Description Rudi Mising name 2009-03-27 04:11:52 EDT

Hello,

I have discovered a strange behavior on virtual tables and scrollbars.

The following snippet opens a shell and shows a virtual table. No problem so far.

public class Main {

static int[] data = new int[0];

public static void main(String[] args) {

final Display display = new Display();
Shell shell = new Shell(display);
shell.setLayout(new FillLayout());
shell.setSize(300, 220);

final boolean showPic = false;

final List<String> values = new Vector<String>();
for (int i = 0; i < 10; i++) {

values.add("Value " + i);
}

final Table table = new Table(shell, SWT.BORDER | SWT.VIRTUAL);
table.setLinesVisible(true);
table.setHeaderVisible(true);

TableColumn column;

column = new TableColumn(table, SWT.NONE);
column.setText("Image");
column.setWidth(40);

column = new TableColumn(table, SWT.NONE);
column.setText("Value");
column.setWidth(100);

table.addListener(SWT.SetData, new Listener() {
public void handleEvent(Event e) {
TableItem item = (TableItem) e.item;

Image image = getImage(display);

if (showPic)
item.setImage(0, image);
item.setText(1, "Item " + values.get(e.index));
}
});

table.setItemCount(values.size());
table.clearAll();

shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}

static Image getImage(Display display) {
    Image image = new Image(display, 24, 24);
    GC gc = new GC(image);
    gc.setBackground(display.getSystemColor(SWT.COLOR_RED));
    gc.fillOval(0, 0, 24, 24);
    gc.setForeground(display.getSystemColor(SWT.COLOR_DARK_GREEN));
    gc.drawLine(0, 0, 24, 24);
    gc.drawLine(24, 0, 0, 24);
    gc.dispose();
    return image;
  }
}

If you change the line final boolean showPic = false;
to
final boolean showPic = true;
and run the snippet again, you will see, that the height of the table is bigger then the height of the shell, but the scrollbar dosn't appear. The scrollbar appears, when you resize the window for the first time.

I found out, that if you insert table.addListener(SWT.MeasureItem, new Listener() {

public void handleEvent(Event event) {

event.height = 30;
}
});

just after creating the table, the snippets works fine, that is to say the scrollbar is visible immediately.

I guess that the height of the image is not considered when the table is drawn for the first time and the sum of the heights of the rows without the images fit into the available space of the table, so the scrollbar is not shown.

I'm using eclipse 3.4.0

In the Eclipse-Forum they told me, that this could be a bug.

Thank you,
Rudi