Nullsafety

lib/characteristic.dart

@@ -69,7 +69,7 @@ class Characteristic extends InternalCharacteristic {
   /// The value can be written only if [isWritableWithResponse] or
   /// [isWritableWithoutResponse] is `true` and argument [withResponse] is
   /// set accordingly.
-  Future<void> write(
+  Future<Characteristic?> write(
     Uint8List value,
     bool withResponse, {
     String? transactionId,

lib/peripheral.dart

@@ -143,7 +143,7 @@ class Peripheral {
   /// [serviceUuid]. Optional [transactionId] could be used to cancel operation.
   ///
   /// Will result in error if discovery was not done during this connection.
-  Future<Characteristic> writeCharacteristic(
+  Future<Characteristic?> writeCharacteristic(
     String serviceUuid,
     String characteristicUuid,
     Uint8List value,

lib/service.dart

@@ -37,7 +37,7 @@ class Service extends InternalService {
   /// [Characteristic.isWritableWithResponse] or
   /// [Characteristic.isWritableWithoutResponse] is `true` and
   /// [withResponse] is specified accordingly can be written to.
-  Future<Characteristic> writeCharacteristic(
+  Future<Characteristic?> writeCharacteristic(
     String characteristicUuid,
     Uint8List value,
     bool withResponse, {

lib/src/_managers_for_classes.dart

@@ -52,7 +52,7 @@ abstract class ManagerForPeripheral {
     String transactionId,
   );
 
-  Future<Characteristic> writeCharacteristicForDevice(
+  Future<Characteristic?> writeCharacteristicForDevice(
       Peripheral peripheral,
       String serviceUuid,
       String characteristicUuid,
@@ -101,7 +101,7 @@ abstract class ManagerForService {
     String transactionId,
   );
 
-  Future<Characteristic> writeCharacteristicForService(
+  Future<Characteristic?> writeCharacteristicForService(
     Peripheral peripheral,
     InternalService service,
     String characteristicUuid,
@@ -145,7 +145,7 @@ abstract class ManagerForCharacteristic {
     String transactionId,
   );
 
-  Future<void> writeCharacteristicForIdentifier(
+  Future<Characteristic?> writeCharacteristicForIdentifier(
     Peripheral peripheral,
     InternalCharacteristic characteristic,
     Uint8List value,

lib/src/bridge/bluetooth_state_mixin.dart

@@ -1,9 +1,11 @@
 part of _internal;
 
 mixin BluetoothStateMixin on FlutterBLE {
-  final Stream<dynamic> _adapterStateChanges =
-      const EventChannel(ChannelName.adapterStateChanges)
-          .receiveBroadcastStream();
+  final Stream<String> _adapterStateChanges =
+    const EventChannel(ChannelName.adapterStateChanges)
+      .receiveBroadcastStream()
+      .where((event) => event is String)
+      .cast<String>();
 
   Future<void> enableRadio(String transactionId) async {
     await _methodChannel.invokeMethod(
@@ -26,7 +28,7 @@ mixin BluetoothStateMixin on FlutterBLE {
   }
 
   Future<BluetoothState> state() => _methodChannel
-      .invokeMethod(MethodName.getState)
+      .invokeMethod<String>(MethodName.getState)
       .then(_mapToBluetoothState);
 
   Stream<BluetoothState> observeBluetoothState(bool emitCurrentValue) async* {
@@ -37,7 +39,7 @@ mixin BluetoothStateMixin on FlutterBLE {
     yield* _adapterStateChanges.map(_mapToBluetoothState);
   }
 
-  BluetoothState _mapToBluetoothState(dynamic rawValue) {
+  BluetoothState _mapToBluetoothState(String? rawValue) {
     switch (rawValue) {
       case "Unknown":
         return BluetoothState.UNKNOWN;

lib/src/bridge/characteristics_mixin.dart

@@ -11,23 +11,23 @@ mixin CharacteristicsMixin on FlutterBLE {
     String transactionId,
   ) =>
       _methodChannel
-          .invokeMethod(
+          .invokeMethod<String>(
             MethodName.readCharacteristicForIdentifier,
             <String, dynamic>{
               ArgumentName.characteristicIdentifier: characteristicIdentifier,
               ArgumentName.transactionId: transactionId
             },
           )
-          .catchError((errorJson) =>
-              Future.error(BleError.fromJson(jsonDecode(errorJson.details))))
+          .catchError((errorJson) async =>
+            throw BleError.fromJson(jsonDecode(errorJson.details))
+          )
           .then((rawValue) {
-            String rawJsonValue = "";
-            if (rawValue is String) {
-              rawJsonValue = rawValue;
+            if (rawValue == null) {
+              return Uint8List.fromList([]);
             }
             return _parseCharacteristicWithValueWithTransactionIdResponse(
               peripheral, 
-              rawJsonValue
+              rawValue
             ).value;
           });
 
