Error with generating parameters for downloading a map for use offline?

[CoraColeman]

Hello, I am trying to download a map for offline use but am running into trouble with generating the parameters as per this error I get (I have included my code also):

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_offline);

    // inflate MapView from layout
    aMapView = (MapView) findViewById(R.id.mapView);
    map = new ArcGISMap(Basemap.Type.LIGHT_GRAY_CANVAS_VECTOR, 48.6596, -113.7870, 9);
    aMapView.setMap(map);
    // create a graphics overlay and symbol to mark the extent
    mGraphicsOverlay = new GraphicsOverlay();
    aMapView.getGraphicsOverlays().add(mGraphicsOverlay);

    mProgressLayout = (RelativeLayout) findViewById(R.id.progressLayout);
    final ProgressBar progressBar = (ProgressBar) findViewById(R.id.taskProgressBar);
    mProgressTextView = (TextView) findViewById(R.id.progressTextView);

    // get the callout that shows attributes
    //aCallout = aMapView.getCallout();
    // layer 0, facilities
    table0 = new ServiceFeatureTable(getResources().getString(R.string.layer0_url));
    final FeatureLayer featureLayer0 = new FeatureLayer(table0);
    map.getOperationalLayers().add(featureLayer0);
    // get the callout that shows attributes
    //aCallout = aMapView.getCallout();
    // layer 1, trails
    table1 = new ServiceFeatureTable(getResources().getString(R.string.layer1_url));
    final FeatureLayer featureLayer1 = new FeatureLayer(table1);
    map.getOperationalLayers().add(featureLayer1);

    // create a graphics overlay and symbol to mark the extent
    final GraphicsOverlay graphicsOverlay = new GraphicsOverlay();
    aMapView.getGraphicsOverlays().add(graphicsOverlay);
    final SimpleLineSymbol boundarySymbol = new SimpleLineSymbol(SimpleLineSymbol.Style.SOLID, Color.RED, 5);

    final Button startdownload = (Button) findViewById(R.id.startdownload);
    // create a geodatabase sync task
    final GeodatabaseSyncTask geodatabaseSyncTask = new GeodatabaseSyncTask(getString(R.string.glacier_sync));
    geodatabaseSyncTask.loadAsync();
    geodatabaseSyncTask.addDoneLoadingListener(() -> {

        // generate the geodatabase sync task
        startdownload.setOnClickListener(new View.OnClickListener() {
            @Override public void onClick(View v) {

                // show the progress layout
                progressBar.setProgress(0);
                mProgressLayout.setVisibility(View.VISIBLE);

                // clear any previous operational layers and graphics if button clicked more than once
                map.getOperationalLayers().clear();
                graphicsOverlay.getGraphics().clear();

                // show the extent used as a graphic
                Envelope extent = aMapView.getVisibleArea().getExtent();
                Graphic boundary = new Graphic(extent, boundarySymbol);
                graphicsOverlay.getGraphics().add(boundary);

                // create generate geodatabase parameters for the current extent
                final ListenableFuture<GenerateGeodatabaseParameters> defaultParameters = geodatabaseSyncTask
                        .createDefaultGenerateGeodatabaseParametersAsync(extent);
                defaultParameters.addDoneListener(new Runnable() {
                    @Override public void run() {
                        try {
                            // set parameters and don't include attachments
                    ******* GenerateGeodatabaseParameters parameters = defaultParameters.get();


                            // set the sync model to per layer
                            parameters.setSyncModel(SyncModel.PER_LAYER);

                            // define the layers and features to include
                            int facilities = 1;
                            int trails = 3;

                            // Clear and re-create the layer options
                            parameters.getLayerOptions().clear();
                            parameters.getLayerOptions().add(new GenerateLayerOption(facilities));
                            parameters.getLayerOptions().add(new GenerateLayerOption(trails));

                            parameters.setReturnAttachments(false);

