Implement readRSSI on Android and Darwin (#203)

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 1.1.0
+* Add readRssi method
+
 ## 1.0.1
 * Enforce C++20 standard for Windows builds
 

README.low_level.md

@@ -131,3 +131,19 @@ This method will **attempt** to set the MTU (Maximum Transmission Unit) but it i
 ```dart
 int mtu = await UniversalBle.requestMtu(widget.deviceId, 247);
 ```
+
+### Read RSSI
+
+Read the signal strength (RSSI) of a connected device.
+
+```dart
+int rssi = await UniversalBle.readRssi(deviceId);
+```
+
+> ⚠️ Note: The device must be connected before reading RSSI.
+
+#### Platform Limitations
+
+* **Android / iOS / macOS**: Fully supported.
+
+* **Windows / Linux / Web**: Not supported.

README.md

@@ -27,6 +27,7 @@ A cross-platform (Android/iOS/macOS/Windows/Linux/Web) Bluetooth Low Energy (BLE
 - [Pairing](#pairing)
 - [Bluetooth Availability](#bluetooth-availability)
 - [Requesting MTU](#requesting-mtu)
+- [Reading RSSI](#reading-rssi)
 - [Command Queue](#command-queue)
 - [Timeout](#timeout)
 - [Error Handling](#error-handling)
@@ -52,6 +53,7 @@ A cross-platform (Android/iOS/macOS/Windows/Linux/Web) Bluetooth Low Energy (BLE
 | enable/disable Bluetooth      |   ✔️    | ❌  |  ❌   |   ✔️    |  ✔️   | ❌  |
 | onAvailabilityChange          |   ✔️    | ✔️  |  ✔️   |   ✔️    |  ✔️   | ✔️  |
 | requestMtu                    |   ✔️    | ✔️  |  ✔️   |   ✔️    |  ✔️   | ❌  |
+| readRssi                      |   ✔️    | ✔️  |  ✔️   |   ❌    |  🚧   | ❌  |
 | requestPermissions            |   ✔️    | ✔️  |  ✔️   |   ✔️    |  ✔️   | ✔️  |
 
 ## Getting Started
@@ -409,7 +411,7 @@ UniversalBle.disableBluetooth();
 
 ```dart
 int mtu = await bleDevice.requestMtu(256);
-````
+```
 
 > ⚠️ Note: Requesting an MTU is a *best-effort* operation.
 > On many platforms the final MTU is fully controlled by the OS and remote device.
@@ -460,6 +462,23 @@ When developing cross-platform BLE applications and devices:
 * Take advantage of higher MTUs when available, without depending on them
 
 
+### Reading RSSI
+
+Read the signal strength (RSSI) of a connected device.
+
+```dart
+int rssi = await bleDevice.readRssi();
+```
+
+> ⚠️ Note: The device must be connected before reading RSSI.
+
+#### Platform Limitations
+
+* **Android / iOS / macOS**: Fully supported.
+
+* **Windows / Linux / Web**: Not supported.
+
+
 ## Command Queue
 
 By default, all commands are executed in a global queue (`QueueType.global`), with each command waiting for the previous one to finish. While this method is slower it is the safest to avoid command exceptions and therefore is the default.

