JList In Java

JList Constructors👇

The constructors of JList are explained further below:

JList Methods💫

JList methods that are frequently used are:

Creating a Simple JList ✍️

We will be creating a simple JList in Java, in which the list will be of various colors. To run the below program, you should use offline IDE(Integrated Development Environment).

Code

package com.codingninjas.javaswing;

import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.DefaultListModel;
import javax.swing.SwingUtilities;

public class CodingNinjas_JListInJava_Example extends JFrame {
   private JList<String> colorList;
   public CodingNinjas_JListInJava_Example() {

       // To create our own model and add the elements in JList
       DefaultListModel<String> JlistModel = new DefaultListModel<>();
       JlistModel.addElement("Red");
       JlistModel.addElement("Pink");
       JlistModel.addElement("Green");
       JlistModel.addElement("Brown");
       JlistModel.addElement("Black");
       JlistModel.addElement("Yellow");
       JlistModel.addElement("Blue");
       JlistModel.addElement("Violet");
       
       // To create the Jlist in Java
       colorList = new JList<>(JlistModel);
       add(colorList);
       
       this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       this.setTitle("Coding Ninjas: JList in Java Example");
       
       // To set the size of frame      
       this.setSize(400,400);
       this.setVisible(true);
       this.setLocationRelativeTo(null);
   }
   
   public static void main(String[] args) {
       SwingUtilities.invokeLater(new Runnable() {
           @Override
           public void run() {
               new CodingNinjas_JListInJava_Example();
           }
       });
   }      
}

You can also try this code with Online Java Compiler

Run Code

Output

Tip: Try the code in VSCode after installing the Java extensions.

Creating Scrollbar in JList ✨

To insert a scrollbar to the frame, we will have to add the command: “ add(new JScrollPane(colorList)); ” under the public class in the above code.
After adding the scrollbar, the frame will generate a scrollbar upon resizing the frame.
The output has been shown below:

Creating Event Listener in JList 😎

We will be creating an event listener in JList in Java, where we will be getting the element as output upon selecting it in JList. We have provided the working output for your better understanding. 

Code

package com.codingninjas.javaswing;

import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JScrollPane;
import java.util.List;
import javax.swing.DefaultListModel;
import javax.swing.SwingUtilities;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;

public class CodingNinjas_JListInJava_Example extends JFrame {
   private JList<String> colorList;
   public CodingNinjas_JListInJava_Example() {

       // To create our own model and add the elements in JList
       DefaultListModel<String> JlistModel = new DefaultListModel<>();
       JlistModel.addElement("Red");
       JlistModel.addElement("Pink");
       JlistModel.addElement("Green");
       JlistModel.addElement("Brown");
       JlistModel.addElement("Black");
       JlistModel.addElement("Yellow");
       JlistModel.addElement("Blue");
       JlistModel.addElement("Violet");
       
       // To create the Jlist in Java
       colorList = new JList<>(JlistModel);
       add(colorList);
       
       colorList.addListSelectionListener(new ListSelectionListener() {
           @Override
           public void valueChanged(ListSelectionEvent e) {
               if (!e.getValueIsAdjusting()) {
                   final List<String> selectedValuesList = colorList.getSelectedValuesList();
                   System.out.println(selectedValuesList);
               }
           }
       });
       
       this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       this.setTitle("Coding Ninjas: JList in Java Example");
       
       // To set the size of frame      
       this.setSize(400,400);
       this.setVisible(true);
       this.setLocationRelativeTo(null);
       add(new JScrollPane(colorList));
   }
   
   public static void main(String[] args) {
       SwingUtilities.invokeLater(new Runnable() {
           @Override
           public void run() {
               new CodingNinjas_JListInJava_Example();
           }
       });
   }      
}

You can also try this code with Online Java Compiler

Run Code

Output

Frequently Asked Questions

Which package contains JList in Java?

Java.swing package contains all the Java components like JList.

What exactly is a Swing Event?

A swing event is defined as a change in an object's state.

How do we add the data to JList in Java?

We don't explicitly insert data to JLists. We utilize a different model instead. The contents of the list will be maintained by that model. If we wish to render items from an array or vector, we will simply feed the array into the JList constructor, and the JList will create the ListModel for us. When working with data from collections, however, we should almost always use ListModel. ListModel also defines a number of methods that we can utilize to alter our data.

What are the advantages of using Swing's lightweight components?

Components that are lightweight can rely on a native collection of other components. These components are simple kinds that allow the outcome to be transparent to others while displaying themselves on the screen. Each component renders itself using the graphics objects and operations that are available.

What is the function of a layout manager?

It is the manager of all layouts or the framework that offers functionality amongst the components automatically.

It also establishes the space between each component as well as provides support for it.

Conclusion

In this blog, we learned about JList in Java and also discussed the class declaration, constructors and methods of JList in Java, along with a working example. We learned that JList is a Java class that can be used to display object data in a list. It can be used to trigger events based on the selection of a specific value from a list. JList can be used in Java applications to represent data in a very orderly manner.

Check out here for other Java Swing blogs:

• JCheckBox In Java
• JTextField In Java
• JTable In Java
• JButton In Java
   

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