                            /*
                            // define the local path where the geodatabase will be stored
                            final String localGeodatabasePath =
                                    getCacheDir().toString() + File.separator + getString(R.string.file_name);


                            // create and start the job
                            final GenerateGeodatabaseJob generateGeodatabaseJob = geodatabaseSyncTask
                                    .generateGeodatabaseAsync(parameters, localGeodatabasePath);
                            generateGeodatabaseJob.start();
                            mProgressTextView.setText(getString(R.string.progress_started));

                            // update progress
                            generateGeodatabaseJob.addProgressChangedListener(() -> {
                                progressBar.setProgress(generateGeodatabaseJob.getProgress());
                                mProgressTextView.setText(getString(R.string.progress_fetching));
                            });

                            // get geodatabase when done
                            generateGeodatabaseJob.addJobDoneListener(new Runnable() {
                                @Override public void run() {
                                    mProgressLayout.setVisibility(View.INVISIBLE);
                                    if (generateGeodatabaseJob.getStatus() == Job.Status.SUCCEEDED) {
                                        final Geodatabase geodatabase = generateGeodatabaseJob.getResult();
                                        geodatabase.loadAsync();
                                        geodatabase.addDoneLoadingListener(new Runnable() {
                                            @Override public void run() {
                                                if (geodatabase.getLoadStatus() == LoadStatus.LOADED) {
                                                    mProgressTextView.setText(getString(R.string.progress_done));
                                                    for (GeodatabaseFeatureTable geodatabaseFeatureTable : geodatabase
                                                            .getGeodatabaseFeatureTables()) {
                                                        geodatabaseFeatureTable.loadAsync();
                                                        map.getOperationalLayers().add(new FeatureLayer(geodatabaseFeatureTable));
                                                    }
                                                    startdownload.setVisibility(View.GONE);
                                                    Log.i(TAG, "Local geodatabase stored at: " + localGeodatabasePath);
                                                } else {
                                                    Log.e(TAG, "Error loading geodatabase: " + geodatabase.getLoadError().getMessage());
                                                }
                                            }
                                        });
                                        // unregister since we're not syncing
                                        ListenableFuture unregisterGeodatabase = geodatabaseSyncTask
                                                .unregisterGeodatabaseAsync(geodatabase);
                                        unregisterGeodatabase.addDoneListener(new Runnable() {
                                            @Override public void run() {
                                                Log.i(TAG, "Geodatabase unregistered since we wont be editing it in this sample.");
                                                Toast.makeText(OfflineActivity.this,
                                                        "Geodatabase unregistered since we wont be editing it in this sample.",
                                                        Toast.LENGTH_LONG).show();
                                            }
                                        });
                                    } else if (generateGeodatabaseJob.getError() != null) {
                                        Log.e(TAG, "Error generating geodatabase: " + generateGeodatabaseJob.getError().getMessage());
                                    } else {
                                        Log.e(TAG, "Unknown Error generating geodatabase");
                                    }
                                }
                            });*/
                        } catch (InterruptedException | ExecutionException e) {
                            Log.e(TAG, "Error generating geodatabase parameters : " + e.getMessage());
                        }
                    }
                });
            }
        });
    });
}
E/CRGdb: Error generating geodatabase parameters : com.esri.arcgisruntime.ArcGISRuntimeException: Invalid response

*******I have commented out portions of the code because it was returning this error each time and I wanted to know when it began (apparently it was after this line: 

                            GenerateGeodatabaseParameters parameters = defaultParameters.get();

[khalligan]

I realize this thread is ancient, but curious if anyone else has encountered this or has a solution?  I am having the same issue when upgrading an app to 100.*  The specific error message when running the .get() method is: "extent geometry and spatial reference must be non-null.  The createDefaultGenerateGeodatabaseParametersAsync method doesn't take a spatial reference parameter and I am passing an extent into the the method, so the error message doesn't make sense in this context.