Hi Sascha,

asynchExec does not fork a thread to do work, but it ensures that work
that is invoked from a background thread gets performed in the main UI
thread.  A good example is linked below.  It forks a Thread to populate a
Table; this forked thread then syncExec's all operations performed on the
Table, since SWT widgets can only be used in the main thread.  Add a
Thread.sleep(1000) line right after the "for" line and you'll see that the
UI stays responsive while the table is populating.

http://dev.eclipse.org/viewcvs/index.cgi/%7Echeckout%7E/platform-swt-home/snippits/snippet7.html

Grant


Sascha wrote:

> Dave Wegener wrote:

> > Sascha wrote:

> > > Hi!

> > > I have a long running process starting from the GUI. If I only start the
> > > process, the GUI is not working until the process stops. So I decided to
> > > make the process implementing Runnable and start the process out of the
> > > GUI via Display.getCurrent().asyncExec(MyProcess). But there is no new
> > > thread generated for this method. When I make my process a subclass of
> > > Thread, I always get a "org.eclipse.swt.SWTError : Invalid thread
access".
> > > I've tried to write a little process which returns a message every
second.
> > > The same happens: I cannot use the GUI until the process stop because it
> > > is running in thread main.
> > > Can somebody help me?

> > > I'm using Eclipse 2.0.2.

> > > Thanks

> > You are on the right track, you are just calling the asyncExec method with
> > the wrong runnable.  The purpose of this method is to provide a way for a
> > multi-threaded application to update the GUI.  The runnable that you pass
> > to this method should only update the necessary GUI components and then
> > return.

> > What you need to do, is create a thread for your long running process and
> > kick it off.  In this long running thread create another runnable that
> > displays the message and returns.  Then have your long running thread call
> > asyncExec() every second passing in this second runnable.

> > In summary, you create a thread for your long running process.  That
> > thread creates a GUI update runnable and passes it to asyncExec() every
> > second.

> Sorry, but I don't understand your answer. I think my test which outputs a
> message every second is confuse.
> Now I explain the problem in detail. I have a view with a toolbar. The
> toolbar has a button start which starts my long running process. The
> toolbar also has a stop button. After I start the long running process the
> stop button is active, so the user can terminate the long running process.
> There is no process dialog for the long running process. In the view I
> start the long running process via Display.getCurrent().asyncExec(long
> running process). Because there is no new thread, the button stop cannot
> be pushed while the long running process is active. It is important that
> the úser can stop the long running process via the GUI.
> Can you please send me a little code snippset. Thanks!