ListSelection example

With this tutorial we shall show you how to perform List Selection activities using JList components and ListSelectionListener interface. List selection is a very useful feature, when you applications requires user input with fixed choices.

In order to use JList and ListSelectionListener, one should perform the following steps:

• Create a class that implements ListSelectionListener interface.
• Override the methods that correspond to the events you want to monitor about the list e.g valueChanged and customize it to customize the handling of the respective event.
• Create a new JList
• Use the addListSelectionListener mehtod of the JList class to add to it the ListSelectionListener you’ve created.

Let’s take a look at the code snippet that follows:

package com.javacodegeeks.snippets.desktop;

import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;

public class ListSelectionExample extends JPanel {

    String labelArray[] = {"1", "2", "3"};
    JCheckBox checkBoxArray[] = new JCheckBox[labelArray.length];

    JList listLable = new JList(labelArray);

    public ListSelectionExample() {

  JScrollPane scrollPane = new JScrollPane(listLable);

  add(scrollPane);

  listLable.addListSelectionListener(new SelectionListen());

  for (int i = 0; i < labelArray.length; i++) {

checkBoxArray[i] = new JCheckBox("Option " + i);

add(checkBoxArray[i]);

  }
    }

    public static void main(String args[]) {

  JFrame jFrame = new JFrame("Selection example");

  jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

  jFrame.setContentPane(new ListSelectionExample());

  jFrame.pack();

  jFrame.setVisible(true);

    }
}
class SelectionListen implements ListSelectionListener {

    @Override
    public void valueChanged(ListSelectionEvent evetn) {

  if ((!evetn.getValueIsAdjusting()) || (evetn.getFirstIndex() == -1)) {

return;

  }

  for (int i = evetn.getFirstIndex(); i <= evetn.getLastIndex(); i++) {

System.out.println(((JList) evetn.getSource()).isSelectedIndex(i));

  }
    }
}

 
This was an example on how how to perform List Selection activities using JList components and ListSelectionListener interface.