Sometimes the user will change their mind; they may have selected the wrong option, or something more important may have come up. The progress monitor allows for two-way communication; the user can signify when they want to cancel as well. There is a method, isCancelled()
, which returns true
if the user has signified in some way that he/she wishes the Job
to finish early. Periodically checking this during the operation of the Job
allows the user to cancel a long-running Job
before it reaches the end.
Modify the
for
loop in theHelloHandler
to check on each iteration whether the monitor is cancelled or not.for(int i=0;i<50 && !monitor.isCanceled(); i++) { ... } if(!monitor.isCancelled()) { Display.getDefault().asyncExec(new Runnable() {…}); }
Run the Eclipse instance and click on the Hello command. This time, go into the Progress view and click on the red stop square next to the job. The job should cancel and the dialog showing the...