android/src/main/kotlin/com/navideck/universal_ble/UniversalBle.g.kt

@@ -529,6 +529,7 @@ interface UniversalBlePlatformChannel {
   fun unPair(deviceId: String)
   fun getSystemDevices(withServices: List<String>, callback: (Result<List<UniversalBleScanResult>>) -> Unit)
   fun getConnectionState(deviceId: String): Long
+  fun readRssi(deviceId: String, callback: (Result<Long>) -> Unit)
   fun setLogLevel(logLevel: UniversalBleLogLevel)
 
   companion object {
@@ -919,6 +920,26 @@ interface UniversalBlePlatformChannel {
           channel.setMessageHandler(null)
         }
       }
+      run {
+        val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.universal_ble.UniversalBlePlatformChannel.readRssi$separatedMessageChannelSuffix", codec)
+        if (api != null) {
+          channel.setMessageHandler { message, reply ->
+            val args = message as List<Any?>
+            val deviceIdArg = args[0] as String
+            api.readRssi(deviceIdArg) { result: Result<Long> ->
+              val error = result.exceptionOrNull()
+              if (error != null) {
+                reply.reply(UniversalBlePigeonUtils.wrapError(error))
+              } else {
+                val data = result.getOrNull()
+                reply.reply(UniversalBlePigeonUtils.wrapResult(data))
+              }
+            }
+          }
+        } else {
+          channel.setMessageHandler(null)
+        }
+      }
       run {
         val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.universal_ble.UniversalBlePlatformChannel.setLogLevel$separatedMessageChannelSuffix", codec)
         if (api != null) {

android/src/main/kotlin/com/navideck/universal_ble/UniversalBleHelper.kt

@@ -344,3 +344,8 @@ class SubscriptionResultFuture(
     val serviceId: String,
     val result: (Result<Unit>) -> Unit,
 )
+
+class RssiResultFuture(
+    val deviceId: String,
+    val result: (Result<Long>) -> Unit,
+)

android/src/main/kotlin/com/navideck/universal_ble/UniversalBlePlugin.kt

@@ -60,6 +60,7 @@ class UniversalBlePlugin : UniversalBlePlatformChannel, BluetoothGattCallback(),
     private val writeResultFutureList = mutableListOf<WriteResultFuture>()
     private val subscriptionResultFutureList = mutableListOf<SubscriptionResultFuture>()
     private val pairResultFutures = mutableMapOf<String, (Result<Boolean>) -> Unit>()
+    private val rssiResultFutureList = mutableListOf<RssiResultFuture>()
 
     override fun onAttachedToEngine(flutterPluginBinding: FlutterPlugin.FlutterPluginBinding) {
         UniversalBlePlatformChannel.setUp(flutterPluginBinding.binaryMessenger, this)
@@ -279,6 +280,49 @@ class UniversalBlePlugin : UniversalBlePlatformChannel, BluetoothGattCallback(),
         UniversalBleLogger.setLogLevel(logLevel)
     }
 
+    override fun readRssi(deviceId: String, callback: (Result<Long>) -> Unit) {
+        try {
+            val gatt = deviceId.toBluetoothGatt()
+            if (gatt.readRemoteRssi()) {
+                rssiResultFutureList.add(RssiResultFuture(deviceId, callback))
+            } else {
+                callback(
+                    Result.failure(
+                        createFlutterError(
+                            UniversalBleErrorCode.FAILED,
+                            "Failed to read RSSI"
+                        )
+                    )
+                )
+            }
+        } catch (e: FlutterError) {
+            callback(Result.failure(e))
+        }
+    }
+
+    override fun onReadRemoteRssi(gatt: BluetoothGatt?, rssi: Int, status: Int) {
+        val deviceId = gatt?.device?.address ?: return
+        rssiResultFutureList.removeAll {
+            if (it.deviceId == deviceId) {
+                if (status == BluetoothGatt.GATT_SUCCESS) {
+                    it.result(Result.success(rssi.toLong()))
+                } else {
+                    it.result(
+                        Result.failure(
+                            createFlutterError(
+                                UniversalBleErrorCode.FAILED,
+                                "Failed to read RSSI"
+                            )
+                        )
+                    )
+                }
+                true
+            } else {
+                false
+            }
+        }
+    }
+
     override fun discoverServices(
         deviceId: String,
         withDescriptors: Boolean,
@@ -311,36 +355,44 @@ class UniversalBlePlugin : UniversalBlePlatformChannel, BluetoothGattCallback(),
 
     override fun onServicesDiscovered(gatt: BluetoothGatt, status: Int) {
         if (status != BluetoothGatt.GATT_SUCCESS) {
-            discoverServicesFutureList.filter { it.deviceId == gatt.device.address }.forEach {
-                discoverServicesFutureList.remove(it)
-                it.result(
-                    Result.failure(
-                        createFlutterError(
-                            UniversalBleErrorCode.FAILED,
-                            "Failed to discover services"
+            discoverServicesFutureList.removeAll {
+                if (it.deviceId == gatt.device.address) {
+                    it.result(
+                        Result.failure(
+                            createFlutterError(
+                                UniversalBleErrorCode.FAILED,
+                                "Failed to discover services"
+                            )
                         )
                     )
-                )
+                    true
