Unzip File in Android Assets

Question

I put a zip file in the android assets. How do i extract the file in the android internal storage? I know how to get the file, but i don't know how to extract it. This is my code..

Util zip ;

zip = new Util();

zip.copyFileFromAsset(this, "myfile.zip", getExternalStorage()+ "/android/data/edu.binus.profile/");

Thanks for helping :D

Answer 1

Based on Sreedev R solution, I added the option to read the file from assets and use buffer:

package com.pixoneye.api.utils;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import android.content.Context;
import android.util.Log;

public class Decompress {
    private static final int BUFFER_SIZE = 1024 * 10;
    private static final String TAG = "Decompress";

    public static void unzipFromAssets(Context context, String zipFile, String destination) {
        try {
            if (destination == null || destination.length() == 0)
                destination = context.getFilesDir().getAbsolutePath();
            InputStream stream = context.getAssets().open(zipFile);
            unzip(stream, destination);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void unzip(String zipFile, String location) {
        try {
            FileInputStream fin = new FileInputStream(zipFile);
            unzip(fin, location);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }

    }

    public static void unzip(InputStream stream, String destination) {
        dirChecker(destination, "");
        byte[] buffer = new byte[BUFFER_SIZE];
        try {
            ZipInputStream zin = new ZipInputStream(stream);
            ZipEntry ze = null;

            while ((ze = zin.getNextEntry()) != null) {
                Log.v(TAG, "Unzipping " + ze.getName());

                if (ze.isDirectory()) {
                    dirChecker(destination, ze.getName());
                } else {
                    File f = new File(destination, ze.getName());
                    if (!f.exists()) {
                        boolean success = f.createNewFile();
                        if (!success) {
                            Log.w(TAG, "Failed to create file " + f.getName());
                            continue;
                        }
                        FileOutputStream fout = new FileOutputStream(f);
                        int count;
                        while ((count = zin.read(buffer)) != -1) {
                            fout.write(buffer, 0, count);
                        }
                        zin.closeEntry();
                        fout.close();
                    }
                }

            }
            zin.close();
        } catch (Exception e) {
            Log.e(TAG, "unzip", e);
        }

    }

    private static void dirChecker(String destination, String dir) {
        File f = new File(destination, dir);

        if (!f.isDirectory()) {
            boolean success = f.mkdirs();
            if (!success) {
                Log.w(TAG, "Failed to create folder " + f.getName());
            }
        }
    }
}

Answer 2

You can also make use of the zip4j external library that provides additional features like encryption. Also, it has functions to extract files to a particular location provided the path.

Answer 3

This piece of code will help you....Just pass the zipfile location and the location where you want the extracted files to be saved to this class while making an object...and call unzip method...

    public class Decompress { 
  private String zip; 
  private String loc; 

  public Decompress(String zipFile, String location) { 
    zip = zipFile; 
    loc = location; 

    dirChecker(""); 
  } 

  public void unzip() { 
    try  { 
      FileInputStream fin = new FileInputStream(zip); 
      ZipInputStream zin = new ZipInputStream(fin); 
      ZipEntry ze = null; 
      while ((ze = zin.getNextEntry()) != null) { 
        Log.v("Decompress", "Unzipping " + ze.getName()); 

        if(ze.isDirectory()) { 
          dirChecker(ze.getName()); 
        } else { 
          FileOutputStream fout = new FileOutputStream(loc + ze.getName()); 
          for (int c = zin.read(); c != -1; c = zin.read()) { 
            fout.write(c); 
          } 

          zin.closeEntry(); 
          fout.close(); 
        } 

      } 
      zin.close(); 
    } catch(Exception e) { 
      Log.e("Decompress", "unzip", e); 
    } 

  } 

  private void dirChecker(String dir) { 
    File f = new File(_location + dir); 

    if(!f.isDirectory()) { 
      f.mkdirs(); 
    } 
  } 
} 

Answer 4

I haven't tested yet,but while doing a project on OCR I came across this library,where there is method of unzipping a downloaded file from the net. The exact method for unzipping file is installZipFromAssets(String sourceFilename,File destinationDir,File destinationFile) found under this class.Hope this is what you are looking for

Answer 5

Maybe you should try using a FileOutputStream in combination with an inputstream from the zip file. With a package file, this should work.

To quote @wordy from this question:

PackageManager pm = context.getPackageManager();
String apkFile = pm.getApplicationInfo(context.getPackageName(), 0).sourceDir;
ZipFile zipFile = new ZipFile(apkFile); 
ZipEntry entry = zipFile.getEntry("assets/FILENAME");
myInput = zipFile.getInputStream(entry);
myOutput = new FileOutputStream(file);
    byte[] buffer = new byte[1024*4];
int length;
int total = 0;
int counter = 1;
while ((length = myInput.read(buffer)) > 0) {
    total += length;
    counter++;
    if (counter % 32 == 0) {
        publishProgress(total);
    }
        myOutput.write(buffer, 0, length);
}

Looks like there may be problems with ProGuard but hopefully the code sample works for you.