Bug 156537 [Viewers] Virtual tree viewer does not populate with initial children
I20060830-1650 When a tree viewer is created with the SWT.Vitrual flag and uses an ILazyTreeContentProvider, the viewew does not populate with the initial children in the model. The method TreeViewer.createChildren(Widget) only updates existing items if the parent (root)element has been mapped to data, and does not query the content provider for the number of children it has. Attached is a sample plug-in showing the problem. The tree "model" looks like this: root one two three When the input is set to the viewer ("root") a call is made to "createChildren", but the content provider is never used.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
import org.eclipse.swt.events.TreeListener;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Item;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeColumn;
import org.eclipse.swt.widgets.TreeItem;
import org.eclipse.swt.widgets.Widget;
/**
 * A concrete viewer based on an SWT <code>Tree</code> control.
 * <p>
 * This class is not intended to be subclassed outside the viewer framework. It
 * is designed to be instantiated with a pre-existing SWT tree control and
 * configured with a domain-specific content provider, label provider, element
 * filter (optional), and element sorter (optional).
 * </p>
 * <p>
 * Content providers for tree viewers must implement either the
 * {@link ITreeContentProvider} interface or (as of 3.2) the
 * {@link ILazyTreeContentProvider} interface. If the content provider is an
 * <code>ILazyTreeContentProvider</code>, the underlying Tree must be created
 * using the {@link SWT#VIRTUAL} style bit, and the tree viewer will not support
 * sorting or filtering.
 * </p>
 */
public class TreeViewer extends AbstractTreeViewer {