+                } else {
+                    false
+                }
             }
             return
         }
         setCachedServices(gatt.device.address, gatt.services.map { it.uuid.toString() })
-        discoverServicesFutureList.filter { it.deviceId == gatt.device.address }.forEach {
-            discoverServicesFutureList.remove(it)
-            it.result(Result.success(gatt.services.map { service ->
-                UniversalBleService(
-                    uuid = service.uuid.toString(),
-                    characteristics = service.characteristics.map { char ->
-                        UniversalBleCharacteristic(
-                            uuid = char.uuid.toString(),
-                            properties = char.getPropertiesList(),
-                            descriptors = if (it.withDescriptors) char.descriptors.map { descriptor ->
-                                UniversalBleDescriptor(descriptor.uuid.toString())
-                            } else listOf()
-                        )
-                    }
-                )
-            }))
+        discoverServicesFutureList.removeAll {
+            if (it.deviceId == gatt.device.address) {
+                it.result(Result.success(gatt.services.map { service ->
+                    UniversalBleService(
+                        uuid = service.uuid.toString(),
+                        characteristics = service.characteristics.map { char ->
+                            UniversalBleCharacteristic(
+                                uuid = char.uuid.toString(),
+                                properties = char.getPropertiesList(),
+                                descriptors = if (it.withDescriptors) char.descriptors.map { descriptor ->
+                                    UniversalBleDescriptor(descriptor.uuid.toString())
+                                } else listOf()
+                            )
+                        }
+                    )
+                }))
+                true
+            } else {
+                false
+            }
         }
     }
 
@@ -517,29 +569,31 @@ class UniversalBlePlugin : UniversalBlePlatformChannel, BluetoothGattCallback(),
         value: ByteArray,
         status: Int,
     ) {
-        readResultFutureList.filter {
-            it.deviceId == gatt.device.address &&
-                    it.characteristicId == characteristic.uuid.toString() &&
-                    it.serviceId == characteristic.service.uuid.toString()
-        }.forEach {
-            readResultFutureList.remove(it)
-            if (status == BluetoothGatt.GATT_SUCCESS) {
-                it.result(Result.success(value))
-            } else {
-                UniversalBleLogger.logError(
-                    "READ_FAILED <- ${gatt.device.address} ${characteristic.uuid} status=$status"
-                )
-                it.result(
-                    Result.failure(
-                        createFlutterError(
-                            gattStatusToUniversalBleErrorCode(status),
-                            "Failed to read",
-                            status.toString()
+        readResultFutureList.removeAll {
+            if (it.deviceId == gatt.device.address &&
+                it.characteristicId == characteristic.uuid.toString() &&
+                it.serviceId == characteristic.service.uuid.toString()
+            ) {
+                if (status == BluetoothGatt.GATT_SUCCESS) {
+                    it.result(Result.success(value))
+                } else {
+                    UniversalBleLogger.logError(
+                        "READ_FAILED <- ${gatt.device.address} ${characteristic.uuid} status=$status"
+                    )
+                    it.result(
+                        Result.failure(
+                            createFlutterError(
+                                gattStatusToUniversalBleErrorCode(status),
+                                "Failed to read",
+                                status.toString()
+                            )
                         )
                     )
-                )
+                }
+                true
+            } else {
+                false
             }
-
         }
     }
 
@@ -640,27 +694,30 @@ class UniversalBlePlugin : UniversalBlePlatformChannel, BluetoothGattCallback(),
         characteristic: BluetoothGattCharacteristic,
         status: Int,
     ) {
-        writeResultFutureList.filter {
-            it.deviceId == gatt?.device?.address &&
-                    it.characteristicId == characteristic.uuid.toString() &&
-                    it.serviceId == characteristic.service.uuid.toString()
-        }.forEach {
-            writeResultFutureList.remove(it)
-            if (status == BluetoothGatt.GATT_SUCCESS) {
-                it.result(Result.success(Unit))
-            } else {
-                UniversalBleLogger.logError(
-                    "WRITE_FAILED <- ${gatt?.device?.address} ${characteristic.uuid} status=$status"
-                )
-                it.result(
-                    Result.failure(
-                        createFlutterError(
-                            gattStatusToUniversalBleErrorCode(status),
-                            "Failed to write",
-                            status.toString()
+        writeResultFutureList.removeAll {
+            if (it.deviceId == gatt?.device?.address &&
+                it.characteristicId == characteristic.uuid.toString() &&
