SWT table: how to set/get "focused" row - swt

Question

On Windows and Linux, when holding down the Ctrl key one can move up and down using the caret keys without changing the selection. The table shows some visual feedback.
I've played with an SWT snippet which uses TableCursor but it seems half-baked, because it introduced a couple of new bugs - e.g. when pressing Ctrl+End, it jumped back to the previous selection after releasing the Ctrl key.
How to get or set this "focused" row?

Answer 1

This doesn't look like a property that can be get/set directly, but you can detect the focused row from paint event and custom paint the focus.
Add a Listener to your table for SWT.PaintItem event:
handleEvent(PaintEvent e) {
if (e.detail & SWT.FOSCUSED != 0)
myFocusedRow = ((Table)e.widget).indexOf((TableItem)e.item);
...
if (e.item == myFocusedItem)
e.gc.drawFocus(e.x, e.y, e.width, e.height);
}

Answer 2

I'm not sure this is exactly what you're looking for, but if you've wrapped your Table in a TableViewer, you can use a TableViewerEditor as part of the cell-editing support. (I believe you can use the focus-functionality of TableViewerEditor without actually having any cell editing.)
This actually overrides the operating system's focus handling but allows you to customize the focus handling programatically. I've used this to enable keyboard traversal for cell editing.
Here's some quick and dirty sample code that can support focusing a cell. (Untested. It's possible, for example, that cell editing support must be enabled for the TableViewerEditor support to work.)
FocusCellHighlighter cellHighlighter = new FocusCellHighlighter(tableViewer);
TableViewerFocusCellManager focusManager = new TableViewerFocusCellManager(tableViewer, cellHighlighter);
TableViewerEditor.create(tableViewer, focusCellManager, new ColumnViewerActivationStrategy(tableViewer), TableViewerEditor.KEYBOARD_NAVIGATION);
You can then get the focused cell by:
ViewerCell focusedCell = viewer.getColumnViewerEditor().getFocusCell();
TableItem focusedItem = focusedCell != null ? focusedCell.getItem() : null;
Note that this is only enabled in Eclipse >= 3.3.

Answer 3

To detect whether a TableItem is focused you can add a Listener of type SWT.EraseItem or SWT.PaintItem to the table and let it check if the bit flag SWT.FOCUSED is set in the detail field of the Event. (See also this Eclipse forum post.)
I could not find any API to set the focused item, but there is an ugly work around: post mouse events that simulate a click on the item. This requires the item to be selected and be visible on the display. The following utility class contains a method that does this:
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableItem;
import org.eclipse.swt.widgets.Widget;
/**
* Utility class for tables.
*
* #author Henno Vermeulen
*/
public final class Tables {
private Tables() {
}
/**
* Shows and selects the table <code>item</code> and lets it get the
* keyboard focus.
*
* <p>
* Windows has a "focused" row (drawn with a dotted line) that can be moved
* independently of the selected row (when pressing ctrl + up/down). This
* method ensures that this focused row is made equal to the selected row so
* that the selection does not jump to an unwanted location when the user
* uses the up or down arrow on the keyboard.
*
* <p>
* Implementation detail: there is no API to get/set the focused row (see
* also <a href="https://www.eclipse.org/forums/index.php/t/241852/">this
* post</a> and <a href=
* "http://stackoverflow.com/questions/8852574/swt-table-how-to-set-get-focused-row">
* this one</a>), so we use a filthy hack: faking a mouse click in the
* table.
*/
public static void selectAndFocus(TableItem item) {
fakeMouseClickTableItem(item);
}
private static void fakeMouseClickTableItem(TableItem item) {
Table table = item.getParent();
table.showItem(item);
Point cursorLocation = item.getDisplay().getCursorLocation();
fakeMouseClick(table, getCenter(item.getBounds(0)));
item.getDisplay().setCursorLocation(cursorLocation);
}
private static Point getCenter(Rectangle bounds) {
return new Point(bounds.x + bounds.width / 2,
bounds.y + bounds.height / 2);
}
/**
* Actually moves the mouse cursor to the given <code>location</code> so
* that the OS gives the correct click behavior.
*/
private static void fakeMouseClick(Control control, Point location) {
control.getDisplay().setCursorLocation(control.toDisplay(location));
control.getDisplay()
.post(createMouseEvent(SWT.MouseDown, control, location));
control.getDisplay()
.post(createMouseEvent(SWT.MouseUp, control, location));
}
public static Event createMouseEvent(int type, Widget widget,
Point position) {
Event e = new Event();
e.display = widget.getDisplay();
e.widget = widget;
e.type = type;
e.x = position.x;
e.y = position.y;
e.count = 1;
e.button = 1;
e.doit = true;
return e;
}
}