Make scan button persistent

2026-02-09 21:23:29 +01:00
parent 8ad6bbf125
commit 061e0ae633
7 changed files with 280 additions and 55 deletions
@@ -0,0 +1,134 @@
+import 'package:flutter/foundation.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+import 'package:universal_ble/universal_ble.dart';
+import 'package:universal_ble_example/data/company_identifier_service.dart';
+
+/// Shared controller for BLE scan state so the scan button can be shown
+/// on both the scanner screen and the peripheral detail screen.
+class ScanController extends ChangeNotifier {
+  bool _isScanning = false;
+  bool get isScanning => _isScanning;
+
+  /// Syncs [isScanning] with the actual native state (e.g. after app restart).
+  Future<void> syncState() async {
+    final value = await UniversalBle.isScanning();
+    if (_isScanning != value) {
+      _isScanning = value;
+      notifyListeners();
+    }
+  }
+
+  Future<void> startScan() async {
+    if (_isScanning) return;
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final filter = await _loadFilterFromPrefs(prefs);
+      final platformConfig = _loadPlatformConfigFromPrefs(prefs);
+
+      await UniversalBle.startScan(
+        scanFilter: filter,
+        platformConfig: platformConfig,
+      );
+      _isScanning = true;
+      notifyListeners();
+    } catch (e) {
+      _isScanning = false;
+      notifyListeners();
+      rethrow;
+    }
+  }
+
+  Future<void> stopScan() async {
+    if (!_isScanning) return;
+    try {
+      await UniversalBle.stopScan();
+      _isScanning = false;
+      notifyListeners();
+    } catch (e) {
+      rethrow;
+    }
+  }
+
+  Future<ScanFilter?> _loadFilterFromPrefs(SharedPreferences prefs) async {
+    final services = prefs.getString('scan_filter_services') ?? '';
+    final namePrefix = prefs.getString('scan_filter_name_prefix') ?? '';
+    final manufacturerData =
+        prefs.getString('scan_filter_manufacturer_data') ?? '';
+
+    if (services.isEmpty &&
+        namePrefix.isEmpty &&
+        manufacturerData.isEmpty) {
+      return null;
+    }
+
+    await CompanyIdentifierService.instance.load();
+
+    final serviceUUids = <String>[];
+    if (services.isNotEmpty) {
+      for (final s in services.split(',').map((e) => e.trim())) {
+        if (s.isEmpty) continue;
+        try {
+          serviceUUids.add(BleUuidParser.string(s));
+        } on FormatException catch (_) {
+          continue;
+        }
+      }
+    }
+
+    final namePrefixes = namePrefix.isEmpty
+        ? <String>[]
+        : namePrefix.split(',').map((e) => e.trim()).toList();
+
+    final manufacturerDataFilters = <ManufacturerDataFilter>[];
+    if (manufacturerData.isNotEmpty) {
+      final companyService = CompanyIdentifierService.instance;
+      for (final s in manufacturerData
+          .split(',')
+          .map((e) => e.trim())
+          .where((s) => s.isNotEmpty)) {
+        final id = companyService.parseCompanyIdentifier(s);
+        if (id != null) {
+          manufacturerDataFilters.add(ManufacturerDataFilter(
+            companyIdentifier: id,
+          ));
+        }
+      }
+    }
+
+    if (serviceUUids.isEmpty &&
+        namePrefixes.isEmpty &&
+        manufacturerDataFilters.isEmpty) {
+      return null;
+    }
+
+    return ScanFilter(
+      withServices: serviceUUids,
+      withNamePrefix: namePrefixes,
+      withManufacturerData: manufacturerDataFilters,
+    );
+  }
+
+  PlatformConfig _loadPlatformConfigFromPrefs(SharedPreferences prefs) {
+    WebOptions? web;
+    if (kIsWeb) {
+      final webServices = prefs.getString('scan_filter_web_services') ?? '';
+      if (webServices.isNotEmpty) {
+        final list = webServices
+            .split(',')
+            .where((s) => s.trim().isNotEmpty)
+            .map((s) {
+          try {
+            return BleUuidParser.string(s.trim());
+          } catch (_) {
+            return s.trim();
+          }
+        }).toList();
+        web = WebOptions(optionalServices: list);
+      }
+    }
+    return PlatformConfig(
+      android: AndroidOptions(scanMode: AndroidScanMode.lowLatency),
+      web: web,
+    );
+  }
+}
@@ -6,12 +6,14 @@ import 'package:shared_preferences/shared_preferences.dart';
 import 'package:universal_ble/universal_ble.dart';
 import 'package:universal_ble_example/data/company_identifier_service.dart';
 import 'package:universal_ble_example/data/mock_universal_ble.dart';
+import 'package:universal_ble_example/data/scan_controller.dart';
 import 'package:universal_ble_example/home/widgets/ble_availability_icon.dart';
 import 'package:universal_ble_example/home/widgets/drawer.dart';
 import 'package:universal_ble_example/home/widgets/scan_filter_widget.dart';
 import 'package:universal_ble_example/home/widgets/scanned_devices_placeholder_widget.dart';
 import 'package:universal_ble_example/home/widgets/scanned_item_widget.dart';
 import 'package:universal_ble_example/peripheral_details/peripheral_detail_page.dart';
+import 'package:universal_ble_example/widgets/scan_controller_scope.dart';

