See when a mousebutton is clicked without adding mouselisteners to all components

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.

Answer 2

This would be a world of mess and pain at the best of times...

Check here Global Event Listeners with AWTEventListener & how to pull MouseEvent's from it for an alternative concept. Basically it's a global mouse listener. You need to do a lot of work to get this to work for you (checking the children belong to the parent etc), but it does work well.

Answer 3

Try using MouseEvent Class, with static method MOUSE_CLICKED

See here for further details:

http://docs.oracle.com/javase/6/docs/api/java/awt/event/MouseEvent.html

See this example from roseindia

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

public class MouseClick {
  Label lbl;
  public static void main(String[] args) {
  MouseClick MC = new MouseClick();
  }

  public MouseClick(){
  Frame f = new Frame("Checking the mouse click");
  Panel p = new Panel();
  Button button = new Button("Click Me");
  button.addMouseListener(new MyMouseListener());
  p.add(button, BorderLayout.NORTH);
  f.add(p,BorderLayout.NORTH);
  lbl = new Label("Roseindia.net");
  f.add(lbl, BorderLayout.CENTER);
  f.addWindowListener(new WindowAdapter(){
  public void windowClosing(WindowEvent we){
  System.exit(0);
  }
  });
  f.setSize(400,400);
  f.setVisible(true);
  }

  public class MyMouseListener extends MouseAdapter{
  public void mouseClicked(MouseEvent me){
  String str = lbl.getText();
  if (str.equals("Roseindia.net")){
  lbl.setText("You have clicke the button.");
  }
  else if (str.equals("You have clicke the button.")){
  lbl.setText("Roseindia.net");
  }
  }
  }
}

See this example from Oracle

 public class MouseEventDemo ... implements MouseListener {
            //where initialization occurs:
            //Register for mouse events on blankArea and the panel.
            blankArea.addMouseListener(this);
            addMouseListener(this);
        ...

        public void mousePressed(MouseEvent e) {
           saySomething("Mouse pressed; # of clicks: "
                        + e.getClickCount(), e);
        }

        public void mouseReleased(MouseEvent e) {
           saySomething("Mouse released; # of clicks: "
                        + e.getClickCount(), e);
        }

        public void mouseEntered(MouseEvent e) {
           saySomething("Mouse entered", e);
        }

        public void mouseExited(MouseEvent e) {
           saySomething("Mouse exited", e);
        }

        public void mouseClicked(MouseEvent e) {
           saySomething("Mouse clicked (# of clicks: "
                        + e.getClickCount() + ")", e);
        }

        void saySomething(String eventDescription, MouseEvent e) {
            textArea.append(eventDescription + " detected on "
                            + e.getComponent().getClass().getName()
                            + "." + newline);
        }
    }