Hi,

Im trying to list all the drives in the local machine in a combo box and when a drive selected all the folders and files in that drive must be listed ina list box.

I was succesfull in listing the drives in the combobos.But when i try to list the folders in the list box im getting error like this:

Error:
Prod_applet.java:226: Cannot find symbol
symbol : variable local_jlist
location: class Prod_applet
local_jlist.addElement(local_files[i]);

1 error

Can any one help me in solving this problem ASAP please?Just got struck with it
i have given the code below.

Thankyou



Prod_applet.java
--------------------
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.File;
import java.io.FilenameFilter;
import java.io.FileFilter;

public class Prod_applet extends JFrame implements ItemListener{
boolean inAnApplet = true;
final boolean shouldFill = true;
final boolean shouldWeightX = true;

public Prod_applet() {
JPanel local_window = new JPanel();
JPanel server_window = new JPanel();
JPanel button_window = new JPanel();
JPanel action_window = new JPanel();
JButton connect = new JButton("Connect");
connect.setMargin(new Insets(0, 0, 0, 0));
JButton disconnect = new JButton("Disconnect");
disconnect.setMargin(new Insets(0, 0, 0, 0));
JButton up_but = new JButton(">>");
up_but.setMargin(new Insets(0, 0, 0, 0));
JButton down_but = new JButton("<<");
down_but.setMargin(new Insets(0, 0, 0, 0));
JLabel local_lbl = new JLabel("Local Site");
JLabel server_lbl = new JLabel("Remote Site");
JComboBox local_combobox = new JComboBox();
local_combobox.setEditable(true);
JComboBox server_combobox = new JComboBox();


List local_jlist = new List();
//local_jlist.setMargin(new Insets(0, 0, 0, 0));
List server_jlist = new List();
//server_jlist.setMargin(new Insets(0, 0, 0, 0));
JButton local_mkdir = new JButton("MkDir");
local_mkdir.setMargin(new Insets(0, 0, 0, 0));
JButton server_mkdir = new JButton("MkDir");
server_mkdir.setMargin(new Insets(0, 0, 0, 0));
JButton local_delete = new JButton("Delete");
local_delete.setMargin(new Insets(0, 0, 0, 0));
JButton server_delete = new JButton("Delete");
server_delete.setMargin(new Insets(0, 0, 0, 0));
JButton local_refresh = new JButton("Refresh");
local_refresh.setMargin(new Insets(0, 0, 0, 0));
JButton server_refresh = new JButton("Refresh");
server_refresh.setMargin(new Insets(0, 0, 0, 0));
Container contentPane = getContentPane();
BorderLayout border = new BorderLayout();
contentPane.setLayout(border);
contentPane.add(local_window, BorderLayout.WEST);
contentPane.add(server_window, BorderLayout.EAST);
contentPane.add(button_window, BorderLayout.CENTER);
contentPane.add (action_window, BorderLayout.SOUTH);
GridBagLayout gridbag = new GridBagLayout();
GridBagConstraints c = new GridBagConstraints();
c.insets = new Insets(2, 2, 2, 2);
GridBagConstraints c1 = new GridBagConstraints();
c1.insets = new Insets(2, 2, 2, 2);
GridBagConstraints c2 = new GridBagConstraints();
c2.insets = new Insets(2, 2, 2, 2);
GridBagConstraints c3 = new GridBagConstraints();
c3.insets = new Insets(2, 2, 2, 2);
GridBagConstraints c4 = new GridBagConstraints();
c4.insets = new Insets(2, 2, 2, 2);
GridBagConstraints c5 = new GridBagConstraints();
c5.insets = new Insets(2, 2, 2, 2);
GridBagConstraints c6 = new GridBagConstraints();
c6.insets = new Insets(2, 2, 2, 2);
local_window.setLayout(gridbag);
server_window.setLayout(gridbag);
button_window.setLayout(gridbag);
action_window.setLayout(gridbag);
File[] drives = File.listRoots();
for(int i = 0 ; i <drives.length;i++)
{
local_combobox.addItem(drives[i]);
server_combobox.addItem(drives[i]);
}
local_combobox. addItemListener(this);
server_combobox. addItemListener(this);
//Connect Button
c.gridx = 0;
c.gridy = 0;
gridbag.setConstraints(connect, c);
local_window.add(connect);
//Disconnect Button
c.gridx = 25;
c.gridy = 0;
gridbag.setConstraints(disconnect, c);
server_window.add(disconnect);

//Local Label
c1.gridx = 0;
c1.gridy = 3;
gridbag.setConstraints(local_lbl, c1);
local_window.add(local_lbl);
//Local combobox
c1.gridx = 10;
c1.gridy = 3;
gridbag.setConstraints(local_combobox, c1);
local_window.add(local_combobox);
//Server Label
c1.gridx = 25;
c1.gridy = 3;
gridbag.setConstraints(server_lbl, c1);
server_window.add(server_lbl);
//Server combobox
c1.gridx = 35;
c1.gridy = 3;
gridbag.setConstraints(server_combobox, c1);
server_window.add(server_combobox);

