Refreshing an Applet

hi Group,
I have an applet which initially asks the user to authenticate himself, by presenting a login screen. Upon successful authentication, i want to present some more UI components on the applet, on the fly.
Now, how do i dynamically stick in a few more components and refresh the applet so that the new applet has the old as well the newly added components.
I tried calling the init() method after adding the components, but it renderes the components twice.
I would highly appreciate any tips from the gurus regarding this.
Thanks and Regards,
Ranjit Iyer

Thanks for your respective tips..
Ya i will try either of those 2 options. Indeed using CardLayout also makes complete sense in such a situation. It never struck me.
A solution suggested by my professor was to initially layout all the components that would ever be necessary on the Applet but set some of them to visible(false) and then set them to true as and when needed.
Thanks both,
Regards,
Ranjit

Similar Messages

Refreshing Swing Applet

I have an applet (javax.swing.JApplet) running with textarea. I am updating the text area for each successful process. When the application is running, if any other window is opened, then minimised, the applet window will have the print of the opened window. I mean, that will not show the exact applet window it is suppose to show. even i tried repaint(), validate() methods to refresh it.
When there will be always a process running updating textarea. how can i refresh the applet ?

repaint();

How can i refresh the applet context

I want to make my applet refresh after some time that is 10 seconds.
i want to change the picture on the applet by this time please tell me how to do this i have used
public void repaint(long time);
But this did not work for me
thanx Alot

hi,
you need a thread which will sleep for 10 seconds, call repaint() and then goes to sleep again. Something like this:public class MyApplet implements Runnable
private Thread repaintThread = null;
public void run ()
    while (true)
      myThread.sleep (10000);
      repaint();
    // + catch Exceptions
public void init ()
    myThread = new Thread (this);
    myThread.start();
greetz,
Stijn

Refresh an applet

Here is my code. In the fonction start(), i have a "automate" that set visible one panel depending on the variable "etat". The others panel are setVisible(false)
That was my theory !
Under IE 5.5 or Opera 5, this automate doen't work. When i come for the second time in the automate , the variable etat is at 2 but the panel "panneau_2" is not loaded until i change the size manually of the window of opera, what make the window refresh and then it works !
Can i refresh it in the code ??
I try repaint, i try to destroy the applet and then to call init(), ...
Here is my code
Thank you
// Import des classes Java
import java.applet.Applet;
import java.awt.event.*;
import java.lang.Object;
import java.awt.Graphics;
import IHM_client_affaire;
import database_manager;
import DB_client_affaire;
import IHM_connection;
import DB_connection;
import IHM_ft;
import DB_ft;
import IHM_panneau_FT;
import DB_panneau_FT;
import IHM_signalement;
import DBB_signalement;
/** Classe principale de lancement de l'applet */
public class principal extends Applet implements ActionListener
private int fonction;
private int exit = 0;
private int etat = 1;
private int etat_modification_client = 0;
private int etat_ajout_valid_2 = 0;
private int etat_signalement_ajout_valid_3 = 0;
private int etat_FT_ajout_valid_3 = 0;
private IHM_connection panneau_1 = new IHM_connection(this);
private IHM_panneau_FT panneau_2 = new IHM_panneau_FT(this);
private IHM_client_affaire panneau_3 = new IHM_client_affaire(this);
private IHM_signalement panneau_4 = new IHM_signalement(this);
private IHM_ft panneau_5 = new IHM_ft(this);
private IHM_nouvel_utilisateur panneau_6 = new IHM_nouvel_utilisateur();
/** Initialiser l'applet */
public void init()
// this.removeAll();
System.out.println("coucou2");
setLayout(null);
add(panneau_1.get_pane());
panneau_1.setVisible(false);
add(panneau_2.get_pane());
panneau_2.setVisible(false);
add(panneau_3.get_pane());
panneau_3.setVisible(false);
add(panneau_4.get_pane());
panneau_4.setVisible(false);
add(panneau_5.get_pane());
panneau_5.setVisible(false);
add(panneau_6.get_pane());
panneau_6.setVisible(false);
System.out.println("coucou3");
public void start()
switch (etat)
case 1 : panneau_1.setVisible(true);
panneau_2.setVisible(false);
panneau_3.setVisible(false);
panneau_4.setVisible(false);
panneau_5.setVisible(false);
panneau_6.setVisible(false);
this.setSize(983,571);
break;
case 2 :
panneau_2.setVisible(true);
panneau_1.setVisible(false);
panneau_3.setVisible(false);
panneau_4.setVisible(false);
panneau_5.setVisible(false);
panneau_6.setVisible(false);
if (etat_modification_client == 1)
{panneau_2.rebuild();}
this.setSize(984,572);
break;
case 3 : panneau_1.setVisible(false);
panneau_2.setVisible(false);
panneau_3.setVisible(true);
panneau_4.setVisible(false);
panneau_5.setVisible(false);
panneau_6.setVisible(false);
if (etat_ajout_valid_2 == 0)
{panneau_3.rebuild_ajout();}
else if (etat_ajout_valid_2 == 1)
{panneau_3.rebuild_valid();}
this.setSize(981,570);
break;
case 4 : panneau_1.setVisible(false);
panneau_2.setVisible(false);
panneau_3.setVisible(false);
panneau_4.setVisible(true);
panneau_5.setVisible(false);
panneau_6.setVisible(false);
if (etat_signalement_ajout_valid_3 == 0)
{panneau_4.rebuild_ajout();}
else if (etat_signalement_ajout_valid_3 == 1)
{panneau_4.rebuild_valid();}
this.setSize(981,569);
break;
case 5 : panneau_1.setVisible(false);
panneau_2.setVisible(false);
panneau_3.setVisible(false);
panneau_4.setVisible(false);
panneau_5.setVisible(true);
panneau_6.setVisible(false);
if (etat_FT_ajout_valid_3 == 0)
{panneau_5.rebuild_ajout();}
else if (etat_FT_ajout_valid_3 == 1)
{panneau_5.rebuild_valid();}
this.setSize(982,569);
break;
case 6 : panneau_1.setVisible(false);
panneau_2.setVisible(false);
panneau_3.setVisible(false);
panneau_4.setVisible(false);
panneau_5.setVisible(false);
panneau_6.setVisible(true);
this.setSize(983,569);
break;
public void actionPerformed(ActionEvent event)
}