+                it.serviceId == characteristic.service.uuid.toString()
+            ) {
+                if (status == BluetoothGatt.GATT_SUCCESS) {
+                    it.result(Result.success(Unit))
+                } else {
+                    UniversalBleLogger.logError(
+                        "WRITE_FAILED <- ${gatt?.device?.address} ${characteristic.uuid} status=$status"
+                    )
+                    it.result(
+                        Result.failure(
+                            createFlutterError(
+                                gattStatusToUniversalBleErrorCode(status),
+                                "Failed to write",
+                                status.toString()
+                            )
                         )
                     )
-                )
+                }
+                true
+            } else {
+                false
             }
         }
     }
@@ -679,19 +736,23 @@ class UniversalBlePlugin : UniversalBlePlatformChannel, BluetoothGattCallback(),
 
     override fun onMtuChanged(gatt: BluetoothGatt?, mtu: Int, status: Int) {
         val deviceId = gatt?.device?.address ?: return
-        mtuResultFutureList.filter { it.deviceId == deviceId }.forEach {
-            mtuResultFutureList.remove(it)
-            if (status == BluetoothGatt.GATT_SUCCESS) {
-                it.result(Result.success(mtu.toLong()))
-            } else {
-                it.result(
-                    Result.failure(
-                        createFlutterError(
-                            UniversalBleErrorCode.FAILED,
-                            "Failed to change MTU"
+        mtuResultFutureList.removeAll {
+            if (it.deviceId == deviceId) {
+                if (status == BluetoothGatt.GATT_SUCCESS) {
+                    it.result(Result.success(mtu.toLong()))
+                } else {
+                    it.result(
+                        Result.failure(
+                            createFlutterError(
+                                UniversalBleErrorCode.FAILED,
+                                "Failed to change MTU"
+                            )
                         )
                     )
-                )
+                }
+                true
+            } else {
+                false
             }
         }
     }
@@ -941,6 +1002,14 @@ class UniversalBlePlugin : UniversalBlePlatformChannel, BluetoothGattCallback(),
                 false
             }
         }
+        rssiResultFutureList.removeAll {
+            if (it.deviceId == gatt.device.address) {
+                it.result(Result.failure(deviceDisconnectedError))
+                true
+            } else {
+                false
+            }
+        }
     }
 
     private fun onBondStateUpdate(deviceId: String, bonded: Boolean, error: String? = null) {
@@ -1116,24 +1185,27 @@ class UniversalBlePlugin : UniversalBlePlatformChannel, BluetoothGattCallback(),
         service: String,
         status: Int,
     ) {
-        subscriptionResultFutureList.filter {
-            it.deviceId == deviceId &&
-                    it.characteristicId == characteristic &&
-                    it.serviceId == service
-        }.forEach {
-            subscriptionResultFutureList.remove(it)
-            if (status != BluetoothGatt.GATT_SUCCESS) {
-                it.result(
-                    Result.failure(
-                        createFlutterError(
-                            gattStatusToUniversalBleErrorCode(status),
-                            "Failed to update subscription state",
-                            status.toString()
+        subscriptionResultFutureList.removeAll {
+            if (it.deviceId == deviceId &&
+                it.characteristicId == characteristic &&
+                it.serviceId == service
+            ) {
+                if (status != BluetoothGatt.GATT_SUCCESS) {
+                    it.result(
+                        Result.failure(
+                            createFlutterError(
+                                gattStatusToUniversalBleErrorCode(status),
+                                "Failed to update subscription state",
+                                status.toString()
+                            )
                         )
                     )
-                )
+                } else {
+                    it.result(Result.success(Unit))
+                }
+                true
             } else {
-                it.result(Result.success(Unit))
+                false
             }
         }
     }

darwin/Classes/UniversalBle.g.swift

@@ -548,6 +548,7 @@ protocol UniversalBlePlatformChannel {
   func unPair(deviceId: String) throws
   func getSystemDevices(withServices: [String], completion: @escaping (Result<[UniversalBleScanResult], Error>) -> Void)
   func getConnectionState(deviceId: String) throws -> Int64
+  func readRssi(deviceId: String, completion: @escaping (Result<Int64, Error>) -> Void)
   func setLogLevel(logLevel: UniversalBleLogLevel) throws
 }
 
@@ -882,6 +883,23 @@ class UniversalBlePlatformChannelSetup {
     } else {
       getConnectionStateChannel.setMessageHandler(nil)
     }
+    let readRssiChannel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.universal_ble.UniversalBlePlatformChannel.readRssi\(channelSuffix)", binaryMessenger: binaryMessenger, codec: codec)
+    if let api = api {
+      readRssiChannel.setMessageHandler { message, reply in
+        let args = message as! [Any?]
