Question

I have a JFrame with a lot of subcomponents and subpanels with different functions. I have added mouseListeners to some of them.

I want to be able to call a function when a mousebutton is clicked in the frame, regardless of what component is at focus. I dont want to add mouselisteners to all of the components. Much like keyEventDispacher, I am useing it for the keyboard.

I have looked at this Dispatch MouseEvent but I wasn’t able to work it out. Could anyone give me a small example to demonstrate how it works?

Answer 1

Here is a simple example of global mouse listener:

public static void main ( String[] args )
{
    final JFrame frame = new JFrame ();

    // Some content
    frame.getContentPane ().setLayout ( new FlowLayout ( FlowLayout.CENTER, 5, 5 ) );
    frame.getContentPane ().add ( new JButton ( "Test" ) );
    frame.getContentPane ().add ( new JLabel ( "Test" ) );
    frame.getContentPane ().add ( new JTextField ( "Test" ) );

    // Global mouse listener
    final AWTEventListener listener = new AWTEventListener ()
    {
        public void eventDispatched ( AWTEvent event )
        {
            // Event and component that recieved that event
            MouseEvent me = ( MouseEvent ) event;
            Component c = me.getComponent ();

            // Ignoring mouse events from any other frame
            if ( SwingUtilities.getWindowAncestor ( c ) == frame )
            {
                if ( event.getID () == MouseEvent.MOUSE_PRESSED )
                {
                    System.out.println ( "Mouse pressed on " + c.getClass ().getCanonicalName () );
                }
                if ( event.getID () == MouseEvent.MOUSE_RELEASED )
                {
                    System.out.println ( "Mouse released on " + c.getClass ().getCanonicalName () );
                }
                if ( event.getID () == MouseEvent.MOUSE_ENTERED )
                {
                    System.out.println ( "Mouse entered " + c.getClass ().getCanonicalName () );
                }
                if ( event.getID () == MouseEvent.MOUSE_EXITED )
                {
                    System.out.println ( "Mouse exited " + c.getClass ().getCanonicalName () );
                }
            }
        }
    };
    Toolkit.getDefaultToolkit ().addAWTEventListener ( listener, AWTEvent.MOUSE_EVENT_MASK );

    frame.pack ();
    frame.setLocationRelativeTo ( null );
    frame.setVisible ( true );
}

Be aware that this listener will inform you about every mouse event inside any frame/dialog/window/popup. That is why you should limit your actions to some specific frame like i did in the example in case you don’t need events from other frames/windows/…

By the way, you can easily listen to some other events globally (for example key events) using the same approach. For example – use the AWTEvent.KEY_EVENT_MASK key instead of AWTEvent.MOUSE_EVENT_MASK and cast AWTEvent to KeyEvent instead of MouseEvent.