興味深いことに、つい最近、私は同様の問題に遭遇したので、これを克服するために SwingUtilities.invokeAndWait(Runnable runnable) を使用しました。これにより、作成していたSSCCEが期待どおりに動作するようになりました。 invokeLater()を使用すると、2 つの違いがはっきりとわかります。
Java Doc からの引用は次のように述べています。
Causes doRun.run() to be executed synchronously on the AWT event dispatching thread.
This call blocks until all pending AWT events have been processed and
(then) doRun.run() returns. This method should be used when an application thread
needs to update the GUI.
これは、Bubble Sort Animation を表すためにSSCCEとして作成した小さなプログラムです。
import javax.swing.*;
public class BubbleSortFrame extends JFrame
{
private BubbleSortView contentPane;
private void displayGUI()
{
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
contentPane = new BubbleSortView();
setContentPane(contentPane);
pack();
setLocationByPlatform(true);
setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
@Override
public void run()
{
new BubbleSortFrame().displayGUI();
}
});
}
}
import java.awt.*;
import java.awt.event.*;
import java.lang.reflect.InvocationTargetException;
import javax.swing.*;
public class BubbleSortView extends JPanel
{
private JLabel sizeLabel;
private JTextField sizeField;
private JTextField[] vField;
private JLabel[] vLabel;
private JButton startButton, createButton;
private int size;
private JPanel createPanel, animationPanel;
private BubbleSort bubbleSort;
public BubbleSortView()
{
size = 5;
displayAndCreateGUI();
}
private void displayAndCreateGUI()
{
setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
setOpaque(true);
setBackground(Color.WHITE);
JPanel basePanel = new JPanel();
basePanel.setLayout(new GridLayout(2, 1, 5, 5));
basePanel.setOpaque(true);
basePanel.setBackground(Color.WHITE);
JPanel topPanel = new JPanel();
topPanel.setOpaque(true);
topPanel.setBackground(Color.WHITE);
topPanel.setBorder(
BorderFactory.createTitledBorder("Input : "));
topPanel.setLayout(new GridLayout(2, 1, 5, 5));
/*
* This will act as the area
* for taking the input for
* number of elements in an Array.
*/
JPanel sizePanel = new JPanel();
sizePanel.setOpaque(true);
sizePanel.setBackground(Color.WHITE);
sizeLabel = new JLabel("Enter Number of Elements : ");
sizeField = new JTextField(10);
createButton = new JButton("CREATE");
/*
* This will act as the area
* where we will specify the values
* for each index in an Array.
*/
createPanel = new JPanel();
createPanel.setOpaque(true);
createPanel.setBackground(Color.WHITE);
createPanel.setBorder(
BorderFactory.createTitledBorder("Please Enter values for an Array : "));
createPanel.setVisible(false);
animationPanel = new JPanel();
animationPanel.setOpaque(true);
animationPanel.setBackground(Color.WHITE);
animationPanel.setBorder(
BorderFactory.createTitledBorder("Animation : "));
animationPanel.setVisible(false);
createButton.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent ae)
{
if (sizeField.getDocument().getLength() > 0)
{
size = Integer.parseInt(sizeField.getText());
vField = new JTextField[size];
createPanel.setVisible(true);
for (int i = 0; i < size; i++)
{
vField[i] = new JTextField(5);
/*
* Adding the Listener to the
* last JTextField on the Right
* Side.
*/
if (i == (size - 1))
{
vField[i].addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent ae)
{
animationPanel.setLayout(
new GridLayout(1, size, 2, 2));
animationPanel.setVisible(true);
vLabel = new JLabel[size];
for (int i = 0; i < size; i++)
{
vLabel[i] = new JLabel(
vField[i].getText(), JLabel.CENTER);
vLabel[i].setOpaque(true);
vLabel[i].setBackground(Color.YELLOW);
vLabel[i].setForeground(Color.RED);
animationPanel.add(vLabel[i]);
}
animationPanel.revalidate();
animationPanel.repaint();
bubbleSort = new BubbleSort(vLabel, size);
Thread t = new Thread(bubbleSort);
t.start();
}
});
}
createPanel.add(vField[i]);
}
createPanel.revalidate();
createPanel.repaint();
createButton.setEnabled(false);
}
else
size = 5;
}
});
sizePanel.add(sizeLabel);
sizePanel.add(sizeField);
sizePanel.add(createButton);
/*
* Initializing JTextField Array
* so that it can be first presented
* to the USER to take input for
* 5 values.
*/
//for (int i = 0; i < size; i++)
// vField[i] = new JTextField(5);
topPanel.add(sizePanel);
topPanel.add(createPanel);
basePanel.add(topPanel);
basePanel.add(animationPanel);
add(basePanel);
}
private class BubbleSort implements Runnable
{
private int[] arr;
private JLabel[] vLabel;
private int size;
private int pass;
public BubbleSort(JLabel[] label, int size)
{
vLabel = label;
this.size = size;
pass = 1;
for (int i = 0; i < size; i++)
System.out.print("" + vLabel[i].getText() + "\t");
System.out.println("");
}
@Override
public void run()
{
try
{
bubbleSorting();
}
catch (InvocationTargetException ite)
{
ite.printStackTrace();
}
catch(InterruptedException ie)
{
ie.printStackTrace();
}
}
private void bubbleSorting()
throws InterruptedException, InvocationTargetException
{
while (pass < size)
{
for (int i = 0; i < (size - pass); i++)
{
final int j = i;
SwingUtilities.invokeAndWait(new Runnable()
{
@Override
public void run()
{
vLabel[j].setBackground(Color.RED);
vLabel[j].setForeground(Color.WHITE);
vLabel[j + 1].setBackground(Color.RED);
vLabel[j + 1].setForeground(Color.WHITE);
}
});
try
{
Thread.sleep(1500);
}
catch(InterruptedException ie)
{
ie.printStackTrace();
}
int left = Integer.parseInt(vLabel[i].getText());
int right = Integer.parseInt(vLabel[i + 1].getText());
if (left > right)
{
String temp = vLabel[i].getText();
vLabel[i].setText(vLabel[i + 1].getText());
vLabel[i + 1].setText(temp);
}
SwingUtilities.invokeAndWait(new Runnable()
{
@Override
public void run()
{
vLabel[j].setBackground(Color.YELLOW);
vLabel[j].setForeground(Color.RED);
vLabel[j + 1].setBackground(Color.YELLOW);
vLabel[j + 1].setForeground(Color.RED);
}
});
}
System.out.println("Pass : " + pass + "\tSize : " + size);
SwingUtilities.invokeAndWait(new Runnable()
{
@Override
public void run()
{
vLabel[size - pass].setBackground(Color.GREEN);
vLabel[size - pass].setForeground(Color.BLUE);
}
});
pass++;
}
SwingUtilities.invokeAndWait(new Runnable()
{
@Override
public void run()
{
vLabel[0].setBackground(Color.GREEN);
vLabel[0].setForeground(Color.BLUE);
}
});
}
}
}