 class ScannerScreen extends StatefulWidget {
  const ScannerScreen({super.key});
@@ -23,7 +25,8 @@ class ScannerScreen extends StatefulWidget {
 class _ScannerScreenState extends State<ScannerScreen> {
  final _bleDevices = <BleDevice>[];
  final _hiddenDevices = <BleDevice>[];
-  bool _isScanning = false;
+  ScanController? _scanController;
+  void _onScanStateChanged() => setState(() {});
  QueueType _queueType = QueueType.global;
  TextEditingController servicesFilterController = TextEditingController();
  TextEditingController namePrefixController = TextEditingController();
@@ -48,10 +51,6 @@ class _ScannerScreenState extends State<ScannerScreen> {

    _scanSubscription = UniversalBle.scanStream.listen(_handleScanResult);

-    UniversalBle.isScanning().then(
-      (isScanning) => setState(() => _isScanning = isScanning),
-    );
-
    // Get initial Bluetooth availability state
    UniversalBle.getBluetoothAvailabilityState().then((state) {
      if (mounted) {
@@ -92,38 +91,10 @@ class _ScannerScreenState extends State<ScannerScreen> {
  }

  Future<void> _startScan() async {
-    setState(() {
-      _bleDevices.clear();
-      _isScanning = true;
-    });
+    setState(() => _bleDevices.clear());
    try {
-      PlatformConfig platformConfig = PlatformConfig(
-        android: AndroidOptions(
-          scanMode: AndroidScanMode.lowLatency,
-        ),
-      );
-      if (kIsWeb && _webServicesController.text.isNotEmpty) {
-        List<String> webServices = _webServicesController.text
-            .split(',')
-            .where((s) => s.trim().isNotEmpty)
-            .map((s) {
-          try {
-            return BleUuidParser.string(s.trim());
-          } catch (_) {
-            return s.trim();
-          }
-        }).toList();
-        platformConfig.web = WebOptions(optionalServices: webServices);
-      }
-
-      await UniversalBle.startScan(
-        scanFilter: scanFilter,
-        platformConfig: platformConfig,
-      );
+      await _scanController?.startScan();
    } catch (e) {
-      setState(() {
-        _isScanning = false;
-      });
      showSnackbar(e.toString());
    }
  }
@@ -136,11 +107,13 @@ class _ScannerScreenState extends State<ScannerScreen> {
      final manufacturerData =
          prefs.getString('scan_filter_manufacturer_data') ?? '';
      final searchFilter = prefs.getString('scan_filter_search') ?? '';
+      final webServices = prefs.getString('scan_filter_web_services') ?? '';

      servicesFilterController.text = services;
      namePrefixController.text = namePrefix;
      manufacturerDataController.text = manufacturerData;
      _searchFilterController.text = searchFilter;
+      _webServicesController.text = webServices;

