How to unzip files programmatically in Android

Question

I need a small code snippet which unzips a few files from a given  zip file and gives the separate files according to the format they were in the zipped file  Please post your knowledge and help me out

User · Answer

The Kotlin way    FileExt kt  data class ZipIO  val entry  ZipEntry  val output  File   fun File unzip unzipLocationRoot  File    null         val rootFolder   unzipLocationRoot    File parentFile absolutePath   File separator   nameWithoutExtension      if   rootFolder exists             rootFolder mkdirs              ZipFile this  use   zip - gt          zip          entries            asSequence            map               val outputFile   File rootFolder absolutePath   File separator   it name              ZipIO it  outputFile                     map               it output parentFile  run                  if   exists    mkdirs                             it                    filter    it entry isDirectory            forEach    entry  output  - gt              zip getInputStream entry  use   input - gt                  output outputStream   use   output - gt                      input copyTo output                                                       Usage  val zipFile   File  path to your zip file   file unzip

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Had peno s version optimised a bit  The increase in performance is perceptible   private boolean unpackZip String path  String zipname                InputStream is       ZipInputStream zis       try                  String filename           is   new FileInputStream path   zipname            zis   new ZipInputStream new BufferedInputStream is                       ZipEntry ze           byte   buffer   new byte 1024            int count            while   ze   zis getNextEntry       null                           filename   ze getName                     Need to create directories if not exists  or                 it will generate an Exception                 if  ze isDirectory                      File fmd   new File path   filename                   fmd mkdirs                    continue                               FileOutputStream fout   new FileOutputStream path   filename                 while   count   zis read buffer      -1                                   fout write buffer  0  count                                             fout close                                zis closeEntry                         zis close                 catch IOException e                  e printStackTrace             return false              return true

User · Answer

Android has build-in Java API  Check out java util zip package   The class ZipInputStream is what you should look into  Read ZipEntry from the ZipInputStream and dump it into filesystem folder  Check similar example to compress into zip file

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While the answers that are already here work well  I found that they were slightly slower than I had hoped for  Instead I used zip4j  which I think is the best solution because of its speed  It also allowed for different options for the amount of compression  which I found useful

User · Answer

According to  zapl answer Unzip with progress report   public interface UnzipFile Progress       void Progress int percent  String FileName         unzip new File   sdcard pictures zip    new File   sdcard     public static void UnzipFile File zipFile  File targetDirectory  UnzipFile Progress progress  throws IOException          FileNotFoundException       long total len   zipFile length        long total installed len   0       ZipInputStream zis   new ZipInputStream new BufferedInputStream new FileInputStream zipFile         try               ZipEntry ze          int count          byte   buffer   new byte 1024           while   ze   zis getNextEntry       null                        if  progress    null                                total installed len    ze getCompressedSize                    String file name   ze getName                    int percent    int  total installed len   100   total len                   progress Progress percent  file name                              File file   new File targetDirectory  ze getName                 File dir   ze isDirectory     file   file getParentFile                if   dir isDirectory    amp  amp   dir mkdirs                    throw new FileNotFoundException  Failed to ensure directory      dir getAbsolutePath                 if  ze isDirectory                    continue              FileOutputStream fout   new FileOutputStream file               try                               while   count   zis read buffer      -1                      fout write buffer  0  count                 finally                               fout close                                  if time should be restored as well             long time   ze getTime                if  time  gt  0                  file setLastModified time                   finally               zis close

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I m working with zip files which Java s ZipFile class isn t able to handle  Java 8 apparently can t handle compression method 12  bzip2 I believe   After trying a number of methods including zip4j  which also fails with these particular files due to another issue   I had success with Apache s commons-compress which supports additional compression methods as mentioned here   Note that the ZipFile class below is not the one from java util zip   It s actually org apache commons compress archivers zip ZipFile so be careful with the imports   try  ZipFile zipFile   new ZipFile archiveFile         Enumeration lt ZipArchiveEntry gt  entries   zipFile getEntries        while  entries hasMoreElements              ZipArchiveEntry entry   entries nextElement            File entryDestination   new File destination  entry getName             if  entry isDirectory                  entryDestination mkdirs              else               entryDestination getParentFile   mkdirs                try  InputStream in   zipFile getInputStream entry   OutputStream out   new FileOutputStream entryDestination                     IOUtils copy in  out                                   catch  IOException ex        log debug  Error unzipping archive file      archiveFile  ex       For Gradle    compile  org apache commons commons-compress 1 18

