Java progressbar feeding

Question

I have MainProgramWindow GUI. This GUI has some variables and one button call createExcel method of Sql class and start progress bar same time.

    public class          


        

Answer 1

You are executing all task in the same thread The Event Dispatch Thread. A good way to solve that is executing business code in a separate thread to don't block the gui and you can update your gui without waiting your business code finish. Swing provides SwingWorker class to achieve that. Here you have a good example with a progressBar. Swing Worker Example.

Read more How to Use Progress Bars.

In a simple what you do is to make a swingWorker sublcass and override doInBackGround().

Example:

  public class Worker extends SwingWorker {

        @Override
        protected Void doInBackground() throws Exception {
           //here you make heavy task this is running in another thread not in EDT
           int i = 0;
           setProgress(i);
           // call query 1
           while(i < 50){
             setProgress(i++);
             Thread.sleep(5); // random magic number
           }
           // then call query 2
           while(i <= 100){
             setProgress(i++);
             Thread.sleep(5); // random magic number
           }

           return null;
        }
    }

And in your client code where you have the progressBar:

SwingWorker myWorker = new Worker();
myWorker.addPropertyChangeListener(new PropertyChangeListener() {
  @Override
  public void propertyChange(final PropertyChangeEvent event) {
    switch (event.getPropertyName()) {
    case "progress":
      myProgressBar.setIndeterminate(false);
      myProgressBar.setValue((Integer) event.getNewValue());
      break;
    }
 }
});
//then to get start you have to use execute()
worker.execute();

Here you have an example and another one