apkx_checker.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="0"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/statusText"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="10dp"
            android:layout_marginLeft="5dp"
            android:layout_marginTop="10dp"
            android:gravity="center_horizontal"
            android:textStyle="bold" />

        <LinearLayout
            android:id="@+id/downloaderDashboard"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical" >

            <RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="0dip"
                android:layout_weight="1" >

                <TextView
                    android:id="@+id/progressAsFraction"
                    style="@android:style/TextAppearance.Small"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_alignParentLeft="true"
                    android:layout_marginLeft="5dp"
                    android:text="0MB / 0MB" >
                </TextView>

                <TextView
                    android:id="@+id/progressAsPercentage"
                    style="@android:style/TextAppearance.Small"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_alignRight="@+id/progressBar"
                    android:text="0%" />

                <ProgressBar
                    android:id="@+id/progressBar"
                    style="?android:attr/progressBarStyleHorizontal"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_below="@+id/progressAsFraction"
                    android:layout_marginBottom="10dp"
                    android:layout_marginLeft="10dp"
                    android:layout_marginRight="10dp"
                    android:layout_marginTop="10dp" />

                <TextView
                    android:id="@+id/progressAverageSpeed"
                    style="@android:style/TextAppearance.Small"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_alignParentLeft="true"
                    android:layout_below="@+id/progressBar"
                    android:layout_marginLeft="5dp" />

                <TextView
                    android:id="@+id/progressTimeRemaining"
                    style="@android:style/TextAppearance.Small"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_alignRight="@+id/progressBar"
                    android:layout_below="@+id/progressBar" />
            </RelativeLayout>

            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center_horizontal"
                android:orientation="horizontal" >

                <Button
                    android:id="@+id/pauseButton"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center_vertical"
                    android:layout_marginBottom="10dp"
                    android:layout_marginLeft="10dp"
                    android:layout_marginRight="5dp"
                    android:layout_marginTop="10dp"
                    android:layout_weight="0"
                    android:minHeight="40dp"
                    android:minWidth="94dp"
                    android:text="@string/text_button_pause" />

                <Button
                    android:id="@+id/cancelButton"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center_vertical"
                    android:layout_marginBottom="10dp"
                    android:layout_marginLeft="5dp"
                    android:layout_marginRight="5dp"
                    android:layout_marginTop="10dp"
                    android:layout_weight="0"
                    android:minHeight="40dp"
                    android:minWidth="94dp"
                    android:text="@string/text_button_cancel"
                    android:visibility="gone" />
            </LinearLayout>
        </LinearLayout>
    </LinearLayout>

    <LinearLayout
        android:id="@+id/approveCellular"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:orientation="vertical"
        android:visibility="gone" >

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:id="@+id/textPausedParagraph1"
            android:text="@string/text_paused_cellular" />

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:id="@+id/textPausedParagraph2"
            android:text="@string/text_paused_cellular_2" />

        <LinearLayout
            android:id="@+id/buttonRow"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal" >

            <Button
                android:id="@+id/resumeOverCellular"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:layout_margin="10dp"
                android:text="@string/text_button_resume_cellular" />

            <Button
                android:id="@+id/wifiSettingsButton"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:layout_margin="10dp"
                android:text="@string/text_button_wifi_settings" />
            </LinearLayout>
    </LinearLayout>

</LinearLayout>

CheckerActivity.java

package kr.pe.meinside.android.apkx;

import java.io.DataInputStream;
import java.io.IOException;
import java.util.zip.CRC32;

import kr.pe.meinside.android.apkx.sampleapp.R;
import android.app.Activity;
import android.app.PendingIntent;
import android.content.Intent;
import android.content.pm.PackageManager.NameNotFoundException;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Messenger;
import android.os.SystemClock;
import android.provider.Settings;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

import com.android.vending.expansion.zipfile.ZipResourceFile;
import com.android.vending.expansion.zipfile.ZipResourceFile.ZipEntryRO;
import com.google.android.vending.expansion.downloader.Constants;
import com.google.android.vending.expansion.downloader.DownloadProgressInfo;
import com.google.android.vending.expansion.downloader.DownloaderClientMarshaller;
import com.google.android.vending.expansion.downloader.DownloaderServiceMarshaller;
import com.google.android.vending.expansion.downloader.Helpers;
import com.google.android.vending.expansion.downloader.IDownloaderClient;
import com.google.android.vending.expansion.downloader.IDownloaderService;
import com.google.android.vending.expansion.downloader.IStub;

