Android Open Source - downloadandunzip File Downloader Task

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License

The source code is released under:

GNU General Public License

Java Source Code

package com.mehmetakiftutuncu.downloadunzipshow;
/*from  ww  w. ja v a  2s  .  c  o m*/
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;

import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.AsyncTask;
import android.os.Environment;
import android.util.Log;

/**
 * An AsyncTask class for handling a single file download with a ProgressDialog<br><br>
 * 
 * Needs use of {@link android.app.Activity.onRetainNonConfigurationInstance}
 * and {@link android.app.Activity.getLastNonConfigurationInstance} methods
 * to keep the progress dialog during any configuration changes (ex: screen orientation)
 * 
 * @author Mehmet Akif Ttnc
 */
public class FileDownloaderTask extends AsyncTask<Void, Integer, Boolean>
{
  /** Tag for the logging */
  public static final String LOG_TAG = "FileDownloaderTask";
  
  /** Context of the downloader object */
  private Context myContext;
  
  /** Input stream of the downloader (obtained by a connection to the specified URL) */
  private InputStream myInputStream;
  
  /** Output stream of the downloader (to save the file) */
  private OutputStream myOutputStream;
  
  /** ProgressDialog to show the progress of the download */
  private ProgressDialog myProgressDialog;
  
  /** URL of the file to download */
  private String URL_TO_DOWNLOAD;
  
  /** Relative path in sd card to save the downloaded file<br><br>
   *  If the sd card location is detected as "/sdcard" and this is given as "example"
   *  then the file will be saved to "/sdcard/example" */
  private String PATH_IN_SD_TO_SAVE;
  
  /** Name of the file to save the downloaded data */
  private String FILE_NAME_TO_SAVE;
  
  /** Full absolute path of the file to be saved */
  private String FULL_PATH;
  
  /** Full absolute path of the file to be saved including the file name */
  private String FULL_PATH_WITH_FILE_NAME;
  
  /** Downloaded size in bytes */
  private double myDownloadedSize = 0;
  
  /** Total size of the file to download in bytes */
  private double myTotalSize = 0;
  
  /** Percentage of the download progress */
  private int myPercentage = 0;
  
  /** Flag indicating if the download was successful or not */
  private boolean isSuccessful = true;
  
  /** Flag indicating if the download was cancelled by clicking cancel button or not */
  private boolean isCancelled = false;
  
  /**
   * Constructor of the downloader object
   * 
   * @param context      Context of the downloader object
   * @param urlToDownload    URL of the file to download (Check {@link FileDownloaderTask#URL_TO_DOWNLOAD})
   * @param pathInSdToSave  Where to save the file in sd card (Check {@link FileDownloaderTask#PATH_IN_SD_TO_SAVE})
   * @param fileNameToSave  Name of the file to save (Check {@link FileDownloaderTask#FILE_NAME_TO_SAVE})
   */
  public FileDownloaderTask(Context context, String urlToDownload, String pathInSdToSave, String fileNameToSave)
  {
    myContext = context;
    
    URL_TO_DOWNLOAD = urlToDownload;
    PATH_IN_SD_TO_SAVE = pathInSdToSave;
    FILE_NAME_TO_SAVE = fileNameToSave;
    
    FULL_PATH = Environment.getExternalStorageDirectory().getPath() + "/" + PATH_IN_SD_TO_SAVE + "/";
    FULL_PATH_WITH_FILE_NAME = Environment.getExternalStorageDirectory().getPath() + "/" + PATH_IN_SD_TO_SAVE + "/" + FILE_NAME_TO_SAVE;
  }
  
  /**
   * Gets a String representation of the download process with the following format:<br><br>
   * 
   * 123 kB / 532 kB
   * 
   * @return A String representation of the download process
   */
  private String getDownloadedMessage()
  {
    if(myTotalSize < 1024)
    {
      return String.format("%d B / %d B", (int) myDownloadedSize, (int) myTotalSize);
    }
    else if(myTotalSize < 1048576)
    {
      return String.format("%.2f KB / %.2f KB", myDownloadedSize / 1024, myTotalSize / 1024);
    }
    else if(myTotalSize < 1073741824)
    {
      return String.format("%.2f MB / %.2f MB", myDownloadedSize / 1048576, myTotalSize / 1048576);
    }
    else
    {
      return String.format("%.2f GB / %.2f GB", myDownloadedSize / 1073741824, myTotalSize / 1073741824);
    }
  }
  
