CODEWITHSUNDEEP
javaswingfilereaderjprogressbar
Some Student
Some Student

Reputation: 67

Reading a big text document and filling up a JProgressBar as it's being read

I'm trying to figure out how to make a JProgressBar fill up as a file is being read. More specifically I need to read in 2 files and fill 2 JProgressBars, and then stop after one of the files has been read.

I am having trouble understanding how to make that work with a file. With two threads I would just put a for(int i = 0; i < 100; i++)loop and setValue(i) to get the current progress. But with files I don't know how to set the progress. Maybe get the size of the file and try something with that? I am really not sure and was hoping someone could throw and idea or two my way.

Thank you!

Update for future readers:

I managed to solve it by using a file.length() which returned the size of the file in bytes, then setting the bar to go from 0 to that size instead of the regular 100, and then using

for(int i = 0; i < fileSize; i++)

To get the bar loading like it should.

Upvotes: 3

Views: 130

Answers (1)

Krzysztof
Krzysztof

Reputation: 517

Example usage of ProgressMonitorInputStream. It automatically display simple dialog with progressbar if reading from InputStream takes longer - you can adjust that time by using: setMillisToPopup, setMillisToDecideToPopup.

public static void main(String[] args) {
        JFrame mainFrame = new JFrame();
        mainFrame.setSize(640, 480);
        mainFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        mainFrame.setVisible(true);

        String filename = "Path to your filename"; // replace with real filename
        File file = new File(filename);

        try (FileInputStream inputStream = new FileInputStream(file);
             ProgressMonitorInputStream progressInputStream = new ProgressMonitorInputStream(mainFrame, "Reading file: " + filename, inputStream)) {
            byte[] buffer = new byte[10];   // Make this number bigger - 10240 bytes for example. 10 is there to show how that dialog looks like

            long totalReaded = 0;
            long totalSize = file.length();
            int readed = 0;

            while((readed = progressInputStream.read(buffer)) != -1) {
                totalReaded += readed;
                progressInputStream.getProgressMonitor().setNote(String.format("%d / %d kB", totalReaded / 1024, totalSize / 1024));

             // Do something with data in buffer
            }
        } catch(IOException ex) {
            System.err.println(ex);
        }
    }

Upvotes: 2

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