How to unzip a 7zip archive in Android?

Question

I have a 7zip archive which contains some hundred files separated into different directories. The target is to download it from a FTP server and then extract it on the phone.

My problem is that the 7zip SDK doesn't contain a lot. I am looking for examples, tutorials and snippets regarding the decompression of 7z files.

(Decompression via Intent is only a secondary option)

Answer 1

i found this page that provides an alternative that works like a charm. You only have to add compile 'org.apache.commons:commons-compress:1.8'

to your build gradle script and use the feature you desire. For this issue i did the following :

AssetManager am = getAssets();
        InputStream inputStream = null;
        try {
            inputStream = am.open("a7ZipedFile.7z");
            File file1 = createFileFromInputStream(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
SevenZFile sevenZFile = null;
        try{
            File f = new File(this.getFilesDir(), "a7ZipedFile.7z");
            OutputStream outputStream = new FileOutputStream(f);
            byte buffer[] = new byte[1024];
            int length = 0;
            while((length=inputStream.read(buffer)) > 0) {
                outputStream.write(buffer,0,length);
            }

            try {
                sevenZFile = new SevenZFile(f);
                SevenZArchiveEntry entry = sevenZFile.getNextEntry();
                while (entry != null) {
                    System.out.println(entry.getName());
                    FileOutputStream out = openFileOutput(entry.getName(), Context.MODE_PRIVATE);
                    byte[] content = new byte[(int) entry.getSize()];
                    sevenZFile.read(content, 0, content.length);
                    out.write(content);
                    out.close();
                    entry = sevenZFile.getNextEntry();
                }
                sevenZFile.close();
                outputStream.close();
                inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }catch (IOException e) {
            //Logging exception
            e.printStackTrace();
        }

The only draw back is approximately 200k for the imported library. Other than that it is really easy to use.

Answer 2

Go here:

LZMA SDK just provides the encoder and decoder for encoding/decoding the raw data, but 7z archive is a complex format for storing multiple files.