      // Reconstruct the scan filter if any values exist
      if (services.isNotEmpty ||
@@ -164,6 +137,8 @@ class _ScannerScreenState extends State<ScannerScreen> {
      await prefs.setString(
          'scan_filter_manufacturer_data', manufacturerDataController.text);
      await prefs.setString('scan_filter_search', _searchFilterController.text);
+      await prefs.setString(
+          'scan_filter_web_services', _webServicesController.text);
    } catch (e) {
      debugPrint('Failed to save scan filters: $e');
    }
@@ -247,10 +222,9 @@ class _ScannerScreenState extends State<ScannerScreen> {
      _deviceAdFlashTrigger.clear();
    });
    await _saveScanFilters();
-    if (_isScanning) {
-      await UniversalBle.stopScan();
+    if (_scanController?.isScanning == true) {
+      await _scanController?.stopScan();
      if (!mounted) return;
-      setState(() => _isScanning = false);
    }
    if (mounted) await _startScan();
  }
@@ -333,8 +307,7 @@ class _ScannerScreenState extends State<ScannerScreen> {

  Future<void> _tryAutoStartScan() async {
    // Only auto-start if Bluetooth is available and not already scanning
-    if (_isBluetoothAvailable && !_isScanning) {
-      // Check again to make sure we're not already scanning
+    if (_isBluetoothAvailable && _scanController?.isScanning != true) {
      final isScanning = await UniversalBle.isScanning();
      if (!isScanning && mounted) {
        await _startScan();
@@ -366,8 +339,16 @@ class _ScannerScreenState extends State<ScannerScreen> {
    if (mounted) super.setState(fn);
  }

+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    _scanController ??= ScanControllerScope.of(context)
+      ..addListener(_onScanStateChanged);
+  }
+
  @override
  void dispose() {
+    _scanController?.removeListener(_onScanStateChanged);
    servicesFilterController.dispose();
    namePrefixController.dispose();
    manufacturerDataController.dispose();
@@ -467,24 +448,23 @@ class _ScannerScreenState extends State<ScannerScreen> {
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 8.0, vertical: 4.0),
            child: FilledButton.icon(
-              onPressed: _isBluetoothAvailable
+              onPressed: _isBluetoothAvailable && _scanController != null
                  ? () async {
-                      if (_isScanning) {
-                        await UniversalBle.stopScan();
-                        setState(() {
-                          _isScanning = false;
-                        });
+                      if (_scanController!.isScanning) {
+                        await _scanController!.stopScan();
                      } else {
                        await _startScan();
                      }
                    }
                  : null,
              icon: Icon(
-                _isScanning ? Icons.stop_circle : Icons.play_arrow,
+                _scanController?.isScanning == true
+                    ? Icons.stop_circle
+                    : Icons.play_arrow,
                size: 20,
              ),
              label: Text(
-                _isScanning ? 'Stop Scan' : 'Start Scan',
+                _scanController?.isScanning == true ? 'Stop Scan' : 'Start Scan',
                style: const TextStyle(
                  fontSize: 14,
                  fontWeight: FontWeight.w600,
@@ -492,9 +472,13 @@ class _ScannerScreenState extends State<ScannerScreen> {
              ),
              style: FilledButton.styleFrom(
                backgroundColor:
-                    _isScanning ? colorScheme.error : colorScheme.primary,
+                    _scanController?.isScanning == true
+                        ? colorScheme.error
+                        : colorScheme.primary,
                foregroundColor:
-                    _isScanning ? colorScheme.onError : colorScheme.onPrimary,
+                    _scanController?.isScanning == true
+                        ? colorScheme.onError
+                        : colorScheme.onPrimary,
                padding: const EdgeInsets.symmetric(
                  horizontal: 16,
                  vertical: 12,
@@ -502,7 +486,7 @@ class _ScannerScreenState extends State<ScannerScreen> {
                shape: RoundedRectangleBorder(
                  borderRadius: BorderRadius.circular(8),
                ),
-                elevation: _isScanning ? 0 : 2,
+                elevation: _scanController?.isScanning == true ? 0 : 2,
              ),
            ),
          ),
@@ -781,7 +765,7 @@ class _ScannerScreenState extends State<ScannerScreen> {
                      ),
                    ),
                  )
-                : _isScanning && _bleDevices.isEmpty
+                : _scanController?.isScanning == true && _bleDevices.isEmpty
                    ? Center(
                        child: Column(
                          mainAxisAlignment: MainAxisAlignment.center,
@@ -803,7 +787,7 @@ class _ScannerScreenState extends State<ScannerScreen> {
                          ],
                        ),
                      )
-                    : !_isScanning && _bleDevices.isEmpty
+                    : _scanController?.isScanning != true && _bleDevices.isEmpty
                        ? ScannedDevicesPlaceholderWidget(onTap: _startScan)
                        : _filteredDevices.isEmpty
                            ? Center(
@@ -1,7 +1,14 @@
 import 'package:flutter/material.dart';
+import 'package:universal_ble_example/data/scan_controller.dart';
 import 'package:universal_ble_example/universal_ble_app.dart';

