google play - Expansion File (Android): "Download failed because the resources could not be found"

Question

I am facing a problem with an expansion file process, I do not know what the problem is. I hope if someone could help.

I have followed the steps by Google; yet I cannot assure I have done it correctly 100%.

/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 */

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;

import android.app.Activity;
import android.app.PendingIntent;
import android.content.Context;
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 java.io.DataInputStream;
import java.io.IOException;
import java.util.zip.CRC32;

/**
 * This is sample code for a project built against the downloader library. It
 * implements the IDownloaderClient that the client marshaler will talk to as
 * messages are delivered from the DownloaderService.
 */
public class ExpansionFileDownloaderActivity extends Activity implements IDownloaderClient {
    private static final String LOG_TAG = "LVLDownloader";
    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 IDownloaderService mRemoteService;

    private IStub mDownloaderClientStub;

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

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

    /**
     * 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.
     */
    private static class XAPKFile {
        public final boolean mIsMain;
        public final int mFileVersion;
        public final long mFileSize;

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

    /**
     * Here is where you place the data that the validator will use to determine
     * if the file was delivered correctly. This is encoded in the source code
     * so the application can easily determine whether the file has been
     * properly delivered without having to talk to the server. If the
     * application is using LVL for licensing, it may make sense to eliminate
     * these checks and to just rely on the server.
     */
    private static final XAPKFile[] xAPKS = {
            new XAPKFile(
                    true, // true signifies a main file
                    1, // the version of the APK that the file was uploaded
                    // against
                    102459993L // the length of the file in bytes
            )
    };

    /**
     * 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 : xAPKS) {
            String fileName = Helpers.getExpansionAPKFileName(this, xf.mIsMain, xf.mFileVersion);
            if (!Helpers.doesFileExist(this, fileName, xf.mFileSize, false))
                return false;
        }
        return true;
    }

    public static boolean expansionFilesDelivered(Context ctx) {
        for (XAPKFile xf : xAPKS) {
            String fileName = Helpers.getExpansionAPKFileName(ctx, xf.mIsMain, xf.mFileVersion);
            if (!Helpers.doesFileExist(ctx, fileName, xf.mFileSize, false))
                return false;
        }
        return true;
    }

    /**
     * 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;

    /**
     * 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 : xAPKS) {
                    String fileName = Helpers.getExpansionAPKFileName(
                            ExpansionFileDownloaderActivity.this,
                            xf.mIsMain, xf.mFileVersion);
                    if (!Helpers.doesFileExist(ExpansionFileDownloaderActivity.this, fileName,
                            xf.mFileSize, false))
                        return false;
                    fileName = Helpers
                            .generateSaveFileName(ExpansionFileDownloaderActivity.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
                                                    )
                                            );
                             

Answer 1

I was having the same problem and no matter what I tried it still didnt work. Finally I managed to download the apk expansion file. What I did was the following.

*Make sure your file size is correct (file size not disk size).

*Make sure versionCode matches with your manifest's versionCode.

*Make sure you have changed the SALT bytes.

Step by step:

1- Create a new app in the developer console.

2- Obtain the LVL Licence Key and repace it in your code.

3- Sign and export your application and create a zip with your expansion file without compression (compression: "store" in win rar).

4-Upload your app to google play but upload it in the Beta Testing Section. (without a production version listed, this is very important you must not have a production version saved in draft).

5- Create a google group with the people you want to allow beta acess and under the Beta Testing tab you must add that group.

5- Now its the scary part, you must click on publish. Your app will not show in google play, it will only be shown to your testing groups, TRUST ME. It should look like this:

*Note: Make sure you don't promote the beta to production or it will be shown, also notice I don't have a production version listed.

6- Under Beta Testing tab there is a link that a you must click in order to use the beta. After that just download the app from google play, you can just type your package name for example: https://play.google.com/store/apps/details?id=com.mydomain.myapp and the app will be installed along with the expansion package.

If you want to test the files download, install the app and then delete the obb file downloaded. This will start the obb download process.

Hope this helps, as it did for me! Cheers.