/**
 * * referenced: <b>http://developer.android.com/google/play/expansion-files.html</b>
 * 
 * <br><br>
 * 
 * * needs: APK Expansion Download Library, APK Expansion Zip Library, Google Play Service Library, and LVL Library.
 * 
 * <br><br>
 * 
 * 1. Add CheckerActivity.java, DownloadService.java, and DownloadAlarmReceiver.java to the project.
 * <br>
 * Also add res/values/strings.xml and res/layout/apkx_checker.xml for the convenience.
 * 
 * <br><br>
 * 
 * 2. Extend classes added above.
 * 
 * <br><br>
 * 
 * 3. Register extended activity, service, and receiver in the manifest file:
 * 
 * <pre>
 * &lt;activity android:name="YOUR_CheckerActivity" /&gt;
 * &lt;service android:name="YOUR_DownloadService" /&gt;
 * &lt;receiver android:name="YOUR_DownloadAlarmReceiver" /&gt;
 * </pre>
 * 
 * <br>
 * 
 * 4. and add following permissions:
 * <pre>
 * &lt;!-- Required to access Android Market Licensing --&gt;
 * &lt;uses-permission android:name="com.android.vending.CHECK_LICENSE" /&gt;
 * &lt;!-- Required to download files from Android Market --&gt;
 * &lt;uses-permission android:name="android.permission.INTERNET" /&gt;
 * &lt;!-- Required to keep CPU alive while downloading files (NOT to keep screen awake) --&gt;
 * &lt;uses-permission android:name="android.permission.WAKE_LOCK" /&gt;
 * &lt;!-- Required to poll the state of the network connection and respond to changes --&gt;
 * &lt;uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /&gt;
 * &lt;!-- Required to check whether Wi-Fi is enabled --&gt;
 * &lt;uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/&gt;
 * &lt;!-- Required to read and write the expansion files on shared storage --&gt;
 * &lt;uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /&gt;
 * </pre>
 * 
 * <br>
 * 
 * 5. Add following element inside <application> element of Manifest.xml file
 * 
 * <br><br>
 * 
 * <pre>
 * &lt;meta-data android:name="com.google.android.gms.version" android:value="@integer/google_play_services_version" /&gt;
 * </pre>
 * 
 * <br>
 * 
 * 6. Build .obo files and upload them with the application .apk file.
 * 
 * <pre>
 * # (example) zip files without compression
 * $ zip -0 main.1.com.sample.app.obo ./*.mp3
 * </pre>
 * 
 * @author meinside@gmail.com
 *
 */
public abstract class CheckerActivity extends Activity implements IDownloaderClient
{
	private static final String LOG_TAG = "APKXChecker";

    private ProgressBar mPB;

    private TextView mStatusText;
    private TextView mProgressFraction;
    private TextView mProgressPercent;
    private TextView mAverageSpeed;
    private TextView mTimeRemaining;

    private View mDashboard;
    private View mCellMessage;

    private Button mPauseButton;
    private Button mWiFiSettingsButton;

    private boolean mStatePaused;
    private int mState;

    private IStub mDownloaderClientStub;
    private IDownloaderService mRemoteService;

    /**
     * Calculating a moving average for the validation speed so we don't get
     * jumpy calculations for time etc.
     */
    static private final float SMOOTHING_FACTOR = 0.005f;

    /**
     * Used by the async task
     */
    private boolean mCancelValidation;

    private void setState(int newState)
    {
        if (mState != newState)
        {
            mState = newState;
            mStatusText.setText(getStateString(newState));
        }
    }

