Problem implementing Java Swing worker

Question

I've just learned about executing swing background tasks and I'm starting to experiment with it but I'm having a little trouble with implementation. My code retrieves an image and returns a result (an integer) that indicates whether the image retrieval was successful result = 0 or unsuccessful result = -1. Here is my problem, I am retrieving the result too soon. I can see statements in the createImage method in the code below executing after the result is read in the done() method. I guess I thought that the done method would not execute until the createImage was done. Here is my code below:

new SwingWorker<int[], Void>() {
int result = -1;
@Override
protected int[] doInBackground() throws Exception {
 // TODO Auto-generated method stub
return createImage();  //returns an integer array of size one indicating the result
                    }

protected void done() {
try {
result = get()[0];  //this result is being read before createImage is done  
                        //executing.  Why?
thisApplet.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
tree.setEnabled(true);
if (result == -1){
    tree.setSelectionPath(null);
     return;
}
   } catch (InterruptedException e) {                                 
         e.printStackTrace();
    } catch (ExecutionException e) {                          
            e.printStackTrace();
    }
      }
}.execute();

jzd · Accepted Answer · 2011-02-09 13:32:11Z

2

The done method will not execute until the doInBackground method is completed. So there must be something else going on here. I would guess that you might be calling done and doInBackground instead of run()? If not, try to find the issue by creating an SSCCE.

answered Feb 9, 2011 at 13:32

jzd

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1 Comment

Elliott Over a year ago

Yes. A stupid programming error. When I fixed it everything worked.

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