即使在SWT中选择了TreeItem，如何强制实施TreeItem的前景色

Question

I follow this example to create a simple test with a Table where the foreground color was changed . This works as expected.

But if I change the example to use a Tree instead of a Table , the foreground color is not kept when I select the item.

In this code snippet, the foreground color of selected item is changed to red when the button is pressed:

public static void main(String[] args)
{
    final Display display = new Display();
    Shell shell = new Shell(display);
    shell.setLayout(new GridLayout(1, false));
    shell.setText("StackOverflow");

    final Tree table = new Tree(shell, SWT.BORDER | SWT.MULTI);
    table.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

    for (int i = 0; i < 10; i++)
    {
        TreeItem item = new TreeItem(table, SWT.NONE);
        item.setText("item " + i);
    }

    Button button = new Button(shell, SWT.PUSH);
    button.setText("Color selected");

    button.addListener(SWT.Selection, new Listener()
    {
        @Override
        public void handleEvent(Event arg0)
        {
            List<TreeItem> allItems = new ArrayList<>(Arrays.asList(table.getItems()));
            TreeItem[] selItems = table.getSelection();

            for (TreeItem item : selItems)
            {
                item.setForeground(display.getSystemColor(SWT.COLOR_RED));
                allItems.remove(item);
            }

            for (TreeItem item : allItems)
            {
                item.setForeground(display.getSystemColor(SWT.COLOR_LIST_FOREGROUND));
            }
        }
    });

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

item0 is selected but color is black:

but if we deselect the item we can see the foreground color was actually changed:

Does anyone know why this works correctly in Table but not in Tree ? Is there a way to make this work?

Answer 1

This seems to be a slight difference in how selected items are shown, between table and tree on Windows. Probably the only workaround is to let your application draw the tree items if you really want to override the default selection colors.

See also the Custom drawing table and tree items article here: https://www.eclipse.org/articles/article.php?file=Article-CustomDrawingTableAndTreeItems/index.html