如何将文件从我的应用程序上传到谷歌硬盘

Question

如何将文件从我的应用程序上传到Google云端硬盘。对于这个应用程序，我按照https://developers.google.com/drive/quickstart-android步骤正常工作拍照，然后图片将不会上传到googel驱动器。

public class MainActivity extends Activity {

static final int REQUEST_ACCOUNT_PICKER = 1;
  static final int REQUEST_AUTHORIZATION = 2;
  static final int CAPTURE_IMAGE = 3;

  private static Uri fileUri;
  private static Drive service;
  private GoogleAccountCredential credential;

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_list_item);
    credential = GoogleAccountCredential.usingOAuth2(this, DriveScopes.DRIVE);
    startActivityForResult(credential.newChooseAccountIntent(), REQUEST_ACCOUNT_PICKER);
  }

  @Override
  protected void onActivityResult(final int requestCode, final int resultCode, final Intent data) {
    switch (requestCode) {
    case REQUEST_ACCOUNT_PICKER:
      if (resultCode == RESULT_OK && data != null && data.getExtras() != null) {
        String accountName = data.getStringExtra(AccountManager.KEY_ACCOUNT_NAME);
        if (accountName != null) {
          credential.setSelectedAccountName(accountName);
          service = getDriveService(credential);
          startCameraIntent();
        }
      }
      break;
    case REQUEST_AUTHORIZATION:
      if (resultCode == Activity.RESULT_OK) {
        saveFileToDrive();
      } else {
        startActivityForResult(credential.newChooseAccountIntent(), REQUEST_ACCOUNT_PICKER);
      }
      break;
    case CAPTURE_IMAGE:
      if (resultCode == Activity.RESULT_OK) {
        saveFileToDrive();
      }
    }
  }

  private void startCameraIntent() {
    String mediaStorageDir = Environment.getExternalStoragePublicDirectory(
        Environment.DIRECTORY_PICTURES).getPath();
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US).format(new Date());
    fileUri = Uri.fromFile(new java.io.File(mediaStorageDir + java.io.File.separator + "IMG_"
        + timeStamp + ".jpg"));

    Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
    startActivityForResult(cameraIntent, CAPTURE_IMAGE);
  }

  private void saveFileToDrive() {
    Thread t = new Thread(new Runnable() {
      @Override
      public void run() {
        try {
          // File's binary content
          java.io.File fileContent = new java.io.File(fileUri.getPath());
          FileContent mediaContent = new FileContent("image/jpeg", fileContent);

          // File's metadata.
          File body = new File();
          body.setTitle(fileContent.getName());
          body.setMimeType("image/jpeg");

          File file = service.files().insert(body, mediaContent).execute();
          if (file != null) {
            showToast("Photo uploaded: " + file.getTitle());
            startCameraIntent();
          }
        } catch (UserRecoverableAuthIOException e) {
          startActivityForResult(e.getIntent(), REQUEST_AUTHORIZATION);
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
    });
    t.start();
  }

  private Drive getDriveService(GoogleAccountCredential credential) {
    return new Drive.Builder(AndroidHttp.newCompatibleTransport(), new GsonFactory(), credential)
        .build();
  }

  public void showToast(final String toast) {
    runOnUiThread(new Runnable() {
      @Override
      public void run() 
      {
        Toast.makeText(getApplicationContext(), toast, Toast.LENGTH_SHORT).show();
      }
    });
  }
}