimeSeriesCollection tsc = new TimeSeriesCollection();
TimeSeries ts = new TimeSeries(title);
tsc.addSeries(ts);
return tsc;
}
}
}