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public class MainActivity extends Activity    private String LOG TAG   MainActivity class getSimpleName     private File zipFile  private File destination   private TextView status    Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout activity main        status    TextView  findViewById R id main status       status setGravity Gravity CENTER        if   initialize               zipFile   new File destination   BlueBoxnew zip            try               Unzipper unzip zipFile  destination               status setText  Extracted to  n  destination getAbsolutePath               catch  ZipException e                Log e LOG TAG  e getMessage               catch  IOException e                Log e LOG TAG  e getMessage                     else           status setText  Unable to initialize sd card              public boolean initialize         boolean result   false       File sdCard   new File Environment getExternalStorageDirectory     zip           File sdCard   Environment getExternalStorageDirectory        if   sdCard    null             destination   sdCard          if    destination exists                   if   destination mkdir                       result   true                          else               result   true                       return result          - Helper Class Unzipper java       import java io File      import java io FileInputStream     import java io FileOutputStream      import java io IOException         import java util zip ZipEntry      import java util zip ZipException      import java util zip ZipInputStream       import android util Log      public class Unzipper    private static String LOG TAG   Unzipper class getSimpleName     public static void unzip final File file  final File destination  throws ZipException  IOException       new Thread             public void run                 long START TIME   System currentTimeMillis                long FINISH TIME   0              long ELAPSED TIME   0              try                   ZipInputStream zin   new ZipInputStream new FileInputStream file                    String workingDir   destination getAbsolutePath                         byte buffer     new byte 4096                   int bytesRead                  ZipEntry entry   null                  while   entry   zin getNextEntry       null                        if  entry isDirectory                              File dir   new File workingDir  entry getName                             if   dir exists                                  dir mkdir                                                      Log i LOG TAG    DIR    entry getName                           else                           FileOutputStream fos   new FileOutputStream workingDir   entry getName                             while   bytesRead   zin read buffer      -1                                fos write buffer  0  bytesRead                                                     fos close                            Log i LOG TAG    FILE    entry getName                                                             zin close                     FINISH TIME   System currentTimeMillis                    ELAPSED TIME   FINISH TIME - START TIME                  Log i LOG TAG   COMPLETED in    ELAPSED TIME 1000    seconds                   catch  Exception e                    Log e LOG TAG   FAILED                                   start              - xml layout activity main xml     lt RelativeLayout xmlns android  http   schemas android com apk res android     xmlns tools  http   schemas android com tools     android layout width  match parent   android layout height  match parent   tools context   MainActivity   gt    lt TextView     android id    id main status      android layout width  wrap content      android layout height  wrap content      android layout centerHorizontal  true      android layout centerVertical  true      android text   string hello world    gt    lt  RelativeLayout gt    - permission in Menifest file    lt uses-permission android name  android permission WRITE EXTERNAL STORAGE   gt

