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<TITLE>Firing Item Events
(Java Developers Almanac Example)
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<h3>
e654.
Firing Item Events</h3>
An object wishing to fire item events must implement <code>ItemSelectable</code>.
This example shows typical code that an object must implement to
fire item events. When an item event is to be fired, <code>fireItemEvent()</code>
should be called.
<pre>
public class <font color="#0066ff"><i>MyComponent</i></font> implements ItemSelectable {
protected EventListenerList listenerList = new EventListenerList();
public Object[] getSelectedObjects() {
return <font color="#0066ff"><i>selectedObjects</i></font>;
}
public void addItemListener(ItemListener l) {
listenerList.add(ItemListener.class, l);
}
public void removeItemListener(ItemListener l) {
listenerList.remove(ItemListener.class, l);
}
// If the item is selected, sel should be true.
void fireItemEvent(Object item, boolean sel) {
ItemEvent evt = new ItemEvent(this, ItemEvent.ITEM_STATE_CHANGED,
item, sel ? ItemEvent.SELECTED : ItemEvent.DESELECTED);
// Get list of listeners
Object[] listeners = listenerList.getListenerList();
// Send event to all listeners
for (int i=0; i<listeners.length-2; i+=2) {
if (listeners[i] == ItemListener.class) {
((ItemListener)listeners[i+1]).itemStateChanged(evt);
}
}
}
}
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Related Examples
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e647. <a class="eglink" href="InnerHandler.html?l=rel">
Handling Events with an Anonymous Class
</a>
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e648. <a class="eglink" href="ActionEvents.html?l=rel">
Handling Action Events
</a>
<br>
e649. <a class="eglink" href="KeyEvents.html?l=rel">
Handling Key Presses
</a>
<br>
e650. <a class="eglink" href="MouseEvents.html?l=rel">
Handling Mouse Clicks
</a>
<br>
e651. <a class="eglink" href="MouseMotion.html?l=rel">
Handling Mouse Motion
</a>
<br>
e652. <a class="eglink" href="MultiClicks.html?l=rel">
Detecting Double and Triple Clicks
</a>
<br>
e653. <a class="eglink" href="FocusEvents.html?l=rel">
Handling Focus Changes
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