 void main() async {
+  WidgetsFlutterBinding.ensureInitialized();
  bool hasPermission = await initializeApp();
-  runApp(UniversalBleApp(hasPermission: hasPermission));
+  final scanController = ScanController();
+  await scanController.syncState();
+  runApp(UniversalBleApp(
+    hasPermission: hasPermission,
+    scanController: scanController,
+  ));
 }
@@ -3,10 +3,13 @@ import 'dart:io';
 import 'package:device_preview_screenshot/device_preview_screenshot.dart';
 import 'package:flutter/material.dart';
 import 'package:path_provider/path_provider.dart';
+import 'package:universal_ble_example/data/scan_controller.dart';
 import 'package:universal_ble_example/universal_ble_app.dart';

 void main() async {
  bool hasPermission = await initializeApp();
+  final scanController = ScanController();
+  await scanController.syncState();

  // On macOS: ~/Library/Containers/com.navideck.universalble/Data/Documents/screenshots
  final screenshotsDir = await getScreenshotsDirectory();
@@ -17,6 +20,7 @@ void main() async {
      enabled: true,
      builder: (context) => UniversalBleApp(
        hasPermission: hasPermission,
+        scanController: scanController,
        locale: DevicePreview.locale(context),
        builder: DevicePreview.appBuilder,
      ),
@@ -11,8 +11,10 @@ import 'package:universal_ble_example/peripheral_details/widgets/result_header_b
 import 'package:universal_ble_example/peripheral_details/widgets/result_widget.dart';
 import 'package:universal_ble_example/peripheral_details/widgets/services_list_widget.dart';
 import 'package:universal_ble_example/peripheral_details/widgets/services_side_widget.dart';
+import 'package:universal_ble_example/data/scan_controller.dart';
 import 'package:universal_ble_example/widgets/company_info_widget.dart';
 import 'package:universal_ble_example/widgets/responsive_view.dart';
+import 'package:universal_ble_example/widgets/scan_controller_scope.dart';

 class PeripheralDetailPage extends StatefulWidget {
  final BleDevice bleDevice;
@@ -26,6 +28,9 @@ class PeripheralDetailPage extends StatefulWidget {

 class _PeripheralDetailPageState extends State<PeripheralDetailPage> {
  late final bleDevice = widget.bleDevice;
+  ScanController? _scanController;
+  void _onScanStateChanged() => setState(() {});
+
  bool isConnected = false;
  GlobalKey<FormState> valueFormKey = GlobalKey<FormState>();
  List<BleService> discoveredServices = [];
@@ -91,8 +96,16 @@ class _PeripheralDetailPageState extends State<PeripheralDetailPage> {
    _loadFavoriteServices();
  }

