I have got an assignment and I really need help or any tips..thanks

**celz** · August 7th, 2011, 04:00 PM

Hi I have got to codes one it is basically the interface and the other is the code.
Basically my program needs to this:

import java.io.File;
 
public class Main {
  public static void main(String[] argv) throws Exception {
    File dir = new File("C:/Program Files/java");
 
    String[] children = dir.list();
    if (children == null) {
      System.out.println("does not exist or is not a directory");
    } else {
      for (int i = 0; i < children.length; i++) {
        String filename = children[i];
        System.out.println(filename);
      }
    }
  }
}

If you compile and run you will see that will show files saved under the entered folder.

I can creat the interface apart but I don't know how to combine both code and make it run.

The path of the folder (C:/Program Files/java) needs to be entered in a text box and need two buttons one is OK and the other Cancel.
The files need to be listed or displayed in another windows which also has a button Ok which return to the previous window.

Any help is wellcome.
Thanks.

**Junky** · August 7th, 2011, 07:17 PM

So you need to write a GUI. You would not have been set this assignment if you have not covered the material in class. You need to revise your course material, read your textbook and read the online tutorials. Once you have done that you can start to write some code and when you have some code you can post it here and ask specific questions. Nobody is going to do it for you.

**Norm** · August 7th, 2011, 07:31 PM

You can also look at the Java Tutorials for ideas and code samples:
The Really Big Index
Go to this site and do a Find for GUI

**javapenguin** · August 7th, 2011, 08:45 PM

A text box.

Hmmmmm, are you allowed to use JOptionPane? If so, it can make a text box, and an ok and cancel button for you.

You'll have to use the right JOptionPane method and tell it what to do if cancel or ok is hit.

If you aren't allowed to do that,

Try this:

JTextField jtf = new JTextField(Enter a character limit, a.k.a. size, here);

JButton ok = new JButton("Ok");
JButton cancel = new JButton("Cancel");

and to get it to tell what the buttons to do

simply

ok.addActionListener(have an Action Listener as a parameter here).

Either use an anonymous class, i.e. a new ActionListener with the method actionPerformed enclosed or have another class, an inner class that's part of your class but probably private, extend ActionListener and use that.

As for the files being listed, I have an idea to show them.

You could possibly make a JLabel and make a for loop to add each index of the array to it and use html encoding

<html> "A line" "Another line" "A third line" etc </html> to add each index, one per line

Or you could simply pass the array you got as a parameter to a new JList and it'll show them in a list, though if there are lots of files and stuff, you should use a JScrollPane to make it so all of it can be seen and scrolled to.

JList fileList = new JList(children);

Also, make sure you have some kind of Container, look up Container in the Java API, to put all your stuff into.

Some like JFrame and JPanel, among others, require you to call setVisible(true) to make them visible

and JFrame normally will hide but not stop running on close so if you use that

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

to make sure it exits when you hit the X button, though if you use two JFrames, make sure only the main one that you want open has that close operation, otherwise your entire program will exit if either of those windows are closed.

Look at JOptionPane (Java Platform SE 7 )

Look at the subclasses of Component (Java Platform SE 6)

**celz** · August 9th, 2011, 04:54 AM

I got nice ideas from your post guys, for helping me out.
If any of you got any other ideas I would appreciate.

I managed to creat the interface code, now I need some light to combine both codes:

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

public class Events extends JFrame
implements ActionListener {

JButton btnClick = new JButton("OK");
JButton btnClick2 = new JButton("CANCEL");
JLabel label = new JLabel("Path");
JTextField text = new JTextField(15);
JList fileList = new JList(children);

public Events() {
super("Input");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

btnClick.addActionListener(this);

JPanel pane = new JPanel();

pane.add(label);
pane.add(text);
pane.add(btnClick);
pane.add(btnClick2);

add(pane);
setSize(400,200);
pack();
setVisible(true);
}

public void actionPerformed(ActionEvent evt) {
Object source = evt.getSource();

if (source.equals(btnClick)) {
JOptionPane.showMessageDialog(null, "The files saved in a folder should be displayed here(Think so)");
}
}

public static void main(String args[]) {
new Events();
}

}

**Norm** · August 9th, 2011, 06:24 AM

I need some light to combine both codes:

Can you explain what your problem is?
Where are the two pieces of of code you want to combine?
You posted some GUI code. Describe what you want added to it.

