我现在面临与扩展文件过程中存在问题，我不知道是什么问题。我希望如果有人可以帮助。

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

我按照步骤由谷歌;但我不能保证我正确100％做到了。

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
                                                    )
                                            );
                                        }
                                        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.VISIBLE);
                    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);
                } else {
                    mDashboard.setVisibility(View.VISIBLE);
                    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);
                }
                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, SampleDownloaderService.class);
        setContentView(R.layout.downloader_ui);

        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);
            }
        });

    }

    /**
     * Called when the activity is first create; we wouldn't create a layout in
     * the case where we have the file and are moving to another activity
     * without downloading.
     */
    @Override
    public 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 = ExpansionFileDownloaderActivity.this
                        .getIntent();
                Intent intentToLaunchThisActivityFromNotification = new Intent(
                        ExpansionFileDownloaderActivity
                                .this, ((Object) this).getClass() //..... this.getClass()
                );
                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(
                        ExpansionFileDownloaderActivity.this,
                        0, intentToLaunchThisActivityFromNotification,
                        PendingIntent.FLAG_UPDATE_CURRENT);
                // Request to start the download
                int startResult = DownloaderClientMarshaller.startDownloadServiceIfRequired(this,
                        pendingIntent, SampleDownloaderService.class);

                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();
        }

    }

    /**
     * Connect the stub to our service on start.
     */
    @Override
    protected void onStart() {
        if (null != mDownloaderClientStub) {
            mDownloaderClientStub.connect(this);
        }
        super.onStart();
    }

    /**
     * Disconnect the stub from our service on stop
     */
    @Override
    protected void onStop() {
        if (null != mDownloaderClientStub) {
            mDownloaderClientStub.disconnect(this);
        }
        super.onStop();
    }

    /**
     * Critical implementation detail. In onServiceConnected we create the
     * remote service and marshaler. This is how we pass the client information
     * back to the service so the client can be properly notified of changes. We
     * must do this every time we reconnect to the service.
     */
    @Override
    public void onServiceConnected(Messenger m) {
        mRemoteService = DownloaderServiceMarshaller.CreateProxy(m);
        mRemoteService.onClientUpdated(mDownloaderClientStub.getMessenger());
    }

    /**
     * The download state should trigger changes in the UI --- it may be useful
     * to show the state as being indeterminate at times. This sample can be
     * considered a guideline.
     */
    @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);
    }

    /**
     * Sets the state of the various controls based on the progressinfo object
     * sent from the downloader service.
     */
    @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));
    }

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

这是SampleDownloaderService类，

this is the SampleDownloaderService class,

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

/**
 * Created by Abdulkarim Kanaan on 22-Mar-14.
 */
public class SampleDownloaderService extends DownloaderService {
    // You must use the public key belonging to your publisher account
    public static final String BASE64_PUBLIC_KEY = "<Place Key provided by Google Play Publisher>";
    // You should also modify this salt
    public static final byte[] SALT = new byte[] { 1, 42, -12, -1, 54, 98,
            -100, -12, 43, 2, -8, -4, 9, 5, -106, -107, -33, 45, -1, 84
    };

    @Override
    public String getPublicKey() {
        return BASE64_PUBLIC_KEY;
    }

    @Override
    public byte[] getSALT() {
        return SALT;
    }

    @Override
    public String getAlarmReceiverClassName() {
        return SampleAlarmReceiver.class.getName();
    }
}

最后，这是主要活动创建方法，其中，执行检查以查看扩张文件是否存在或不

Finally, this is the Main Activity creation method, where the check is carried out to see whether the expansion file exists or not.

public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        String.valueOf(ExpansionFileDownloaderActivity.expansionFilesDelivered(this)));

       if (!ExpansionFileDownloaderActivity.expansionFilesDelivered(this)){
           startActivity(new Intent(this, ExpansionFileDownloaderActivity.class));
       }

        //startApp(); // Expansion files are available, start the app
    }

问题是，上传的扩展文件来谷歌播放，在程序启动时后，它表明下载过程将要进行。经过短暂的时期，它停止说下载失败，因为资源不能找到。当我把文件（OBB文件）的SD卡，如预期该应​​用程序的工作原理。不过，我现在想下载从谷歌播放文件。

the problem is that after uploading the expansion file to Google Play, when the program starts, it shows that downloading process is going to be carried out. After a short period, it stops saying that "Download failed because the resources could not be found". When I place the file (obb file) in the SD Card, the application works as expected. However, I am trying now to download the file from Google Play.

这是什么问题？

感谢你在前进，

推荐答案

我有同样的问题，不管是什么我想它仍然没有工作。 最后，我设法下载APK扩展文件。我所做的是以下几点。

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.

*请确保您的文件大小是正确的（文件大小不磁盘大小）。

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

*确保版本code你清单的版本code匹配。

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

*确保你已经改变了SALT字节。

*Make sure you have changed the SALT bytes.

步骤一步：

1，在开发者控制台创建一个新的应用程序。

1- Create a new app in the developer console.

2 - 获取LVL许可证密钥和repace它在你的code。

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

3注册和导出应用程序，并用您的扩展文件的zip没有COM pression（COM pression：在Win RAR存储）。

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

4，上传您的应用程序添加到Google Play，但把它上传在Beta测试部分。 （没有上市的量产版，这是非常重要的，你不能有保存在草稿的产品版本）。

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你要允许测试接取人民和beta测试标签必须添加组下创建一个谷歌组。

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现在，它的可怕的一部分，你必须点击发布。您的应用程序将无法在谷歌播放显示，它只会显示你的测试组，相信我。它应该是这样的：

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:

*注：请确保您不提倡测试到生产或将显示，还会注意到我没有量产版上市

*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处于测试卡有一个链接，一个你必须点击才能使用测试版。 之后，只需下载从谷歌播放应用程序，只需输入例如你的包的名字： https://play.google.com/store/apps/details?id=com.mydomain.myapp 和应用程序将随扩展包安装。

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.

。这将启动OBB下载过程。

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.

希望这会有所帮助，因为它为我做的！ 干杯。

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