TextArea Problem since Java 1.4, Screen flickers in WinXP

Since the old code was in 1.1 I definitely think you need to give Jaspre's reply more weight.There have been so many changes to the language. 1.5 might just be making a bug you have in your code more visible.

Either way you might just want to rewrite some of the code to utilize some of the improvements in Java.

zadoka at 2007-7-8 23:16:28 >

And here the code comes which is causing this :-)

compile with normal java1.5 compiler no special settings needed and run with java 1.5 no special settings needed.

This code causes flickering of desktop, because TextArea is added in Constructor of Class. Open a Command prompt and start the class a dialog will pop up and all icons on desktop will flicker :-)

import java.lang.*;

import java.net.*;

import java.io.*;

import java.util.*;

import java.awt.*;

import java.awt.event.*;

import java.text.*;

/**************************************************************************************************

*

*************************************************************************************************/

public class Test extends Frame

{

public static TextAreaitsEdit;

public static Frame itsFrame;

/**********************************************************************************************

*

*********************************************************************************************/

private Test()

{

enableEvents(AWTEvent.WINDOW_EVENT_MASK);

setTitle("Test");

setLayout(null);

setResizable(false);

setBackground(SystemColor.control);

setLocation(5, 5);

// edit field

itsEdit = new TextArea("", 20, 6, TextArea.SCROLLBARS_BOTH);

itsEdit.setBackground(SystemColor.window);

itsEdit.setVisible(false);

add(itsEdit);

show();

}

/**********************************************************************************************

*

*********************************************************************************************/

static public void mywait(long millis)

{

try

{

Thread.sleep(millis);

}

catch ( Exception ex )

{

}

}

/**********************************************************************************************

*

*********************************************************************************************/

static public void appendStatusText(String aText)

{

itsEdit.append(aText);

itsFrame.repaint();

}

/**********************************************************************************************

* STARTUP

*********************************************************************************************/

static public void main(String[] args)

{

try

{

itsFrame = new Test();

Test.mywait(1000);

while ( !itsFrame.isVisible() )

{

Test.mywait(100);

}

appendStatusText("Bitte warten ...");

for (int idx=0; idx<10000; idx++)

{

appendStatusText("Loop #" + idx + "\n");

Test.mywait(100);

itsEdit.setVisible(true);

}

}

catch ( Exception ex )

{

ex.printStackTrace();

}

// cleanup and exit

System.out.flush();

System.exit(0);

}

/**********************************************************************************************

*

*********************************************************************************************/

public void paint(Graphics g)

{

g.setColor(SystemColor.control);

g.fillRect(0 , 0, getBounds().width, getBounds().height);

super.paint(g);

}

/**********************************************************************************************

*

*********************************************************************************************/

private void updateSize()

{

Insets insets = getInsets();

int logoHeight = 0;

setSize(400, 300);

// edit field

itsEdit.setBounds(insets.left + 5, insets.top + 5, 350, 106);

itsEdit.setEditable(false);

itsEdit.setVisible(true);

}

/**********************************************************************************************

* handle Window Events

*********************************************************************************************/

protected void processWindowEvent(WindowEvent e)

{

if ( e.getID() == WindowEvent.WINDOW_OPENED )

{

updateSize();

///add(itsEdit);

}

else if ( e.getID() == WindowEvent.WINDOW_CLOSING )

{

if ( null != itsFrame )

{

itsFrame.dispose();

}

}

else if ( e.getID() == WindowEvent.WINDOW_CLOSED )

{

itsFrame = null;

}

}

}

/*************************************************************************************************/

This code adds the TextArea itsEdit in processWindowEvent WINDOW_OPENED event, no flickering at all.

import java.lang.*;

import java.net.*;

import java.io.*;

import java.util.*;

import java.awt.*;

import java.awt.event.*;

import java.text.*;

/**************************************************************************************************

*

*************************************************************************************************/

public class Test extends Frame

{

public static TextAreaitsEdit;

public static Frame itsFrame;

/**********************************************************************************************

*

*********************************************************************************************/

private Test()

{

enableEvents(AWTEvent.WINDOW_EVENT_MASK);

setTitle("Test");

setLayout(null);

setResizable(false);

setBackground(SystemColor.control);

setLocation(5, 5);

