Extrakting Zip to SD-Card is very slow. How can i optimize performance?

Question

my app downloads a zip with about 350 files. A mix of JPG and HTML files. The function i wrote to do it works just fine but the unzipping takes for ever. At first i thought

Answer 1

Just use this method once and believe me its a super fast process.. It will unzip all the files without skipping any file with in 1 second.

    public boolean rajDhaniSuperFastUnzip(String inputZipFile, String destinationDirectory)
        {
    try {
        int BUFFER = 2048;
        List<String> zipFiles = new ArrayList<String>();
        File sourceZipFile = new File(inputZipFile);
        File unzipDestinationDirectory = new File(destinationDirectory);
        unzipDestinationDirectory.mkdir();
        ZipFile zipFile;
        zipFile = new ZipFile(sourceZipFile, ZipFile.OPEN_READ);
        Enumeration<?> zipFileEntries = zipFile.entries();
        while (zipFileEntries.hasMoreElements()) {
            ZipEntry entry = (ZipEntry) zipFileEntries.nextElement();
            String currentEntry = entry.getName();
            File destFile = new File(unzipDestinationDirectory, currentEntry);
            if (currentEntry.endsWith(".zip")) {
                zipFiles.add(destFile.getAbsolutePath());
            }

            File destinationParent = destFile.getParentFile();

            destinationParent.mkdirs();

            try {
                if (!entry.isDirectory()) {
                    BufferedInputStream is =
                            new BufferedInputStream(zipFile.getInputStream(entry));
                    int currentByte;
                    byte data[] = new byte[BUFFER];

                    FileOutputStream fos = new FileOutputStream(destFile);
                    BufferedOutputStream dest =
                            new BufferedOutputStream(fos, BUFFER);
                    while ((currentByte = is.read(data, 0, BUFFER)) != -1) {
                        dest.write(data, 0, currentByte);
                    }
                    dest.flush();
                    dest.close();
                    is.close();
                }
            } catch (IOException ioe) {
                ioe.printStackTrace();
            }
        }
        zipFile.close();

        for (Iterator<String> iter = zipFiles.iterator(); iter.hasNext();) {
            String zipName = (String)iter.next();
            doUnzip(
                zipName,
                destinationDirectory +
                    File.separatorChar +
                    zipName.substring(0,zipName.lastIndexOf(".zip"))
            );
        }
    } catch (IOException e) {
        e.printStackTrace();
        return false ;
    }
    return true;
}

Hope this will help you.. Happy Coding :)

Answer 2

You are reading and writing a byte at a time. Consider reading and writing a larger block at a time.