  /**
   * Updates the value and message of the ProgressDialog
   * 
   * @param progress Value of the ProgressBar
   * @param message Message in the ProgressDialog
   */
  private void updateProgressDialog(int progress, String message)
  {
    myProgressDialog.setProgress(progress);
    myProgressDialog.setMessage(message);
  }
  
  /**
   * Prepares and shows a ProgressDialog
   * 
   * @param progress Value that the ProgressBar will have at the beginning
   */
  private void prepareProgressDialog(int progress)
  {
    myProgressDialog = new ProgressDialog(myContext);
    myProgressDialog.setTitle("Downloading...");
    myProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
    myProgressDialog.setMax(100);
    myProgressDialog.setCancelable(false);
    myProgressDialog.setButton(Dialog.BUTTON_NEGATIVE, "Cancel", new OnClickListener()
    {
      @Override
      public void onClick(DialogInterface dialog, int whichButton)
      {
        isCancelled = true;
        myProgressDialog.cancel();
        cancel(true);
      }
    });
    updateProgressDialog(progress, getDownloadedMessage());
    myProgressDialog.show();
  }
  
  /**
   * Sets the context of the downloader object
   * 
   * @param context New context
   */
  public void setContext(Context context)
  {
    this.myContext = context;
    
    if(context == null)
    {
      cancel(true);
    }
    else
    {
      prepareProgressDialog(myPercentage);
    }
  }
  
  /**
   * Gets the ProgressDialog of the downloader object
   * 
   * @return ProgressDialog of the downloader object
   */
  public ProgressDialog getProgressDialog()
  {
    return myProgressDialog;
  }
  
  @Override
  protected void onPreExecute()
  {
    super.onPreExecute();
    prepareProgressDialog(0);
    
    Log.d(LOG_TAG, "Going to download " + URL_TO_DOWNLOAD + " to: " + FULL_PATH_WITH_FILE_NAME);
  }
  
  @Override
  protected Boolean doInBackground(Void... params)
  {
    int countOfBytesRead;
    
    try
    {
      URL url = new URL(URL_TO_DOWNLOAD);
      URLConnection connection = url.openConnection();
      
      connection.connect();
      
      myTotalSize = connection.getContentLength();
      
      File path = new File(FULL_PATH);
      if(!path.exists())
      {
        path.mkdir();
      }
      
      myInputStream = new BufferedInputStream(url.openStream());
      myOutputStream = new FileOutputStream(FULL_PATH_WITH_FILE_NAME);
      
      byte[] data = new byte[1024];
      
      myDownloadedSize = 0;
      
      while(!isCancelled() && (countOfBytesRead = myInputStream.read(data)) != -1)
      {
        myDownloadedSize += countOfBytesRead;
        
        myPercentage = (int) ((myDownloadedSize / myTotalSize) * 100);
        
        publishProgress(myPercentage);
        
        myOutputStream.write(data, 0, countOfBytesRead);
      }
      
      myOutputStream.flush();
      myOutputStream.close();
      myInputStream.close();
    }
    catch(Exception e)
    {
      isSuccessful = false;
      Log.e(LOG_TAG, "An error occured while downloading. Details: " + e.getMessage());
    }
    
    return isSuccessful;
  }
  
  @Override
  protected void onProgressUpdate(Integer... values)
  {
    super.onProgressUpdate(values);
    
    updateProgressDialog(values[0], getDownloadedMessage());
  }
  
  @Override
  protected void onCancelled()
  {
    super.onCancelled();
    
    if(isCancelled)
    {
      Log.d(LOG_TAG, "Download is cancelled.");
      
      try
      {
        myOutputStream.close();
        myInputStream.close();
        
        File file = new File(FULL_PATH_WITH_FILE_NAME);
        if(file.exists())
        {
          file.delete();
        }
      }
      catch(Exception e)
      {
        Log.e(LOG_TAG, "An error occured while cancelling the download. Details: " + e.getMessage());
      }
    }
  }
  
  @Override
  protected void onPostExecute(Boolean result)
  {
    super.onPostExecute(result);
    
    if(result)
    {
      Log.d(LOG_TAG, "File is successfully downloaded to: " + FULL_PATH_WITH_FILE_NAME);
      
      DecompressorTask myDecompressor = new DecompressorTask(myContext, PATH_IN_SD_TO_SAVE, FILE_NAME_TO_SAVE, PATH_IN_SD_TO_SAVE);
      myDecompressor.execute();
    }
    
    myProgressDialog.dismiss();
  }
}

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