Try:
1. public void doLayout()
http://java.sun.com/j2se/1.3/docs/api/java/awt/Container.html#doLayout()
2. public void update(Graphics g)
http://java.sun.com/j2se/1.3/docs/api/java/awt/Container.html#update(java.awt.Graphics)
Vishal

Refresh the applet !!!!!!

We developed an internationalizated applet with jdk1.3.0 and we used hide and show functions
to repaint the applet and obtain the applet with the new language selected.
Now in Swing with jdk1.3.1 hide and show are deprecated and the setVisible doesn't do the same.
We have tried some options, here you have the code of the function that realizes the change of
the idiom:
private void canviIdioma( String str )
if( str.equals( "Angl?s" ) )
language = new String( "en" );
country = new String( "US" );
if(str.equals( "Catal?" ))
language = new String( "ca" );
country = new String( "CA" );
currentLocale = new Locale( language,country );
missatges = ResourceBundle.getBundle( "ResourceBundle",currentLocale );
myCollator=Collator.getInstance( currentLocale );
repaint();
System.out.println(missatges.getString("titol1"));
// getContentPane().invalidate();
// getContentPane().validate();
// setVisible(false); //hide
// setVisible(true); //show
// hide();
// show();
// invalidate();
// repaint();
// revalidate();
// getContentPane().revalidate();
// doLayout();
// setVisible(true);
The change of the idiom is done correctly because the System.out.println writes the correct string.
What must we do to repaint ?
Thanks

The only thing which comes to my mind now is that you are not specifying what to repaint.
If the applet is in the same class, try
this.repaint();
If you the applet in a different class like
class hello extends applet
//code
then you can call
hello.repaint();

Refresh applet sqlj NullPointerException URGENT!

