(Android™) Unzip Binary File to Stream

Demonstrates how to unzip a large binary file to a stream to allow the application to process the uncompressed bytes chunk by chunk.

Note: This example requires Chilkat v9.5.0.67 or greater.

Chilkat Android™ Downloads Android™ Java Libraries Android C/C++ Libraries

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // This requires the Chilkat Zip API to have been previously unlocked.
    // See Unlock Chilkat Zip for sample code.

    CkZip zip = new CkZip();

    // First open a .zip.
    boolean success = zip.OpenZip("qa_data/zips/big.zip");
    if (success != true) {
        Log.i(TAG, zip.lastErrorText());
        return;
        }

    // Get the entry to be unzipped to a stream..
    CkZipEntry entry = zip.GetEntryByIndex(0);
    if (zip.get_LastMethodSuccess() != true) {
        Log.i(TAG, zip.lastErrorText());
        return;
        }

    CkStream dataStream = new CkStream();

    CkTask unzipTask = entry.UnzipToStreamAsync(dataStream);
    if (entry.get_LastMethodSuccess() != true) {
        Log.i(TAG, entry.lastErrorText());

        return;
        }

    // Start the background unzip thread.
    unzipTask.Run();

    // We'll read the uncompressed data chunk-by-chunk and write to an output file.
    CkFileAccess fac = new CkFileAccess();
    success = fac.OpenForWrite("qa_output/out.dat");
    if (success != true) {
        Log.i(TAG, fac.lastErrorText());

        return;
        }

    // Read the stream.  (this is reading the unzipped file data)
    CkBinData bd = new CkBinData();
    while (dataStream.get_EndOfStream() != true) {
        // Get the next chunk of decompressed bytes.
        dataStream.ReadBd(bd);
        // Do something with it..
        // In this simple example, we'll just write to the file.
        fac.FileWriteBd(bd,0,0);
        // Clear for the next read.
        bd.Clear();
        }

    fac.FileClose();

    Log.i(TAG, "Success.");

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}