(Android™) Chilkat Zip API Concepts

This example helps clarify some common misconceptions w/ using the Chilkat Zip API.

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();

    // To clarify some concepts, this example will create a new .zip containing 2 files.

    // The NewZip method is called to initialize the zip object to a new and empty state.
    // It does not actually create the .zip file.  It simply intializes the object.
    // if the zip object did not contain anything previously, then this method could be skipped
    // altogether.  It has the side-effect of setting the zip.FileName property.
    boolean success = zip.NewZip("test.zip");
    if (success != true) {
        Log.i(TAG, zip.lastErrorText());
        return;
        }

    // The FileName property should now contain "test.zip".  This is the name of the .zip
    // that is written when WriteZip or WriteZipAndClose is called.
    Log.i(TAG, "zip filename = " + zip.fileName());

    // When a file is "appended" to the zip object, we are really just appending a reference
    // to the file in the filesystem.  A "zip entry" is added to the zip object and this entry
    // can be one of several types.  It can point to a file.  It can contain uncompressed binary
    // or text data, it can point to an entry in the already-opened zip (if we had called OpenZip 
    // instead), etc.  

    // Now.. add a reference to a single file by calling AppendOneFileOrDir
    // Note: On Windows, forward slashes are equivalent to backslashes
    boolean saveExtraPath = false;
    success = zip.AppendOneFileOrDir("/temp/abc123/HelloWorld123.txt",saveExtraPath);
    if (success != true) {
        Log.i(TAG, zip.lastErrorText());
        return;
        }

    // We now have a zip object with one entry, which points to the file /temp/abc123/HelloWorld123.txt
    // If desired, we could change the filename of the zip entry so that when the zip is written,
    // the file has a different name:
    CkZipEntry entry = zip.GetEntryByIndex(0);
    entry.put_FileName("helloWorld.txt");

    // When the zip is actually written, the entry's data will stream from /temp/abc123/HelloWorld123.txt
    // and be compressed into an entry within the .zip having the filename "helloWorld.txt"

    // Now add another entry, this time from a string containing the file content:
    entry = zip.AppendString2("HelloWorld2.txt","hello world!","utf-8");

    // Examine the entries in the zip so far..
    // Each entry can be one of the following types:

    // 0 -- Mapped Entry: An entry in an existing Zip file.
    // 1 -- File Entry: A file not yet in memory, but referenced. 
    //      These entries are added by calling AppendFiles, AppendFilesEx, AppendOneFileOrDir, etc.
    // 2 -- Data Entry: An entry containing uncompressed data from memory. 
    //      These entries are added by calling AppendData, AppendString, etc.
    // 3 -- Null Entry: An entry that no longer exists in the .zip.
    // 4 -- New Directory Entry: A directory entry added by calling AppendNewDir. 

    int i;
    int n = zip.get_NumEntries();
    for (i = 0; i <= n - 1; i++) {

        entry = zip.GetEntryByIndex(i);
        Log.i(TAG, entry.fileName() + ", type=" + String.valueOf(entry.get_EntryType()));

        }

    // Write the "test.zip" file.
    success = zip.WriteZip();
    if (success != true) {
        Log.i(TAG, zip.lastErrorText());
        return;
        }

    // Our zip object still contains 2 entries, but now they point to the entries within the 
    // test.zip  (We called WriteZip, which writes the .zip but does not close it.  Instead,
    // the entries of the zip object are updated to become "mapped" entries.
    // For example:

    n = zip.get_NumEntries();
    for (i = 0; i <= n - 1; i++) {

        entry = zip.GetEntryByIndex(i);
        Log.i(TAG, entry.fileName() + ", type=" + String.valueOf(entry.get_EntryType()));

        }

    // Finally, close the zip
    zip.CloseZip();

  }

  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."
  }
}