(Android™) Unzip One File to a Stream

Demonstrates how to unzip a particular file contained within a .zip archive to a Chilkat stream.

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 example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkZip zip = new CkZip();

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

    // Find the entry to be unzipped to a stream..
    CkZipEntry entry = zip.FirstMatchingEntry("*hamlet.xml");
    if (zip.get_LastMethodSuccess() != true) {
        Log.i(TAG, zip.lastErrorText());
        return;
        }

    // There are three ways we can unzip (inflate) to a stream.
    // 
    // 1) Set a sink file on the stream object and call UnzipToStream synchronously.
    //    This unzips to the stream's sink (which is to simply unzip to a file in the filesystem).
    // 
    // 2) Create a stream object and call UnzipToStreamAsync.  This starts the unzip in a background
    //    thread (after Task.Run is called).  Your application can then read the unzipped (inflated) file
    //    directly from the stream.
    // 
    // 3) (not shown in this example) Unzip to a stream object that is the source of something else.
    //    

    // ----------------------------------------------------------------
    // Case 1: Unzip to a file by setting the sink of streamA to a file.
    CkStream streamA = new CkStream();
    streamA.put_SinkFile("qa_output/hamletA.xml");

    success = entry.UnzipToStream(streamA);
    if (success != true) {
        Log.i(TAG, entry.lastErrorText());

        return;
        }

    // Close the stream to close the output file.
    success = streamA.WriteClose();

    // ----------------------------------------------------------------
    // Case 2a: Uzip to a stream asynchronously. 
    CkStream streamB = new CkStream();

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

        return;
        }

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

    // Read the stream.  (this is reading the unzipped file data)
    CkStringBuilder sb = new CkStringBuilder();
    while (streamB.get_EndOfStream() != true) {
        // Each call to ReadSb appends to the contents of sb.
        streamB.ReadSb(sb);
        }

    sb.WriteFile("qa_output/hamletB.xml","utf-8",false);

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

    // ----------------------------------------------------------------
    // Case 2b: Uzip to a stream asynchronously and emit output while reading. 
    CkStream streamC = new CkStream();

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

        return;
        }

    unzipTask.Run();

    while (streamC.get_EndOfStream() != true) {
        String s = streamC.readString();
        Log.i(TAG, s);
        }

    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."
  }
}