    private int getStateString(int state)
    {
        int stateRes;
        switch (state)
        {
        case IDownloaderClient.STATE_IDLE:
        	stateRes = R.string.state_idle;
        	break;
        case IDownloaderClient.STATE_FETCHING_URL:
        	stateRes = R.string.state_fetching_url;
        	break;
        case IDownloaderClient.STATE_CONNECTING:
        	stateRes = R.string.state_connecting;
        	break;
        case IDownloaderClient.STATE_DOWNLOADING:
        	stateRes = R.string.state_downloading;
        	break;
        case IDownloaderClient.STATE_COMPLETED:
        	stateRes = R.string.state_completed;
        	break;
        case IDownloaderClient.STATE_PAUSED_NETWORK_UNAVAILABLE:
        	stateRes = R.string.state_paused_network_unavailable;
        	break;
        case IDownloaderClient.STATE_PAUSED_BY_REQUEST:
        	stateRes = R.string.state_paused_by_request;
        	break;
        case IDownloaderClient.STATE_PAUSED_WIFI_DISABLED_NEED_CELLULAR_PERMISSION:
        	stateRes = R.string.state_paused_wifi_disabled;
        	break;
        case IDownloaderClient.STATE_PAUSED_NEED_CELLULAR_PERMISSION:
        	stateRes = R.string.state_paused_wifi_unavailable;
        	break;
        case IDownloaderClient.STATE_PAUSED_WIFI_DISABLED:
        	stateRes = R.string.state_paused_wifi_disabled;
        	break;
        case IDownloaderClient.STATE_PAUSED_NEED_WIFI:
        	stateRes = R.string.state_paused_wifi_unavailable;
        	break;
        case IDownloaderClient.STATE_PAUSED_ROAMING:
        	stateRes = R.string.state_paused_roaming;
        	break;
        case IDownloaderClient.STATE_PAUSED_NETWORK_SETUP_FAILURE:
        	stateRes = R.string.state_paused_network_setup_failure;
        	break;
        case IDownloaderClient.STATE_PAUSED_SDCARD_UNAVAILABLE:
        	stateRes = R.string.state_paused_sdcard_unavailable;
        	break;
        case IDownloaderClient.STATE_FAILED_UNLICENSED:
        	stateRes = R.string.state_failed_unlicensed;
        	break;
        case IDownloaderClient.STATE_FAILED_FETCHING_URL:
        	stateRes = R.string.state_failed_fetching_url;
        	break;
        case IDownloaderClient.STATE_FAILED_SDCARD_FULL:
        	stateRes = R.string.state_failed_sdcard_full;
        	break;
        case IDownloaderClient.STATE_FAILED_CANCELED:
        	stateRes = R.string.state_failed_cancelled;
        	break;
        default:
        	stateRes = R.string.state_unknown;
        	break;
        }
        
        return stateRes;
    }

    private void setButtonPausedState(boolean paused)
    {
        mStatePaused = paused;
        int stringResourceID = paused ? R.string.text_button_resume : R.string.text_button_pause;
        mPauseButton.setText(stringResourceID);
    }

    @Override
	protected void onCreate(Bundle savedInstanceState)
    {
		super.onCreate(savedInstanceState);

        /**
         * Both downloading and validation make use of the "download" UI
         */
        initializeDownloadUI();

        /**
         * Before we do anything, are the files we expect already here and
         * delivered (presumably by Market) For free titles, this is probably
         * worth doing. (so no Market request is necessary)
         */
        if (!expansionFilesDelivered())
        {
            try
            {
                Intent launchIntent = CheckerActivity.this.getIntent();
                Intent intentToLaunchThisActivityFromNotification = new Intent(CheckerActivity.this, getActivityClass());
                intentToLaunchThisActivityFromNotification.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP);
                intentToLaunchThisActivityFromNotification.setAction(launchIntent.getAction());

                if (launchIntent.getCategories() != null)
                {
                    for (String category : launchIntent.getCategories())
                    {
                        intentToLaunchThisActivityFromNotification.addCategory(category);
                    }
                }

                // Build PendingIntent used to open this activity from Notification
                PendingIntent pendingIntent = PendingIntent.getActivity(CheckerActivity.this, 0, intentToLaunchThisActivityFromNotification, PendingIntent.FLAG_UPDATE_CURRENT);
                // Request to start the download
                int startResult = DownloaderClientMarshaller.startDownloadServiceIfRequired(this, pendingIntent, getDownloadServiceClass());

                if (startResult != DownloaderClientMarshaller.NO_DOWNLOAD_REQUIRED)
                {
                    // The DownloaderService has started downloading the files, show progress
                    initializeDownloadUI();
                    return;
                } // otherwise, download not needed so we fall through to starting the movie
            }
            catch (NameNotFoundException e)
            {
                Log.e(LOG_TAG, "Cannot find own package! MAYDAY!");
                e.printStackTrace();
            }
        }
        else
        {
            validateXAPKZipFiles();
        }
	}