I have the following sqlj code in an applet to retrive data from an oracle database. After this the code goes onto draw the data in the applet using AWT (that code isn't shown here). My trouble is that when I get to the following line Connection con = Oracle.connect("jdbc:oracle:thin:@ebalpha:1525:ORCL", "flowmanager", "xxxxx").getConnection(); I get a Null Pointer exception only after refreshing the page using F5.
So to overcap I get a NullPointerException only when I refresh the applet. It runs perfectly the first time. The applet need to be refreshed because the data in the table get updated and the applet need to be refreshed to show the data changes.
public void getFlowSpaceData() throws SQLException {
// MyIter iter;
String strUserName = getParameter("paramUserName");
String strFlowName = new String();
Connection con = Oracle.connect("jdbc:oracle:thin:@ebalpha:1525:ORCL", "flowmanager", "xxxxx").getConnection();
strQuery = "select FLOWNAME FROM FLOWMANAGER.TMP_FLOWNAMES WHERE USERNAME ='" + strUserName +"'";
PreparedStatement pstmt0 = con.prepareStatement(strQuery);
ResultSet rs0 = pstmt0.executeQuery();
while (rs0.next()) {
strFlowName = rs0.getString(1);
rs0.close();
pstmt0.close();
strQuery = "select FLOWNAME, USERNAME, PANELROW, PANELCOL, RELATEROW, RELATECOL, OBJTYPE, BASECODE, INDUSTRYID, PANELNUM, BUSINESSPROCESSID FROM flows WHERE flowname ='" + strFlowName + "' AND username ='" + strUserName +"' ORDER BY PANELNUM";
PreparedStatement pstmt1 = con.prepareStatement(strQuery);
ResultSet rs1 = pstmt1.executeQuery();
int r = 0;
int c = 0;
while (rs1.next()) {
intObjType[r][c]= rs1.getInt(7);
strID[r][c] = rs1.getString(11);
//strIDQuery = strIDQuery + 'or ID =' + strinID
intRowRelation[r][c] = rs1.getInt(5);
intColRelation[r][c] = rs1.getInt(6);
c++;
if(c > 4) {
r++;
c = 0;
rs1.close();
pstmt1.close();
PreparedStatement pstmt2 = con.prepareStatement(strQuery);
ResultSet rs2 = pstmt2.executeQuery();
r = 0;
c = 0;
int i = 0;
int intSTRLENGTH = 0;
while(i < 24){
strQuery = "select name, descr, role from BUSINESSPROCESS WHERE ID = '" + strID[r][c] + "'";
pstmt2 = con.prepareStatement(strQuery);
rs2 = pstmt2.executeQuery();
rs2.next();
intSTRLENGTH = rs2.getString(1).length();
if (intSTRLENGTH > 17){
strLabel1[r][c] = rs2.getString(1).substring(0,17);
strLabel2[r][c] = rs2.getString(1).substring(18,intSTRLENGTH);
}else {
strLabel1[r][c] = rs2.getString(1).substring(0,intSTRLENGTH);
strLabel2[r][c] = " ";
intSTRLENGTH = rs2.getString(2).length();
if (intSTRLENGTH > 17){
strDescr1[r][c] = rs2.getString(2).substring(0, 17);
strDescr2[r][c] = rs2.getString(2).substring(18,intSTRLENGTH);
}else{
strDescr1[r][c] = rs2.getString(1).substring(0,intSTRLENGTH);
strDescr2[r][c] = " ";
c++;
i++;
if(c > 4) {
r++;
c = 0;
rs2.close();
pstmt2.close();
con.close();
con = null;
Thanks for you Assistance! It's greatly appreciated!
Chris Wallace

After further research I notice that if I Clear classload cache after every load before I refresh the applet it works fine. I can't have the user brining up the the consule windows and pressing x to clear classloader. Just thought I would give this futher information to help limit what the problem could be.

Applet refresh problem in Ajax appln

I have a drag and drop applet in an Ajax application.
The drag and drop applet comes in a dialog box when user clicks on one button from the ajax page.
From the applet user can do drag and drop files ,and click on ok the file names will be transferred to the ajax page .
The problem is when user clicks the dialog box for selecting different files ,then the previously selected files will be there in the applet. If we do a refresh (f5) of the web page then the problem is not there. But since it�s a ajax application we are not doing any refresh or reload in the processing,only when the application start for the frist time the page gets reloaded.Other wise only resetting the form values in each transaction
Is there any way to do an automatic refresh of applet each time user selects the dialog box for file selection.?
Please do help in solving the issue
Thanks

Hi
i would start of by searching the forums "refresh applet". This question has been answered many times.
HTH

Is there method to refresh applet?

