Thread: Could someone explain this to me?

I am working on making a GUI for a program that I had written a while back. I wanted to include a progress bar to show its progress. However, the progress bar does not refresh and show the current percentage, it merely stays blank until the program is finished at which time it shows 100%. How do I make it to where it shows real time progress?

Here is my current code of the particular section of the GUI:

 private void beginSortButtonActionPerformed(java.awt.event.ActionEvent evt) {                                                
        //Variables
        Scanner s = new Scanner(System.in);
        String warningMessage = "WARNING!: Organizing files can be somewhat dangerous." + "\n" + "Do you wish to continue? (y/n) : ";
        String userConfirmation;
        String currentDirectoryPath;
        String RootPath;
        String goAgain = "y";
        String goAgain2;
        Receipt[] sortedReceipts;
        ArrayList<Receipt> tempArrayList = new ArrayList<>();
        Vector filePaths = new Vector<String>();
        int value = 0;
 
        currentDirectoryPath = this.currentDirectory.getText();
        RootPath = this.rootPath.getText();
 
        Path p = Paths.get(currentDirectoryPath);
        DirectoryStream<Path> dir = null;
        try {
            dir = Files.newDirectoryStream(p);
        } catch (IOException ex) {
            Logger.getLogger(fileSortWindow.class.getName()).log(Level.SEVERE, null, ex);
        }
 
        Path newDir = Paths.get(RootPath);
        try {
            Files.createDirectories(newDir);
        } catch (IOException ex) {
            Logger.getLogger(fileSortWindow.class.getName()).log(Level.SEVERE, null, ex);
        }
 
        for (Path file : dir) {
            String name = file.getFileName().toString();
            if (name.endsWith(".receipt")) {
 
                //String representation of the files directory.
                String fileDir = currentDirectoryPath.toString() + "\\" + name;
                filePaths.add(fileDir);
 
                //Making new Receipt object and getting the info from the methods in order to sort into the directories.
                Receipt newReceipt = null;
                try {
                    newReceipt = new Receipt(fileDir);
                } catch (FileNotFoundException ex) {
                    Logger.getLogger(fileSortWindow.class.getName()).log(Level.SEVERE, null, ex);
                } catch (IOException ex) {
                    Logger.getLogger(fileSortWindow.class.getName()).log(Level.SEVERE, null, ex);
                }
                String firstName = newReceipt.getCustomerFirstName();
                String lastName = newReceipt.getCustomerLastName();
                String year = Integer.toString(newReceipt.getYear());
                String month = Integer.toString(newReceipt.getMonth());
                String wholeName = lastName + ", " + firstName;
 
                //Progress bar.
                progress.setValue(value);
                progress.repaint();
 
 
                //Creates the new path for the file.
                Path tempDir = Paths.get(RootPath, wholeName, year, month);
                try {
                    Files.createDirectories(tempDir);
                } catch (IOException ex) {
                    Logger.getLogger(fileSortWindow.class.getName()).log(Level.SEVERE, null, ex);
                }
 
                //Adds 1 to the progress bar.
                value++;
 
 
 
                Path newPath = Paths.get(tempDir.toString(), name);
 
 
                if (Files.notExists(newPath)) {
                    try {
                        Files.copy(file, newPath);
                    } catch (IOException ex) {
                        Logger.getLogger(fileSortWindow.class.getName()).log(Level.SEVERE, null, ex);
                    }
                }
            }
        }
 
        this.output.setText("Done.");
 
    }

Can you isolate the mechanism you're using to increase the progress bar from a minimum to the maximum and just show that part?

I suspect what you're seeing is the task starting at the minimum (maybe) and then a full progress bar when complete but there's essentially no visible difference between the two states because they occur so close together. You may have to slow down the activity by using a timer or similar device to show the progress at a perceptible speed, but then do you really want to make the user wait for a frill that they wouldn't normally have to wait for?

Someone told me that I need to make the progress bar update in a separate thread but I'm having a hard time figuring out how to do that.

Yea I did. And when you run the program it takes a about 30 seconds or more to run through. It sorts 3000 files into multiple directories.

Is the task that does the sorting of 3,000 files done on the EDT or in a separate thread? More importantly, does the task doing the sorting track its progress? Can you get from the sorting task its progress using a method, something like:

sortTask.getProgress();

If so, it would be easy to create a javax.swing.Timer task to retrieve that progress and set the progress bar accordingly.