Progress Percentage Problem

[Arthur Buliva]

Am making an application that downloads updates from the Internet. It should update a JProgressBar appropriately as the download proceeds. There is the point of interest:

/**
     * Updates the progress bar with how much of the update has been got
     */
    public static void updateProgressBar()
    {
File copy = new File(originaldb);
        long downloadedSize = copy.length();
        long totalDownloadSize = updater.getSizeOfUpdate();

        int downloadedInInt = (int) downloadedSize;
        int totalInInt = (int) totalDownloadSize;

        System.out.println("Downloaded : " + downloadedInInt + " out of " + totalInInt);

        int percentage = (downloadedInInt / totalInInt) * 100;

        System.out.println("Progress: " + percentage + "%");

        progressBar.setString(percentage + "%");
        progressBar.setValue(percentage);
        progressBar.setStringPainted(true);
  }

Here this is the output:

init:
deps-jar:
Compiling 1 source file to /home/arthur/NetBeansProjects/KamusiDesktop/build/classes
compile:
run:
Downloaded : 1024 out of 8192
Progress: 0%
Downloaded : 2048 out of 8192
Progress: 0%
Downloaded : 3072 out of 8192
Progress: 0%
Downloaded : 4096 out of 8192
Progress: 0%
Downloaded : 5120 out of 8192
Progress: 0%
Downloaded : 6144 out of 8192
Progress: 0%
Downloaded : 7168 out of 8192
Progress: 0%
Downloaded : 8192 out of 8192
Progress: 100%

Please, but why is it stuck at 0% then jump t0 100% yet the gradual progress is clear? Why doesn't it update?

[Joanne Neal]

Your problem is here

int percentage = (downloadedInInt / totalInInt) * 100; 

Suppose totalInInt is 100 and downloadedInInt is 12. Now 12/100 = 0.12 but as you are using ints this will be rounded to 0. You then multiply this by 100 and get 0. This will be the result until downloadedInInt and totalInInt are equal when the division will give you 1 as a result.
Do the multiplication first and it should work

int percentage = (downloadedInInt * 100) / totalInInt; 

[Arthur Buliva]

Thanks a million for the clarification, Joanne. That has worked.

[Arthur Buliva]

Ok, Here is my terminal output:

init:
deps-jar:
Compiling 2 source files to /home/arthur/NetBeansProjects/KamusiDesktop/build/classes
Note: /home/arthur/NetBeansProjects/KamusiDesktop/src/org/kamusi/MainWindow.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
compile:
run:
Downloaded : 1024 out of 6659072
//snip
Progress: 56%
Downloaded : 3780608 out of 6659072
Progress: 56%
Downloaded : 3781632 out of 6659072
Progress: 56%
Downloaded : 3782656 out of 6659072
Progress: 56%
Downloaded : 3783680 out of 6659072
Progress: 56%
Downloaded : 3784704 out of 6659072
Progress: 56%
Downloaded : 3785728 out of 6659072
Progress: 56%
Downloaded : 3786752 out of 6659072
Progress: 56%
//snip
Downloaded : 6657024 out of 6659072
Progress: 99%
Downloaded : 6658048 out of 6659072
Progress: 99%
Downloaded : 6659072 out of 6659072
Progress: 100%
BUILD SUCCESSFUL (total time: 14 seconds)

I now face this problem; The progress bar does not gradually update, but instead "hangs" till the updating gets to 100%, then it shows 100%

This is the updated code:

public static void updateProgressBar()
    {
        long downloadedSize = updater.getSizeOfDatabase();
        long totalDownloadSize = updater.getSizeOfUpdate();

        int downloadedInInt = (int) downloadedSize;
        int totalInInt = (int) totalDownloadSize;

        System.out.println("Downloaded : " + downloadedInInt + " out of " + totalInInt);

        int percentage = (downloadedInInt * 100) / totalInInt;

        System.out.println("Progress: " + percentage + "%");

        progressBar.setString(percentage + "%");
        progressBar.setValue(percentage);
        progressBar.setStringPainted(true);
    }