I was wondering if theres a method to refresh an applet or refresh a panel in an applet. My problem is that at the click of a button i set a new content panel, but it appears as if nothing has happened, and i need to minimize and then restore the applet viewer and it changes.

do you want to refresh component like button, label etc
like
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class applet_component_refresh extends Applet implements ActionListener {
Button[] button;
Button changeButton;
String[] buttonString= {"Normal Text ", "Changed Text"};
int number = 260;
int count;
public void init()
     setBackground(new Color(225,225, 255));
     button = new Button[number];
     for (int i=0; i<number; i++)
          button[i] = new Button(buttonString[count%2]);
          add(button);
     changeButton = new Button("Change buttons label");
     changeButton.setBackground(new Color(150, 255, 150));
     add(changeButton);
     changeButton.addActionListener(this);
public void actionPerformed(ActionEvent ae)
     if (ae.getSource() == changeButton)
          count++;
          for (int i=0; i<number; i++) button[i].setLabel(buttonString[count%2]);
          invalidate();
          validate();
} // END OF Class component_refresh
you cant use location.reload method of javascript to do this....

Appletis getting refreshed

I have an applet in .html file. when the applet link is clicked applet gets reloaded. If it's already opened it's get refreshed.
Problem is, i do not want to refresh my applet once it's started. In my .html, i want to know if this applet window is already opened, if it is, then i do not want to refresh my applet.
anyone knows how to do it.
regards
Srikant

I have an applet in .html file. when the applet link
is clicked applet gets reloaded. If it's already
opened it's get refreshed.Lucky you. Many have the problem that it doesn't refresh.
Problem is, i do not want to refresh my applet once
it's started. In my .html, i want to know if this
applet window is already opened, if it is, then i do
not want to refresh my applet.
anyone knows how to do it.Well, you could make it interact with some magic Javascript, turning the link off or on.

Applet needs to be refreshed!

Hello friends,
Actually am a new user in java. Wanted to know how to refresh an applet containing tables .((i.e.Suppose i have a list of users, if i check out some users and block them, then i want the status column to get refreshed to blocked)). Please lemme know if anyone can help me out!!
Thanks
cheeks

// executed together.
somecomponent.validate();
somecomponent.repaint();
// somecomponent might be your applet.

