I'm trying to add ActionListener to JMenuItem in my java menu.

Here is a screenshot of the menu:

enter image description here

I want to add ActionListener to "Rectangle" JMenuItem in order to show up the rectangle shape upon clicking on the "Rectangle" menu item. I tried many times to add the ActionListener but I fail every time.

Here is my code:

Class "menubar.java" :

import javax.swing.*;

public class menubar extends JFrame{

public menubar(){
    JMenuBar menubar = new JMenuBar();
    setJMenuBar(menubar);

    JMenu shape = new JMenu("Shape");
    menubar.add(shape);

    JMenuItem rect = new JMenuItem("Rectangle");
    shape.add(rect);

    JMenuItem star = new JMenuItem("Star");
    shape.add(star);

    JMenu color = new JMenu("Color");
    menubar.add(color);

    JMenuItem black = new JMenuItem("Black");
    color.add(black);

    JMenuItem orange = new JMenuItem("Orange");
    color.add(orange);
}

public static void main(String[] args) {
    menubar gui = new menubar();
    gui.setTitle("Menu Bar");
    gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    shapes SPS = new shapes();
    gui.add(SPS);
    gui.setSize(500,300);
    gui.setVisible(true);
    gui.setLocationRelativeTo(null);
}
}

Class "shapes.java" :

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

public class shapes extends JPanel{
int midX = 220;
int midY = 90;
int radius[] = {60,20,50,20};
int nPoints = 16;
int[] X = new int[nPoints];
int[] Y = new int[nPoints];

public void paintComponent(Graphics gphcs){
super.paintComponent(gphcs);
this.setBackground(Color.WHITE);

gphcs.setColor(Color.BLUE);
gphcs.fillRect(20,35,100,30);

gphcs.setColor(Color.RED);
gphcs.drawString("Welcome to Java", 20, 20);

for (int i=0; i < nPoints; i++) {
       double x = Math.cos(i * ((2 * Math.PI) / nPoints)) * radius[i % 4];
       double y = Math.sin(i * ((2 * Math.PI) / nPoints)) * radius[i % 4];

       X[i] = (int) x + midX;
       Y[i] = (int) y + midY;
}
gphcs.setColor(Color.GREEN);
gphcs.fillPolygon(X, Y, nPoints);
}
}

I would be very thankful if anybody helped me with this issue.

Thanks for your time..

有帮助吗?

解决方案

One way that you can add an ActionListener to your container is :

public class JMenuClass extends JFrame implements ActionListener

Then, for each JMenuItem that you need a listener, you would do

item.addActionListener(this)

At the bottom of your class, you would need to add your actionPerformed methods, or however you want to implement it.

Cheers

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