Feature layer definition expression

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Sample viewer app

Limit the features displayed on a map with a definition expression.

Image of feature layer definition expression

Use case

Set a definition expression to filter out the features to be displayed. You might filter a dataset of tree quality selecting for only those trees which require maintenance or are damaged.

How to use the sample

Press the 'expression' button to limit the features requested from the feature layer to those specified by the SQL query definition expression. Click the 'expression' button again to de-press it and remove the definition expression on the feature layer, which returns all the records.

How it works

  1. Create a service feature table from a URL.
  2. Create a feature layer from the service feature table.
  3. Set the limit of the features on your feature layer using FeatureLayer.setDefinitionExpression("Expression").

Relevant API

  • FeatureLayer
  • ServiceFeatureTable

About the data

This map displays point features related to crime incidents that have been reported by city residents.

Tags

definition expression, filter, limit data, query, restrict data, SQL, where clause

Sample Code

FeatureLayerDefinitionExpressionSample.java
                                                                                                                                    
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/*
 * Copyright 2017 Esri.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package com.esri.samples.feature_layer_definition_expression;

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.ToggleButton;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

import com.esri.arcgisruntime.ArcGISRuntimeEnvironment;
import com.esri.arcgisruntime.data.ServiceFeatureTable;
import com.esri.arcgisruntime.geometry.Point;
import com.esri.arcgisruntime.geometry.SpatialReferences;
import com.esri.arcgisruntime.layers.FeatureLayer;
import com.esri.arcgisruntime.mapping.ArcGISMap;
import com.esri.arcgisruntime.mapping.BasemapStyle;
import com.esri.arcgisruntime.mapping.view.MapView;

public class FeatureLayerDefinitionExpressionSample extends Application {

  private MapView mapView;
  private FeatureLayer featureLayer;

  private final static String FEATURE_SERVICE_URL =
      "https://sampleserver6.arcgisonline.com/arcgis/rest/services/SF311/FeatureServer/0";

  @Override
  public void start(Stage stage) {

    try {
      // create stack pane and application scene
      StackPane stackPane = new StackPane();
      Scene scene = new Scene(stackPane);
      scene.getStylesheets().add(getClass().getResource("/feature_layer_definition_expression/style.css").toExternalForm());

      // set title, size, and add scene to stage
      stage.setTitle("Feature Layer Definition Expression Sample");
      stage.setWidth(800);
      stage.setHeight(700);
      stage.setScene(scene);
      stage.show();

      // authentication with an API key or named user is required to access basemaps and other location services
      String yourAPIKey = System.getProperty("apiKey");
      ArcGISRuntimeEnvironment.setApiKey(yourAPIKey);

      // create renderer toggle switch
      ToggleButton definitionSwitch = new ToggleButton();
      definitionSwitch.setText("expression");

      // set the definition expression
      definitionSwitch.selectedProperty().addListener((observable, oldValue, newValue) -> {
        if (definitionSwitch.isSelected()) {
          featureLayer.setDefinitionExpression("req_Type = 'Tree Maintenance or Damage'");
        } else {
          // reset the definition expression
          featureLayer.setDefinitionExpression("");
        }
      });

      // create service feature table
      final ServiceFeatureTable featureTable = new ServiceFeatureTable(FEATURE_SERVICE_URL);

      // create feature layer from service feature table
      featureLayer = new FeatureLayer(featureTable);

      // create a map with the topographic basemap style
      final ArcGISMap map = new ArcGISMap(BasemapStyle.ARCGIS_TOPOGRAPHIC);

      // add the feature layer to the map's operational layers
      map.getOperationalLayers().add(featureLayer);

      // create a map view and set the map to it
      mapView = new MapView();
      mapView.setMap(map);

      // starting location for sample
      Point startPoint = new Point(-13630845, 4544861, SpatialReferences.getWebMercator());

      // set the viewpoint for the map view
      mapView.setViewpointCenterAsync(startPoint, 150000);

      // add the map view and control panel to stack pane
      stackPane.getChildren().addAll(mapView, definitionSwitch);
      StackPane.setAlignment(definitionSwitch, Pos.TOP_LEFT);
      StackPane.setMargin(definitionSwitch, new Insets(10, 0, 0, 10));

    } catch (Exception e) {
      // on any error, display the stack trace
      e.printStackTrace();
    }
  }

  /**
   * Stops and releases all resources used in application.
   */
  @Override
  public void stop() {

    if (mapView != null) {
      mapView.dispose();
    }
  }

  /**
   * Opens and runs application.
   *
   * @param args arguments passed to this application
   */
  public static void main(String[] args) {

    Application.launch(args);
  }

}

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