PhysiGo/app/lib/walking/walking_permission.dart

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_activity_recognition/flutter_activity_recognition.dart';
import 'package:flutter_activity_recognition/models/permission_request_result.dart';
import 'package:geolocator/geolocator.dart';
import 'package:physigo/walking/walking_counter.dart';

class WalkingPermission extends StatelessWidget {
  WalkingPermission({Key? key}) : super(key: key);
  final FlutterActivityRecognition activityRecognition =
      FlutterActivityRecognition.instance;

  @override
  Widget build(BuildContext context) {
    return(
     FutureBuilder(
        future: Future.wait([isPermissionGrants(), _getPermissions()]),
        builder: (context, snapshot) {
          if (snapshot.connectionState == ConnectionState.waiting) {
            return CircularProgressIndicator();
          } else if (snapshot.hasError) {
            return Text("Error");
          } else {
            return WalkingCounter();
          }
        },
      )
    );
  }

  Future<void> isPermissionGrants() async {
    // Check if the user has granted permission. If not, request permission.
    PermissionRequestResult reqResult;
    reqResult = await activityRecognition.checkPermission();
    if (reqResult == PermissionRequestResult.PERMANENTLY_DENIED) {
      print('Permission is permanently denied.');
      return Future.error('Activity permissions are denied');
    } else if (reqResult == PermissionRequestResult.DENIED) {
      reqResult = await activityRecognition.requestPermission();
      if (reqResult != PermissionRequestResult.GRANTED) {
        print('Permission is denied.');
        return Future.error('Activity permissions are denied');
      }
    }
  }

  Future<void> _getPermissions() async {
    bool serviceEnabled;
    LocationPermission permission;

    // Test if location services are enabled.
    serviceEnabled = await Geolocator.isLocationServiceEnabled();
    if (!serviceEnabled) {
      // Location services are not enabled don't continue
      // accessing the position and request users of the
      // App to enable the location services.
      return Future.error('Location services are disabled.');
    }

    permission = await Geolocator.checkPermission();
    if (permission == LocationPermission.denied) {
      permission = await Geolocator.requestPermission();
      if (permission == LocationPermission.denied) {
        // Permissions are denied, next time you could try
        // requesting permissions again (this is also where
        // Android's shouldShowRequestPermissionRationale
        // returned true. According to Android guidelines
        // your App should show an explanatory UI now.
        return Future.error('Location permissions are denied');
      }
    }

    if (permission == LocationPermission.deniedForever) {
      // Permissions are denied forever, handle appropriately.
      return Future.error(
          'Location permissions are permanently denied, we cannot request permissions.');
    }
  }
}