Java Code Examples for org.eclipse.swt.widgets.Widget#addDisposeListener()

/** 
 * @see org.eclipse.jface.viewers.StructuredViewer#mapElement(java.lang.Object, org.eclipse.swt.widgets.Widget)
 */
protected void mapElement(Object element, final Widget item) {
	super.mapElement(element, item);
	// make sure to unmap elements if the tree is virtual
	if ((getTree().getStyle() & SWT.VIRTUAL) != 0) {
		// only add a dispose listener if item hasn't already on assigned
		// because it is reused
		if (item.getData(VIRTUAL_DISPOSE_KEY) == null) {
			item.setData(VIRTUAL_DISPOSE_KEY, Boolean.TRUE);
			item.addDisposeListener(new DisposeListener() {
				public void widgetDisposed(DisposeEvent e) {
					if (!treeIsDisposed) {
						Object data = item.getData();
						if (usingElementMap() && data != null) {
							unmapElement(data, item);
						}
					}
				}
			});
		}
	}
}
 

/**
 * This method should be called by *all* Widgets which use resources
 * provided by this SWTResourceManager. When widgets are disposed,
 * they are removed from the "users" Vector, and when no more
 * registered Widgets are left, all resources are disposed.
 * <P>
 * If this method is not called for all Widgets then it should not be called
 * at all, and the "dispose" method should be explicitly called after all
 * resources are no longer being used.
 */
public static void registerResourceUser(Widget widget) {
	if (users.contains(widget))
		return;
	users.add(widget);
	widget.addDisposeListener(disposeListener);
}
 

/**
 * Adds the given widget to the list of which will participate in the event
 * listening mechanism of the example tab. In other words, if a user has chosen
 * to listen for a specific event, and that event is fired on the given widget,
 * the event's details will print in the event text area in the example.
 *
 * This method is primarily used to include a widget's <code>Item</code>
 * children in the event listening mechanism.
 *
 * @param widget
 */
protected void addEventParticipant(final Widget widget) {
	additionalEventParticipants.add(widget);
	widget.addDisposeListener(e -> additionalEventParticipants.remove(widget));
}
 

/**
 * Dispose safely any SWT resource when a widget is disposed
 *
 * @param widget widget attached to the resource
 * @param resource the resource to dispose
 */
public static void addDisposer(final Widget widget, final Resource resource) {
	widget.addDisposeListener(e -> {
		safeDispose(resource);
	});
}