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<div class="linkAHEAD"><a href="generalrules.html">General Information about Writing Event Listeners</a></div>
<div class="linkAHEAD"><a href="eventsandcomponents.html">Listeners Supported by Swing Components</a></div>
<div class="linkAHEAD"><a href="handling.html">Implementing Listeners for Commonly Handled Events</a></div>
<div class="linkBHEAD"><a href="actionlistener.html">How to Write an Action Listener</a></div>
<div class="linkBHEAD"><a href="caretlistener.html">How to Write a Caret Listener</a></div>
<div class="linkBHEAD"><a href="changelistener.html">How to Write a Change Listener</a></div>
<div class="linkBHEAD"><a href="componentlistener.html">How to Write a Component Listener</a></div>
<div class="linkBHEAD"><a href="containerlistener.html">How to Write a Container Listener</a></div>
<div class="linkBHEAD"><a href="documentlistener.html">How to Write a Document Listener</a></div>
<div class="linkBHEAD"><a href="focuslistener.html">How to Write a Focus Listener</a></div>
<div class="linkBHEAD"><a href="internalframelistener.html">How to Write an Internal Frame Listener</a></div>
<div class="linkBHEAD"><a href="itemlistener.html">How to Write an Item Listener</a></div>
<div class="linkBHEAD"><a href="keylistener.html">How to Write a Key Listener</a></div>
<div class="linkBHEAD"><a href="listdatalistener.html">How to Write a List Data Listener</a></div>
<div class="linkBHEAD"><a href="listselectionlistener.html">How to Write a List Selection Listener</a></div>
<div class="nolinkBHEAD">How to Write a Mouse Listener</div>
<div class="linkBHEAD"><a href="mousemotionlistener.html">How to Write a Mouse-Motion Listener</a></div>
<div class="linkBHEAD"><a href="mousewheellistener.html">How to Write a Mouse-Wheel Listener</a></div>
<div class="linkBHEAD"><a href="propertychangelistener.html">How to Write a Property Change Listener</a></div>
<div class="linkBHEAD"><a href="tablemodellistener.html">How to Write a Table Model Listener</a></div>
<div class="linkBHEAD"><a href="treeexpansionlistener.html">How to Write a Tree Expansion Listener</a></div>
<div class="linkBHEAD"><a href="treemodellistener.html">How to Write a Tree Model Listener</a></div>
<div class="linkBHEAD"><a href="treeselectionlistener.html">How to Write a Tree Selection Listener</a></div>
<div class="linkBHEAD"><a href="treewillexpandlistener.html">How to Write a Tree-Will-Expand Listener</a></div>
<div class="linkBHEAD"><a href="undoableeditlistener.html">How to Write an Undoable Edit Listener</a></div>
<div class="linkBHEAD"><a href="windowlistener.html">How to Write Window Listeners</a></div>
<div class="linkAHEAD"><a href="api.html">Listener API Table</a></div>
<div class="linkAHEAD"><a href="problems.html">Solving Common Event-Handling Problems</a></div>
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            <div id=PageTitle>How to Write a Mouse Listener</div>
            <blockquote>

Mouse events tell you    
when the user uses the mouse
(or similar input device)
to interact with a component.
Mouse events occur when  
the cursor enters or exits a component's onscreen area
and when the user presses or releases one of
the mouse buttons.

<p>
Tracking the cursor's motion
involves significantly more system overhead
than tracking other mouse events, so
mouse-motion events are separated 
into a separate listener type 
(see <a href="mousemotionlistener.html">How to
Write a Mouse Motion Listener</a>).

<p>
To track mouse wheel events, you can register
a mouse-wheel listener.  See <a href="mousewheellistener.html">
How to Write a Mouse Wheel Listener</a> for more information.

<p>
If your program needs to detect both mouse events
and mouse-motion events,
you can use Swing's convenient <code>MouseInputAdapter</code> class,
which implements both <code>MouseListener</code> and
<code>MouseMotionListener</code>. It does not implement
the <code>MouseWheelListener</code> interface.
<font color=red>[Footnote: <code>MouseInputAdapter</code>
doesn't directly implement <code>MouseListener</code> and
<code>MouseMotionListener</code>. Instead, it implements
<code>MouseInputListener</code>, a convenience interface that
implements <code>MouseListener</code> and
<code>MouseMotionListener</code>.]</font>
 

<p>
The following example shows a mouse listener.
At the top of the window is a blank area
(implemented, strangely enough, 
by a class named <code>BlankArea</code>).
The mouse listener listens for events 
both on the <code>BlankArea</code>
and on its container,
an instance of <code>MouseEventDemo</code>.
Each time a mouse event occurs,
a descriptive message is displayed 
under the blank area.
By moving the cursor on top of the blank area
and occasionally pressing mouse buttons,
you can fire mouse events.

