bring JInternalFrame to the front

I have a JDeskto开发者_如何学PythonpPane which contains a number of JInternalFrames. I'd like to be able to bring any JInternalFrame to the front, overlaying any other active frames. I found a number of code samples to do this, but none seem to work - the frame does NOT go on top of other active JInternalFrames. E.g.

public static void moveToFront(final JInternalFrame fr) {
        if (fr != null) {
            processOnSwingEventThread(new Runnable() {
                public void run() {
                    fr.moveToFront();
                    fr.setVisible(true);
                    try {
                        fr.setSelected(true);
                        if (fr.isIcon()) {
                            fr.setIcon(false);
                        }
                        fr.setSelected(true);
                    } catch (PropertyVetoException ex) {
                        ex.printStackTrace();
                    }
                    fr.requestFocus();
                    fr.toFront();
                }
            });
        }
    }

According to the API toFront or moveToFront should work (though toFront looks to be the better of the two from my reading of the API). Are these JInternalFrames sitting in a JDesktopPane? According to your post it seems they are. I wonder if the error lies elsewhere.

Consider creating and posting an SSCCE (please click on the link), a small compilable, runnable program that demonstrates your best attempt at solving this. Then we can inspect your code, run it, modify it and best be able to help you fix it.

Here is my example of an SSCCE:

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.util.Random;

import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class InternalFrameToFront extends JPanel {
   private static final int FRAME_MAX = 21;
   private static final int DT_WIDTH = 700;
   private static final int DT_HEIGHT = 500;
   private static final Dimension DESKTOP_SIZE = new Dimension(DT_WIDTH, DT_HEIGHT);
   private static final int IF_WIDTH = 150;
   private static final int IF_HEIGHT = 100;
   private static final Dimension INT_FRAME_SIZE = new Dimension(IF_WIDTH, IF_HEIGHT);
   private Random random = new Random();
   private JInternalFrame[] internalFrames = new JInternalFrame[FRAME_MAX];

   public InternalFrameToFront() {
      JDesktopPane desktop = new JDesktopPane();
      desktop.setPreferredSize(DESKTOP_SIZE);
      for (int i = 0; i < internalFrames.length; i++) {
         JInternalFrame intFrame = new JInternalFrame("Frame Number " + i);
         intFrame.setSize(INT_FRAME_SIZE);
         int x = random.nextInt(DT_WIDTH - IF_WIDTH);
         int y = random.nextInt(DT_HEIGHT - IF_HEIGHT);
         intFrame.setLocation(x, y);
         intFrame.setVisible(true);
         desktop.add(intFrame);

         internalFrames[i] = intFrame;
      }

      JSlider slider = new JSlider(0, FRAME_MAX - 1, 0);
      slider.setMajorTickSpacing(5);
      slider.setMinorTickSpacing(1);
      slider.setPaintLabels(true);
      slider.setPaintTicks(true);
      JPanel sliderPanel = new JPanel();
      sliderPanel.add(slider);
      slider.addChangeListener(new ChangeListener() {
         public void stateChanged(ChangeEvent ce) {
            JSlider slider = (JSlider) ce.getSource();
            if (!slider.getValueIsAdjusting()) {
               int value = slider.getValue();
               internalFrames[value].toFront();
            }
         }
      });

      setLayout(new BorderLayout());
      add(desktop, BorderLayout.CENTER);
      add(sliderPanel, BorderLayout.SOUTH);
   }

   private static void createAndShowUI() {
      JFrame frame = new JFrame("InternalFrameToFront");
      frame.getContentPane().add(new InternalFrameToFront());
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      java.awt.EventQueue.invokeLater(new Runnable() {
         public void run() {
            createAndShowUI();
         }
      });
   }
}