Wait for writeWithoutResponse completion (#166)

* Wait for writeWithoutResponse request completion on Android

* Wait for writeWithoutResponse request completion on Darwin

* Add WriteWithoutResponse button in example app

* Update changelog and bump version

* Apply suggestions from code review

Co-authored-by: Foti Dim <foti@navideck.com>

---------

Co-authored-by: Foti Dim <foti@navideck.com>

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 0.20.1
+* Fix `writeWithoutResponse()` which was not properly waiting for completion on Android and Apple
+
 ## 0.20.0
 * Add new high level API. Services are auto-discovered. the BleDevice class offers convenient member methods and properties.
 * BREAKING CHANGE: `bleDevice.isPaired` is now `bleDevice.paired`

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

@@ -153,6 +153,9 @@ fun Int.parseGattErrorCode(): String? {
         BluetoothGatt.GATT_INSUFFICIENT_ENCRYPTION -> "GATT_INSUFFICIENT_ENCRYPTION"
         BluetoothGatt.GATT_CONNECTION_CONGESTED -> "GATT_CONNECTION_CONGESTED"
         BluetoothGatt.GATT_FAILURE -> "GATT_FAILURE"
+        BluetoothStatusCodes.ERROR_GATT_WRITE_NOT_ALLOWED -> "ERROR_GATT_WRITE_NOT_ALLOWED"
+        BluetoothStatusCodes.ERROR_GATT_WRITE_REQUEST_BUSY -> "ERROR_GATT_WRITE_REQUEST_BUSY"
+        BluetoothStatusCodes.FEATURE_NOT_CONFIGURED -> "FEATURE_NOT_CONFIGURED"
         0x01 -> "GATT_INVALID_HANDLE"
         0x04 -> "GATT_INVALID_PDU"
         0x09 -> "GATT_PREPARE_QUEUE_FULL"

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

@@ -469,34 +469,39 @@ class UniversalBlePlugin : UniversalBlePlatformChannel, BluetoothGattCallback(),
                 writeType = BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE
             }
 
+
+            val writeFuture = WriteResultFuture(
+                gatt.device.address,
+                gattCharacteristic.uuid.toString(),
+                gattCharacteristic.service.uuid.toString(),
+                callback
+            )
+
+            // Wait for the result
+            writeResultFutureList.add(writeFuture)
+
             val result = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
-                val writeResult = gatt.writeCharacteristic(gattCharacteristic, value, writeType)
+                gatt.writeCharacteristic(gattCharacteristic, value, writeType)
-                writeResult == BluetoothGatt.GATT_SUCCESS
             } else {
                 @Suppress("DEPRECATION")
                 gattCharacteristic.value = value
                 gattCharacteristic.writeType = writeType
                 @Suppress("DEPRECATION")
-                gatt.writeCharacteristic(gattCharacteristic)
+                val status = gatt.writeCharacteristic(gattCharacteristic)
+                if (status) BluetoothGatt.GATT_SUCCESS else BluetoothGatt.GATT_FAILURE
             }
 
-            if (!result) {
+            if (result != BluetoothGatt.GATT_SUCCESS) {
-                callback(Result.failure(FlutterError("Failed", "Failed to write", null)))
+                writeResultFutureList.remove(writeFuture)
-                return
+                callback(
-            }
+                    Result.failure(
-
+                        FlutterError(
-            if (writeType == BluetoothGattCharacteristic.WRITE_TYPE_DEFAULT) {
+                            "WriteError",
-                // wait for the result
+                            "Failed to write: ${result.parseGattErrorCode()}",
-                writeResultFutureList.add(
+                            null
-                    WriteResultFuture(
+                        )
-                        gatt.device.address,
-                        gattCharacteristic.uuid.toString(),
-                        gattCharacteristic.service.uuid.toString(),
-                        callback
                     )
                 )
-            } else {
-                callback(Result.success(Unit))
             }
         } catch (e: FlutterError) {
             callback(Result.failure(e))

darwin/Classes/UniversalBlePlugin.swift

@@ -36,6 +36,7 @@ private class BleCentralDarwin: NSObject, UniversalBlePlatformChannel, CBCentral
   private var discoveredServicesProgressMap: [String: [UniversalBleService]] = [:]
   private var characteristicReadFutures = [CharacteristicReadFuture]()
   private var characteristicWriteFutures = [CharacteristicWriteFuture]()
+  private var characteristicWriteWithoutResponseFutures = [CharacteristicWriteFuture]()
   private var characteristicNotifyFutures = [CharacteristicNotifyFuture]()
   private var discoverServicesFutures = [DiscoverServicesFuture]()
 
@@ -263,11 +264,12 @@ private class BleCentralDarwin: NSObject, UniversalBlePlatformChannel, CBCentral
     }
     peripheral.writeValue(value.data, for: gattCharacteristic, type: type)
 