<p>

<p><center><IMG SRC="../../figures/uiswing/events/MouseEventDemo.png" WIDTH="412" HEIGHT="287" ALIGN="BOTTOM" ALT=""></center></p>

<p>


<blockquote><hr><strong>Try this:</strong>&nbsp;
<ol>
<li> <a href="http://java.sun.com/docs/books/tutorialJWS/uiswing/events/examples/MouseEventDemo.jnlp">Run
     MouseEventDemo</a> using
     <a href=http://java.sun.com/products/javawebstart>
     Java<sup><font size=-2>TM</font></sup> Web Start</a>.
     Or, to compile and run the example yourself,
     consult the
     <a href="examples/index.html#MouseEventDemo">example index</a>.

<li> Move the cursor into the yellow rectangle
     at the top of the window.
     <br>
     You'll see one or more mouse-entered events.

<li> Press and hold the mouse button.
     <br>
     You'll see a mouse-pressed event.
     You might see some extra mouse events,
     such as mouse-exited and then mouse-entered.

<li> Release the mouse button.
     <br>
     You'll see a mouse-released event.
     If you didn't move the mouse,
     a mouse-clicked event will follow.

<li> Press and hold the mouse button,
     and then drag the mouse so that the cursor ends up
     outside the window.
     Release the mouse button.
     <br>
     You'll see a mouse-pressed event,
     followed by a mouse-exited event,
     followed by a mouse-released event.
     You are <em>not</em> notified
     of the cursor's motion.
     To get mouse-motion events,
     you need to implement a 
     <a href="mousemotionlistener.html">mouse-motion listener.</a>

</ol>
<hr></blockquote>

You can find the demo's code in

<a class="SourceLink" target="_blank" href="examples/MouseEventDemo.java"><code>MouseEventDemo.java</code></a>
and

<a class="SourceLink" target="_blank" href="examples/BlankArea.java"><code>BlankArea.java</code></a>.
Here is the demo's mouse event handling code:

<blockquote><pre>
public class MouseEventDemo ... implements MouseListener {
	<em>//where initialization occurs:</em>
        //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);
    }
}
</pre></blockquote>

</blockquote>
<h3>
<a name="api">The Mouse Listener API</a>
</h3>
<blockquote>

<p align=center><a name="mouselistener">The MouseListener
   Interface</a>
<p><em>The corresponding adapter class is
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/java/awt/event/MouseAdapter.html"><code>MouseAdapter</code></a>. You can also use the Swing adapter class,
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/javax/swing/event/MouseInputAdapter.html"><code>MouseInputAdapter</code></a>, which has all the methods available from <code>MouseListener</code>
and <code>MouseMotionListener</code>.</em>
<table border=1>
<tr>
<th align=left>Method</th>
<th align=left>Purpose</th>
</tr>

<tr>
<td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/java/awt/event/MouseListener.html#mouseClicked(java.awt.event.MouseEvent)">mouseClicked(MouseEvent)</a></td>
<td> Called just after the user clicks the listened-to component.
</td>
</tr>

<tr>
<td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/java/awt/event/MouseListener.html#mouseEntered(java.awt.event.MouseEvent)">mouseEntered(MouseEvent)</a></td>
<td> Called just after the cursor enters the bounds
     of the listened-to component.
</td>
</tr>

<tr>
<td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/java/awt/event/MouseListener.html#mouseExited(java.awt.event.MouseEvent)">mouseExited(MouseEvent)</a></td>
<td> Called just after the cursor exits the bounds
     of the listened-to component.
</td>
</tr>

<tr>
<td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/java/awt/event/MouseListener.html#mousePressed(java.awt.event.MouseEvent)">mousePressed(MouseEvent)</a></td>
<td> Called just after the user presses a mouse button
     while the cursor is over the listened-to component.
</td>
</tr>

<tr>
<td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/java/awt/event/MouseListener.html#mouseReleased(java.awt.event.MouseEvent)">mouseReleased(MouseEvent)</a></td>
<td> Called just after the user releases a mouse button
     after a mouse press over the listened-to component.
</td>
</tr>
</table>

<p align=center><a name="mouseevent">The MouseEvent Class</a>
<p>
<table border=1>
<tr>
<th align=left>Method</th>
<th align=left>Purpose</th>
</tr>

<tr>
<td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/java/awt/event/MouseEvent.html#getClickCount()">int getClickCount()</a></td>
<td>Return the number of quick, consecutive clicks the user has made
    (including this event).  For example, returns 2 for a double click.
</td>
</tr>

<tr>
<td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/java/awt/event/MouseEvent.html#getX()">int getX()</a><br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/java/awt/event/MouseEvent.html#getY()">int getY()</a><br>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/java/awt/event/MouseEvent.html#getPoint()">Point getPoint()</a></td>
<td>Return the (x,y) position at which the event occurred,
    relative to the component that fired the event.
</td>
</tr>

<tr>
<td>
<a class="APILink" target="_blank" href="http://java.sun.com/javase/6/docs/api/java/awt/event/MouseEvent.html#getButton()">int getButton()</a></td>
<td>Return which mouse button, if any, has changed state.  One of
    the following constants is returned: <code>NOBUTTON</code>,
    <code>BUTTON1</code>, <code>BUTTON2</code>, or <code>BUTTON3</code>.
    Introduced in release 1.4.
</td>
</tr>

<tr>
<td>