i am using any app that include flutter_blue package . I want to read , write and notify to some characteristics.
I'm having trouble writing to a characteristic. When i use another package or another app , i can write to this characteristic. But when i use flutter blue , It says me "there is no ability to write to this characteristic" something like this. I mean "characteristic.properties.write=false " .
What can i do ?
Thanks...
The properties are defined here in fluter_blue > bluetooth_characteristic.dart
// Copyright 2017, Paul DeMarco.
// All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
part of flutter_blue;
class BluetoothCharacteristic {
final Guid uuid;
final DeviceIdentifier deviceId;
final Guid serviceUuid;
final Guid secondaryServiceUuid;
final CharacteristicProperties properties;
final List<BluetoothDescriptor> descriptors;
bool get isNotifying {
try {
var cccd =
descriptors.singleWhere((d) => d.uuid == BluetoothDescriptor.cccd);
return ((cccd.lastValue[0] & 0x01) > 0 || (cccd.lastValue[0] & 0x02) > 0);
} catch (e) {
return false;
}
}
BehaviorSubject<List<int>> _value;
Stream<List<int>> get value => Observable.merge([
_value.stream,
_onValueChangedStream,
]);
List<int> get lastValue => _value.value;
BluetoothCharacteristic.fromProto(protos.BluetoothCharacteristic p)
: uuid = new Guid(p.uuid),
deviceId = new DeviceIdentifier(p.remoteId),
serviceUuid = new Guid(p.serviceUuid),
secondaryServiceUuid = (p.secondaryServiceUuid.length > 0)
? new Guid(p.secondaryServiceUuid)
: null,
descriptors = p.descriptors
.map((d) => new BluetoothDescriptor.fromProto(d))
.toList(),
properties = new CharacteristicProperties.fromProto(p.properties),
_value = BehaviorSubject.seeded(p.value);
Stream<BluetoothCharacteristic> get _onCharacteristicChangedStream =>
FlutterBlue.instance._methodStream
.where((m) => m.method == "OnCharacteristicChanged")
.map((m) => m.arguments)
.map(
(buffer) => new protos.OnCharacteristicChanged.fromBuffer(buffer))
.where((p) => p.remoteId == deviceId.toString())
.map((p) => new BluetoothCharacteristic.fromProto(p.characteristic))
.where((c) => c.uuid == uuid)
.map((c) {
// Update the characteristic with the new values
_updateDescriptors(c.descriptors);
// _value.add(c.lastValue);
// print('c.lastValue: ${c.lastValue}');
return c;
});
Stream<List<int>> get _onValueChangedStream =>
_onCharacteristicChangedStream.map((c) => c.lastValue);
void _updateDescriptors(List<BluetoothDescriptor> newDescriptors) {
for (var d in descriptors) {
for (var newD in newDescriptors) {
if (d.uuid == newD.uuid) {
d._value.add(newD.lastValue);
}
}
}
}
/// Retrieves the value of the characteristic
Future<List<int>> read() async {
var request = protos.ReadCharacteristicRequest.create()
..remoteId = deviceId.toString()
..characteristicUuid = uuid.toString()
..serviceUuid = serviceUuid.toString();
FlutterBlue.instance._log(LogLevel.info,
'remoteId: ${deviceId.toString()} characteristicUuid: ${uuid.toString()} serviceUuid: ${serviceUuid.toString()}');
await FlutterBlue.instance._channel
.invokeMethod('readCharacteristic', request.writeToBuffer());
return FlutterBlue.instance._methodStream
.where((m) => m.method == "ReadCharacteristicResponse")
.map((m) => m.arguments)
.map((buffer) =>
new protos.ReadCharacteristicResponse.fromBuffer(buffer))
.where((p) =>
(p.remoteId == request.remoteId) &&
(p.characteristic.uuid == request.characteristicUuid) &&
(p.characteristic.serviceUuid == request.serviceUuid))
.map((p) => p.characteristic.value)
.first
.then((d) {
_value.add(d);
return d;
});
}
/// Writes the value of a characteristic.
