Display clusters

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//
// Copyright 2024 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
//
//   https://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.
//

import 'package:arcgis_maps/arcgis_maps.dart';
import 'package:arcgis_maps_sdk_flutter_samples/common/common.dart';
import 'package:flutter/material.dart';

class DisplayClusters extends StatefulWidget {
  const DisplayClusters({super.key});

  @override
  State<DisplayClusters> createState() => _DisplayClustersState();
}

class _DisplayClustersState extends State<DisplayClusters>
    with SampleStateSupport {
  // Create a map view controller.
  final _mapViewController = ArcGISMapView.createController();
  late ArcGISMap _map;
  late FeatureLayer _featureLayer;
  // A flag to track whether feature clustering is enabled to display in the UI.
  var _featureReductionEnabled = false;
  // A flag for when the map view is ready and controls can be used.
  var _ready = false;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SafeArea(
        top: false,
        left: false,
        right: false,
        child: Stack(
          children: [
            Column(
              children: [
                Expanded(
                  // Add a map view to the widget tree and set a controller.
                  child: ArcGISMapView(
                    controllerProvider: () => _mapViewController,
                    onMapViewReady: onMapViewReady,
                    onTap: onTap,
                  ),
                ),
                Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  spacing: 10,
                  children: [
                    // Add a button to toggle feature clustering.
                    ElevatedButton(
                      onPressed: toggleFeatureClustering,
                      child: const Text('Toggle feature clustering'),
                    ),
                    // Display the current feature reduction state.
                    Text(
                      _featureReductionEnabled
                          ? 'Feature Reduction: On'
                          : 'Feature Reduction: Off',
                    ),
                  ],
                ),
              ],
            ),
            // Display a progress indicator and prevent interaction until state is ready.
            LoadingIndicator(visible: !_ready),
          ],
        ),
      ),
    );
  }

  Future<void> onMapViewReady() async {
    // Get the power plants web map from the default portal.
    final portal = Portal.arcGISOnline();
    final portalItem = PortalItem.withPortalAndItemId(
      portal: portal,
      itemId: '8916d50c44c746c1aafae001552bad23',
    );
    // Load the portal item.
    await portalItem.load();
    // Create a map from the portal item.
    _map = ArcGISMap.withItem(portalItem);
    // Set the map to the map view controller.
    _mapViewController.arcGISMap = _map;
    // Load the map.
    await _map.load();
    // Get the power plant feature layer once the map has finished loading.
    if (_map.operationalLayers.isNotEmpty &&
        _map.operationalLayers.first is FeatureLayer) {
      // Get the first layer from the web map a feature layer.
      _featureLayer = _map.operationalLayers.first as FeatureLayer;
      if (_featureLayer.featureReduction != null) {
        // Set the ready state variable to true to enable the sample UI.
        // Set the feature reduction flag to the current state of the feature
        setState(() {
          _ready = true;
          _featureReductionEnabled = _featureLayer.featureReduction!.enabled;
        });
      } else {
        showMessageDialog(
          'Feature layer does not have feature reduction enabled.',
          title: 'Warning',
        );
      }
    } else {
      showMessageDialog(
        'Unable to access a feature layer on the web map.',
        title: 'Warning',
      );
    }
  }

  Future<void> onTap(Offset localPosition) async {
    // Clear any existing selected features.
    _featureLayer.clearSelection();
    // Perform an identify result on the map view controller, using the feature layer and tapped location.
    final identifyLayerResult = await _mapViewController.identifyLayer(
      _featureLayer,
      screenPoint: localPosition,
      tolerance: 12,
    );
    // Get the aggregate geoelements from the identify result.
    final aggregateGeoElements =
        identifyLayerResult.geoElements.whereType<AggregateGeoElement>();
    if (aggregateGeoElements.isEmpty) return;
    // Select the first aggregate geoelement.
    final aggregateGeoElement = aggregateGeoElements.first;
    aggregateGeoElement.isSelected = true;

    // Get the list of geoelements associated with the aggregate geoelement.
    final geoElements = await aggregateGeoElement.getGeoElements();
    // Display a dialog with information about the geoelements.
    showResultsDialog(geoElements);
  }

  void showResultsDialog(List<GeoElement> geoElements) {
    // Create a dialog that lists the count and names of the provided list of geoelements.
    showDialog(
      context: context,
      builder: (context) {
        return AlertDialog(
          title: const Text('Contained GeoElements'),
          content: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.start,
            spacing: 10,
            children: [
              Text(
                'Total GeoElements: ${geoElements.length}',
                style: Theme.of(context).textTheme.titleMedium,
              ),
              SizedBox(
                height: 200,
                child: SingleChildScrollView(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children:
                        geoElements
                            .map(
                              (geoElement) => Text(
                                geoElement.attributes['name'] ??
                                    'Geoelement: ${geoElements.indexOf(geoElement)}}',
                              ),
                            )
                            .toList(),
                  ),
                ),
              ),
            ],
          ),
        );
      },
    );
  }

  void toggleFeatureClustering() {
    if (_featureLayer.featureReduction != null) {
      // Toggle the feature reduction.
      final featureReduction = _featureLayer.featureReduction!;
      featureReduction.enabled = !featureReduction.enabled;
      setState(() => _featureReductionEnabled = featureReduction.enabled);
    }
  }
}