+    // Wait for future response
+    let future = CharacteristicWriteFuture(deviceId: deviceId, characteristicId: gattCharacteristic.uuid.uuidStr, serviceId: gattCharacteristic.service?.uuid.uuidStr, result: completion)
     if type == CBCharacteristicWriteType.withResponse {
-      // Wait for future response
+      characteristicWriteFutures.append(future)
-      characteristicWriteFutures.append(CharacteristicWriteFuture(deviceId: deviceId, characteristicId: gattCharacteristic.uuid.uuidStr, serviceId: gattCharacteristic.service?.uuid.uuidStr, result: completion))
     } else {
-      completion(Result.success({}()))
+      characteristicWriteWithoutResponseFutures.append(future)
     }
   }
 
@@ -412,6 +414,16 @@ private class BleCentralDarwin: NSObject, UniversalBlePlatformChannel, CBCentral
     }
   }
 
+  public func peripheralIsReady(toSendWriteWithoutResponse peripheral: CBPeripheral) {
+    characteristicWriteWithoutResponseFutures.removeAll { future in
+      if future.deviceId == peripheral.uuid.uuidString {
+        future.result(Result.success({}()))
+        return true
+      }
+      return false
+    }
+  }
+
   public func peripheral(_ peripheral: CBPeripheral, didWriteValueFor characteristic: CBCharacteristic, error: Error?) {
     characteristicWriteFutures.removeAll { future in
       if future.deviceId == peripheral.uuid.uuidString && future.characteristicId == characteristic.uuid.uuidStr && future.serviceId == characteristic.service?.uuid.uuidStr {

example/lib/peripheral_details/peripheral_detail_page.dart

@@ -129,7 +129,7 @@ class _PeripheralDetailPageState extends State<PeripheralDetailPage> {
     }
   }
 
-  Future<void> _writeValue() async {
+  Future<void> _writeValue({required bool withResponse}) async {
     BleCharacteristic? selectedCharacteristic = this.selectedCharacteristic;
     if (selectedCharacteristic == null ||
         !valueFormKey.currentState!.validate() ||
@@ -146,13 +146,8 @@ class _PeripheralDetailPageState extends State<PeripheralDetailPage> {
     }
 
     try {
-      await selectedCharacteristic.write(
+      await selectedCharacteristic.write(value, withResponse: withResponse);
-        value,
+      _addLog('Write${withResponse ? "" : "WithoutResponse"}', value);
-        withResponse: _hasSelectedCharacteristicProperty(
-          [CharacteristicProperty.writeWithoutResponse],
-        ),
-      );
-      _addLog('Write', value);
     } catch (e) {
       debugPrint(e.toString());
       _addLog('WriteError', e);
@@ -377,11 +372,19 @@ class _PeripheralDetailPageState extends State<PeripheralDetailPage> {
                                   discoveredServices.isNotEmpty &&
                                   _hasSelectedCharacteristicProperty([
                                     CharacteristicProperty.write,
-                                    CharacteristicProperty.writeWithoutResponse
                                   ]),
-                              onPressed: _writeValue,
+                              onPressed: () => _writeValue(withResponse: true),
                               text: 'Write',
                             ),
+                            PlatformButton(
+                              enabled: isConnected &&
+                                  discoveredServices.isNotEmpty &&
+                                  _hasSelectedCharacteristicProperty([
+                                    CharacteristicProperty.writeWithoutResponse,
+                                  ]),
+                              onPressed: () => _writeValue(withResponse: false),
+                              text: 'WriteWithoutResponse',
+                            ),
                             PlatformButton(
                               enabled: isConnected &&
                                   discoveredServices.isNotEmpty &&

example/macos/Podfile.lock

@@ -20,9 +20,9 @@ EXTERNAL SOURCES:
     :path: Flutter/ephemeral/.symlinks/plugins/universal_ble/darwin
 
 SPEC CHECKSUMS:
-  device_info_plus: b0fafc687fb901e2af612763340f1b0d4352f8e5
+  device_info_plus: 5401765fde0b8d062a2f8eb65510fb17e77cf07f
   FlutterMacOS: 8f6f14fa908a6fb3fba0cd85dbd81ec4b251fb24
-  universal_ble: ff19787898040d721109c6324472e5dd4bc86adc
+  universal_ble: cf52a7b3fd2e7c14d6d7262e9fdadb72ab6b88a6
 
 PODFILE CHECKSUM: 236401fc2c932af29a9fcf0e97baeeb2d750d367
 

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: 0.20.0
+version: 0.20.1
 homepage: https://navideck.com
 repository: https://github.com/Navideck/universal_ble
 issue_tracker: https://github.com/Navideck/universal_ble/issues