JList Java

The object of JList class represents a list of text items. The list of text items can be set up so that the user can choose either one item or multiple items. It inherits JComponent class.

Class Declaration

Following is the declaration for javax.swing.JList class −

public class JList
   extends JComponent
      implements Scrollable, Accessible

Field

Following are the fields for javax.swing.JList class −

• static int HORIZONTAL_WRAP − Indicates a "newspaper style" layout with cells flowing horizontally then vertically.
• static int VERTICAL − Indicates a vertical layout of cells, in a single column; the default layout.
• static int VERTICAL_WRAP − Indicates a "newspaper style" layout with cells flowing vertically then horizontally.

Class Constructors

Sr.No.	Constructor & Description
1	JList() Constructs a JList with an empty, read-only, model.
2	JList(ListModel dataModel) Constructs a JList that displays elements from the specified, non-null, model.
3	JList(Object[] listData) Constructs a JList that displays the elements in the specified array.
4	JList(Vector<?> listData) Constructs a JList that displays the elements in the specified Vector.

Class Methods

Here is the list of methods in Swing JList class.

Methods Inherited

This class inherits methods from the following classes −

• javax.swing.JComponent
• java.awt.Container
• java.awt.Component
• java.lang.Object

JList Example

Create the following Java program using any editor of your choice or any Integrated Development Environment (IDE)

1. import javax.swing.*;  
2. public class ListExample  
3. {  
4.      ListExample(){  
5.         JFrame f= new JFrame();  //create an object of JFrame 
6.         DefaultListModel<String> l1 = new DefaultListModel<>();  //Create an object of listmodel
7.           l1.addElement("Item1");  //Add element to listmodel
8.           l1.addElement("Item2");  //Add element to listmodel
9.           l1.addElement("Item3");  //Add element to listmodel
10.           l1.addElement("Item4");  //Add element to listmodel
11.           JList<String> list = new JList<>(l1);  //Create an object of JList
12.           list.setBounds(100,100, 75,75);  //set list bound
13.           f.add(list);  //Add list to the object of JFrame 
14.           f.setSize(400,400);  
15.           f.setLayout(null);  
16.           f.setVisible(true);  //set JFrame visible
17.      }  
18. public static void main(String args[])  
19. {  
20.    new ListExample();  
21.  }}  

Output:

---

Java JList Example with ActionListener

1. import javax.swing.*;  
2. import java.awt.event.*;  
3. public class ListExample  
4. {  
5.      ListExample(){  
6.         JFrame frame= new JFrame(); //create an object of JFrame 
7.         final JLabel label = new JLabel();   //create an object of JLabel       
8.         label.setSize(500,100);  
9.         JButton b=new JButton("Show");  //Create and object of a JButton
10.         b.setBounds(200,150,80,30);  
11.         final DefaultListModel<String> list1 = new DefaultListModel<>();  //Create an object of listmodel
12.           list1.addElement("C");  //add first element to listmodel1
13.           list1.addElement("C++");  //add Second element to listmodel1
14.           list1.addElement("Java");  //add third element to listmodel1
15.           list1.addElement("PHP");  //add fourth element to listmodel1
16.           final JList<String> dlist1 = new JList<>(list1);  //create an object of JList and add listmodel1 to JList
17.           dlist1.setBounds(100,100, 75,75);  //Set the bounds of JList2
18.           DefaultListModel<String> list2 = new DefaultListModel<>();  //Create an object of listmodel
19.           list2.addElement("Turbo C++");  //add first element to listmodel2
20.           list2.addElement("Struts");   //add second element to listmodel2
21.           list2.addElement("Spring");   //add third element to listmodel2
22.           list2.addElement("YII");   //add fourth element to listmodel2
23.           final JList<String> dlist2 = new JList<>(list2);   //create an object of JList and add listmodel2 to JList
24.           dlist2.setBounds(100,200, 75,75);  //Set the bounds of JList2
25.           frame.add(dlist1); //add object of JList to JFrame 
26.           frame.add(dlist2);  //add object of JList to JFrame 
27.           frame.add(b);//add object of a JButton to JFrame
28.           frame.add(label);  //add object of a JLabel to  JFrame
29.           frame.setSize(450,450);  
30.           frame.setLayout(null);  
31.           frame.setVisible(true);  //set JFrame visible
32.           b.addActionListener(new ActionListener() {  
33.               public void actionPerformed(ActionEvent e) {   
34.                  String data = "";  
35.                  if (list1.getSelectedIndex() != -1) {                       
36.                     data = "Programming language Selected: " + list1.getSelectedValue();   
37.                     label.setText(data);  
38.                  }  
39.                  if(list2.getSelectedIndex() != -1){  
40.                     data += ", FrameWork Selected: ";  
41.                     for(Object frame :list2.getSelectedValues()){  
42.                        data += frame + " ";  
43.                     }  
44.                  }  
45.                  label.setText(data);  
46.               }  
47.            });   
48.      }  
49. public static void main(String args[])  
50. {  
51.    new ListExample();  
52. }}  

Output:

ALSO ANOTHE EXAMPLE OF JLIST

package com.sjavaspot.gui;
 
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class JListDemo {
   private JFrame mainFrame;
   private JLabel headerLabel;
   private JLabel statusLabel;
   private JPanel controlPanel;
   
   public JListDemo(){
      prepareGUI();
   }
   public static void main(String[] args){
      JListDemo  jListDemo = new JListDemo();      
      jListDemo.showListDemo();
   }
   private void prepareGUI(){
      mainFrame = new JFrame("Java Swing Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new JLabel("", JLabel.CENTER);        
      statusLabel = new JLabel("",JLabel.CENTER);    
      statusLabel.setSize(350,100);

      controlPanel = new JPanel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }
   private void showListDemo(){                                       
      headerLabel.setText("Control in action: JList"); 
      final DefaultListModel fruitsName = new DefaultListModel();

      fruitsName.addElement("Apple");
      fruitsName.addElement("Grapes");
      fruitsName.addElement("Mango");
      fruitsName.addElement("Peer");

      final JList fruitList = new JList(fruitsName);
      fruitList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
      fruitList.setSelectedIndex(0);
      fruitList.setVisibleRowCount(3);        

      JScrollPane fruitListScrollPane = new JScrollPane(fruitList);    
      final DefaultListModel vegName = new DefaultListModel();

      vegName.addElement("Lady Finger");
      vegName.addElement("Onion");
      vegName.addElement("Potato");
      vegName.addElement("Tomato");

      final JList vegList = new JList(vegName);
      vegList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
      vegList.setSelectedIndex(0);
      vegList.setVisibleRowCount(3);        

      JScrollPane vegListScrollPane = new JScrollPane(vegList);       
      JButton showButton = new JButton("Show");

      showButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) { 
            String data = "";
            if (fruitList.getSelectedIndex() != -1) {                     
               data = "Fruits Selected: " + fruitList.getSelectedValue(); 
               statusLabel.setText(data);
            }
            if(vegList.getSelectedIndex() != -1){
               data += " Vegetables selected: ";
               for(Object vegetable:vegList.getSelectedValues()){
                  data += vegetable + " ";
               }
            }
            statusLabel.setText(data);
         }
      }); 
      controlPanel.add(fruitListScrollPane);    
      controlPanel.add(vegListScrollPane);    
      controlPanel.add(showButton);    
   
      mainFrame.setVisible(true);             
   }
}

VERIFY THE OUTPUT