Name: skT45625 Date: 06/05/2000


java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-C)
Java HotSpot(TM) Client VM (build 1.3.0-C, mixed mode)

UI components which are completely hidden by a frame in front do not reflect any
changes made to them when the frame is closed and they become visible.

The code below demonstrates this.

1. Compile and run the DemoApp file. A BackFrame appears with a JTextField,
JList and JButton.
2. Click the 'Show Frame' button to create a FrontFrame which completely hides
the BackFrame.
3. Click the 'Set Hidden Text' button in the FrontFrame to set the JTextField to
"Some Text" and to add "Some Text" to the JList.
4. Close the FrontFrame.

Using version 1.2.010 everything works fine with the BackFrame showing the
JTextField and JList updated with their new values.

Using version 1.3.0 the JTextField and JList remain blank until another repaint
is forced such as when the BackFrame is minimized then restored.

Source code follows: DemoApp.java

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

public class DemoApp
{
boolean packFrame = false;

public DemoApp()
{
BackFrame frame = new BackFrame();
if (packFrame)
frame.pack();
else
frame.validate();
frame.setVisible(true);
}

public static void main(String[] args)
{
try
{

UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
}
catch(Exception e)
{
}
new DemoApp();
}
}

class BackFrame extends JFrame
{
JTextField jTextField1 = new JTextField();
JButton jButton_SHOW_FRAME = new JButton();
JList jList1 = new JList();
BorderLayout borderLayout1 = new BorderLayout();
DefaultListModel model = new DefaultListModel();

public BackFrame()
{
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
try
{
this.getContentPane().setLayout(borderLayout1);
this.setSize(new Dimension(300, 300));
this.setTitle("Demo Frame");
jButton_SHOW_FRAME.setText("Show Frame");
jButton_SHOW_FRAME.addActionListener(new
java.awt.event.ActionListener()
{
public void actionPerformed(ActionEvent e)
{
jButton_SHOW_FRAME_actionPerformed(e);
}
});
jTextField1.setPreferredSize(new Dimension(100, 22));

jList1.setBorder(BorderFactory.createLineBorder(Color.black));
jList1.setModel(model);
this.getContentPane().add(jTextField1,
BorderLayout.NORTH);
this.getContentPane().add(jList1, BorderLayout.CENTER);
this.getContentPane().add(jButton_SHOW_FRAME,
BorderLayout.SOUTH);
}
catch(Exception e)
{
e.printStackTrace();
}
}

protected void processWindowEvent(WindowEvent e)
{
super.processWindowEvent(e);
if(e.getID() == WindowEvent.WINDOW_CLOSING)
{
System.exit(0);
}
}

void jButton_SHOW_FRAME_actionPerformed(ActionEvent e)
{
// create and show the front frame which hides the back frame
FrontFrame frontFrame = new FrontFrame(this);
frontFrame.setSize(400,400);
frontFrame.setVisible(true);
}

public void addText(String text)
{
// called by the front frame to set the textfield text and
// add text to the list while the back frame is hidden
jTextField1.setText(text);
model.addElement(text);
}
}


class FrontFrame extends JFrame
{

private BackFrame backFrame;

JButton jButton_SET_TEXT = new JButton();
JButton jButton_CLOSE = new JButton();
FlowLayout flowLayout1 = new FlowLayout();

public FrontFrame(BackFrame frame)
{
backFrame = frame;
try
{
jButton_SET_TEXT.setText("Set Hidden Text");
jButton_SET_TEXT.addActionListener(new
java.awt.event.ActionListener()
{
public void actionPerformed(ActionEvent e)
{
jButton_SET_TEXT_actionPerformed(e);
}
});
jButton_CLOSE.setText("Close");
jButton_CLOSE.addActionListener(new
java.awt.event.ActionListener()
{
public void actionPerformed(ActionEvent e)
{
jButton_CLOSE_actionPerformed(e);
}
});
this.getContentPane().setLayout(flowLayout1);
this.setTitle("Front Frame");
this.getContentPane().add(jButton_SET_TEXT, null);
this.getContentPane().add(jButton_CLOSE, null);
}
catch(Exception e)
{
e.printStackTrace();
}
}

void jButton_SET_TEXT_actionPerformed(ActionEvent e)
{
// set the text in the hidden (back) frame
backFrame.addText("Some Text");
}

void jButton_CLOSE_actionPerformed(ActionEvent e)
{
this.setVisible(false);
}
}
(Review ID: 105653)
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