@@ -38,7 +38,7 @@ mixin CharacteristicsMixin on FlutterBLE {
     String transactionId,
   ) =>
       _methodChannel
-          .invokeMethod(
+          .invokeMethod<String>(
             MethodName.readCharacteristicForDevice,
             <String, dynamic>{
               ArgumentName.deviceIdentifier: peripheral.identifier,
@@ -47,16 +47,16 @@ mixin CharacteristicsMixin on FlutterBLE {
               ArgumentName.transactionId: transactionId
             },
           )
-          .catchError((errorJson) =>
-              Future.error(BleError.fromJson(jsonDecode(errorJson.details))))
+          .catchError((errorJson) async =>
+              throw BleError.fromJson(jsonDecode(errorJson.details))
+          )
           .then((rawValue) {
-            String rawJsonValue = "";
-            if (rawValue is String) {
-              rawJsonValue = rawValue;
+            if (rawValue == null) {
+              throw Exception("rawValue cannot be null");
             }
             return _parseCharacteristicWithValueWithTransactionIdResponse(
               peripheral, 
-              rawJsonValue
+              rawValue
             );
           });
 
@@ -67,7 +67,7 @@ mixin CharacteristicsMixin on FlutterBLE {
     String transactionId,
   ) =>
       _methodChannel
-          .invokeMethod(
+          .invokeMethod<String>(
             MethodName.readCharacteristicForService,
             <String, dynamic>{
               ArgumentName.serviceIdentifier: serviceIdentifier,
@@ -76,87 +76,123 @@ mixin CharacteristicsMixin on FlutterBLE {
             },
           )
           .catchError((errorJson) =>
-              Future.error(BleError.fromJson(jsonDecode(errorJson.details))))
+            throw BleError.fromJson(jsonDecode(errorJson.details))
+          )
           .then((rawValue) {
-            String rawJsonValue = "";
-            if (rawValue is String) {
-              rawJsonValue = rawValue;
+            if (rawValue == null) {
+              throw Exception("rawValue cannot be null");
             }
             return _parseCharacteristicWithValueWithTransactionIdResponse(
               peripheral, 
-              rawJsonValue
+              rawValue
             );
           });
 
-  Future<void> writeCharacteristicForIdentifier(
+  Future<Characteristic?> writeCharacteristicForIdentifier(
     Peripheral peripheral,
     int characteristicIdentifier,
     Uint8List value,
     bool withResponse,
     String transactionId,
-  ) =>
-      _methodChannel.invokeMethod(
-        MethodName.writeCharacteristicForIdentifier,
-        <String, dynamic>{
-          ArgumentName.characteristicIdentifier: characteristicIdentifier,
-          ArgumentName.value: value,
-          ArgumentName.withResponse: withResponse,
-          ArgumentName.transactionId: transactionId,
-        },
-      ).catchError((errorJson) =>
-          Future.error(BleError.fromJson(jsonDecode(errorJson.details))));
-
-  Future<Characteristic> writeCharacteristicForDevice(
-          Peripheral peripheral,
-          String serviceUuid,
-          String characteristicUuid,
-          Uint8List value,
-          bool withResponse,
-          String transactionId) =>
-      _methodChannel
-          .invokeMethod(
-            MethodName.writeCharacteristicForDevice,
-            <String, dynamic>{
-              ArgumentName.deviceIdentifier: peripheral.identifier,
-              ArgumentName.serviceUuid: serviceUuid,
-              ArgumentName.characteristicUuid: characteristicUuid,
-              ArgumentName.value: value,
-              ArgumentName.withResponse: withResponse,
-              ArgumentName.transactionId: transactionId,
-            },
-          )
-          .catchError((errorJson) =>
-              Future.error(BleError.fromJson(jsonDecode(errorJson.details))))
-          .then(
-            (rawJsonValue) =>
-                _parseCharacteristicResponse(peripheral, rawJsonValue),
-          );
+  ) async {
+    final inv = _methodChannel.invokeMethod<String>(
+      MethodName.writeCharacteristicForIdentifier,
+      <String, dynamic>{
+        ArgumentName.characteristicIdentifier: characteristicIdentifier,
+        ArgumentName.value: value,
+        ArgumentName.withResponse: withResponse,
+        ArgumentName.transactionId: transactionId,
+      },
+    ).catchError((errorJson) =>
+      throw BleError.fromJson(jsonDecode(errorJson.details))
+    ).then((rawJsonValue) {
+      if (withResponse == false) {
+        return null;
+      }
+      if (rawJsonValue == null) {
+        return null;
+      }
+      return _parseCharacteristicResponse(peripheral, rawJsonValue);
+    });
+    if (withResponse == false) {
+      return null;
+    }
+    return await inv;
+  }
+
+
+
+  Future<Characteristic?> writeCharacteristicForDevice(
+    Peripheral peripheral,
+    String serviceUuid,
+    String characteristicUuid,
+    Uint8List value,
+    bool withResponse,
+    String transactionId
+  ) async {
+    final inv = _methodChannel.invokeMethod<String>(
+      MethodName.writeCharacteristicForDevice,
+      <String, dynamic>{
+        ArgumentName.deviceIdentifier: peripheral.identifier,
+        ArgumentName.serviceUuid: serviceUuid,
+        ArgumentName.characteristicUuid: characteristicUuid,
+        ArgumentName.value: value,
+        ArgumentName.withResponse: withResponse,
+        ArgumentName.transactionId: transactionId,
+      },
+    )
+    .catchError((errorJson) async =>
+      throw BleError.fromJson(jsonDecode(errorJson.details))
+    )
+    .then((rawJsonValue) {
+      if (withResponse == false) {
+        return null;
+      }
+      if (rawJsonValue == null) {
+        return null;
+      }
+      return _parseCharacteristicResponse(peripheral, rawJsonValue);
+    });
+    if (withResponse == false) {
+      return null;
+    }
+    return await inv;
+  }
 
