Show labels on layer in 3D

// Copyright 2025 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 ShowLabelsOnLayerIn3d extends StatefulWidget {
  const ShowLabelsOnLayerIn3d({super.key});

  @override
  State<ShowLabelsOnLayerIn3d> createState() => _ShowLabelsOnLayerIn3dState();
}

class _ShowLabelsOnLayerIn3dState extends State<ShowLabelsOnLayerIn3d>
    with SampleStateSupport {
  // Create a controller for the scene view.
  final _sceneViewController = ArcGISSceneView.createController();
  // 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: Stack(
        children: [
          // Add a scene view to the widget tree and set a controller.
          ArcGISSceneView(
            controllerProvider: () => _sceneViewController,
            onSceneViewReady: onSceneViewReady,
          ),
          // Display a progress indicator and prevent interaction until state is ready.
          LoadingIndicator(visible: !_ready),
        ],
      ),
    );
  }

  Future<void> onSceneViewReady() async {
    // Create the portal item with the item ID for the web scene.
    const itemId = '850dfee7d30f4d9da0ebca34a533c169';
    final portalItem = PortalItem.withPortalAndItemId(
      portal: Portal.arcGISOnline(),
      itemId: itemId,
    );
    // Create the scene with the portal item.
    final scene = ArcGISScene.withItem(portalItem);
    // Set the scene to the scene view controller.
    _sceneViewController.arcGISScene = scene;
    // Load the scene.
    await scene.load();

    // Find the gas layer, then the gas sublayer.
    final gasLayer = scene.operationalLayers.firstWhere((l) => l.name == 'Gas');
    // Obtain the 'Gas Main' feature sublayer.
    final gasMainLayer = gasLayer.subLayerContents
        .whereType<FeatureLayer>()
        .firstWhere((l) => l.name == 'Gas Main');

    gasMainLayer.labelDefinitions.clear();
    // Set the feature layer's labelsEnabled property to true.
    gasMainLayer.labelsEnabled = true;

    // Create a text symbol for the label definition.
    final textSymbol = TextSymbol(color: Colors.orange, size: 16)
      ..haloColor = Colors.white
      ..haloWidth = 2.0;

    // Create a label definition from an arcade label expression and the text symbol.
    final labelDefinition = LabelDefinition(
      labelExpression: ArcadeLabelExpression(
        arcadeString: r'Text($feature.INSTALLATIONDATE, `DD MMM YY`)',
      ),
      textSymbol: textSymbol,
    );

    // Add the label definition to the feature layer's label definitions.
    gasMainLayer.labelDefinitions.add(labelDefinition);

    // Set the ready state variable to true to enable the sample UI.
    setState(() => _ready = true);
  }
}