Problem with Displaying ListBox (i.e. JList)

User_AYF65

Hi,

I am to store values in a listbox. I have created frame & a panel inside a frame & i am using BorderLayout inside panel. I have created a button & a listBox & added them to the panel. But when i run the application, it displays the button only & when i increase the size of window then it displays the listbox neighboring to the button.

My code is:

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

/**  the panel

*/

public class ListBoxEg extends JFrame{

     private JButton button;

     JList<String> listbox;

     DefaultListModel<String> model;

     public ListBoxEg() {

        JFrame frame = new JFrame("Test");

        frame.setVisible(true);

        frame.setSize(500,200);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();

        frame.add(panel);

        panel.setLayout( new BorderLayout() );

        button=new JButton("Hello");

        panel.add(button, BorderLayout.WEST);

       

        String listData = "ABCDE";

       

        // Create a new DefaultListModel

        model = new DefaultListModel<> ( );

        //Adding Elements in the model

        model.addElement(listData);

  listData ="12345";

        model.addElement(listData);

        listData ="!!!!!!";

        model.addElement(listData);

@";

        model.addElement(listData);

        //Creating a new ListBox

  listbox= new JList<>();

        //Adding Elements in the ListBox

        listbox.setModel(model);

  panel.add( listbox, BorderLayout.CENTER );

        pack();

       

        MyActionListener listener=new MyActionListener();   //added

        button.addActionListener(listener);

    }

    public static void main(String args[ ]) {

       ListBoxEg obj = new ListBoxEg( );

    }

}

   

class MyActionListener implements ActionListener{

        public void actionPerformed (ActionEvent e) {

        System.out.println("pressed button");

        }

}

Some body please guide me.

Zulfi.

User_AYF65

Hi,

Thanks. Actually problem was with BorderLayout.CENTER. I replaced it with BorderLayout.EAST. Also my setVisible(..) statement was misplaced. The complete code is:

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

/**  the panel

*/

public class ListBoxEg2 extends JFrame{

     private JButton button;

     JList<String> listbox;

DefaultListModel<String> model;

     public ListBoxEg2() {

        JFrame frame = new JFrame("Test");

       

        frame.setSize(500,200);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();

        frame.add(panel);

        panel.setLayout( new BorderLayout() );

        button=new JButton("Hello");

        panel.add(button, BorderLayout.WEST);

       

        String            listData = "ABCDE";

                               

       

        // Create a new DefaultListModel

        model = new DefaultListModel<> ( );

        //Adding Elements in the model

model.addElement(listData);

                listData ="12345";

model.addElement(listData);

        listData ="!!!!!!";

        model.addElement(listData);

@";

model.addElement(listData);

        //Creating a new ListBox

                listbox= new JList<>();

        //Adding Elements in the ListBox

        listbox.setModel(model);

                panel.add( listbox, BorderLayout.EAST );

        pack();

       

        MyActionListener listener=new MyActionListener();              //added

button.addActionListener(listener);

        frame.setVisible(true);

    }

    public static void main(String args[ ]) {

       // Run the GUI construction in the Event-Dispatching thread for thread-safety

SwingUtilities.invokeLater(new Runnable() {

         @Override

         public void run() {

            new ListBoxEg2(); // Let the constructor do the job

         }

      });

    }

}

    Zulfi.

836548

Hi Zulfi,

replace the below code

<code>

        frame.setVisible(true);

        frame.setSize(500,200);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

<code>

after adding the listbox to panel.

example

<code>

panel.add( listbox, BorderLayout.EAST );

frame.setVisible(true);

frame.setSize(500,200);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

pack();

<code>

User_AYF65

Hi,

Thanks. Actually problem was with BorderLayout.CENTER. I replaced it with BorderLayout.EAST. Also my setVisible(..) statement was misplaced. The complete code is:

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

/**  the panel

*/

public class ListBoxEg2 extends JFrame{

     private JButton button;

     JList<String> listbox;

DefaultListModel<String> model;

     public ListBoxEg2() {

        JFrame frame = new JFrame("Test");

       

        frame.setSize(500,200);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();

        frame.add(panel);

        panel.setLayout( new BorderLayout() );

        button=new JButton("Hello");

        panel.add(button, BorderLayout.WEST);

       

        String            listData = "ABCDE";

                               

       

        // Create a new DefaultListModel

        model = new DefaultListModel<> ( );

        //Adding Elements in the model

model.addElement(listData);

                listData ="12345";

model.addElement(listData);

        listData ="!!!!!!";

        model.addElement(listData);

@";

model.addElement(listData);

        //Creating a new ListBox

                listbox= new JList<>();

        //Adding Elements in the ListBox

        listbox.setModel(model);

                panel.add( listbox, BorderLayout.EAST );

        pack();

       

        MyActionListener listener=new MyActionListener();              //added

button.addActionListener(listener);

        frame.setVisible(true);

    }

    public static void main(String args[ ]) {

       // Run the GUI construction in the Event-Dispatching thread for thread-safety

SwingUtilities.invokeLater(new Runnable() {

         @Override

         public void run() {

            new ListBoxEg2(); // Let the constructor do the job

         }

      });

    }

}

    Zulfi.