	@Override
	protected void onStart()
	{
        if (null != mDownloaderClientStub)
        {
            mDownloaderClientStub.connect(this);
        }
        super.onStart();
	}

	@Override
	protected void onStop()
	{
        if (null != mDownloaderClientStub)
        {
            mDownloaderClientStub.disconnect(this);
        }
        super.onStop();
	}

    @Override
    protected void onDestroy()
    {
        this.mCancelValidation = true;
        super.onDestroy();
    }

	/**
     * This is a little helper class that demonstrates simple testing of an
     * Expansion APK file delivered by Market. You may not wish to hard-code
     * things such as file lengths into your executable... and you may wish to
     * turn this code off during application development.
     */
    public static class XAPKFile
    {
        public final boolean mIsMain;
        public final int mFileVersion;
        public final long mFileSize;

        public XAPKFile(boolean isMain, int fileVersion, long fileSize)
        {
            mIsMain = isMain;
            mFileVersion = fileVersion;
            mFileSize = fileSize;
        }
    }

	/**
     * Go through each of the APK Expansion files defined in the structure above
     * and determine if the files are present and match the required size. Free
     * applications should definitely consider doing this, as this allows the
     * application to be launched for the first time without having a network
     * connection present. Paid applications that use LVL should probably do at
     * least one LVL check that requires the network to be present, so this is
     * not as necessary.
     * 
     * @return true if they are present.
     */
    boolean expansionFilesDelivered()
    {
        for (XAPKFile xf : getXAPKs())
        {
            String fileName = Helpers.getExpansionAPKFileName(this, xf.mIsMain, xf.mFileVersion);
            if (!Helpers.doesFileExist(this, fileName, xf.mFileSize, false))
                return false;
        }
        return true;
    }

	@Override
	public void onServiceConnected(Messenger m)
	{
        mRemoteService = DownloaderServiceMarshaller.CreateProxy(m);
        mRemoteService.onClientUpdated(mDownloaderClientStub.getMessenger());
	}

	@Override
	public void onDownloadStateChanged(int newState)
	{
        setState(newState);

        boolean showDashboard = true;
        boolean showCellMessage = false;
        boolean paused;
        boolean indeterminate;
        switch (newState) {
            case IDownloaderClient.STATE_IDLE:
                // STATE_IDLE means the service is listening, so it's safe to start making calls via mRemoteService.
                paused = false;
                indeterminate = true;
                break;
            case IDownloaderClient.STATE_CONNECTING:
            case IDownloaderClient.STATE_FETCHING_URL:
                showDashboard = true;
                paused = false;
                indeterminate = true;
                break;
            case IDownloaderClient.STATE_DOWNLOADING:
                paused = false;
                showDashboard = true;
                indeterminate = false;
                break;

            case IDownloaderClient.STATE_FAILED_CANCELED:
            case IDownloaderClient.STATE_FAILED:
            case IDownloaderClient.STATE_FAILED_FETCHING_URL:
            case IDownloaderClient.STATE_FAILED_UNLICENSED:
                paused = true;
                showDashboard = false;
                indeterminate = false;
                break;
            case IDownloaderClient.STATE_PAUSED_NEED_CELLULAR_PERMISSION:
            case IDownloaderClient.STATE_PAUSED_WIFI_DISABLED_NEED_CELLULAR_PERMISSION:
                showDashboard = false;
                paused = true;
                indeterminate = false;
                showCellMessage = true;
                break;

            case IDownloaderClient.STATE_PAUSED_BY_REQUEST:
                paused = true;
                indeterminate = false;
                break;
            case IDownloaderClient.STATE_PAUSED_ROAMING:
            case IDownloaderClient.STATE_PAUSED_SDCARD_UNAVAILABLE:
                paused = true;
                indeterminate = false;
                break;
            case IDownloaderClient.STATE_COMPLETED:
                showDashboard = false;
                paused = false;
                indeterminate = false;
                validateXAPKZipFiles();
                return;
            default:
                paused = true;
                indeterminate = true;
                showDashboard = true;
        }
        int newDashboardVisibility = showDashboard ? View.VISIBLE : View.GONE;
        if (mDashboard.getVisibility() != newDashboardVisibility) {
            mDashboard.setVisibility(newDashboardVisibility);
        }
        int cellMessageVisibility = showCellMessage ? View.VISIBLE : View.GONE;
        if (mCellMessage.getVisibility() != cellMessageVisibility) {
            mCellMessage.setVisibility(cellMessageVisibility);
        }

