Feature selection in multiple shapefile layers

Question

I've followed the geotools selection lab tutorial. It works perfectly. Now I would like to add another layer, using another shapefile. So I used JFileDataStoreChooser to select another shapefile and added that layer to the existing map. Both layers are now shown on the map frame.

But when I click on a feature, only one type of feature is selected. For example, I have loaded a nodes layer and a lines layer. When I click on a node, it's selected but when I click on a line it's not selected.

I've seen that SimpleFeatureIterator uses featureSource. What should be the approach I follow in this kind of a scenario?

Answer 1

I've found a sample answer. Just find the available layers in the map and apply a filter for each layer separately. Following is the code I used.

    MapContent con = mapPane.getMapContent();
    con.layers();
    for (Layer l: con.layers()) {
        FeatureType schema = l.getFeatureSource().getSchema();
        String geometryPropertyName = schema.getGeometryDescriptor().getLocalName(); // "THE_GEOM"
        System.out.println("Layer : " + geometryPropertyName);

        Point screenPos = ev.getPoint();
    Rectangle screenRect = new Rectangle(screenPos.x-2, screenPos.y-2, 5, 5);
        AffineTransform screenToWorld = mapPane.getScreenToWorldTransform();
    Rectangle2D worldRect = screenToWorld.createTransformedShape(screenRect).getBounds2D();
        ReferencedEnvelope bbox = new ReferencedEnvelope(
            worldRect,
            mapPane.getMapContent().getCoordinateReferenceSystem());
         Filter filternew = ff.intersects(ff.property(geometryAttributeName), ff.literal(bbox));
        try {
            FeatureCollection self = l.getFeatureSource().getFeatures(filternew);
            FeatureIterator iter = self.features();
            System.out.println("New : " + iter.hasNext());
        } catch (IOException ex) {
            Logger.getLogger(NewJFrame.class.getName()).log(Level.SEVERE, null, ex);
        }

    }

    /*
     * Construct a 5x5 pixel rectangle centred on the mouse click position
     */
    Point screenPos = ev.getPoint();
    Rectangle screenRect = new Rectangle(screenPos.x-2, screenPos.y-2, 5, 5);

    /*
     * Transform the screen rectangle into bounding box in the coordinate
     * reference system of our map context. Note: we are using a naive method
     * here but GeoTools also offers other, more accurate methods.
     */
    AffineTransform screenToWorld = mapPane.getScreenToWorldTransform();
    Rectangle2D worldRect = screenToWorld.createTransformedShape(screenRect).getBounds2D();
    ReferencedEnvelope bbox = new ReferencedEnvelope(
            worldRect,
            mapPane.getMapContent().getCoordinateReferenceSystem());

    /*
     * Create a Filter to select features that intersect with
     * the bounding box
     */
    Filter filter = ff.intersects(ff.property(geometryAttributeName), ff.literal(bbox));

    /*
     * Use the filter to identify the selected features
     */
    try {
        SimpleFeatureCollection selectedFeatures =
                featureSource.getFeatures(filter);

        SimpleFeatureIterator iter = selectedFeatures.features();
        System.out.println("1 Has next ? " + iter.hasNext());


        SimpleFeatureCollection selectedFeatures2 =
                featureSource2.getFeatures(filter);

        SimpleFeatureIterator iter2 = selectedFeatures.features();
        System.out.println("2 Has next ? " + iter2.hasNext());




        Set<FeatureId> IDs = new HashSet<FeatureId>();
        try {
            while (iter.hasNext()) {
                SimpleFeature feature = iter.next();
                IDs.add(feature.getIdentifier());

                System.out.println("   " + feature.getIdentifier());
            }

        } finally {
            iter.close();
        }

        if (IDs.isEmpty()) {
            System.out.println("   no feature selected");
        }

        displaySelectedFeatures(IDs);

    } catch (Exception ex) {
        System.out.println(ex.getMessage());
        ex.printStackTrace();
        return;
    }