+        let deviceIdArg = args[0] as! String
+        api.readRssi(deviceId: deviceIdArg) { result in
+          switch result {
+          case .success(let res):
+            reply(wrapResult(res))
+          case .failure(let error):
+            reply(wrapError(error))
+          }
+        }
+      }
+    } else {
+      readRssiChannel.setMessageHandler(nil)
+    }
     let setLogLevelChannel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.universal_ble.UniversalBlePlatformChannel.setLogLevel\(channelSuffix)", binaryMessenger: binaryMessenger, codec: codec)
     if let api = api {
       setLogLevelChannel.setMessageHandler { message, reply in

darwin/Classes/UniversalBleHelper.swift

@@ -258,3 +258,13 @@ class DiscoverServicesFuture {
         self.result = result
     }
 }
+
+class RssiReadFuture {
+    let deviceId: String
+    let result: (Result<Int64, Error>) -> Void
+
+    init(deviceId: String, result: @escaping (Result<Int64, Error>) -> Void) {
+        self.deviceId = deviceId
+        self.result = result
+    }
+}

darwin/Classes/UniversalBlePlugin.swift

@@ -40,6 +40,7 @@ private class BleCentralDarwin: NSObject, UniversalBlePlatformChannel, CBCentral
   private var characteristicWriteWithoutResponseFutures = [CharacteristicWriteFuture]()
   private var characteristicNotifyFutures = [CharacteristicNotifyFuture]()
   private var discoverServicesFutures = [DiscoverServicesFuture]()
+  private var rssiReadFutures = [RssiReadFuture]()
   private var isManageScanning = false
 
   init(callbackChannel: UniversalBleCallbackChannel) {
@@ -200,6 +201,15 @@ private class BleCentralDarwin: NSObject, UniversalBlePlatformChannel, CBCentral
       }
       return false
     }
+    rssiReadFutures.removeAll { future in
+      if future.deviceId == deviceId {
+        future.result(
+          Result.failure(createFlutterError(code: .deviceDisconnected, message: "Device Disconnected"))
+        )
+        return true
+      }
+      return false
+    }
     activeServiceDiscoveries[deviceId]?.cleanup()
     activeServiceDiscoveries[deviceId] = nil
   }
@@ -334,6 +344,16 @@ private class BleCentralDarwin: NSObject, UniversalBlePlatformChannel, CBCentral
     completion(Result.success(mtuResult))
   }
 
+  func readRssi(deviceId: String, completion: @escaping (Result<Int64, Error>) -> Void) {
+    UniversalBleLogger.shared.logDebug("READ_RSSI -> \(deviceId)")
+    guard let peripheral = deviceId.findPeripheral(manager: manager) else {
+      completion(Result.failure(createFlutterError(code: .deviceNotFound, message: "Unknown deviceId:\(deviceId)")))
+      return
+    }
+    peripheral.readRSSI()
+    rssiReadFutures.append(RssiReadFuture(deviceId: deviceId, result: completion))
+  }
+
   func isPaired(deviceId _: String, completion: @escaping (Result<Bool, Error>) -> Void) {
     completion(Result.failure(createFlutterError(code: .notSupported)))
   }
@@ -531,6 +551,21 @@ private class BleCentralDarwin: NSObject, UniversalBlePlatformChannel, CBCentral
       return false
     }
   }
+
+  public func peripheral(_ peripheral: CBPeripheral, didReadRSSI RSSI: NSNumber, error: Error?) {
+    rssiReadFutures.removeAll { future in
+      if future.deviceId == peripheral.uuid.uuidString {
+        if let flutterError = error?.toFlutterError() {
+          UniversalBleLogger.shared.logError("READ_RSSI_FAILED <- \(peripheral.uuid.uuidString): \(flutterError.message ?? "")")
+          future.result(Result.failure(flutterError))
+        } else {
+          future.result(Result.success(RSSI.int64Value))
+        }
+        return true
+      }
+      return false
+    }
+  }
 }
 
 extension CBPeripheral {

example/lib/data/mock_universal_ble.dart

@@ -113,6 +113,12 @@ class MockUniversalBle extends UniversalBlePlatform {
     return 512;