        mPB.setIndeterminate(indeterminate);
        setButtonPausedState(paused);
	}

	@Override
	public void onDownloadProgress(DownloadProgressInfo progress)
	{
        mAverageSpeed.setText(getString(R.string.kilobytes_per_second, Helpers.getSpeedString(progress.mCurrentSpeed)));
        mTimeRemaining.setText(getString(R.string.time_remaining, Helpers.getTimeRemaining(progress.mTimeRemaining)));

        progress.mOverallTotal = progress.mOverallTotal;
        mPB.setMax((int) (progress.mOverallTotal >> 8));
        mPB.setProgress((int) (progress.mOverallProgress >> 8));
        mProgressPercent.setText(Long.toString(progress.mOverallProgress * 100 / progress.mOverallTotal) + "%");
        mProgressFraction.setText(Helpers.getDownloadProgressString(progress.mOverallProgress, progress.mOverallTotal));
	}

    /**
     * Go through each of the Expansion APK files and open each as a zip file.
     * Calculate the CRC for each file and return false if any fail to match.
     * 
     * @return true if XAPKZipFile is successful
     */
    void validateXAPKZipFiles()
    {
        AsyncTask<Object, DownloadProgressInfo, Boolean> validationTask = new AsyncTask<Object, DownloadProgressInfo, Boolean>(){
            @Override
            protected void onPreExecute()
            {
                mDashboard.setVisibility(View.VISIBLE);
                mCellMessage.setVisibility(View.GONE);
                mStatusText.setText(R.string.text_verifying_download);
                mPauseButton.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view)
                    {
                        mCancelValidation = true;
                    }
                });
                mPauseButton.setText(R.string.text_button_cancel_verify);
                super.onPreExecute();
            }

            @Override
            protected Boolean doInBackground(Object... params)
            {
                for (XAPKFile xf : getXAPKs())
                {
                    String fileName = Helpers.getExpansionAPKFileName(CheckerActivity.this, xf.mIsMain, xf.mFileVersion);
                    
                    Log.v(LOG_TAG, "checking for filename: " + fileName);

                    if (!Helpers.doesFileExist(CheckerActivity.this, fileName, xf.mFileSize, false))
                        return false;
                    fileName = Helpers.generateSaveFileName(CheckerActivity.this, fileName);
                    ZipResourceFile zrf;
                    byte[] buf = new byte[1024 * 256];
                    try
                    {
                        zrf = new ZipResourceFile(fileName);
                        ZipEntryRO[] entries = zrf.getAllEntries();
                        /**
                         * First calculate the total compressed length
                         */
                        long totalCompressedLength = 0;
                        for (ZipEntryRO entry : entries)
                        {
                            totalCompressedLength += entry.mCompressedLength;
                        }
                        float averageVerifySpeed = 0;
                        long totalBytesRemaining = totalCompressedLength;
                        long timeRemaining;
                        /**
                         * Then calculate a CRC for every file in the Zip file,
                         * comparing it to what is stored in the Zip directory.
                         * Note that for compressed Zip files we must extract
                         * the contents to do this comparison.
                         */
                        for (ZipEntryRO entry : entries)
                        {
                            if (-1 != entry.mCRC32)
                            {
                                long length = entry.mUncompressedLength;
                                CRC32 crc = new CRC32();
                                DataInputStream dis = null;
                                try
                                {
                                    dis = new DataInputStream(zrf.getInputStream(entry.mFileName));

