protected void onPostExecute(Boolean result) {
      DLog.LOGD("LoadTrackerTask::onPostExecute: execution " + (result ? "successful" : "failed"));

      if (result) {
        // Done loading the tracker, update application status:
        updateApplicationStatus(AppStatus.APPSTATUS_INITED);
      } else {
        // Create dialog box for display error:
        AlertDialog dialogError = new AlertDialog.Builder(CopyOfQCARInitActivity_xxx.this).create();

        dialogError.setButton(
            DialogInterface.BUTTON_POSITIVE,
            "Close",
            new DialogInterface.OnClickListener() {
              public void onClick(DialogInterface dialog, int which) {
                // Exiting application:
                System.exit(1);
              }
            });

        // Show dialog box with error message:
        dialogError.setMessage("Failed to load tracker data.");
        dialogError.show();
      }
    }
  @Override
  protected void onDestroy() {
    DLog.LOGD("onDestroy");
    super.onDestroy();
    SysMng.OnDeInit();
    // Cancel potentially running tasks
    if (mInitVuforiaTask != null
        && mInitVuforiaTask.getStatus() != InitVuforiaTask.Status.FINISHED) {
      mInitVuforiaTask.cancel(true);
      mInitVuforiaTask = null;
    }

    if (mLoadTrackerTask != null
        && mLoadTrackerTask.getStatus() != LoadTrackerTask.Status.FINISHED) {
      mLoadTrackerTask.cancel(true);
      mLoadTrackerTask = null;
    }

    // Ensure that all asynchronous operations to initialize Vuforia
    // and loading the tracker datasets do not overlap:
    synchronized (mShutdownLock) {

      // Do application deinitialization in native code:
      deinitApplicationNative();

      // Unload texture:
      mTextures.clear();
      mTextures = null;

      // Destroy the tracking data set:
      destroyTrackerData();

      // Deinit the tracker:
      deinitTracker();

      // Deinitialize Vuforia SDK:
      QCAR.deinit();
    }

    System.gc();
  }
    protected void onPostExecute(Boolean result) {
      // Done initializing Vuforia, proceed to next application
      // initialization status:
      if (result) {
        DLog.LOGD("InitVuforiaTask::onPostExecute: Vuforia " + "initialization successful");
        updateApplicationStatus(AppStatus.APPSTATUS_INIT_TRACKER);

      } else {
        // Create dialog box for display error:
        AlertDialog dialogError = new AlertDialog.Builder(CopyOfQCARInitActivity_xxx.this).create();

        dialogError.setButton(
            DialogInterface.BUTTON_POSITIVE,
            "Close",
            new DialogInterface.OnClickListener() {
              public void onClick(DialogInterface dialog, int which) {
                // Exiting application:
                System.exit(1);
              }
            });

        String logMessage;

        if (mProgressValue == QCAR.INIT_DEVICE_NOT_SUPPORTED) {
          logMessage = "Failed to initialize Vuforia because this " + "device is not supported.";
        } else {
          logMessage = "Failed to initialize Vuforia.";
        }

        // Log error:
        DLog.LOGE("InitVuforiaTask::onPostExecute: " + logMessage + " Exiting.");

        // Show dialog box with error message:
        dialogError.setMessage(logMessage);
        dialogError.show();
      }
    }