   }
 
+  @override
+  Future<int> readRssi(String deviceId) async {
+    await Future.delayed(const Duration(milliseconds: 500));
+    return -50; // Mock RSSI value in dBm
+  }
+
   @override
   Future<void> setNotifiable(String deviceId, String service,
       String characteristic, BleInputProperty bleInputProperty) async {}

example/lib/peripheral_details/peripheral_detail_page.dart

@@ -1097,6 +1097,30 @@ class _PeripheralDetailPageState extends State<PeripheralDetailPage> {
                         ),
                       ),
                     ),
+                    OutlinedButton.icon(
+                      onPressed: isConnected
+                          ? () async {
+                              try {
+                                int rssi = await bleDevice.readRssi();
+                                _addLog('RSSI', '$rssi dBm');
+                              } catch (e) {
+                                _addLog('ReadRssiError (${e.runtimeType})', e);
+                              }
+                            }
+                          : null,
+                      icon: const Icon(Icons.signal_cellular_alt),
+                      label: const Text('Get RSSI'),
+                      style: OutlinedButton.styleFrom(
+                        foregroundColor: colorScheme.onSurface,
+                        padding: const EdgeInsets.symmetric(
+                          horizontal: 16,
+                          vertical: 12,
+                        ),
+                        shape: RoundedRectangleBorder(
+                          borderRadius: BorderRadius.circular(8),
+                        ),
+                      ),
+                    ),
                     if (BleCapabilities.supportsRequestMtuApi)
                       ElevatedButton.icon(
                         onPressed: isConnected

lib/src/models/ble_device.dart

@@ -26,6 +26,19 @@ class BleDevice {
   Future<BleConnectionState> get connectionState =>
       UniversalBle.getConnectionState(deviceId);
 
+  /// Read the RSSI value of this connected device.
+  ///
+  /// Returns the current RSSI value in dBm. This value indicates the signal strength
+  /// between the device and the connected peripheral. Lower (more negative) values
+  /// indicate weaker signal, while higher (less negative) values indicate stronger signal.
+  ///
+  /// **Note**: The device must be connected before reading RSSI.
+  ///
+  /// Throws [BleException] if:
+  /// - The device is not connected
+  /// - Reading RSSI fails
+  Future<int> readRssi() => UniversalBle.readRssi(deviceId);
+
   /// On web, it returns true if the web browser supports receiving advertisements from this device.
   /// The rest of the platforms will always return true.
   bool get receivesAdvertisements =>

lib/src/universal_ble.dart

@@ -340,6 +340,28 @@ class UniversalBle {
     );
   }
 
+  /// Read the RSSI value of a connected device.
+  ///
+  /// Returns the current RSSI value in dBm. This value indicates the signal strength
+  /// between the device and the connected peripheral. Lower (more negative) values
+  /// indicate weaker signal, while higher (less negative) values indicate stronger signal.
+  ///
+  /// **Note**: The device must be connected before reading RSSI.
+  ///
+  /// Throws [BleException] if:
+  /// - The device is not connected
+  /// - Reading RSSI fails
+  static Future<int> readRssi(
+    String deviceId, {
+    Duration? timeout,
+  }) async {
+    return await _bleCommandQueue.queueCommand(
+      () => _platform.readRssi(deviceId),
+      timeout: timeout,
+      deviceId: deviceId,
+    );
+  }
+
   /// Check if a device is paired.
   ///
   /// For `Apple` and `Web`, you have to pass a "pairingCommand" with an encrypted read or write characteristic.

