Re: MouseListener

From:

"Fred Kleinschmidt" <fred.l.kleinmschmidt@boeing.com>

Newsgroups:

comp.lang.java.gui

Date:

Mon, 5 Jun 2006 19:24:11 GMT

Message-ID:

<J0EJ88.6Iz@news.boeing.com>

"DJ Zenith" <djzenith@djzenith.com> wrote in message
news:1149529971.814099.79420@y43g2000cwc.googlegroups.com...

Hi

I agree. However, the examples provided in the docs were confusing
to me. However, I will mod the class. But, The GWT class reference
doesn't list the methods mentioned below. The code compiled. I will
rework it though. Haven't done Java in a bit.

Ah - I missed that you were using GWT. I thought you were using
the standard Java MouseListener.

The GWT MouseListener does not follow the normal Java model
for listeners. In a "normal" Java listener, each method usually is passed
one parameter - the Event being listened for.

GWT breaks this paradigm by passing the component that fired the event,
and sometimes the coordinates of the event - but not the event itself.

Stephanie

Bastide wrote:

Futhermoren lines such as :
public void onMouseEnter(Widget sender)
        {
                sender = onFocusImage;

        }
are no-ops. I think you misunderstand the basics of parameter passing
in java.

Fred Kleinschmidt wrote:

"DJ Zenith" <djzenith@djzenith.com> wrote in message
news:1149276142.259198.204180@c74g2000cwc.googlegroups.com...

Hi

I implemented mouse listener in this classes below but when I put
my mouse over this button, it doesn't work. Help!

public class MouseListenerImpl implements MouseListener
{

I don't see any of the required methods for a class that
implements MouseListener. Where are:
  mouseClicked()
  mouseEntered()
  mouseExited()
  mousePressed()
  mouseReleased()
?

/**
* The onFocusImage.
*/
private Image onFocusImage;

/**
* The lostFocusImage.
*/
private Image lostFocusImage;

public MouseListenerImpl(Image onFocusImage, Image lostFocusImage)
{
this.onFocusImage = onFocusImage;
this.lostFocusImage = lostFocusImage;

}

/* (non-Javadoc)
* @see
com.google.gwt.user.client.ui.MouseListener#onMouseDown(com.google.gwt.user.client.ui.Widget,
int, int)
*/
public void onMouseDown(Widget sender, int x, int y)
{
// TODO Auto-generated method stub

}

/* (non-Javadoc)
* @see
com.google.gwt.user.client.ui.MouseListener#onMouseEnter(com.google.gwt.user.client.ui.Widget)
*/
public void onMouseEnter(Widget sender)
{
sender = onFocusImage;

}

/* (non-Javadoc)
* @see
com.google.gwt.user.client.ui.MouseListener#onMouseLeave(com.google.gwt.user.client.ui.Widget)
*/
public void onMouseLeave(Widget sender)
{
sender = lostFocusImage;

}

/* (non-Javadoc)
* @see
com.google.gwt.user.client.ui.MouseListener#onMouseMove(com.google.gwt.user.client.ui.Widget,
int, int)
*/
public void onMouseMove(Widget sender, int x, int y)
{
// TODO Auto-generated method stub

}

/* (non-Javadoc)
* @see
com.google.gwt.user.client.ui.MouseListener#onMouseUp(com.google.gwt.user.client.ui.Widget,
int, int)
*/
public void onMouseUp(Widget sender, int x, int y)
{
// TODO Auto-generated method stub

}

/**
* @param args
*/
public static void main(String[] args)
{
// TODO Auto-generated method stub

}

}

then i call it here

   Image onFocusTop = new Image("latoureiffel8.jpg");
   Image lostFocusTop = new Image("Illuminaughti.jpg");

   MouseListenerImpl mouseListenerTopButton = new
MouseListenerImpl(onFocusTop, lostFocusTop);

   lostFocusTop.addMouseListener(mouseListenerTopButton);

lostFocusTop is an Image. Image has no addMouseListener method.

topButtonPanel.add(lostFocusTop);

RootPanel.get("topButton").add(topButtonPanel);

--
Fred L. Kleinschmidt
Boeing Associate Technical Fellow
Technical Architect, Software Reuse Project