// edit field

itsEdit = new TextArea("", 20, 6, TextArea.SCROLLBARS_BOTH);

itsEdit.setBackground(SystemColor.window);

itsEdit.setVisible(false);

////add(itsEdit);

show();

}

/**********************************************************************************************

*

*********************************************************************************************/

static public void mywait(long millis)

{

try

{

Thread.sleep(millis);

}

catch ( Exception ex )

{

}

}

/**********************************************************************************************

*

*********************************************************************************************/

static public void appendStatusText(String aText)

{

itsEdit.append(aText);

itsFrame.repaint();

}

/**********************************************************************************************

* STARTUP

*********************************************************************************************/

static public void main(String[] args)

{

try

{

itsFrame = new Test();

Test.mywait(1000);

while ( !itsFrame.isVisible() )

{

Test.mywait(100);

}

appendStatusText("Bitte warten ...");

for (int idx=0; idx<10000; idx++)

{

appendStatusText("Loop #" + idx + "\n");

Test.mywait(100);

itsEdit.setVisible(true);

}

}

catch ( Exception ex )

{

ex.printStackTrace();

}

// cleanup and exit

System.out.flush();

System.exit(0);

}

/**********************************************************************************************

*

*********************************************************************************************/

public void paint(Graphics g)

{

g.setColor(SystemColor.control);

g.fillRect(0 , 0, getBounds().width, getBounds().height);

super.paint(g);

}

/**********************************************************************************************

*

*********************************************************************************************/

private void updateSize()

{

Insets insets = getInsets();

int logoHeight = 0;

setSize(400, 300);

// edit field

itsEdit.setBounds(insets.left + 5, insets.top + 5, 350, 106);

itsEdit.setEditable(false);

itsEdit.setVisible(true);

}

/**********************************************************************************************

* handle Window Events

*********************************************************************************************/

protected void processWindowEvent(WindowEvent e)

{

if ( e.getID() == WindowEvent.WINDOW_OPENED )

{

updateSize();

add(itsEdit);

}

else if ( e.getID() == WindowEvent.WINDOW_CLOSING )

{

if ( null != itsFrame )

{

itsFrame.dispose();

}

}

else if ( e.getID() == WindowEvent.WINDOW_CLOSED )

{

itsFrame = null;

}

}

}

/*************************************************************************************************/

MGodehardta at 2007-7-8 23:16:28 >

I have a much simpler demonstration of TextArea severely impacting Windows XP. And I when I say "severe", I mean it affects _other_ applications, non-java ones. The _ENTIRE_ screen flickers, all Windows widgets, every one, with the following code on my Windows XP SP2 machine under both JRE 1.5 and JRE 1.6. If I alt-tab the JFrame into the background behind a full-screen window of, say, Firefox, then my entire screen stops flickering, but the JFrame flickers through, as if it were momentarily in-focus and then behind Firefox again. The flicker is exactly timed with x.append(..) - that is, the action of appending to a TextBox causes these disastrous results. If you change the sleep cycle from 1000ms to something else, you'll notice the flicker frequency (of the ALL WinXP widgets, even those belonging to other processes) matches.

class Buggy

{

public static void main(String[] args) throws Exception

{

JFrame frame = new JFrame("Socket Test");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setSize(370, 400);

final TextArea x = new TextArea();

x.setEditable(false);

JTabbedPane bug = new JTabbedPane();

bug.addTab("Buggy", x);

frame.add(bug);

frame.validate();

frame.setVisible(true);

new Thread(new Runnable()

{

public void run() {

try {

for(int i = 0; true; i++) {

x.append("Message["+i+"]: foobar\n");

Thread.sleep(1000);

}

} catch(InterruptedException e) {

e.printStackTrace();

}

}

}).start();

}

}

synackfina at 2007-7-8 23:16:28 >

In addition to the desktop, gaim apparently also flickers with the x.append(..), as does intellij as previously stated. This issue occurs only when the TextArea is added to a JTabbedPane (and I'm assuming other lightweight panels have bad interaction with TextArea as well). I do not notice any system-wide flickering issues when TextArea is directly added to JFrame.

synackfina at 2007-7-8 23:16:28 >