1 files changed, 84 insertions, 0 deletions
diff --git a/examples/org.eclipse.swt.examples/org/eclipse/swt/examples/fileviewer/TreeExpandDropListener.java b/examples/org.eclipse.swt.examples/org/eclipse/swt/examples/fileviewer/TreeExpandDropListener.java
new file mode 100755
index 0000000000..32e3c20b4d
--- /dev/null
+++ b/examples/org.eclipse.swt.examples/org/eclipse/swt/examples/fileviewer/TreeExpandDropListener.java
@@ -0,0 +1,84 @@
+package org.eclipse.swt.examples.fileviewer;
+
+/*
+ * (c) Copyright IBM Corp. 2000, 2001.
+ * All Rights Reserved
+ */
+
+import org.eclipse.swt.*;
+import org.eclipse.swt.dnd.*;
+import org.eclipse.swt.graphics.*;
+import org.eclipse.swt.widgets.*;
+
+/**
+ * TreeExpandDropListener provides automatic expansion for Trees during drag and drop
+ * operations.
+ * <p>
+ * If the pointer hovers for a time over an item in the Tree that has not yet been
+ * expanded, the item is expanded automatically.  This behaviour is consistent with
+ * that of popular GUI systems.
+ * </p><p>
+ * To use it send addDropListener(new TreeExpandDropListener(tree)) to the DropTarget
+ * object attached to the Tree.
+ * </p>
+ */
+public class TreeExpandDropListener extends DropTargetAdapter {
+	public static final long DEFAULT_EXPAND_DELAY = 1000; // millis
+
+	private long     hoverThreshhold = DEFAULT_EXPAND_DELAY;	
+	private long     hoverBegin = 0;
+	private TreeItem hoverItem = null;
+	private Tree     tree;
+	
+	/**
+	 * Constructs a Tree expanding Drop Listener
+	 * 
+	 * @param tree the Tree that the DropTarget is attached to
+	 */
+	public TreeExpandDropListener(final Tree tree) {
+		this.tree = tree;
+	}
+
+	/**
+	 * Handles dragEnter events.
+	 * This is an implementation detail.
+	 */
+	public void dragEnter(DropTargetEvent event) {
+		hoverItem = null;
+	}
+
+	/**
+	 * Handles dragOver events.
+	 * This is an implementation detail.
+	 */
+	public void dragOver(DropTargetEvent event) {
+		Point point = tree.toControl(new Point(event.x, event.y));
+
+		// Get the item directly under the point
+		TreeItem item = tree.getItem(point);
+		if (item != hoverItem) {
+			// We just started hovering, remember this item
+			if ((item != null) && (! item.getExpanded())) {
+				hoverBegin = System.currentTimeMillis();
+				hoverItem = item;
+			} else {
+				hoverItem = null;
+			}
+		} else if (hoverItem != null) {
+			// We've been hovering for a while, expand if our timer elapsed
+			long hoverCurrent = System.currentTimeMillis();
+
+			if (hoverCurrent - hoverBegin >= hoverThreshhold) {
+				// Fake as if the user expanded the item manually
+				Event hoverEvent = new Event();
+				hoverEvent.x = event.x;
+				hoverEvent.y = event.y;
+				hoverEvent.item = hoverItem;
+				hoverEvent.time = (int) hoverCurrent;
+				hoverItem.setExpanded(true);
+				hoverItem = null;
+				tree.notifyListeners(SWT.Expand, hoverEvent);
+			}
+		}
+	}	
+}
+\ No newline at end of file