//Local jlist
c2.gridx = 0;
c2.gridy = 6;
gridbag.setConstraints(local_jlist, c2);
local_window.add(local_jlist);

//Server jlist
c2.gridx = 25;
c2.gridy = 6;
gridbag.setConstraints(server_jlist, c2);
server_window.add(server_jlist);

//Up Button
c3.gridx = 10;
c3.gridy = 8;
gridbag.setConstraints(up_but, c3);
button_window.add(up_but);

//Down Button
c3.gridx = 10;
c3.gridy = 9;
gridbag.setConstraints(down_but, c3);
button_window.add(down_but);

//local_mkdir
c4.gridx = 0;
c4.gridy = 10;
gridbag.setConstraints(local_mkdir,c4);
action_window.add(local_mkdir);

//server_mkdir
c4.gridx = 25;
c4.gridy = 10;
gridbag.setConstraints (server_mkdir, c4);
action_window.add(server_mkdir);

//local_delete
c5.gridx = 1;
c5.gridy = 10;
gridbag.setConstraints(local_delete, c5);
action_window.add(local_delete);

//server_delete
c5.gridx = 26;
c5.gridy = 10;
gridbag.setConstraints(server_delete, c5);
action_window.add(server_delete);

//local_refresh
c6.gridx = 2;
c6.gridy = 10;
gridbag.setConstraints(local_refresh, c6);
action_window.add(local_refresh);

//server_refresh
c6.gridx = 27;
c6.gridy = 10;
gridbag.setConstraints(server_refresh, c6);
action_window.add(server_refresh);

addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
if (inAnApplet) {
dispose();
} else {
System.exit(0);
}
}
});
}
public void itemStateChanged(ItemEvent e)
{
JComboBox local_combobox = (JComboBox)e.getSource();
JComboBox server_combobox = (JComboBox)e.getSource();
String newSelectionStrName_local = null;
String newSelectionStrName_server = null;
if ( local_combobox.getSelectedItem() instanceof File)
{
File newSelection_local = (File)local_combobox.getSelectedItem();
newSelectionStrName_local = newSelection_local.getPath();
}
else if (local_combobox.getSelectedItem() instanceof String)
{
newSelectionStrName_local = (String) local_combobox.getSelectedItem();
}
if ( server_combobox.getSelectedItem() instanceof File)
{
File newSelection_server = (File)server_combobox.getSelectedItem();
newSelectionStrName_server = newSelection_server.getPath();
}
else if (server_combobox.getSelectedItem() instanceof String)
{
newSelectionStrName_server = (String) server_combobox.getSelectedItem();
}
File file1 = new File(newSelectionStrName_local);
File file2 = new File(newSelectionStrName_server);
String[] local_files = file1.list();
for (int i=0;i<local_files.length;i++)
{

local_jlist.addElement(local_files[i]);

}

}

public static void main(String args[]) {
Prod_applet window = new Prod_applet();
window.setSize(800,600);
window.inAnApplet = false;
window.setTitle("FTP_CLIENT");
window.pack();
window.setVisible(true);
}
}

Looks like local_jlist is a function local variable (inpublic Prod_applet()).. and not in the scope where you're using it (line 226).. make it a member variable.. it should work..

I have declared all the variables public only. No problem with other components only the listbox is bugging up.

Thnak you

I have declared all the variables public only. No problem with other components only the listbox is bugging up.

Im new for this just now trying practically.Can you help me in this more.

Thnak you

As thekashyap mentioned, which mean you can not access it in public void itemStateChanged(ItemEvent e). So you need to declare it on top level to be accesible by other methods

Also List doesn't have method addElement() so add() would be solution check reference

OK just seen this application running...
1. TextArea to list files is very-very small you should do something bigger. Play with settings for each component
2. In remote site I chosed my optical drive which made lots of un-catched errors and on top of that list was displayed in wrong TextArea (under my local disk)
3. Puzzled with functionality of buttons Connect & Disconnect. What do they do? If this application is supposed to work as FTP client you have to be able define location where you want to connect (like ftp.adobe.pub.com plus user name), but cann't say to much I doon't know what research you did into FTP clients

Hi thanks,
I have tried that also.Its now showing erro like"variable local_jlistmight not have been initialized"

Post the updated code and I will look at it

This just means that you must set a value for the variable before it is used. You could change it's declaration to Note, you cannot simply say new List(), since List is an interface and not a class. You need to choose one of the List implementations to create.

Am I mistaken and List is not a class? What about this. However, you right List can be also interface but with less option then List class