OpenMenu in Java Using Netbeans IDE

Introduction

This article describes how to create an OpenMenu bar in Java. The Netbeans IDE is used for the development of the example.

Packages Imported

java.io.*;

This package is used for system input and output through serialization, data streams and the file system.

java.awt.*;

AWT stands for Abstract Window ToolKit. The AWT package is imported to use the AWT components like label, checkbox and so on.

javax.swing.*;

Swing is an extended version of AWT. It supports some new components, like JComboBox, JScroll Pane and so on. Swing provides a Graphical User Interface to programs.

Java.awt.event.*;

This package is for dealing with various types of events fired by AWT components. This package provides classes and interfaces for dealing with these events.

What is Menu

A Menu is basically to be displayed to the user to help the user find information or execute a program function.

Example

In this example; we define how to create an OpenMenu in Java using the Netbeans IDE. There are certain steps in the Netbeans IDE that we need to follow as explained below.

Step 1

Open the Netbeans IDE then click on "File" -> "New project" then select "Java project" then provide a name (for example Menu) then click on "Ok" then right-click on our project and choose "New" -> Java class and then provide your class name (as Menu.java) and click "Ok" and use the following code for the class.

Step 2

In this class write the following code (the class name is "Menu"):

import java.awt.*;

import javax.swing.*;

import java.awt.event.*;

import java.io.*; 

public class Menu extends JFrame implements ActionListener{

JMenuBar db;

JMenu newfile;

JMenuItem demoopen;

JTextArea jt;

Menu()

{

demoopen=new JMenuItem("Open File");

demoopen.addActionListener(this);             

newfile=new JMenu("File");

newfile.add(demoopen);             

db=new JMenuBar();

db.setBounds(0,0,800,20);

db.add(newfile);          

jt=new JTextArea(800,800);

jt.setBounds(0,20,800,800);          

add(db);

add(jt);             

}

public void actionPerformed(ActionEvent e)

{

if(e.getSource()==demoopen)

{

openFile();

}

}      

void openFile()

{

JFileChooser cf=new JFileChooser();

int i=cf.showOpenDialog(this);             

if(i==JFileChooser.APPROVE_OPTION)

{

File f=cf.getSelectedFile();

String filepath=f.getPath();                    

displayContent(filepath);                    

}             

} 

void displayContent(String fpath)

{

try

{

BufferedReader br=new BufferedReader(new FileReader(fpath));

String s1="",s2="";                    

while((s1=br.readLine())!=null)

{

s2+=s1+"\n";

}

jt.setText(s2);

br.close();

}catch (Exception e) {e.printStackTrace();      }

} 

public static void main(String[] args)

{

       Menu mu=new Menu();

       mu.setSize(300,300);

       mu.setLayout(null);

       mu.setVisible(true);

       mu.setDefaultCloseOperation(EXIT_ON_CLOSE);

}

}

 

d1.jpg

 

d2.jpg

 

d3.jpg

 

Step 3

 

Now go to Menu and right-click on that, click on "Run" from the menu bar as in the following:

 

d4.jpg

 

Output

 

A window will appear and in that the file menu is displayed in the menu bar.

 

d5.jpg

 

Now click on "File" and then click on "Open File".

 

d6.jpg

 

From the window that is shown you can select any file from your system and you can open it.

 

d7.jpg