JFrame doesn't display components at first

[Jos� Alberto Mu�iz Navarro]

Good day. I have an application to write and read a file. However, when the JFrame displays, it is SOMETIMES just an empty JFrame. If you resize it or move it, then the components (Some Checkboxes and a JButton) appear.
I have no idea about what it could be. Could you please help me?

 
import java.io.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class FileReader2 extends JFrame implements ActionListener
{
CheckboxGroup options;
Checkbox createData;
Checkbox readData;
JButton doIt;
JPanel optionPanel;

public static void main(String args[])
{
new FileReader();
}
public FileReader2()
{
setSize(250, 140);
setTitle("Base de Datos");
options = new CheckboxGroup();
createData = new Checkbox("Crear nuevo base de datos", options, false);
readData = new Checkbox("Leer base de datos", options, false);
doIt = new JButton("?Ir!");
optionPanel = new JPanel();

getContentPane().setLayout(new BorderLayout());
optionPanel.setLayout(new GridLayout(2, 1));
optionPanel.add(createData);
optionPanel.add(readData);
getContentPane().add("Center", optionPanel);
getContentPane().add("South", doIt);
doIt.setActionCommand("ManageData");
doIt.addActionListener(this);
setVisible(true);
}

public void actionPerformed(ActionEvent e)
{
if (e.getActionCommand().equals("ManageData"))
{
if (createData.getState())
new WriteDialog();
else if (readData.getState())
new ReadDialog();
}
}
}
class WriteDialog extends JDialog implements ActionListener
{
FileWriter  out;
JLabel matriculaLabel = new JLabel ("MatrМcula");
JTextField matriculaField = new JTextField(10);
JLabel nombreLabel = new JLabel ("Nombre");
JTextField nombreField = new JTextField(10);
JLabel edadLabel = new JLabel( "Edad");
JTextField edadField = new JTextField(10);
JButton siguiente = new JButton("Siguiente");
JButton guardar = new JButton("Terminado");
public WriteDialog()
{
setTitle("Escribir datos");
setSize(300, 300);
siguiente.addActionListener(this);
siguiente.setActionCommand("Next");
guardar.addActionListener(this);
guardar.setActionCommand("Done");
getContentPane().setLayout(new GridLayout(4, 2, 0, 50));
getContentPane().add(matriculaLabel);
getContentPane().add(matriculaField);
getContentPane().add(nombreLabel);
getContentPane().add(nombreField);
getContentPane().add(edadLabel);
getContentPane().add(edadField);
getContentPane().add(siguiente);
getContentPane().add(guardar);
try
{
out = new FileWriter("archivo.txt");
}
catch (Exception e)
{
System.err.println("Error. Could not open file. Exception: " + e.toString());
}
setVisible(true);
}
public void actionPerformed(ActionEvent e)
{
try
{
out.write(matriculaField.getText());
out.write("\t");
out.write(nombreField.getText());
out.write("\t");
out.write(edadField.getText());
out.write("\n");
}
catch (IOException ioe)
{
System.out.println("Error. Could not write data. " +
   "Exception: " + ioe.toString());
}
if (e.getActionCommand().equals("Next"))
{
matriculaField.setText("");
nombreField.setText("");
edadField.setText("");
}
else if (e.getActionCommand().equals("Done"))
{
try
{
out.close();
setVisible(false);
}
catch (IOException ioe)
{
System.out.println("Error. Could not write data. " +
   "Exception: " + ioe.toString());
}
}
}
}
class ReadDialog extends JDialog
{
JTextArea printPlace = new JTextArea();
int readChar;
java.io.FileReader in;
public ReadDialog()
{
setTitle("Leer datos");
setSize(300, 300);
setVisible(true);
printPlace.setEditable(false);
getContentPane().add(printPlace);
try
{
 in = new java.io.FileReader("archivo.txt");
}
catch (Exception e)
{
System.err.println("Error. No se pudo abrir el archivo " +
   "Excepcion: " + e.toString());
}
try
{
printPlace.setText("Matricula \t Nombre \t Edad \n");
readChar = in.read();
do
{
printPlace.append((char) readChar + "");
readChar = in.read();
}
while (readChar != -1);
}
catch (Exception e) {}
try
{
in.close();
}
catch (IOException e) {}
}

}

[Nathaniel Stoddard]

Jose,
It looks fine to me. You may want to pack() the contents of the frame before you display it. That may help.

[Jos� Alberto Mu�iz Navarro]

It didn't work :S It still does the same thing. I repeat, only the JFrame appears but it is blank. Nothing appears inside. Just as if you had displayed a blank frame. However, if I resize the window (even to make it smaller... or making it bigger and then adjusting it to the previous size), all the components appear, although they previously had had the space to display them.
It's not a matter of the components not having enough space (I think). Otherwise the pack() would have solved it, am I wrong?

[Craig Wood]

Move the call to setSize down to the bottom of the constructor:

        setSize(250, 140);
        setVisible(true);
    }

setSize or pack create the peer and signal the layout manager to layout its components. You want to call one of them after you add you components to the content pane. Otherwise you will have to validate the layout.