-  Future<Characteristic> writeCharacteristicForService(
+  Future<Characteristic?> writeCharacteristicForService(
     Peripheral peripheral,
     int serviceIdentifier,
     String characteristicUuid,
     Uint8List value,
     bool withResponse,
     String transactionId,
-  ) =>
-      _methodChannel
-          .invokeMethod(
-            MethodName.writeCharacteristicForService,
-            <String, dynamic>{
-              ArgumentName.serviceIdentifier: serviceIdentifier,
-              ArgumentName.characteristicUuid: characteristicUuid,
-              ArgumentName.value: value,
-              ArgumentName.withResponse: withResponse,
-              ArgumentName.transactionId: transactionId,
-            },
-          )
-          .catchError((errorJson) =>
-              Future.error(BleError.fromJson(jsonDecode(errorJson.details))))
-          .then(
-            (rawJsonValue) =>
-                _parseCharacteristicResponse(peripheral, rawJsonValue),
-          );
+  ) async {
+    final inv = _methodChannel.invokeMethod(
+      MethodName.writeCharacteristicForService,
+      <String, dynamic>{
+        ArgumentName.serviceIdentifier: serviceIdentifier,
+        ArgumentName.characteristicUuid: characteristicUuid,
+        ArgumentName.value: value,
+        ArgumentName.withResponse: withResponse,
+        ArgumentName.transactionId: transactionId,
+      },
+    )
+    .catchError((errorJson) =>
+        Future.error(BleError.fromJson(jsonDecode(errorJson.details))))
+    .then((rawJsonValue) {
+      if (withResponse == false) {
+        return null;
+      }
+      if (rawJsonValue == null) {
+        return null;
+      }
+      return _parseCharacteristicResponse(peripheral, rawJsonValue);
+    });
+    if (withResponse == false) {
+      return null;
+    }
+    return await inv;
+  }
 
   Stream<Uint8List> monitorCharacteristicForIdentifier(
     Peripheral peripheral,

lib/src/internal_ble_manager.dart

@@ -233,7 +233,7 @@ class InternalBleManager
       );
 
   @override
-  Future<void> writeCharacteristicForIdentifier(
+  Future<Characteristic?> writeCharacteristicForIdentifier(
           Peripheral peripheral,
           InternalCharacteristic characteristic,
           Uint8List value,
@@ -248,7 +248,7 @@ class InternalBleManager
       );
 
   @override
-  Future<Characteristic> writeCharacteristicForDevice(
+  Future<Characteristic?> writeCharacteristicForDevice(
           Peripheral peripheral,
           String serviceUuid,
           String characteristicUuid,
@@ -265,7 +265,7 @@ class InternalBleManager
       );
 
   @override
-  Future<Characteristic> writeCharacteristicForService(
+  Future<Characteristic?> writeCharacteristicForService(
           Peripheral peripheral,
           InternalService service,
           String characteristicUuid,

test/characteristic_test.dart

@@ -14,10 +14,10 @@ import 'test_util/characteristic_generator.dart';
 import 'test_util/descriptor_generator.dart';
 
 @GenerateMocks(
-  [Peripheral, ManagerForDescriptor, DescriptorWithValue],
-  customMocks: [
-    MockSpec<Service>(returnNullOnMissingStub: true),
-  ]
+  [Peripheral, ManagerForDescriptor, DescriptorWithValue, Service],
+  // customMocks: [
+  //   MockSpec<Service>(returnNullOnMissingStub: true),
+  // ]
 )
 void main() {
   final peripheral = MockPeripheral();
@@ -44,6 +44,9 @@ void main() {
   ).thenAnswer(
     (_) async => MockDescriptorWithValue()
   );
+  when(
+    managerForCharacteristic.writeCharacteristicForIdentifier(any, any, any, any, any)
+  ).thenAnswer((_) async => null);
   final characteristicGenerator =
       CharacteristicGenerator(managerForCharacteristic);
   final descriptorGenerator =