                                    long startTime = SystemClock.uptimeMillis();
                                    while (length > 0)
                                    {
                                        int seek = (int) (length > buf.length ? buf.length : length);
                                        dis.readFully(buf, 0, seek);
                                        crc.update(buf, 0, seek);
                                        length -= seek;
                                        long currentTime = SystemClock.uptimeMillis();
                                        long timePassed = currentTime - startTime;
                                        if (timePassed > 0)
                                        {
                                            float currentSpeedSample = (float) seek / (float) timePassed;
                                            if (0 != averageVerifySpeed)
                                            {
                                                averageVerifySpeed = SMOOTHING_FACTOR * currentSpeedSample + (1 - SMOOTHING_FACTOR) * averageVerifySpeed;
                                            }
                                            else
                                            {
                                                averageVerifySpeed = currentSpeedSample;
                                            }
                                            totalBytesRemaining -= seek;
                                            timeRemaining = (long) (totalBytesRemaining / averageVerifySpeed);
                                            this.publishProgress(
                                                    new DownloadProgressInfo(
                                                            totalCompressedLength,
                                                            totalCompressedLength - totalBytesRemaining,
                                                            timeRemaining,
                                                            averageVerifySpeed)
                                                   );
                                        }
                                        startTime = currentTime;
                                        if (mCancelValidation)
                                            return true;
                                    }
                                    if (crc.getValue() != entry.mCRC32)
                                    {
                                        Log.e(Constants.TAG, "CRC does not match for entry: " + entry.mFileName);
                                        Log.e(Constants.TAG, "In file: " + entry.getZipFileName());
                                        return false;
                                    }
                                }
                                finally
                                {
                                    if (null != dis)
                                    {
                                        dis.close();
                                    }
                                }
                            }
                        }
                    }
                    catch (IOException e)
                    {
                        e.printStackTrace();
                        return false;
                    }
                }
                return true;
            }

            @Override
            protected void onProgressUpdate(DownloadProgressInfo... values)
            {
                onDownloadProgress(values[0]);
                super.onProgressUpdate(values);
            }

            @Override
            protected void onPostExecute(Boolean result)
            {
                if (result)
                {
                    mDashboard.setVisibility(View.INVISIBLE);
                    mCellMessage.setVisibility(View.GONE);
                    mStatusText.setText(R.string.text_validation_complete);
                    mPauseButton.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view)
                        {
                            finish();
                        }
                    });
                    mPauseButton.setText(android.R.string.ok);
                    
                    onCheckSuccess(true);
                }
                else
                {
                    mDashboard.setVisibility(View.INVISIBLE);
                    mCellMessage.setVisibility(View.GONE);
                    mStatusText.setText(R.string.text_validation_failed);
                    mPauseButton.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view)
                        {
                            finish();
                        }
                    });
                    mPauseButton.setText(android.R.string.cancel);

                    onCheckSuccess(false);
                }

                super.onPostExecute(result);
            }

        };
        validationTask.execute(new Object());
    }


    /**
     * If the download isn't present, we initialize the download UI. This ties
     * all of the controls into the remote service calls.
     */
    private void initializeDownloadUI()
    {
        mDownloaderClientStub = DownloaderClientMarshaller.CreateStub(this, getDownloadServiceClass());
        setContentView(R.layout.apkx_checker);

        mPB = (ProgressBar) findViewById(R.id.progressBar);
        mStatusText = (TextView) findViewById(R.id.statusText);
        mProgressFraction = (TextView) findViewById(R.id.progressAsFraction);
        mProgressPercent = (TextView) findViewById(R.id.progressAsPercentage);
        mAverageSpeed = (TextView) findViewById(R.id.progressAverageSpeed);
        mTimeRemaining = (TextView) findViewById(R.id.progressTimeRemaining);
        mDashboard = findViewById(R.id.downloaderDashboard);
        mCellMessage = findViewById(R.id.approveCellular);
        mPauseButton = (Button) findViewById(R.id.pauseButton);
        mWiFiSettingsButton = (Button) findViewById(R.id.wifiSettingsButton);

        mPauseButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view)
            {
                if (mStatePaused)
                {
                    mRemoteService.requestContinueDownload();
                }
                else
                {
                    mRemoteService.requestPauseDownload();
                }
                setButtonPausedState(!mStatePaused);
            }
        });

        mWiFiSettingsButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v)
            {
                startActivity(new Intent(Settings.ACTION_WIFI_SETTINGS));
            }
        });

        Button resumeOnCell = (Button) findViewById(R.id.resumeOverCellular);
        resumeOnCell.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view)
            {
                mRemoteService.setDownloadFlags(IDownloaderService.FLAGS_DOWNLOAD_OVER_CELLULAR);
                mRemoteService.requestContinueDownload();
                mCellMessage.setVisibility(View.GONE);
            }
        });
    }

