如何将图层添加到MapContent但不使地图闪烁

Question

当我向mapcontent添加新图层时，屏幕闪烁。怎么不这样

打开shp文件并显示地图后。我向MapContent添加了新图层，如下所示：每次添加新图层时，屏幕都会闪烁一次：

    public class AddLayer extends SafeAction {

    private File sourceFile;
    private SimpleFeatureSource featureSource;

    public AddLayer(String name) {
        super(name);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void action(ActionEvent e) throws Throwable {
        addLayer();
    }

方法添加层

    private void addLayer() throws IOException {
        sourceFile = JFileDataStoreChooser.showOpenFile("shp", null);
        if (sourceFile == null) {
            return;
        }
        FileDataStore store = FileDataStoreFinder.getDataStore(sourceFile);
        featureSource = store.getFeatureSource();
        Style style = SLD.createSimpleStyle(featureSource.getSchema());
        Layer layer = new FeatureLayer(featureSource, style);
        layer.setTitle("Add Layer: " + MapUI.map.layers().size());

        // MapUI.map is MapContent
        MapUI.map.layers().add(layer);
}

即使我按如下方法在MapContent上绘制一个点，每次单击以选择屏幕绘制点时，它们也会闪烁：

    public class AddClickPoint {

    public void action(MapMouseEvent ev) {
        addClickPoint(ev);
    }

    private void addClickPoint(MapMouseEvent ev) {
    DirectPosition2D pos = ev.getMapPosition();
    double x = pos.x;
    double y = pos.y;

    SimpleFeatureTypeBuilder builder = new SimpleFeatureTypeBuilder();
    builder.setName("MyFeatureType");
    builder.setCRS(DefaultGeographicCRS.WGS84); // set crs
    builder.add("location", MultiPoint.class); // add geometry

    // build the type
    SimpleFeatureType TYPE = builder.buildFeatureType();
    // create features using the type defined
    SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(TYPE);

创建1点

    GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory(null);
    Coordinate coord = new Coordinate(x, y);
    Point point = geometryFactory.createPoint(coord);

    DefaultFeatureCollection featureCollection = new DefaultFeatureCollection();

    featureBuilder.add(point);
    SimpleFeature feature = featureBuilder.buildFeature("FeaturePoint");
    featureCollection.add(feature); // Add feature 1, 2, 3, etc

    Style style = SLD.createPointStyle("circle", Color.BLUE, Color.BLUE, 0.3f, 15);
    Layer layer = new FeatureLayer(featureCollection, style);
    layer.setTitle("Click Point");
    MapUI.map.layers().add(layer);
}
}