Android™

Unzip a Text File Entry into a StringBuilder Using ZipEntry.UnzipToSb

See more Zip Examples

This example demonstrates how to use the ZipEntry.UnzipToSb method to inflate a text file entry directly into a StringBuilder object.

The ZIP entry is uncompressed entirely in memory and appended to the StringBuilder without creating a temporary file on disk.

This is useful when:

• Processing text files directly in memory
• Avoiding temporary filesystem files
• Reading configuration files, JSON, XML, CSV, or source code from ZIP archives
• Automatically converting line endings while inflating the text

The srcCharset argument specifies how the uncompressed bytes should be interpreted, such as:

• utf-8
• utf-16
• windows-1252

The lineEndingBehavior argument controls line-ending conversion:

• 0 — Leave line endings unchanged
• 1 — Convert all line endings to bare LF
• 2 — Convert all line endings to CRLF

Suppose the ZIP archive contains:

config/settings.json

The example inflates the JSON file directly into a StringBuilder.

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/configFiles.zip");
    if (success == false) {
        Log.i(TAG, zip.lastErrorText());
        return;
        }

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

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

    // ------------------------------------------------------------
    // Inflate the ZIP entry directly into a StringBuilder.
    // 
    // The uncompressed text is appended to the StringBuilder.
    // 
    CkStringBuilder sb = new CkStringBuilder();

    // Leave line endings unchanged.
    int lineEndingBehavior = 0;

    // Interpret the uncompressed bytes as UTF-8 text.
    String srcCharset = "utf-8";

    success = entry.UnzipToSb(lineEndingBehavior,srcCharset,sb);
    if (success == false) {
        Log.i(TAG, entry.lastErrorText());
        return;
        }

    Log.i(TAG, "Uncompressed text:");
    Log.i(TAG, "");
    Log.i(TAG, sb.getAsString());

    zip.CloseZip();

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

  }

  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."
  }
}