Android™

Unzip a ZIP Entry Directly into a BinData Object Using ZipEntry.UnzipToBd

See more Zip Examples

This example demonstrates how to use the ZipEntry.UnzipToBd method to inflate a ZIP entry directly into a BinData object.

The entry contents are uncompressed entirely in memory without creating a file on disk.

This is useful when:

• Processing ZIP entry data entirely in memory
• Avoiding temporary filesystem files
• Working with binary files such as images, PDFs, or certificates
• Passing uncompressed ZIP data directly to other APIs

The example opens a ZIP archive, locates a PDF entry, inflates it into a BinData object, and then writes the uncompressed bytes to a new file.

Suppose the ZIP archive contains:

docs/report.pdf

The entry is uncompressed directly into memory before optionally being saved to:

qa_output/report.pdf

Android™

// 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);

    boolean success = false;

    CkZip zip = new CkZip();

    // Open an existing ZIP archive.
    success = zip.OpenZip("qa_data/zips/documents.zip");
    if (success == false) {
        Log.i(TAG, zip.lastErrorText());
        return;
        }

    // Locate the PDF entry within the ZIP archive.
    CkZipEntry entry = new CkZipEntry();

    success = zip.EntryOf("docs/report.pdf",entry);
    if (success == false) {
        Log.i(TAG, "ZIP entry not found.");
        zip.CloseZip();
        return;
        }

    // ------------------------------------------------------------
    // Inflate the ZIP entry directly into a BinData object.
    // 
    // The uncompressed bytes are stored entirely in memory.
    // 
    CkBinData pdfData = new CkBinData();

    success = entry.UnzipToBd(pdfData);
    if (success == false) {
        Log.i(TAG, entry.lastErrorText());
        return;
        }

    Log.i(TAG, "Uncompressed size = " + String.valueOf(pdfData.get_NumBytes()));
    Log.i(TAG, "");

    // ------------------------------------------------------------
    // Optionally save the uncompressed bytes to a file.
    // 
    success = pdfData.WriteFile("qa_output/report.pdf");
    if (success == false) {
        Log.i(TAG, pdfData.lastErrorText());
        return;
        }

    zip.CloseZip();

    Log.i(TAG, "PDF extracted successfully.");

  }

  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."
  }
}