lib/src/universal_ble_linux/universal_ble_linux.dart

@@ -378,6 +378,14 @@ class UniversalBleLinux extends UniversalBlePlatform {
     );
   }
 
+  @override
+  Future<int> readRssi(String deviceId) async {
+    throw UniversalBleException(
+      code: UniversalBleErrorCode.notImplemented,
+      message: "readRssi is not implemented on Linux platform",
+    );
+  }
+
   @override
   Future<bool> pair(String deviceId) async {
     BlueZDevice device = _findDeviceById(deviceId);

lib/src/universal_ble_pigeon/universal_ble.g.dart

@@ -1106,6 +1106,35 @@ class UniversalBlePlatformChannel {
     }
   }
 
+  Future<int> readRssi(String deviceId) async {
+    final pigeonVar_channelName =
+        'dev.flutter.pigeon.universal_ble.UniversalBlePlatformChannel.readRssi$pigeonVar_messageChannelSuffix';
+    final pigeonVar_channel = BasicMessageChannel<Object?>(
+      pigeonVar_channelName,
+      pigeonChannelCodec,
+      binaryMessenger: pigeonVar_binaryMessenger,
+    );
+    final Future<Object?> pigeonVar_sendFuture =
+        pigeonVar_channel.send(<Object?>[deviceId]);
+    final pigeonVar_replyList = await pigeonVar_sendFuture as List<Object?>?;
+    if (pigeonVar_replyList == null) {
+      throw _createConnectionError(pigeonVar_channelName);
+    } else if (pigeonVar_replyList.length > 1) {
+      throw PlatformException(
+        code: pigeonVar_replyList[0]! as String,
+        message: pigeonVar_replyList[1] as String?,
+        details: pigeonVar_replyList[2],
+      );
+    } else if (pigeonVar_replyList[0] == null) {
+      throw PlatformException(
+        code: 'null-error',
+        message: 'Host platform returned null value for non-null return value.',
+      );
+    } else {
+      return (pigeonVar_replyList[0] as int?)!;
+    }
+  }
+
   Future<void> setLogLevel(UniversalBleLogLevel logLevel) async {
     final pigeonVar_channelName =
         'dev.flutter.pigeon.universal_ble.UniversalBlePlatformChannel.setLogLevel$pigeonVar_messageChannelSuffix';

lib/src/universal_ble_pigeon/universal_ble_pigeon_channel.dart

@@ -133,6 +133,10 @@ class UniversalBlePigeonChannel extends UniversalBlePlatform {
       _executeWithErrorHandling(
           () => _channel.requestMtu(deviceId, expectedMtu));
 
+  @override
+  Future<int> readRssi(String deviceId) =>
+      _executeWithErrorHandling(() => _channel.readRssi(deviceId));
+
   @override
   Future<bool> isPaired(String deviceId) =>
       _executeWithErrorHandling(() => _channel.isPaired(deviceId));

lib/src/universal_ble_platform_interface.dart

@@ -79,6 +79,8 @@ abstract class UniversalBlePlatform {
 
   Future<int> requestMtu(String deviceId, int expectedMtu);
 
+  Future<int> readRssi(String deviceId);
+
   Future<bool> isPaired(String deviceId);
 
   Future<bool> pair(String deviceId);

lib/src/universal_ble_web/universal_ble_web.dart

@@ -283,6 +283,15 @@ class UniversalBleWeb extends UniversalBlePlatform {
     );
   }
 
+  /// `Unimplemented`
+  @override
+  Future<int> readRssi(String deviceId) {
+    throw UniversalBleException(
+      code: UniversalBleErrorCode.notImplemented,
+      message: "readRssi is not implemented on Web platform",
+    );
+  }
+
   @override
   Future<bool> isPaired(String deviceId) {
     throw UniversalBleException(

pigeon/universal_ble.dart

@@ -93,6 +93,9 @@ abstract class UniversalBlePlatformChannel {
 
   int getConnectionState(String deviceId);
 
+  @async
+  int readRssi(String deviceId);
+
   void setLogLevel(UniversalBleLogLevel logLevel);
 }
 

pubspec.yaml

@@ -1,6 +1,6 @@
 name: universal_ble
 description: A cross-platform (Android/iOS/macOS/Windows/Linux/Web) Bluetooth Low Energy (BLE) plugin for Flutter
-version: 1.0.1+3
+version: 1.1.0
 homepage: https://navideck.com