Swing applet refresh problem in JRE1.6

Now , i met a problean in java swing project which troubled me for a long time, that i want to ask for some suggestions, I really very very thank you.
The problean is :
we use the swing in the applet , and run it with JRE 1.6, we find that the interface often disappear and appears blank when refresh the page , but when we use the mouse to over the control which in the interface ,then this control will appear . Then we try to reduce some not used codes/packets in this project , then we find that this phenomenon will appear less often.
This defect will not appear in JRE 1.4 and JRE 1.5. And also it will not appear when just run it as a desktop program.
I don't know if it is a bug in JRE 1.6 or it is due to our program. Can you give me some suggestions ? Thank you!
More information like following document :
=================================================================================================
2, Problem happen condition :
     Applet with swing;
     Run in JRE1.6 environment;
     Open or refresh the applet web page;
     IE, Netscape, Mozilla , almost all explorers.
3, Problean describe :
     Open the Start.html page and click the �Pre-Provisioning Tool� button to open the PPT.html page. There is a configuration applet which uses swing in the PPT page. When we open or refresh this page , the applet often disappear and show blank. And when we move the mouse over the position of the control which in the applet , these controls then will appear again. But if we use the buttons which in the applet to open and back to the applet tab page, it will not show blank.
     At last we find that this problem is a very common problem when run applet in JRE1.6. It may happen whenever you run the applet which uses swing controls in JRE1.6.
     And I find that we use �Ctrl + Alt + Del� to lock the computer and then login in again when the page is blank, then the page will turn ok and the applet will appear.
     This prolem just happen in JRE1.6 environment . If in JRE1.4 or 1.5 it performes good.
4, What cause this issue :
     Until now , we have no successful and perfect solution to solve this problem completely. And we still don�t know the real reasons that causes this issue.. We find that there are some people in internet also met this issue and has no solution.
     But we can give some options to try to find the real reasons. And we also have been try some time :
It may a bug for JRE1.6. We can sure that it is not a bug for explorers, because it happens the same in all explorers. If it�s a JRE bug , I think we can only to waite the newer version JRE to solve this issue.
It due to our program. If this is true, I think we may modify the program to solve this sssue. But I�m afraid that it may need us to modify too much.
5, What works we have been try :
5.2 For our program : We try such ways :
     1) If the project too big and too much to download : We remove the not needed modules that in TCOTool project. .
     Result : This problem happened less often
     2) If some methods are not compatible between JRE 1.4/1.5 and JRE1.6 : I try to modify these method to fit JRE1.6 and compile the project by jDK1.6. (Methed such as show() to setVisible(true), hidden() to setVisible(false) )
     result : This problem happened less often but it�s also will happen.
     3) If operator too much when open PPT/SUT : such as load xml file too much times and so on.
6, About our project :
6.1 The applet web page :
<OBJECT
classid = "clsid:8AD9C840-044E-11D1-B3E9-00805F499D93"
codebase = "application/x-java-applet;version=1.6"
width="860" height="640">
<PARAM NAME = CODE VALUE = "com.installApplet" >
<PARAM NAME = CODEBASE VALUE = "./jar/" >
<PARAM NAME = ARCHIVE VALUE = "TCOTools.jar" >
<PARAM NAME = MAYSCRIPT VALUE = true >
<PARAM NAME = "type" VALUE = "application/x-java-applet;version=1.6">
<PARAM NAME = "scriptable" VALUE = "false">
<PARAM NAME = "java.security.manager" VALUE>
<PARAM NAME = "java.security.policy" VALUE="java.policy" />
<PARAM NAME = "func" VALUE="1" />
<COMMENT>
     <EMBED
type = "application/x-java-applet;version=1.6" \
CODE = "com.installApplet" \
JAVA_CODEBASE = "./jar/" \
ARCHIVE = "TCOTools.jar" \
WIDTH = "100px" height="30px" \
MAYSCRIPT = true \
java.security.manager = \
java.security.policy ="java.policy" / \
func="1" \
     scriptable = false \
     pluginspage = "application/x-java-applet;version=1.6">
     <NOEMBED>
</NOEMBED>
     </EMBED>
</COMMENT>
</OBJECT>
6.2 The TCOTools.jar is almost 15Mb totally. So it need sometime to download this file. But we just test it in local.
=======================================================================================================
Welcome you to send mail to [email protected]

I will start by stating that I really have no idea what the problem could be. I will add to that by stating that I am going way out on a limb here.
That said - have you checked all your browser settings, cleared your cache and all the other things one usually does when an Applet acts quirky?
Also, have you tried the Applet tag instead of Object just for a test?
Sorry I can't do better than that, but w/o seeing the code, it's going to be difficult for anyone to help I think unless they have had a similar problem.

Please help with Applet in New Window?

I am trying to write a html page which opens appet into new window.
Tha'ts what i want. My applet has user/passwd authentication and then
makes a socket connection. However i am facing tow problems(kind of one):
1. If i close my applet browser window, socket connection is still active.
(if i use appletviewer.. every thing works perferctly)
2. on my web page, if i click again to open my appet window it refreshes my applet window again ....if it 's already opened. in other words, my applet does not really gets reloaded from my webserver..
Please advise..
Here is my HTML Code
index.html
<HEAD>
<SCRIPT TYPE="text/javascript">
<!--
function popup(mylink, windowname)
if (! window.focus)return true;
var href;
if (typeof(mylink) == 'string')
   href=mylink;
else
   href=mylink.href;
window.open(href, windowname, 'width=840,height=630,scrollbars=yes');
return false;
</SCRIPT>
<A
   HREF="NewJApplet.html"
   onClick="return popup(this, 'notes')">Loads Streamer </A>
</HEAD>NewJApplet.html
<HTML>
<BODY>
<P>
<APPLET code="NewJApplet.class" width=800 height=560></APPLET>
</P>
<HR WIDTH="100%"><FONT SIZE=-1>
</BODY>
</HTML>

You can open a frame, and have a very small applet on your html page. Perhaps you can set the applet size to (0, 0).
You could also open a new browser window that is not resizable and contains your applet in its full size and without the toolbar buttons and menubar. I think you need javascript to configure the new browser window like that.

