Question

as the title states, i need to know how to determine if a menu item was clicked or not, then run the function associated. for instance i have a JMenu with a JMenuItem “exit”, which when clicked should run a close form method.

import javax.swing.*;

public class selector_form extends JFrame {


/**
 * 
 */
private static final long serialVersionUID = -5963842156289770842L;

public selector_form(String name)
{
    super.setTitle(name);
    setupComponents(this);
    super.setVisible(true);

}

private void setupComponents(JFrame frame)
{

    JMenuItem file_items = new JMenuItem("Exit");
    JMenuItem config_items = new JMenuItem("Preferences");
    JMenuItem[] machine_items = {new JMenuItem("Refresh"), 
            new JMenuItem("Add Dynamically"), new JMenuItem("Remove Dynamically")
    };
    JMenuItem[] emulator_items = {new JMenuItem("Start Emulator"),
            new JMenuItem("Stop Emulator"), new JMenuItem("Pause Emulator"),
            new JMenuItem("Reset Emulator"), new JMenuItem("Crash Emulator")
    };
    JMenuItem[] memory_items = {new JMenuItem("View Emulator Memory"),
            new JMenuItem("System Cheats"), new JMenuItem("Dump Emulator Memory"),
            new JMenuItem("Edit Specific Address"), 
            new JMenuItem("Show Allocations"), new JMenuItem("Allocate Memory"),
            new JMenuItem("DeAllocate Memory")
    };
    JMenuItem[] cpu_items = {new JMenuItem("Show Host Specs"),
            new JMenuItem("Show Emulator Specs"), 
            new JMenuItem("Enable HyperThreadding")
    };
    JMenuItem[] about_items = {new JMenuItem("Help Contents"), 
            new JMenuItem("About")
    };

    frame.setSize(800, 600);

    JMenuBar jmb = new JMenuBar();
    JMenu jm_a = new JMenu("File");
    JMenu jm_c = new JMenu("Config");
    JMenu jm_d = new JMenu("Machines");
    JMenu jm_e = new JMenu("Emulator");
    JMenu jm_f = new JMenu("Memory");
    JMenu jm_g = new JMenu("CPU");
    JMenu jm_h = new JMenu("About");

    jm_a.add(file_items);
    jm_c.add(config_items);
    for(JMenuItem item : machine_items)
        jm_d.add(item);
    for(JMenuItem item : emulator_items)
        jm_e.add(item);
    for(JMenuItem item : memory_items)
        jm_f.add(item);
    for(JMenuItem item : cpu_items)
        jm_g.add(item);
    for(JMenuItem item : about_items)
        jm_h.add(item);

    jmb.add(jm_a);
    jmb.add(jm_c);
    jmb.add(jm_d);
    jmb.add(jm_e);
    jmb.add(jm_f);
    jmb.add(jm_g);
    jmb.add(jm_h);
    frame.setDefaultCloseOperation(EXIT_ON_CLOSE);

    frame.setJMenuBar(jmb);

}

}

Answer 1

You can do this with an ActionListener. You can create your own ActionListener class.

class MenuActionListener implements ActionListener {
  public void actionPerformed(ActionEvent e) {
    System.out.println("Selected: " + e.getActionCommand());    
  }
}

Than add it to the JMenuItem.

JMenuItem newMenuItem = new JMenuItem("New");
newMenuItem.addActionListener(new MenuActionListener());