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POJPanel added but not displayed "in time"
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copied!<p>I have a JFrame that displays JPanels depending on the MenuItem you click. It works, but now I need to call a method once a JPanel is added to the frame and it is being shown (because I'm using JFreeChart inside that panel and I have to call <code>chartPanel.repaint()</code> when the JPanel is visible):</p> <pre><code>this.getContentPane().add( myjpanel, BorderLayout.CENTER ); //this = JFrame this.validate(); myjpanel.methodCalledOnceDisplayed(); </code></pre> <p>Does it seem ok? Is <code>myjpanel</code> being shown really? It seems it is not:</p> <pre><code>public void methodCalledOnceDisplayed() { chartPanel.repaint() } </code></pre> <p>This is not working (<code>chartPanel.getChartRenderingInfo().getPlotInfo().getSubplotInfo(0)</code> is throwing IndexOutOfBoundsException). That means that the JPanel was not visible when repaint was called, I've tested the following:</p> <pre><code>public void methodCalledOnceDisplayed() { JOptionPane.showMessageDialog(null,"You should see myjpanel now"); chartPanel.repaint() } </code></pre> <p>Now it works, I see <code>myjpanel</code> behind the alert, just as expected, chartPanel is repainted and no Exception occurs. </p> <p><strong>EDIT</strong>: SSCCE (jfreechart and jcommon needed: <a href="http://www.jfree.org/jfreechart/download.html" rel="nofollow">http://www.jfree.org/jfreechart/download.html</a>)</p> <pre> import java.awt.BorderLayout; import java.awt.EventQueue; import java.awt.Font; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JPanel; import javax.swing.border.EmptyBorder; import org.jfree.chart.ChartMouseEvent; import org.jfree.chart.ChartMouseListener; import org.jfree.chart.JFreeChart; import org.jfree.chart.plot.CombinedDomainXYPlot; import org.jfree.chart.plot.PlotOrientation; import org.jfree.chart.plot.XYPlot; import org.jfree.chart.ChartPanel; import org.jfree.data.time.TimeSeries; import org.jfree.data.time.TimeSeriesCollection; import org.jfree.data.xy.XYDataset; import java.awt.event.ActionListener; import java.awt.event.ActionEvent; public class Window extends JFrame { private JPanel contentPane; public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { try { Window frame = new Window(); frame.setVisible(true); } catch (Exception e) { e.printStackTrace(); } } }); } public Window() { setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setBounds(100, 100, 700, 500); contentPane = new JPanel(); contentPane.setBorder(new EmptyBorder(5, 5, 5, 5)); contentPane.setLayout(new BorderLayout(0, 0)); setContentPane(contentPane); JButton clickme = new JButton("Click me"); clickme.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { contentPane.removeAll(); MyJPanel mypanel = new MyJPanel(); contentPane.add( mypanel, BorderLayout.CENTER ); validate(); mypanel.methodCalledOnceDisplayed(); } }); contentPane.add( clickme, BorderLayout.NORTH ); JPanel example = new JPanel(); example.add( new JLabel("Example JPanel") ); contentPane.add( example, BorderLayout.CENTER ); } } class MyJPanel extends JPanel implements ChartMouseListener { private ChartPanel chartPanel; private JFreeChart chart; private XYPlot subplotTop; private XYPlot subplotBottom; private CombinedDomainXYPlot plot; public MyJPanel() { this.add( new JLabel("This JPanel contains the chart") ); createCombinedChart(); chartPanel = new ChartPanel(chart); chartPanel.addChartMouseListener(this); this.add( chartPanel ); } 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", new Font("Arial", Font.BOLD,20), plot, true); } private void createSubplots() { subplotTop = new XYPlot(); subplotBottom = new XYPlot(); subplotTop.setDataset(emptyDataset("Empty 1")); subplotBottom.setDataset(emptyDataset("Empty 2")); } private XYDataset emptyDataset( String title ) { TimeSeries ts = new TimeSeries(title); TimeSeriesCollection tsc = new TimeSeriesCollection(); tsc.addSeries(ts); return tsc; } @Override public void chartMouseMoved(ChartMouseEvent e) { System.out.println("Mouse moved!"); } @Override public void chartMouseClicked(ChartMouseEvent arg0) {} public void methodCalledOnceDisplayed() { JOptionPane.showMessageDialog(null,"Magic!"); //try to comment this line and see the console chartPanel.repaint(); //now we can get chart areas this.chartPanel.getChartRenderingInfo().getPlotInfo().getSubplotInfo(0).getDataArea(); this.chartPanel.getChartRenderingInfo().getPlotInfo().getSubplotInfo(1).getDataArea(); } }</pre> <p>See what happens with and without the JOptionPane.</p>

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