JFrame:setJMenuBar(JMenuBar bar) Example

JFrame:setJMenuBar(JMenuBar bar) Example

JFrame window has several methods.These include setSize,setLocation, add etc.setJMenuBar is a method that is used to top menu navigation to a JFrame.Below code explains

How to use JFrame:setJMenuBar(JMenuBar bar) method.

[

import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;

public class JFrameSetJMenuBarExample extends JFrame {
    JFrameSetJMenuBarExample()
    {
        super("JMenuBar Example");

        JMenuBar bar=new JMenuBar();
        JMenu menu=new JMenu("File");
        JMenuItem save=new JMenuItem("Save");
        JMenuItem edit=new JMenuItem("Edit");
        menu.add(save);
        menu.add(edit);
        bar.add(menu);
        setJMenuBar(bar);
        setSize(400,400);
        setLocationRelativeTo(null);
        setVisible(true);

    }
    public static void main(String args[])
    {
        new JFrameSetJMenuBarExample();
    }

}

]

Adding Action Listener to JMenuItems

After adding JMenuItems to JMenu, the other thing you are supposed to do is addActionListner to these JMenuItems.Fire up your IDE and execute below code.

[

import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class JFrameSetJMenuBarExample extends JFrame
        implements ActionListener {
    public    JMenuItem save,edit;
    JFrameSetJMenuBarExample()
    {
        super("JMenuBar Example");

        JMenuBar bar=new JMenuBar();
        JMenu menu=new JMenu("File");
        save=new JMenuItem("Save");
        edit=new JMenuItem("Edit");
        save.addActionListener(this);
        edit.addActionListener(this);

        menu.add(save);
        menu.add(edit);
        bar.add(menu);
        setJMenuBar(bar);
        setSize(400,400);
        setLocationRelativeTo(null);
        setVisible(true);

    }
    public void actionPerformed(ActionEvent event)
    {
        if(event.getSource()==save)
        {
            JOptionPane.showMessageDialog(this, "Menu selected is Save",
                    "JMenu Example",JOptionPane.INFORMATION_MESSAGE);
        }
        if(event.getSource()==edit)
        {
            JOptionPane.showMessageDialog(this, "Menu selected is Edit",
                    "JMenu Example",JOptionPane.INFORMATION_MESSAGE);
        }

    }
    public static void main(String args[])
    {
        new JFrameSetJMenuBarExample();
    }

}

]

Code Explanation:

Above class extends JFrame and implements interface ActionListener.

What does it mean when a class extends another class?

If a class extends another class, all non-abstract methods contained in the parent class becomes accessible to the child class.The child class can just call the directly or ovveride them.

What it means when a class implements a certain interface?

If a class implements a certain interface,its the obligation of the class to override all the non-abstract interface methods.

In our case here,JFrame methods that become accessible to our class here are

[bar.add(menu);

setJMenuBar(bar);
setSize(400,400);
setLocationRelativeTo(null);

setVisible(true);]

ActionListener interface method that we need to override is [public void actionPerformed(ActionEvent event)

{
    if(event.getSource()==save)
    {
        JOptionPane.showMessageDialog(this, "Menu selected is Save",
                "JMenu Example",JOptionPane.INFORMATION_MESSAGE);
    }
    if(event.getSource()==edit)
    {
        JOptionPane.showMessageDialog(this, "Menu selected is Edit",
                "JMenu Example",JOptionPane.INFORMATION_MESSAGE);
    }

}]

Other Swing components you should Check out.

JOptionPane:showMessageDialog