Resize applet within a HTML frame

Hi,
I am using an applet to display a tree in a HTML frame of a web page.
I would like to resize or refresh the applet when the HTML frame is resized. Is there a way for the applet to know when the HTML frame is resized?
Any help will be appreciated.
Thanks

I tried using the componentResized() method to solve this problem but I was unsuccessful.
Here is what I tried:
My application consists of using a Java applet to display a tree in a HTML frame. In addition I put the tree in a scroll pane. I tried using addComponentListener(this) to get the componentResized() method to be involked. I tried adding the component listener to the scroll pane:
JScrollPane treeView = new JScrollPane(tree);
treeView.addComponentListener(this);
I tried adding the component listener to the root pane:
JRootPane root = getRootPane();
root.addComponentListener(this);
and I tried adding the comoponent listener to the glass pane and the content pane.
The componentResized() method was involked when the tree was initially displayed in some of my attempts but I was never able to get the componentResized() method to be involked when I resized the html frame.
I believe that I am having a problem determining which component to add the addComponentListener to so that the componentResized() method get invoked when I resize the html frame.

Applet display problem in 1.4.2_10

I recently upgraded JRE from 1.4.2_07 to 1.4.2_10 and my applet page refresh got screwed up. Sometimes when the page with the applet is refreshed, the applet is not displayed. It is loaded for sure but not displayed.
If we switch back to some window and come back to this page again, it shows up !!! or just hit enter on the address bar it shows up !!! ...
Anyone facing the same problem? It would be great if someone could help me one this ...
-arrow

try dis one:
http://v8doc.sas.com/sashtml/
the option bar in the menu in the left frame disappears; but it shows up shortly when refreshing continously or back/forward on the browser rapidly - this sounds like your problem as well?
It might have to do with the recent MS patches (released April 11th) that fix some issues within ActiveX; double clicking the script window then does the trick?

Applet TAB navigation not working with 1.4.1_01

I recently upgraded to Java version 1.4.1_01. Now, when I load my applets, the TAB key cannot be used for navigation until I open the Java console and then close it again. To ensure that my the threads in my specific Applet are not the problem, I came up with the following test applet:
import java.awt.BorderLayout;
import javax.swing.BoxLayout;
import javax.swing.JApplet;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class TestApplet extends JApplet {
    public void init() {
        super.init();
    public void start() {
        JPanel myPanel = new JPanel();
        myPanel.setLayout(new BoxLayout(myPanel, BoxLayout.Y_AXIS));
        JTextField textField1 = new JTextField("Text Field 1");
        myPanel.add(textField1);
        JTextField textField2 = new JTextField("Text Field 2");
        myPanel.add(textField2);
        JTextField textField3 = new JTextField("Text Field 3");
        myPanel.add(textField3);
        getContentPane().add(BorderLayout.CENTER, myPanel);
    public void stop() {
        super.stop();
}To ensure that my build environment/options are not the problem, I compiled this applet as follows:
javac TestApplet.java
I then came up with the following HTML file for the applet:
<HTML>
<HEAD>
<TITLE>Test Applet</TITLE>
</HEAD>
<BODY MARGINWIDTH="0" MARGINHEIGHT="0" BGCOLOR="white">
<APPLET
CODE=TestApplet.class
WIDTH=635
HEIGHT=500
ALIGN=left
VSPACE=10
HSPACE=10
>
</APPLET>
</BODY>
</HTML>When I access this test applet, again I am not able to navigate among the text fields with the TAB key. However, if I open the Java console, close it right back up, and refresh my applet, the TAB navigation works. I've tried simply refreshing my applet (as well as a hundred other things) and have had no success.
Any help would be GREATLY appreciated.
Thanks in advance

Looks like this is related to Bug #4707289. To fix this,
I added the following lines to the above applet:
textField1.setFocusable(true);
textField2.setFocusable(true);
textField3.setFocusable(true);

Refreshing an Applet

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