Adding and removing elements from list during runtime

By default List don’t support methods to add/remove elements from list

Why ???

At the time of creation of List jList creates a ListModel object which stores

data of list and it does not support runtime addition or deletion of objects

For adding elements at runtime you need to change ListModel to DefaultListModel

How to do that ?

Here are the steps to do it.

·         Add a List to your Form

·         Right click on List and Select Properties

·         Now look for Model Property

·         Click ellipsis( button that look like [..]) which is in front of model property

·         Now a dialog box will open

·         Now select custom Code from Combobutton

·         And type code new DefaultListModel()  in the TextField. And click OK

·         Now Open Source Code

To desired event or method write the code

   //Getting ListModel in DefaultListModel

   DefaultListModel  dList = (DefaultListModel) list.getmodel();

//You can add Elements in list in two ways

// 1^st : adding item at the end of list

dList.addelement(“new item”);

//2^nd : Adding eelement at a specific index

dList.add(0,”new Item”);

//here 0 is the index

//to remove any element

dList.removeElementAt(index no);

//OR

dList.removeElement(“Element x”);

Adding an Image as background in Netbeans 2nd Method

This Method is for beginners who are using Netbeans and don't have knowledge
about methods,method overriding etc

This is how you can do it

• Open your application
• Add a new frame to it
• Right Click on Main frame
• Select Set Layout
• Now Select Null Layout

Now your Components (If you added) will Collapse and your Frame will turn into a mini frame

• Re size Frame Add Components (Button,TextField etc)
• Add a new Label
• Right click on the label you've just added
• Select Properties

 

• Look for icon Menu and Select it

• Select the Image

 

Now Resize the Frame and re size over the whole Frame

 

Final Look of Frame

 

Note 

• You will have to set Minimum size of frame from properties

Otherwise Frame will turn into a Small frame that need to be resided every time

Adding an Image as background in Netbeans

Adding an Image as background is little different as no function is available for that.
So what you need is Custom Code.You can add an Image as background
using net beans while using features of Net beans

So here is my Code

Note

1)    Image in background will be visible only at run time not design time

2)    I have Skipped some Part of Code So that you could Understand the Code easily

Add A New Frame to you Application make Changes according to given Code

File :Main Frame.class

import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.*;

class backImage extends JComponent {

Image i;

public backImage(Image i) {
this.i = i;

}

@Override
public void paintComponent(Graphics g) {
g.drawImage(i, 0, 0, null);
}
}

public class MainFrame extends javax.swing.JFrame {
  
    public MainFrame() throws IOException {
          BufferedImage bf = ImageIO.read(new File("E:/bohemia.jpg"));
this.setContentPane(new backImage(bf));
        initComponents();
    }

    public static void main(String args[]) throws IOException {
    
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                try {
                    new MainFrame().setVisible(true);
                } catch (IOException ex) {
                    System.out.print(e.getMessage());
                }
               
            }
        });
    }
                  
}

Result: