使用Google Drive备份和还原SQLite数据库

Question

我已经设法在SD卡上创建我的数据库备份并从那里恢复,但意识到我的备份的目的是确保数据的安全性,在这种情况下,如果物理设备本身损坏,丢失或自发地燃烧SD卡上的备份.因此,在这种情况下将备份放在与原始备份相同的位置,坦率地说,无法实现备份的目的.

因此,我想使用Google Drive作为保存db文件更安全的地方,而且它是免费的.我已经看了谷歌的快速启动演示,我工作得很好.但我仍然不知道如何为我的案子做到这一点.

我发现了一些代码,但仍然使用了一些弃用的方法,到目前为止,我只是在省略不推荐使用的区域时设法运行它,但它只在我的Google云端硬盘中创建了一个空白的二进制文件,所以我认为不推荐使用的区域是实际上传数据库备份内容的地方.如果有人可以提供帮助,那将非常感激.

我会把它留在下面,万一有人可以用它来更好地向我解释.我还在下面标记了已弃用的方法,它已接近尾声.

public class ExpectoPatronum extends Activity implements ConnectionCallbacks, OnConnectionFailedListener {

private static final String TAG = "MainActivity";
private GoogleApiClient api;
private boolean mResolvingError = false;
private DriveFile mfile;
private static final int DIALOG_ERROR_CODE =100;
private static final String DATABASE_NAME = "demodb";
private static final String GOOGLE_DRIVE_FILE_NAME = "sqlite_db_backup";

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

    // Create the Drive API instance
    api = new GoogleApiClient.Builder(this).addApi(Drive.API).addScope(Drive.SCOPE_FILE).
            addConnectionCallbacks(this).addOnConnectionFailedListener(this).build();
}

@Override
public void onStart() {
    super.onStart();
    if(!mResolvingError) {
        api.connect(); // Connect the client to Google Drive
    }
}

@Override
public void onStop() {
    super.onStop();
    api.disconnect(); // Disconnect the client from Google Drive
}

@Override
public void onConnectionFailed(ConnectionResult result) {
    Log.v(TAG, "Connection failed");
    if(mResolvingError) { // If already in resolution state, just return.
        return;
    } else if(result.hasResolution()) { // Error can be resolved by starting an intent with user interaction
        mResolvingError = true;
        try {
            result.startResolutionForResult(this, DIALOG_ERROR_CODE);
        } catch (SendIntentException e) {
            e.printStackTrace();
        }
    } else { // Error cannot be resolved. Display Error Dialog stating the reason if possible.
        ErrorDialogFragment fragment = new ErrorDialogFragment();
        Bundle args = new Bundle();
        args.putInt("error", result.getErrorCode());
        fragment.setArguments(args);
        fragment.show(getFragmentManager(), "errordialog");
    }
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if(requestCode == DIALOG_ERROR_CODE) {
        mResolvingError = false;
        if(resultCode == RESULT_OK) { // Error was resolved, now connect to the client if not done so.
            if(!api.isConnecting() && !api.isConnected()) {
                api.connect();
            }
        }
    }
}

@Override
public void onConnected(Bundle connectionHint) {
    Log.v(TAG, "Connected successfully");

    /* Connection to Google Drive established. Now request for Contents instance, which can be used to provide file contents.
       The callback is registered for the same. */
    Drive.DriveApi.newDriveContents(api).setResultCallback(contentsCallback);
}

final private ResultCallback<DriveApi.DriveContentsResult> contentsCallback = new ResultCallback<DriveApi.DriveContentsResult>() {

    @Override
    public void onResult(DriveApi.DriveContentsResult result) {
        if (!result.getStatus().isSuccess()) {
            Log.v(TAG, "Error while trying to create new file contents");
            return;
        }

        String mimeType = MimeTypeMap.getSingleton().getExtensionFromMimeType("db");
        MetadataChangeSet changeSet = new MetadataChangeSet.Builder()
                .setTitle(GOOGLE_DRIVE_FILE_NAME) // Google Drive File name
                .setMimeType(mimeType)
                .setStarred(true).build();
        // create a file on root folder
        Drive.DriveApi.getRootFolder(api)
                .createFile(api, changeSet, result.getDriveContents())
                .setResultCallback(fileCallback);
    }

};

final private ResultCallback<DriveFileResult> fileCallback = new ResultCallback<DriveFileResult>() {

    @Override
    public void onResult(DriveFileResult result) {
        if (!result.getStatus().isSuccess()) {
            Log.v(TAG, "Error while trying to create the file");
            return;
        }
        mfile = result.getDriveFile();
        mfile.open(api, DriveFile.MODE_WRITE_ONLY, null).setResultCallback(contentsOpenedCallback);
    }
};

final private ResultCallback<DriveApi.DriveContentsResult> contentsOpenedCallback = new ResultCallback<DriveApi.DriveContentsResult>() {

    @Override
    public void onResult(DriveApi.DriveContentsResult result) {

        if (!result.getStatus().isSuccess()) {
            Log.v(TAG, "Error opening file");
            return;
        }

        try {
            FileInputStream is = new FileInputStream(getDbPath());
            BufferedInputStream in = new BufferedInputStream(is);
            byte[] buffer = new byte[8 * 1024];
            DriveContents content = result.getDriveContents();
            BufferedOutputStream out = new BufferedOutputStream(content.getOutputStream());
            int n = 0;
            while( ( n = in.read(buffer) ) > 0 ) {
                out.write(buffer, 0, n);
            }

            in.close();
commitAndCloseContents is DEPRECATED -->/**mfile.commitAndCloseContents(api, content).setResultCallback(new ResultCallback<Status>() {   
                @Override
                public void onResult(Status result) {
                    // Handle the response status
                }
            });**/
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

};

private File getDbPath() {
    return this.getDatabasePath(DATABASE_NAME);
}

@Override
public void onConnectionSuspended(int cause) {
    // TODO Auto-generated method stub
    Log.v(TAG, "Connection suspended");

}

public void onDialogDismissed() {
    mResolvingError = false;
}

public static class ErrorDialogFragment extends DialogFragment {
    public ErrorDialogFragment() {}

    public Dialog onCreateDialog(Bundle savedInstanceState) {
        int errorCode = this.getArguments().getInt("error");
        return GooglePlayServicesUtil.getErrorDialog(errorCode, this.getActivity(), DIALOG_ERROR_CODE);
    }

    public void onDismiss(DialogInterface dialog) {
        ((ExpectoPatronum) getActivity()).onDialogDismissed();
    }
}
}

Answer 1

用于访问Google云端硬盘的两个API都处理二进制内容.因此,您唯一需要做的就是上传二进制数据库文件,为其提供正确的MIME类型和NAME(标题).
API的选择取决于您,GDAA的行为类似于"本地"实体,上传/下载由Google Play服务处理,REST Api更低级别,为您提供更多控制,但您必须处理网络问题(wifi开/关等),即你通常必须建立一个同步服务来这样做.使用GDAA,GooPlaySvcs为您完成.但我离题了.
我可以指出你最近的这个GitHub演示(GooPlaySvcs 7.00.+),我用来测试不同的REST/GDAA问题.MainActivity有点复杂,因为它允许在不同的Google帐户之间切换,但如果您遇到这些障碍,则可以使用REST或GDAA CRUD包装.

看看这一行.byte []缓冲区包含二进制JPEG数据,它带有"image/jpeg"mime类型(和基于时间的名称).如果使用如下结构将DB文件加载到byte []缓冲区中,则唯一需要做的事情是:

  private static final int BUF_SZ = 4096;

  static byte[] file2Bytes(File file) {
    if (file != null) try {
       return is2Bytes(new FileInputStream(file));
    } catch (Exception ignore) {}
   return null;
  }

  static byte[] is2Bytes(InputStream is) {
    byte[] buf = null;
    BufferedInputStream bufIS = null;
    if (is != null) try {
      ByteArrayOutputStream byteBuffer = new ByteArrayOutputStream();
      bufIS = new BufferedInputStream(is);
      buf = new byte[BUF_SZ];
      int cnt;
      while ((cnt = bufIS.read(buf)) >= 0) {
        byteBuffer.write(buf, 0, cnt);
      }
      buf = byteBuffer.size() > 0 ? byteBuffer.toByteArray() : null;
    } catch (Exception e) {le(e);}
    finally {
      try {
        if (bufIS != null) bufIS.close();
      } catch (Exception e) {le(e);}
    }
    return buf;
  }

我现在不记得SQLite DB的MIME类型了,但是我确信它可以完成,因为我只做了一次(不幸的是代码现在已经消失).我记得我实际上可以使用一些网络应用程序访问和修改SQL中的SQLite数据库.

祝好运

更新:
在我写完上面的咆哮后,我看了你正在谈论的演示.如果你有它工作,最简单的方法是在这里插入你的数据库文件,设置正确的MIME,你很高兴.带你去挑选.
并解决您的"已弃用"问题.GDAA仍在开发中,快速启动已有一年多了.这就是我们生活的世界:-)