Monitor changes to map load status

// Copyright 2026 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 'dart:async';
import 'package:arcgis_maps/arcgis_maps.dart';
import 'package:arcgis_maps_sdk_flutter_samples/common/common.dart';
import 'package:flutter/material.dart';

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

  @override
  State<MonitorChangesToMapLoadStatus> createState() =>
      _MonitorChangesToMapLoadStatusState();
}

class _MonitorChangesToMapLoadStatusState
    extends State<MonitorChangesToMapLoadStatus>
    with SampleStateSupport {
  // Create a controller for the map view.
  final _mapViewController = ArcGISMapView.createController();

  // Subscription for map load status changes.
  StreamSubscription<LoadStatus>? _loadStatusSubscription;

  // A variable indicating the load status of the map.
  var _mapLoadStatus = 'Unknown';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: [
          // Add a map view to the widget tree and set a controller.
          ArcGISMapView(
            controllerProvider: () => _mapViewController,
            onMapViewReady: onMapViewReady,
          ),
          // Display the status of the current map.
          MapBanner(text: 'Load Status: $_mapLoadStatus'),
        ],
      ),
    );
  }

  @override
  void dispose() {
    // Cancel the load status subscription when the widget is disposed.
    _loadStatusSubscription?.cancel().ignore();
    super.dispose();
  }

  // Updates the displayed map load status based on the current load state.
  void updateMapStatus(LoadStatus status) {
    setState(() {
      _mapLoadStatus = switch (status) {
        LoadStatus.notLoaded => 'Not Loaded',
        LoadStatus.loading => 'Loading',
        LoadStatus.loaded => 'Loaded',
        LoadStatus.failedToLoad => 'Failed',
        _ => 'Unknown',
      };
    });
  }

  void onMapViewReady() {
    // Create a map with an imagery basemap style
    final map = ArcGISMap.withBasemapStyle(.arcGISImagery);

    // Set the map to the map view controller.
    _mapViewController.arcGISMap = map;

    // Monitor changes to the map's load status.
    _loadStatusSubscription = map.onLoadStatusChanged.listen(updateMapStatus);
  }
}