JWindow showing up as a white box

[Atrus Greyor]

I have the code for a nice JWindow as follows

    
package gui;
 
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JWindow;
 
public class UserInput implements ActionListener
{
private String[] codes = {"N", "V", "A", "v", "C", "P", "!", "r", "D", "I"};
private String[] words = {"Noun", "Verb", "Adejective", "Adverb", "Conjunction", "Preposition", "Interjection", "Pronoun", "Definite Article", "Indefinite Article"};
JButton[] choices;
JButton help = new JButton("Help");
String returnPos = null;

public UserInput()
{

}

public String askForPos(String word, String[] pos)
{
JWindow f = new JWindow();
JLabel l = new JLabel("What is the part of speech for " + word + "?");
choices = new JButton[pos.length];
JPanel p = new JPanel();

for(int i = 0; i < pos.length; i++)
{
choices[i] = new JButton(convertCodeToWord(pos[i]));
choices[i].addActionListener(this);
}
help.addActionListener(this);

f.setLayout(new BorderLayout());
f.add(l, BorderLayout.NORTH);
f.add(help, BorderLayout.CENTER);
f.add(p, BorderLayout.SOUTH);

for(int i = 0; i < choices.length; i++)
p.add(choices[i]);

Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
Dimension labelSize = l.getPreferredSize();
f.setLocation(screenSize.width/2 - (labelSize.width/2), screenSize.height/2 - (labelSize.height/2));
screenSize =null;
labelSize = null;

f.pack();
f.setVisible(true);
f.setAlwaysOnTop(true);

cont();

f.dispose();
return returnPos;
}

public void cont()
{
while(true)
if(returnPos != null)
return;
}

public String convertCodeToWord(String code)
{
for(int i = 0; i < codes.length; i++)
if(codes[i].equals(code))
return words[i];

return "Error";
}

public String convertWordToCode(String word)
{
for(int i = 0; i < words.length; i++)
if(words[i].equals(word))
return codes[i];

return "Error";
}
 
public void actionPerformed(ActionEvent e) 
{
for(int i = 0; i < choices.length; i++)
if(choices[i] == e.getSource())
returnPos = convertWordToCode(choices[i].getText());

if(e.getSource() == help)
{
createHelpWindow();
}

}

public void createHelpWindow()
{
JFrame f = new JFrame("How to ID a part of Speech.");
JLabel l = new JLabel(new ImageIcon(UserInput.class.getResource("images/POSHelp.png")));
JScrollPane b = new JScrollPane(l);

f.add(b);

f.pack();
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
}
}
 

Now all of this works when I run it by itself like as follows

    
import gui.UserInput;
 
public class Test
{
public static void main(String args[])
{
String[] a = {"I", "D"};
UserInput as = new UserInput();
as.askForPos("Bob", a);
}
}

However when it is brought up along with my GUI and another JWindow it just shows up as a white box.

Any ideas as to why it does this?

[dave taubler]

This part:

public void cont()
{
while(true)
if(returnPos != null)
return;
}

and the fact that you call it in the askForPos() method is probably the cause of the problem. Basically, you're blocking the Event Dispatch thread, thus preventing the Window from repainting (or in your cause, painting for the first time). Even if it did paint successfully, it wouldn't be able to process any user input.

Better would be to not block at all, but to instead move the code that eventually disposes the Window (I assume you also want to setVisible(false) on it as well) to the actionPerformed() event handling code.