User · Answer

Based on Vasily Sochinsky s answer a bit tweaked  amp  with a small fix   public static void unzip File zipFile  File targetDirectory  throws IOException       ZipInputStream zis   new ZipInputStream              new BufferedInputStream new FileInputStream zipFile         try           ZipEntry ze          int count          byte   buffer   new byte 8192           while   ze   zis getNextEntry       null                File file   new File targetDirectory  ze getName                 File dir   ze isDirectory     file   file getParentFile                if   dir isDirectory    amp  amp   dir mkdirs                    throw new FileNotFoundException  Failed to ensure directory                              dir getAbsolutePath                 if  ze isDirectory                    continue              FileOutputStream fout   new FileOutputStream file               try                   while   count   zis read buffer      -1                      fout write buffer  0  count                 finally                   fout close                                 if time should be restored as well             long time   ze getTime                if  time  gt  0                  file setLastModified time                                  finally           zis close              Notable differences   public static - this is a static utility method that can be anywhere  2 File parameters because String are    for files and one could not specify where the zip file is to be extracted before  Also path   filename concatenation   https   stackoverflow com a 412495 995891 throws - because catch late - add a try catch if really not interested in them  actually makes sure that the required directories exist in all cases  Not every zip contains all the required directory entries in advance of file entries  This had 2 potential bugs    if the zip contains an empty directory and instead of the resulting directory there is an existing file  this was ignored  The return value of mkdirs   is important  could crash on zip files that don t contain directories   increased write buffer size  this should improve performance a bit  Storage is usually in 4k blocks and writing in smaller chunks is usually slower than necessary  uses the magic of finally to prevent resource leaks    So  unzip new File   sdcard pictures zip    new File   sdcard       should do the equivalent of the original  unpackZip   sdcard     pictures zip

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This is my unzip method  which I use   private boolean unpackZip String path  String zipname                InputStream is       ZipInputStream zis       try                  is   new FileInputStream path   zipname            zis   new ZipInputStream new BufferedInputStream is                       ZipEntry ze            while  ze   zis getNextEntry       null                           ByteArrayOutputStream baos   new ByteArrayOutputStream                 byte   buffer   new byte 1024                int count                String filename   ze getName                 FileOutputStream fout   new FileOutputStream path   filename                    reading and writing              while  count   zis read buffer      -1                                   baos write buffer  0  count                    byte   bytes   baos toByteArray                     fout write bytes                                 baos reset                                 fout close                                zis closeEntry                         zis close                 catch IOException e                  e printStackTrace             return false              return true

User · Answer

use the following class     import java io BufferedOutputStream      import java io File      import java io FileInputStream      import java io FileOutputStream      import java util zip ZipEntry      import java util zip ZipInputStream      import android util Log       public class DecompressFast       private String  zipFile     private String  location       public DecompressFast String zipFile  String location          zipFile   zipFile        location   location          dirChecker  quot  quot              public void unzip          try           FileInputStream fin   new FileInputStream  zipFile          ZipInputStream zin   new ZipInputStream fin          ZipEntry ze   null         while   ze   zin getNextEntry       null             Log v  quot Decompress quot    quot Unzipping  quot    ze getName                if ze isDirectory                  dirChecker ze getName                else              FileOutputStream fout   new FileOutputStream  location   ze getName               BufferedOutputStream bufout   new BufferedOutputStream fout             byte   buffer   new byte 1024             int read   0            while   read   zin read buffer      -1                  bufout write buffer  0  read                                                           bufout close                         zin closeEntry               fout close                                         zin close                         Log d  quot Unzip quot    quot Unzipping complete  path     quot    location          catch Exception e           Log e  quot Decompress quot    quot unzip quot   e                 Log d  quot Unzip quot    quot Unzipping failed quot                      private void  dirChecker String dir         File f   new File  location   dir          if  f isDirectory             f mkdirs                       How to use  String zipFile   Environment getExternalStorageDirectory      quot  the raven zip quot     your zip file location     String unzipLocation   Environment getExternalStorageDirectory      quot  unzippedtestNew  quot      destination folder location   DecompressFast df  new DecompressFast zipFile  unzipLocation       df unzip     Permissions   lt uses-permission android name  quot android permission WRITE EXTERNAL STORAGE quot    gt    lt uses-permission android name  quot android permission READ EXTERNAL STORAGE quot    gt

