insertString() not get displayed right away in some situation

First of all, next time you post code please use the code tags so that it is formatted properly. It makes it much easier to read.

Secondly, your code didn't compile correctly because you cannot add components directly to a JFrame, you have to add them to the contentPane of a JFrame.

Third, your code DID run correctly!

Your computer is just so fast that the time appears to be the same for all append calls. I purposely ran a resource intensive process on my computer and THEN ran your program to find that the time updated itself between iterations.

Other than the compile errors that were easily fixed, your code is fine.

maple_shafta at 2007-7-8 23:07:51 >

Thanks for the help. Though I did not get compile error on direct adding components to JFrame.

Now I have modified the two files with getContentPane();

Run TestPane, you can visually see the messages come out line by line.

Run TestPaneDemo you see the messages coming out all together. It is still not working. In my real application, the reporting messages should be out one by one.

Following is the code

TestPane.java

import java.awt.*;

import java.text.SimpleDateFormat;

import java.text.*;

import java.util.Date;

import javax.swing.*;

import javax.swing.text.*;

public class TestPane extends JTextPane

{

public TestPane()

{

super();

}

public TestPane(StyledDocument doc) {

super(doc);

}

public void append( String s )// this is the simple one

{

try

{

Document doc = getDocument();

int len = doc.getLength();

doc.insertString( len, s, null );

// Scroll so that the new text is visible

Rectangle r = modelToView(doc.getLength());

if ( r != null )

{

scrollRectToVisible(r);

}

}

catch ( BadLocationException e ) {

System.out.println("Failed to append text: " + e );

e.printStackTrace();

}

}

public void append( Color c, String s )// this is the one I need

{

try

{

Document doc = getDocument();

StyleContext sc = StyleContext.getDefaultStyleContext();

AttributeSet aset = sc.addAttribute(SimpleAttributeSet.EMPTY,StyleConstants.Foreground, c);

int len = doc.getLength();

doc.insertString( len, s, aset );

// Scroll so that the new text is visible

Rectangle r = modelToView(doc.getLength());

if ( r != null )

{

scrollRectToVisible(r);

}

}

catch ( BadLocationException e ) {

System.out.println("Failed to append text: " + e );

}

}

// Testing method

public static void main(String[] args)

{

try {

UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");

} catch (Exception evt) {}

JFrame f = new JFrame("Test JTextPane with append");

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

//

TestPane tp = new TestPane();

tp.setText( "" );

tp.setEditable( false );

JScrollPane sp = new JScrollPane( tp );

sp.setVerticalScrollBarPolicy( JScrollPane.VERTICAL_SCROLLBAR_ALWAYS );

Label msg = new Label( "Messages" );

msg.setFont( new Font( "SansSerif", Font.BOLD, 12 ) );

msg.setForeground( Color.red );

JPanel p_msg = new JPanel( new BorderLayout() );

p_msg.add( "North", msg );

p_msg.add( "Center", sp );

// Do not add components direct to JFrame!

Container content = f.getContentPane();

content.add( "Center", p_msg );

content.add( "West", new Label("") );

content.add( "East", new Label("") );

int wid = 400;

int hei = 600;

f.setSize( wid, hei );

f.setVisible(true);

SimpleDateFormat fmt = new SimpleDateFormat("HH:mm:ss");

for ( int i=0; i<50; i++ )

{

String timeString = fmt.format(new Date());

tp.append( "Time=" + timeString + "\n" );

tp.append( Color.red, timeString + "\n" );

tp.append( Color.blue, "abcdefg" );

tp.append( " ..............\n" );

}

tp.setCaretPosition(tp.getDocument().getLength());

}

}// class TestPane

TestPaneDemo.java

import java.awt.*;

import java.awt.event.*;

import java.util.*;

import java.text.*;

import javax.swing.*;

import javax.swing.text.*;

public class TestPaneDemo extends JFrame

implements ActionListener

{

// Action Buttons

JButton b_report = null;

JButton b_reset = null;

TestPane ta = null;// Was TextArea, message area,

public TestPaneDemo()// construtor

{

ta = new TestPane();

ta.setText( "" );

ta.setFont( new Font("Monospaced", Font.PLAIN, 12) );

ta.setEditable( false );

JScrollPane sp = new JScrollPane( ta );

sp.setVerticalScrollBarPolicy( JScrollPane.VERTICAL_SCROLLBAR_ALWAYS );

Label msg = new Label( "Messages" );

msg.setFont( new Font( "SansSerif", Font.BOLD, 12 ) );

msg.setForeground( Color.red );

JPanel p_msg = new JPanel( new BorderLayout() );

p_msg.add( "North", msg );

p_msg.add( "Center", sp );

// Button panel

JPanel button_p = new JPanel();

b_report = new JButton( "Report" );

b_reset = new JButton( "Reset" );

button_p.setLayout( new FlowLayout( FlowLayout.RIGHT, 15, 15 ) );

button_p.add( b_report );

button_p.add( b_reset );

b_reset.addActionListener(this);

b_report.addActionListener(this);

button_p.setFont( new Font( "SansSerif", Font.BOLD, 16 ) );

/*

your code didn't compile correctly because you cannot add components directly to a JFrame,

you have to add them to the contentPane of a JFrame.

*/

JFrame f = new JFrame("Test JTextPane with append");

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

Container content = f.getContentPane();

content.add( "Center", p_msg );

content.add( "West", new Label("") );

content.add( "East", new Label("") );

content.add( "South", button_p);

int wid = 400;

int hei = 300;

f.setSize( wid, hei );

f.setVisible(true);

}

public void actionPerformed(ActionEvent e)

{

Object obj = e.getSource();

if ( obj instanceof JButton )

{

JButton b = (JButton) obj;

if ( b == b_reset ) {ta.setText( "" );}

else if ( b == b_report ) {

ta.setText( "" );

SimpleDateFormat fmt = new SimpleDateFormat("HH:mm:ss");

for ( int i=0; i<50; i++ )

{

String timeString = fmt.format(new Date());

ta.append( "Time=" + timeString + "\n" );

ta.append( Color.red, timeString + "\n" );

ta.append( Color.blue, "abcefg" );

ta.append( " ..............\n" );

}

return;

}

}

}

// Testing method

public static void main(String[] args)

{

TestPaneDemo demo = new TestPaneDemo();

}

} // class TestPaneDemo

chouannaa at 2007-7-8 23:07:51 >

Your computer is just so fast that the time appears to be the same for all append calls.

The messages are appearing very fast, though you can tell they do not come out all together for TestPane. I can see the vertical scroll bar moving down as the messages are being displayed.Do you see this?

For TestPaneDemo, the scroll bar just came out at the end. They act differently in this sense.

In my real application, the coding is similar to TestPaneDemo, It processes several files. Each one takes about one second. Message is issued after every file was processed. I expect them came out one by one. I was using TextArea before, it was fine. Then I changed to JTextPane, because I need color. Then the behavior changed. I need to wait for sevral seconds to see the messages. They came out all together. It is annoying.

chouannaa at 2007-7-8 23:07:51 >