 repository: https://github.com/Navideck/universal_ble
 issue_tracker: https://github.com/Navideck/universal_ble/issues

test/ble_characteristic_test.dart

@@ -132,4 +132,9 @@ class _UniversalBleMock extends UniversalBlePlatformMock {
   Future<void> requestPermissions({bool withAndroidFineLocation = false}) {
     throw UnimplementedError();
   }
+
+  @override
+  Future<int> readRssi(String deviceId) async {
+    return -50; // Mock RSSI value
+  }
 }

windows/src/generated/universal_ble.g.cpp

@@ -1189,6 +1189,35 @@ void UniversalBlePlatformChannel::SetUp(
       channel.SetMessageHandler(nullptr);
     }
   }
+  {
+    BasicMessageChannel<> channel(binary_messenger, "dev.flutter.pigeon.universal_ble.UniversalBlePlatformChannel.readRssi" + prepended_suffix, &GetCodec());
+    if (api != nullptr) {
+      channel.SetMessageHandler([api](const EncodableValue& message, const flutter::MessageReply<EncodableValue>& reply) {
+        try {
+          const auto& args = std::get<EncodableList>(message);
+          const auto& encodable_device_id_arg = args.at(0);
+          if (encodable_device_id_arg.IsNull()) {
+            reply(WrapError("device_id_arg unexpectedly null."));
+            return;
+          }
+          const auto& device_id_arg = std::get<std::string>(encodable_device_id_arg);
+          api->ReadRssi(device_id_arg, [reply](ErrorOr<int64_t>&& output) {
+            if (output.has_error()) {
+              reply(WrapError(output.error()));
+              return;
+            }
+            EncodableList wrapped;
+            wrapped.push_back(EncodableValue(std::move(output).TakeValue()));
+            reply(EncodableValue(std::move(wrapped)));
+          });
+        } catch (const std::exception& exception) {
+          reply(WrapError(exception.what()));
+        }
+      });
+    } else {
+      channel.SetMessageHandler(nullptr);
+    }
+  }
   {
     BasicMessageChannel<> channel(binary_messenger, "dev.flutter.pigeon.universal_ble.UniversalBlePlatformChannel.setLogLevel" + prepended_suffix, &GetCodec());
     if (api != nullptr) {

windows/src/generated/universal_ble.g.h

@@ -435,6 +435,9 @@ class UniversalBlePlatformChannel {
     const flutter::EncodableList& with_services,
     std::function<void(ErrorOr<flutter::EncodableList> reply)> result) = 0;
   virtual ErrorOr<int64_t> GetConnectionState(const std::string& device_id) = 0;
+  virtual void ReadRssi(
+    const std::string& device_id,
+    std::function<void(ErrorOr<int64_t> reply)> result) = 0;
   virtual std::optional<FlutterError> SetLogLevel(const UniversalBleLogLevel& log_level) = 0;
 
   // The codec used by UniversalBlePlatformChannel.

windows/src/universal_ble_plugin.cpp

@@ -451,6 +451,13 @@ void UniversalBlePlugin::RequestMtu(
   }
 }
 
+void UniversalBlePlugin::ReadRssi(
+    const std::string &device_id,
+    std::function<void(ErrorOr<int64_t> reply)> result) {
+  result(create_flutter_error(UniversalBleErrorCode::kNotImplemented,
+                              "readRssi is not implemented on Windows platform"));
+}
+
 void UniversalBlePlugin::IsPaired(
     const std::string &device_id,
     std::function<void(ErrorOr<bool> reply)> result) {

windows/src/universal_ble_plugin.h

@@ -200,6 +200,8 @@ private:
       std::function<void(std::optional<FlutterError> reply)> result) override;
   void RequestMtu(const std::string &device_id, int64_t expected_mtu,
                   std::function<void(ErrorOr<int64_t> reply)> result) override;
+  void ReadRssi(const std::string &device_id,
+                std::function<void(ErrorOr<int64_t> reply)> result) override;
   void IsPaired(const std::string &device_id,
                 std::function<void(ErrorOr<bool> reply)> result) override;
   void Pair(const std::string &device_id,