/// [CharacteristicWriteType.withoutResponse]: the write is not
/// guaranteed and will return immediately with success.
/// [CharacteristicWriteType.withResponse]: the method will return after the
/// write operation has either passed or failed.
Future<Null> write(List<int> value, {bool withoutResponse = false}) async {
final type = withoutResponse
? CharacteristicWriteType.withoutResponse
: CharacteristicWriteType.withResponse;
var request = protos.WriteCharacteristicRequest.create()
..remoteId = deviceId.toString()
..characteristicUuid = uuid.toString()
..serviceUuid = serviceUuid.toString()
..writeType =
protos.WriteCharacteristicRequest_WriteType.valueOf(type.index)
..value = value;
var result = await FlutterBlue.instance._channel
.invokeMethod('writeCharacteristic', request.writeToBuffer());
if (type == CharacteristicWriteType.withoutResponse) {
_value.add(value);
return result;
}
return FlutterBlue.instance._methodStream
.where((m) => m.method == "WriteCharacteristicResponse")
.map((m) => m.arguments)
.map((buffer) =>
new protos.WriteCharacteristicResponse.fromBuffer(buffer))
.where((p) =>
(p.request.remoteId == request.remoteId) &&
(p.request.characteristicUuid == request.characteristicUuid) &&
(p.request.serviceUuid == request.serviceUuid))
.first
.then((w) => w.success)
.then((success) => (!success)
? throw new Exception('Failed to write the characteristic')
: null)
.then((_) => _value.add(value))
.then((_) => null);
}
/// Sets notifications or indications for the value of a specified characteristic
Future<bool> setNotifyValue(bool notify) async {
var request = protos.SetNotificationRequest.create()
..remoteId = deviceId.toString()
..serviceUuid = serviceUuid.toString()
..characteristicUuid = uuid.toString()
..enable = notify;
await FlutterBlue.instance._channel
.invokeMethod('setNotification', request.writeToBuffer());
return FlutterBlue.instance._methodStream
.where((m) => m.method == "SetNotificationResponse")
.map((m) => m.arguments)
.map((buffer) => new protos.SetNotificationResponse.fromBuffer(buffer))
.where((p) =>
(p.remoteId == request.remoteId) &&
(p.characteristic.uuid == request.characteristicUuid) &&
(p.characteristic.serviceUuid == request.serviceUuid))
.first
.then((p) => new BluetoothCharacteristic.fromProto(p.characteristic))
.then((c) {
_updateDescriptors(c.descriptors);
_value.add(c.lastValue);
return (c.isNotifying == notify);
});
}
}
enum CharacteristicWriteType { withResponse, withoutResponse }
@immutable
class CharacteristicProperties {
final bool broadcast;
final bool read;
final bool writeWithoutResponse;
final bool write;
final bool notify;
final bool indicate;
final bool authenticatedSignedWrites;
final bool extendedProperties;
final bool notifyEncryptionRequired;
final bool indicateEncryptionRequired;
CharacteristicProperties(
{this.broadcast = false,
this.read = false,
this.writeWithoutResponse = false,
this.write = false,
this.notify = false,
this.indicate = false,
this.authenticatedSignedWrites = false,
this.extendedProperties = false,
this.notifyEncryptionRequired = false,
this.indicateEncryptionRequired = false});
CharacteristicProperties.fromProto(protos.CharacteristicProperties p)
: broadcast = p.broadcast,
read = p.read,
writeWithoutResponse = p.writeWithoutResponse,
write = p.write,
notify = p.notify,
indicate = p.indicate,
authenticatedSignedWrites = p.authenticatedSignedWrites,
extendedProperties = p.extendedProperties,
notifyEncryptionRequired = p.notifyEncryptionRequired,
indicateEncryptionRequired = p.indicateEncryptionRequired;
}