	/**
	 * return information of expansion APKs
	 * <br>
	 * <br>
	 * * example:
	 * 
	 * <pre>
	 * return new XAPKFile[]{
	 * 	new XAPKFile(
	 * 		true, // true signifies a main file
	 * 		10101001, // the version of the APK that the file was uploaded against
	 * 		80611837L // the length of the file in bytes
	 * 	),
	 * 	new XAPKFile(
	 * 		false, // false signifies a patch file
	 * 		10101001, // the version of the APK that the patch file was uploaded against
	 * 		512860L // the length of the patch file in bytes
	 * 	)
	 * };
	 * </pre>
	 * 
	 * @return an array of Expansion APK information
	 */
	protected abstract XAPKFile[] getXAPKs();

	/**
	 * 
	 * @return
	 */
	@SuppressWarnings("rawtypes")
	protected abstract Class getActivityClass();

	/**
	 * 
	 * @return
	 */
	@SuppressWarnings("rawtypes")
	protected abstract Class getDownloadServiceClass();

	/**
	 * 
	 * @param success
	 */
	protected abstract void onCheckSuccess(boolean success);
}

DownloadAlarmReceiver.java

package kr.pe.meinside.android.apkx;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager.NameNotFoundException;

import com.google.android.vending.expansion.downloader.DownloaderClientMarshaller;

public abstract class DownloadAlarmReceiver extends BroadcastReceiver
{
    @Override
    public void onReceive(Context context, Intent intent)
    {
        try
        {
            DownloaderClientMarshaller.startDownloadServiceIfRequired(context, intent, getDownloadServiceClass());
        }
        catch (NameNotFoundException e)
        {
            e.printStackTrace();
        }       
    }
    
    @SuppressWarnings("rawtypes")
	abstract public Class getDownloadServiceClass();
}

DownloadService.java

package kr.pe.meinside.android.apkx;

import com.google.android.vending.expansion.downloader.impl.DownloaderService;

public abstract class DownloadService extends DownloaderService
{
	@Override
	abstract public String getPublicKey();

	@Override
	abstract public byte[] getSALT();

	@Override
	abstract public String getAlarmReceiverClassName();
}

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">APK Expansion Download Sample</string>

    <string name="text_paused_cellular">Would you like to enable downloading over cellular connections? Depending on your data plan, this may cost you money.</string>
    <string name="text_paused_cellular_2">If you choose not to enable downloading over cellular connections, the download will automatically resume when Wi-Fi is available.</string>
    <string name="text_button_resume_cellular">Resume download</string>
    <string name="text_button_wifi_settings">Wi-Fi settings</string>
    <string name="text_verifying_download">Verifying Download</string>
    <string name="text_validation_complete">Resource File Validation Complete.</string>
    <string name="text_validation_failed">Resource File Validation Failed.</string>
    <string name="text_button_pause">Pause Download</string>
    <string name="text_button_resume">Resume Download</string>
    <string name="text_button_cancel">Cancel</string>
    <string name="text_button_cancel_verify">Cancel Verification</string>

    <string name="notification_download_complete">Download complete</string>
    <string name="notification_download_failed">Download unsuccessful</string>

    <string name="state_unknown"></string>
    <string name="state_idle">Waiting for download to start</string>
    <string name="state_fetching_url">Looking for resources to download</string>
    <string name="state_connecting">Connecting to the download server</string>
    <string name="state_downloading">Downloading resources</string>
    <string name="state_completed">Download finished</string>
    <string name="state_paused_network_unavailable">Download paused because no network is available</string>
    <string name="state_paused_network_setup_failure">Download paused. Test a website in browser</string>
    <string name="state_paused_by_request">Download paused</string>
    <string name="state_paused_wifi_unavailable">Download paused because wifi is unavailable</string>
    <string name="state_paused_wifi_disabled">Download paused because wifi is disabled</string>
    <string name="state_paused_roaming">Download paused because you are roaming</string>
    <string name="state_paused_sdcard_unavailable">Download paused because the external storage is unavailable</string>
    <string name="state_failed_unlicensed">Download failed because you may not have purchased this app</string>
    <string name="state_failed_fetching_url">Download failed because the resources could not be found</string>
    <string name="state_failed_sdcard_full">Download failed because the external storage is full</string>
    <string name="state_failed_cancelled">Download cancelled</string>
    <string name="state_failed">Download failed</string>

    <string name="kilobytes_per_second">%1$s KB/s</string>
    <string name="time_remaining">Time remaining: %1$s</string>
    <string name="time_remaining_notification">%1$s left</string>

</resources>