**celz** · August 9th, 2011, 01:10 PM

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

public class Events extends JFrame
implements ActionListener {

JButton btnClick = new JButton("OK");
JButton btnClick2 = new JButton("CANCEL");
JLabel label = new JLabel("Path");
JTextField text = new JTextField(15);
JList fileList = new JList(children);

public Events() {
super("Input");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

btnClick.addActionListener(this);

JPanel pane = new JPanel();

pane.add(label);
pane.add(text);
pane.add(btnClick);
pane.add(btnClick2);

add(pane);
setSize(400,200);
pack();
setVisible(true);
}

public void actionPerformed(ActionEvent evt) {
Object source = evt.getSource();

if (source.equals(btnClick)) {
JOptionPane.showMessageDialog(null, "The files saved in a folder should be displayed here(Think so)");
}
}

public static void main(String args[]) {
new Events();
}

}

This code Above is the interface.

The next cod is basically what the programs need to do:
import java.io.File;

public class Main {
public static void main(String[] argv) throws Exception {
File dir = new File("C:/Program Files/java");

String[] children = dir.list();
if (children == null) {
System.out.println("does not exist or is not a directory");
} else {
for (int i = 0; i < children.length; i++) {
String filename = children[i];
System.out.println(filename);
}
}
}
}

If you run you'll se that there is a text box wich needs to be filled with a path like:C:/Program Files/java
and what needs to be displayed, will be displayed after you click OK then generate another windows or form with a list of files under the folder chosen previsouly.

**Norm** · August 9th, 2011, 01:15 PM

text box wich needs to be filled with a path like:C:/Program Files/java

The text field class has a method that will set the text of the text field to a String that you provide.

what needs to be displayed, will be displayed after you click OK

What needs to be displayed?
Where should it be displayed?

generate another windows or form with a list of files under the folder chosen

You can create another window using the same technique you used to create the first one:
new JFrame() and then add components to it and then set it visible.
You can get a list of files in a folder by using the File class.

Please wrap you code in code tags to preserve its formatting. [code]
See: http://www.javaprogrammingforums.com...do=bbcode#code

**celz** · August 9th, 2011, 01:40 PM

It needs to be displayed a list of files save any folder as showed like for example:
I enter the following paht C:/Program Files/java
It needs to be display any file which is inside of the folder java.
It should be displayed on the second windows, the one that you recommed to use the same technique which a used adding a new frame and its componets.

I will be able to create the second windows, yet as you suggested I do not have any idea of how write the file class and make all program work properly, so I don't know if you willing to creat for me, or just show me a simple way and I modify somethings doing in my way or you could suggest any tutorial, website or book where I can find something like.

The thing is that I used to program in C# and now the new program state that I need to learn Java, so I don't have bases I can understand codes but I am not yet capable to write the all code by own, that is why I need some help.

Thanks.

**Norm** · August 9th, 2011, 01:47 PM

You should look through the Java Tutorial to see how to do the various things you need.
The Java™ Tutorials
The Really Big Index

Pickout and do one small step at a time.
For example use the File class to get a list of files in a folder.

How do you want to display the list of files?
As a list of lines of text
In a selectable list where a file could be chosen?

**celz** · August 9th, 2011, 01:55 PM

It needs to be displayed in a list of lines.

Thanks for the tutorials.

If a creat the second window what's the code that I will be using to once I click on the button OK display the second window.

**Norm** · August 9th, 2011, 01:57 PM

what's the code that I will be using to once I click on the button OK display the second window.

You can create another window using the same technique you used to create the first one:
new JFrame() and then add components to it and then set it visible.

**celz** · August 9th, 2011, 02:10 PM

Okay, although I did not fully understand I will try to analyse what you have said and my code. Thanks

**celz** · August 9th, 2011, 02:36 PM

Okay, although I did not fully understand I will try to analyse what you have said and my code. Thanks

**javapenguin** · August 9th, 2011, 03:50 PM

Can't recall what the JTextField object was, but you can get a String from it by

(I have to make up an object to use for demonstration)

JTextField field = new JTextField(40);

String path = field.getText();
File dir;
try
{
dir = new File(path);
}

catch(NullPointerException npeRef)
{
// what to do if the file pathname is null
}

String[] children = dir.list();

if (children == null) {
System.out.println("does not exist or is not a directory");
} else {
for (int i = 0; i < children.length; i++) {
String filename = children[i];
System.out.println(filename);
}
}

if (children != null)
{
JList list = new JList(children);

JScrollPane jsp = new JScrollPane(list, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);

pane.add(jsp);
}

Also, I can't see why your main method or whatever needs to be throwing any Exceptions itself, i.e. with a throws clause like you're doing.

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