Unzip compressed file, using java.util.zip

java.util.zip package of Android can help to extract compressed file in ZIP format.

Modify from previous exercise "How to get file extension using java code", implement a function unzip().

If the extention of the returned file using Intent.ACTION_GET_CONTENT" is "zip", call the function unzip() to extract compressed file.

package com.exercise.AndroidPick_a_File;

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

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class AndroidPick_a_File extends Activity {
 
 TextView textFile, textFileName, textFolder;
 TextView textFileName_WithoutExt, textFileName_Ext;
 
 private static final int PICKFILE_RESULT_CODE = 1;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        Button buttonPick = (Button)findViewById(R.id.buttonpick);
        textFile = (TextView)findViewById(R.id.textfile);
        textFolder = (TextView)findViewById(R.id.textfolder);
        textFileName = (TextView)findViewById(R.id.textfilename);
        
        textFileName_WithoutExt 
         = (TextView)findViewById(R.id.textfilename_withoutext);
        textFileName_Ext 
         = (TextView)findViewById(R.id.textfilename_ext);
        
        buttonPick.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub

    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
             intent.setType("file/*");
       startActivityForResult(intent,PICKFILE_RESULT_CODE);
    
   }});
    }

 @Override
 protected void onActivityResult(int requestCode, 
   int resultCode, Intent data) {
  // TODO Auto-generated method stub
  switch(requestCode){
  case PICKFILE_RESULT_CODE:
   if(resultCode==RESULT_OK){
    
    String FilePath = data.getData().getPath();
    String FileName = data.getData().getLastPathSegment();
    int lastPos = FilePath.length() - FileName.length();
    String Folder = FilePath.substring(0, lastPos);
    
    textFile.setText("Full Path: \n" + FilePath + "\n");
    textFolder.setText("Folder: \n" + Folder + "\n");
    textFileName.setText("File Name: \n" + FileName + "\n");
    
    filename thisFile = new filename(FileName);
    
    textFileName_WithoutExt.setText("Filename without Ext: " 
      + thisFile.getFilename_Without_Ext());
          textFileName_Ext.setText("Ext: " + thisFile.getExt());
          
          if(thisFile.getExt().equalsIgnoreCase("zip")){
           unzip(FilePath, Folder);
          }
    
   }
   break;
   
  }
 }
 
 private class filename{
  
  String filename_Without_Ext = "";
  String ext = "";
  
  filename(String file){
      int dotposition= file.lastIndexOf(".");
      filename_Without_Ext = file.substring(0,dotposition);
      ext = file.substring(dotposition + 1, file.length());  
  }
  
  String getFilename_Without_Ext(){
   return filename_Without_Ext;
  }
  
  String getExt(){
   return ext;
  }
 }
 
 private void unzip(String src, String dest){
  
  final int BUFFER_SIZE = 4096;
  
  BufferedOutputStream bufferedOutputStream = null;
     FileInputStream fileInputStream;
     try {
      fileInputStream = new FileInputStream(src);
      ZipInputStream zipInputStream 
       = new ZipInputStream(new BufferedInputStream(fileInputStream));
      ZipEntry zipEntry;
      
      while ((zipEntry = zipInputStream.getNextEntry()) != null){
       
       String zipEntryName = zipEntry.getName();
       File file = new File(dest + zipEntryName);
       
       if (file.exists()){
        
       } else {
        if(zipEntry.isDirectory()){
         file.mkdirs(); 
        }else{
         byte buffer[] = new byte[BUFFER_SIZE];
         FileOutputStream fileOutputStream = new FileOutputStream(file);
         bufferedOutputStream 
          = new BufferedOutputStream(fileOutputStream, BUFFER_SIZE);
         int count;

         while ((count 
          = zipInputStream.read(buffer, 0, BUFFER_SIZE)) != -1) {
          bufferedOutputStream.write(buffer, 0, count);
         }

         bufferedOutputStream.flush();
         bufferedOutputStream.close(); 
        }
       } 
      }
      zipInputStream.close();
     } catch (FileNotFoundException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
 }
}

Keep using the layout file main.xml in the previous exercise "How to get file extension using java code".

In order to write back the extracted files, modify AndroidManifest.xml to grant permission of "android.permission.WRITE_EXTERNAL_STORAGE".

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.exercise.AndroidPick_a_File"
     android:versionCode="1"
     android:versionName="1.0">
   <uses-sdk android:minSdkVersion="4" />
   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>

   <application android:icon="@drawable/icon" android:label="@string/app_name">
       <activity android:name=".AndroidPick_a_File"
                 android:label="@string/app_name">
           <intent-filter>
               <action android:name="android.intent.action.MAIN" />
               <category android:name="android.intent.category.LAUNCHER" />
           </intent-filter>
       </activity>

   </application>
</manifest>

Download the files.