How do I create a right click context menu in Java Swing?

Question

I'm working on a school project and we want to implement a right click pop-up menu in the gui.

Currently we are doing something like creating a JMenu on right click and setting its location to that of the mouse's position...

This seems really ugly and is very buggy, is there any better way of doing this? I'm sure there must be.

Answer 1

There's a section on Bringing Up a Popup Menu in the How to Use Menus article of The Java Tutorials which explains how to use the JPopupMenu class.

The example code in the tutorial shows how to add MouseListeners to the components which should display a pop-up menu, and displays the menu accordingly.

(The method you describe is fairly similar to the way the tutorial presents the way to show a pop-up menu on a component.)

Answer 2

You are probably manually calling setVisible(true) on the menu. That can cause some nasty buggy behavior in the menu.

The show(Component, int x, int x) method handles all of the things you need to happen, (Highlighting things on mouseover and closing the popup when necessary) where using setVisible(true) just shows the menu without adding any additional behavior.

To make a right click popup menu simply create a JPopupMenu.

class PopUpDemo extends JPopupMenu {
    JMenuItem anItem;
    public PopUpDemo(){
        anItem = new JPopupMenu("Click Me!");
        add(anItem);
    }
}

Then, all you need to do is add a custom MouseListener to the components you would like the menu to popup for.

class PopClickListener extends MouseAdapter {
    public void mousePressed(MouseEvent e){
        if (e.isPopupTrigger())
            doPop(e);
    }

    public void mouseReleased(MouseEvent e){
        if (e.isPopupTrigger())
            doPop(e);
    }

    private void doPop(MouseEvent e){
        PopUpDemo menu = new PopUpDemo();
        menu.show(e.getComponent(), e.getX(), e.getY());
    }
}

// Then on your component(s)
component.addMouseListener(new PopClickListener());

Of course, the tutorials have a slightly more in-depth explanation.

Note: If you notice that the popup menu is appearing way off from where the user clicked, try using the e.getXOnScreen() and e.getYOnScreen() methods for the x and y coordinates.