style: refactored esense_input into global singleton

lib/esense_input.dart

@@ -0,0 +1,83 @@
+import 'dart:async';
+import 'dart:io';
+
+import 'package:esense_flutter/esense.dart';
+import 'package:flutter/material.dart';
+import 'package:permission_handler/permission_handler.dart';
+
+class ESenseInput {
+  static final instance = ESenseInput._();
+
+  ESenseManager eSenseManager = ESenseManager('unknown');
+  ValueNotifier<String> deviceStatus = ValueNotifier('');
+
+  String eSenseDeviceName = '';
+  bool connected = false;
+  bool sampling = false;
+
+  ESenseInput._() {
+    _listenToESense();
+  }
+
+  Future<void> _askForPermissions() async {
+    if (!Platform.isAndroid && !Platform.isIOS) return;
+    if (!(await Permission.bluetoothScan.request().isGranted &&
+        await Permission.bluetoothConnect.request().isGranted)) {
+      print(
+          'WARNING - no permission to use Bluetooth granted. Cannot access eSense device.');
+    }
+    // for some strange reason, Android requires permission to location for Bluetooth to work.....?
+    if (Platform.isAndroid) {
+      if (!(await Permission.locationWhenInUse.request().isGranted)) {
+        print(
+            'WARNING - no permission to access location granted. Cannot access eSense device.');
+      }
+    }
+  }
+
+  StreamSubscription _listenToESense() {
+    // if you want to get the connection events when connecting,
+    // set up the listener BEFORE connecting...
+    return eSenseManager.connectionEvents.listen((event) {
+      print('CONNECTION event: $event');
+
+      // when we're connected to the eSense device, we can start listening to events from it
+      // if (event.type == ConnectionType.connected) _listenToESenseEvents();
+
+      connected = false;
+      switch (event.type) {
+        case ConnectionType.connected:
+          deviceStatus.value = 'connected';
+          connected = true;
+          break;
+        case ConnectionType.unknown:
+          deviceStatus.value = 'unknown';
+          break;
+        case ConnectionType.disconnected:
+          deviceStatus.value = 'disconnected';
+          sampling = false;
+          break;
+        case ConnectionType.device_found:
+          deviceStatus.value = 'device_found';
+          break;
+        case ConnectionType.device_not_found:
+          deviceStatus.value = 'device_not_found';
+          break;
+      }
+    });
+  }
+
+  Future<void> connectToESense(String deviceName) async {
+    if (!connected) {
+      await _askForPermissions();
+      print('Trying to connect to eSense device namend \'$deviceName\'');
+      eSenseDeviceName = deviceName;
+      eSenseManager.deviceName = deviceName;
+      connected = await eSenseManager.connect();
+      print('Trying to connect to eSense device namend \'${eSenseManager.deviceName}\'');
+
+      deviceStatus.value = connected ? 'connecting...' : 'connection failed';
+      print(deviceStatus.value);
+    }
+  }
+}

lib/level_selection.dart

@@ -1,10 +1,9 @@
 import 'dart:io';
 
-import 'package:esense_flutter/esense.dart';
 import 'package:file_picker/file_picker.dart';
 import 'package:flutter/material.dart';
-import 'package:permission_handler/permission_handler.dart';
 import 'package:sense_the_rhythm/esense_connect_dialog.dart';
+import 'package:sense_the_rhythm/esense_input.dart';
 import 'package:sense_the_rhythm/simfile.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
@@ -21,88 +20,12 @@ class _LevelSelectionState extends State<LevelSelection> {
   String? stepmaniaCoursesPath;
   List<Simfile> stepmaniaCoursesFolders = [];
 
-  String eSenseDeviceName = '';
-  ESenseManager? eSenseManager;
-  ValueNotifier<String> _deviceStatus = ValueNotifier('');
-  // String _deviceStatus = '';
-  bool connected = false;
-  bool sampling = false;
-
   @override
   void initState() {
     super.initState();
-    _listenToESense();
     loadFolderPath();
   }
 
-  Future<void> _askForPermissions() async {
-    if (!(await Permission.bluetoothScan.request().isGranted &&
-        await Permission.bluetoothConnect.request().isGranted)) {
-      print(
-          'WARNING - no permission to use Bluetooth granted. Cannot access eSense device.');
-    }
-    // for some strange reason, Android requires permission to location for Bluetooth to work.....?
-    if (Platform.isAndroid) {
-      if (!(await Permission.locationWhenInUse.request().isGranted)) {
-        print(
-            'WARNING - no permission to access location granted. Cannot access eSense device.');
-      }
-    }
-  }
-
-  Future<void> _listenToESense() async {
-    await _askForPermissions();
-
-    // if you want to get the connection events when connecting,
-    // set up the listener BEFORE connecting...
-    eSenseManager!.connectionEvents.listen((event) {
-      print('CONNECTION event: $event');
-
-      // when we're connected to the eSense device, we can start listening to events from it
-      // if (event.type == ConnectionType.connected) _listenToESenseEvents();
-
-      setState(() {
-        connected = false;
-        switch (event.type) {
-          case ConnectionType.connected:
-            _deviceStatus.value = 'connected';
-            connected = true;
-            break;
-          case ConnectionType.unknown:
-            _deviceStatus.value = 'unknown';
-            break;
-          case ConnectionType.disconnected:
-            _deviceStatus.value = 'disconnected';
-            sampling = false;
-            break;
-          case ConnectionType.device_found:
-            _deviceStatus.value = 'device_found';
-            break;
-          case ConnectionType.device_not_found:
-            _deviceStatus.value = 'device_not_found';
-            break;
-        }
-      });
-    });
-  }
-
-  Future<void> _connectToESense(String deviceName) async {
-    if (!connected) {
-      await _askForPermissions();
-      print('Trying to connect to eSense device...');
-      setState(() {
-        eSenseDeviceName = deviceName;
-      });
-      print(eSenseDeviceName);
-      eSenseManager = ESenseManager(eSenseDeviceName);
-      connected = await eSenseManager!.connect();
-      print('success!');
-
-      setState(() {
-        _deviceStatus.value = connected ? 'connecting...' : 'connection failed';
-      });
-    }
-  }
 
   Future<void> loadFolderPath() async {
     SharedPreferences prefs = await SharedPreferences.getInstance();
@@ -163,9 +86,9 @@ class _LevelSelectionState extends State<LevelSelection> {
                     context: context,
                     builder: (BuildContext context) {
                       return ESenseConnectDialog(
-                          deviceStatus: _deviceStatus,
+                          deviceStatus: ESenseInput.instance.deviceStatus,
                           connect: (String name) {
-                            _connectToESense(name);
+                            ESenseInput.instance.connectToESense(name);
                           });
                     },
                   ),