"Fixing" the first few columns in an SWT table to prevent them from scrolling horizontally

Question

We have implemented a table-based editor with an SWT tree table. It pretty much does what we want it to, except that we can't find a way to ensure that the first few columns remain at their position when the user scrolls horizontally (so that one can identify the row being edited).

There are a number of third-party table controls in various degrees of being incomplete or abandoned, and a snippet that shows how to use two tables (which get out of sync when they're being scrolled vertically).

What's the best way to solve this?

Answer 1

This 'official' SWT snippet does what you want to do, at least on my machine - it does not get out of sync on vertical scroll. But the price is a second scrollbar - way ugly. To prevent this, you can add the style SWT.NO_SCROLL in the constructor of the left table.

To improve the thing you will have to add a Listener on SWT.Traverse to both Tables, which syncs them if the user navigated using keys, something like this:

  leftTable.addListener(SWT.Traverse, new Listener() {

     public void handleEvent( Event event ) {
        rightTable.setTopIndex(leftTable.getTopIndex());
     }
  });

I wouldn't go with another Table implementation, since you lose the biggest advantage you have with SWT: using a native widget, which looks and feels 'right' in each OS. If you want to do that anyway, Grid from the Nebula project is much more mature than the alpha tag implies. Don't know if it can do what you want, though.

Answer 2

the "syncing problem" only appears on MacOs based SWT. If your target platform is windows you should have no problem with the given SWT-Snippet. There will be more listeners to register on both tables to synchronise all occuring events (collapse, expand, mouse scroll, etc.)