Remove "Characteristic already notifying" error (#110)

lib/src/universal_ble_linux/universal_ble_linux.dart

@@ -199,19 +199,23 @@ class UniversalBleLinux extends UniversalBlePlatform {
   @override
   Future<void> setNotifiable(String deviceId, String service,
       String characteristic, BleInputProperty bleInputProperty) async {
-    final key = "$deviceId-$service-$characteristic";
-
     final char = _getCharacteristic(deviceId, service, characteristic);
+
+    String characteristicKey = "${deviceId}_${service}_$characteristic";
+
     if (bleInputProperty != BleInputProperty.disabled) {
-      if (char.notifying) throw Exception('Characteristic already notifying');
+      if (char.notifying) {
+        UniversalLogger.logInfo('$characteristic already notifying');
+        return;
+      }
 
       await char.startNotify();
 
-      if (_characteristicPropertiesSubscriptions[key] != null) {
-        _characteristicPropertiesSubscriptions[key]?.cancel();
+      if (_characteristicPropertiesSubscriptions[characteristicKey] != null) {
+        _characteristicPropertiesSubscriptions[characteristicKey]?.cancel();
       }
 
-      _characteristicPropertiesSubscriptions[key] =
+      _characteristicPropertiesSubscriptions[characteristicKey] =
           char.propertiesChanged.listen((List<String> properties) {
         for (String property in properties) {
           switch (property) {
@@ -230,9 +234,10 @@ class UniversalBleLinux extends UniversalBlePlatform {
         }
       });
     } else {
-      if (!char.notifying) throw Exception('Characteristic not notifying');
-      await char.stopNotify();
-      _characteristicPropertiesSubscriptions.remove(key)?.cancel();
+      if (char.notifying) await char.stopNotify();
+      _characteristicPropertiesSubscriptions
+          .remove(characteristicKey)
+          ?.cancel();
     }
   }
 

lib/src/universal_ble_web/universal_ble_web.dart

@@ -158,31 +158,22 @@ class UniversalBleWeb extends UniversalBlePlatform {
 
     String characteristicKey = "${deviceId}_${service}_$characteristic";
 
-    if (bleInputProperty == BleInputProperty.notification ||
-        bleInputProperty == BleInputProperty.indication) {
-      if (bleCharacteristic.isNotifying) {
-        throw Exception("Already listening to this characteristic");
-      }
-
+    if (bleInputProperty != BleInputProperty.disabled) {
       if (_characteristicStreamList[characteristicKey] != null) {
         _characteristicStreamList[characteristicKey]?.cancel();
       }
-
       await bleCharacteristic.startNotifications();
-
-      _characteristicStreamList[characteristicKey] = bleCharacteristic.value
-          .map((event) => event.buffer.asUint8List())
-          .listen((event) {
-        updateCharacteristicValue(deviceId, characteristic, event);
+      _characteristicStreamList[characteristicKey] =
+          bleCharacteristic.value.listen((ByteData event) {
+        updateCharacteristicValue(
+          deviceId,
+          characteristic,
+          event.buffer.asUint8List(),
+        );
       });
-    }
-    // Cancel Notification
-    else if (bleInputProperty == BleInputProperty.disabled) {
+    } else {
       await bleCharacteristic.stopNotifications();
-      _characteristicStreamList.removeWhere((key, value) {
-        if (key == characteristicKey) value.cancel();
-        return key == characteristicKey;
-      });
+      _characteristicStreamList.remove(characteristicKey)?.cancel();
     }
   }