User · Answer

Here is a ZipFileIterator  like a java Iterator  but for zip files    package ch epfl bbp io   import java io BufferedInputStream  import java io ByteArrayOutputStream  import java io File  import java io FileInputStream  import java io FileNotFoundException  import java io FileOutputStream  import java io IOException  import java util Iterator  import java util zip ZipEntry  import java util zip ZipInputStream   public class ZipFileIterator implements Iterator lt File gt         private byte   buffer   new byte 1024        private FileInputStream is      private ZipInputStream zis      private ZipEntry ze       public ZipFileIterator File file  throws FileNotFoundException       is   new FileInputStream file       zis   new ZipInputStream new BufferedInputStream is                Override     public boolean hasNext         try           return  ze   zis getNextEntry       null        catch  IOException e            e printStackTrace              return false              Override     public File next         try           ByteArrayOutputStream baos   new ByteArrayOutputStream            int count           String filename   ze getName            File tmpFile   File createTempFile filename   tmp            tmpFile deleteOnExit      TODO make it configurable         FileOutputStream fout   new FileOutputStream tmpFile            while   count   zis read buffer      -1            baos write buffer  0  count           byte   bytes   baos toByteArray            fout write bytes           baos reset                      fout close            zis closeEntry             return tmpFile         catch  Exception e            throw new RuntimeException e                     Override     public void remove         throw new RuntimeException  not implemented               public void close         try           zis close            is close          catch  IOException e      nope

User · Answer

Minimal example I used to unzip a specific file from my zipfile into my applications cache folder  I then read the manifest file using a different method   private void unzipUpdateToCache         ZipInputStream zipIs   new ZipInputStream context getResources   openRawResource R raw update        ZipEntry ze   null       try            while   ze   zipIs getNextEntry       null                if  ze getName   equals  update manifest json                      FileOutputStream fout   new FileOutputStream context getCacheDir   getAbsolutePath       manifest json                     byte   buffer   new byte 1024                   int length   0                   while   length   zipIs read buffer   gt 0                        fout write buffer  0  length                                     zipIs  closeEntry                    fout close                                    zipIs  close           catch  IOException e            e printStackTrace

User · Answer

Based on zapl s answer  adding try   around Closeable s closes the streams automatically after use  public static void unzip File zipFile  File targetDirectory        try  FileInputStream fis   new FileInputStream zipFile             try  BufferedInputStream bis   new BufferedInputStream fis                 try  ZipInputStream zis   new ZipInputStream bis                     ZipEntry ze                  int count                  byte   buffer   new byte Constant DefaultBufferSize                   while   ze   zis getNextEntry       null                        File file   new File targetDirectory  ze getName                         File dir   ze isDirectory     file   file getParentFile                        if   dir isDirectory    amp  amp   dir mkdirs                            throw new FileNotFoundException  quot Failed to ensure directory   quot    dir getAbsolutePath                         if  ze isDirectory                            continue                      try  FileOutputStream fout   new FileOutputStream file                             while   count   zis read buffer      -1                              fout write buffer  0  count                                                                         catch  Exception ex              handle exception          Using Constant DefaultBufferSize  65536  gotten from C   NET 4 Stream CopyTo from Jon Skeet s answer here  https   stackoverflow com a 411605 1876355 I always just see posts using byte 1024  or byte 4096  buffer  never knew it can be much larger which improves performance and is still working perfectly normal  Here is the Stream Source code  https   referencesource microsoft com  mscorlib system io stream cs    We pick a value that is the largest multiple of 4096 that is still smaller than the large object heap threshold  85K      The CopyTo CopyToAsync buffer is short-lived and is likely to be collected at Gen0  and it offers a significant    improvement in Copy performance   private const int  DefaultCopyBufferSize   81920    However  I dialed it back to 65536 which is also a multiple of 4096 just to be safe

User · Answer

Password Protected Zip File if you want to compress files with password you can take a look at this library that can zip files with password easily  Zip  ZipArchive zipArchive   new ZipArchive    zipArchive zip targetPath destinationPath password    Unzip  ZipArchive zipArchive   new ZipArchive    zipArchive unzip targetPath destinationPath password    Rar  RarArchive rarArchive   new RarArchive    rarArchive extractArchive file archive  file destination    The documentation of this library is good enough  I just added a few examples from there  It s totally free and wrote specially for android

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