+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    _scanController ??= ScanControllerScope.of(context)
+      ..addListener(_onScanStateChanged);
+  }
+
  @override
  void dispose() {
+    _scanController?.removeListener(_onScanStateChanged);
    _advertisementSubscription?.cancel();
    connectionStreamSubscription?.cancel();
    pairingStateSubscription?.cancel();
@@ -521,6 +534,56 @@ class _PeripheralDetailPageState extends State<PeripheralDetailPage> {
            centerTitle: false,
            elevation: 0,
            actions: [
+              // Persistent scan button
+              if (_scanController != null)
+                Padding(
+                  padding: const EdgeInsets.only(right: 8.0),
+                  child: FilledButton.icon(
+                    onPressed: () async {
+                      if (_scanController!.isScanning) {
+                        await _scanController!.stopScan();
+                      } else {
+                        try {
+                          await _scanController!.startScan();
+                        } catch (e) {
+                          if (!context.mounted) return;
+                          ScaffoldMessenger.of(context).showSnackBar(
+                            SnackBar(content: Text(e.toString())),
+                          );
+                        }
+                      }
+                    },
+                    icon: Icon(
+                      _scanController!.isScanning
+                          ? Icons.stop_circle
+                          : Icons.play_arrow,
+                      size: 20,
+                    ),
+                    label: Text(
+                      _scanController!.isScanning ? 'Stop Scan' : 'Start Scan',
+                      style: const TextStyle(
+                        fontSize: 14,
+                        fontWeight: FontWeight.w600,
+                      ),
+                    ),
+                    style: FilledButton.styleFrom(
+                      backgroundColor: _scanController!.isScanning
+                          ? colorScheme.error
+                          : colorScheme.primary,
+                      foregroundColor: _scanController!.isScanning
+                          ? colorScheme.onError
+                          : colorScheme.onPrimary,
+                      padding: const EdgeInsets.symmetric(
+                        horizontal: 16,
+                        vertical: 12,
+                      ),
+                      shape: RoundedRectangleBorder(
+                        borderRadius: BorderRadius.circular(8),
+                      ),
+                      elevation: _scanController!.isScanning ? 0 : 2,
+                    ),
+                  ),
+                ),
              Visibility.maintain(
                visible: _isLoading,
                child: Padding(
@@ -1,8 +1,10 @@
 import 'package:flutter/material.dart';
 import 'package:universal_ble/universal_ble.dart';
+import 'package:universal_ble_example/data/scan_controller.dart';
 import 'package:universal_ble_example/data/storage_service.dart';
 import 'package:universal_ble_example/home/permission_screen.dart';
 import 'package:universal_ble_example/home/scanner_screen.dart';
+import 'package:universal_ble_example/widgets/scan_controller_scope.dart';

 /// Initializes the app services and checks permissions.
 /// Returns whether the app has the required permissions.
@@ -17,19 +19,23 @@ Future<bool> initializeApp() async {

 class UniversalBleApp extends StatelessWidget {
  final bool hasPermission;
+  final ScanController scanController;
  final Locale? locale;
  final Widget Function(BuildContext, Widget?)? builder;

  const UniversalBleApp({
    super.key,
    required this.hasPermission,
+    required this.scanController,
    this.locale,
    this.builder,
  });

  @override
  Widget build(BuildContext context) {
-    return MaterialApp(
+    return ScanControllerScope(
+      controller: scanController,
+      child: MaterialApp(
      title: 'Universal BLE',
      debugShowCheckedModeBanner: false,
      locale: locale,
@@ -50,6 +56,7 @@ class UniversalBleApp extends StatelessWidget {
      ),
      themeMode: ThemeMode.system,
      home: hasPermission ? ScannerScreen() : const PermissionScreen(),
+      ),
    );
  }
 }
@@ -0,0 +1,26 @@
+import 'package:flutter/material.dart';
+import 'package:universal_ble_example/data/scan_controller.dart';
+
+/// Provides [ScanController] to the widget tree so the scan button
+/// can be shown on both the scanner and detail screens.
+class ScanControllerScope extends InheritedWidget {
+  const ScanControllerScope({
+    super.key,
+    required this.controller,
+    required super.child,
+  });
+
+  final ScanController controller;
+
+  static ScanController of(BuildContext context) {
+    final scope = context
+        .dependOnInheritedWidgetOfExactType<ScanControllerScope>();
+    assert(scope != null, 'No ScanControllerScope found in context');
+    return scope!.controller;
+  }
+
+  @override
+  bool updateShouldNotify(ScanControllerScope oldWidget) {
+    return controller != oldWidget.controller;
+  }
+}