flutter_ble_lib 2.1.0

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Flutter BLE library logo

FlutterBleLib #

A library for all your Bluetooth Low Energy needs in Flutter. Internally utilises Polidea's MultiPlatformBleAdapter, which runs on RxAndroidBle and RxBluetoothKit.

BLE Simulator #

This library supports BLEmulator, the BLE simulator. The simulation allows one to develop without physical smartphone or BLE peripheral and use one's production BLE–related code in automated testing.

Usage #

To use this plugin, add flutter_ble_lib as a dependency in your pubspec.yaml file.

Overview #

The library is organised around a few base entities, which are:

  • BleManager
  • Peripheral
  • Service
  • Characteristic

You have to create an instance BleManager and initialise underlying native resources. Using that instance you then obtain an instance of Peripheral, which can be used to run operations on the corresponding peripheral.

All operations passing the Dart-native bridge are asynchronous, hence all operations in the plugin return either Future or Stream.

For more informations, see REFERENCE.

Notice: this library will not handle any permissions for you. To be able to scan for peripherals on Android you need ACCESS_FINE_LOCATION according to Android Developer Guide.

Initialising #

BleManager bleManager = BleManager();
bleManager.createClient(); //ready to go!
// your peripheral logic
bleManager.destroyClient(); //remember to release native resources when you're done!

Following snippets assume the library has been initialised.

Handling Bluetooth adapter state #

enum BluetoothState {
  UNKNOWN,
  UNSUPPORTED,
  UNAUTHORIZED,
  POWERED_ON,
  POWERED_OFF,
  RESETTING,
}


bleManager.enableRadio(); //ANDROID-ONLY turns on BT. NOTE: doesn't check permissions
bleManager.disableRadio() //ANDROID-ONLY turns off BT. NOTE: doesn't check permissions
BluetoothState currentState = await bleManager.bluetoothState();
bleManager.observeBluetoothState().listen((btState) {
  print(btState);
  //do your BT logic, open different screen, etc.
});

Scanning for peripherals #

bleManager.startPeripheralScan(
  uuids: [
    "F000AA00-0451-4000-B000-000000000000",
  ],
).listen((scanResult) {
  //Scan one peripheral and stop scanning
  print("Scanned Peripheral ${scanResult.peripheral.name}, RSSI ${scanResult.rssi}");
  bleManager.stopPeripheralScan();
});

The snippet above starts peripheral scan and stops it after receiving first result. It filters the scan results to those that advertise a service with specified UUID.

Connecting to peripheral #

First you must obtain a ScanResult from BleManager.startPeripheralScan().

Peripheral peripheral = scanResult.peripheral;
peripheral.observeConnectionState(emitCurrentValue: true, completeOnDisconnect: true)
  .listen((connectionState) {
    print("Peripheral ${scanResult.peripheral.identifier} connection state is $connectionState");
  });
await peripheral.connect();
bool connected = await peripheral.isConnected();
await peripheral.disconnectOrCancelConnection();

The snippet above starts observing the state of the connection to the peripheral, connects to it, checks if it's connected and then disconnects from it.

Transactions #

Methods that do not have counterpart with opposite effect and are asynchronous accept String transactionId as an optional argument, to allow the user to cancel such an operation. The Future returned to Dart will then finish with a BleError(BleErrorCode.operationCancelled...), but this will only discard the result of the operation, the operation itself will be executed either way.

For example, if I decided that I no longer want to run discovery on the selected peripheral:

//assuming peripheral is connected
peripheral.discoverAllServicesAndCharacteristics(transactionId: "discovery"); 
//will return operation cancelled error after calling the below 
bleManager.cancelTransaction("discovery");

Each new operation with the same transactionId will cause the previous one to be cancelled with error, if it hasn't finished yet. If transactionId is set to null or it isn't specified at all, the library sets unique integer transactionId to such operation.

NOTE: Do not to set integers as transactionId as they are used by the library.

Obtaining characteristics #

To be able to operate on the peripheral, discovery of its services and characteristics must be run first.

//assuming peripheral is connected
await peripheral.discoverAllServicesAndCharacteristics();
List<Service> services = await peripheral.services(); //getting all services
List<Characteristic> characteristics1 = await peripheral.characteristics("F000AA00-0451-4000-B000-000000000000");
List<Characteristic> characteristics2 = await services.firstWhere(
  (service) => service.uuid == "F000AA00-0451-4000-B000-000000000000").characteristics();

//characteristics1 and characteristics2 have the same contents

Objects representing characteristics have a unique identifer, so they point to one specific characteristic, even if there are multiple service/characteristic uuid matches.

Manipulating characteristics #

Below are 3 methods of writing to a characteristic, which all result in the same effect given there's only one service with specified UUID and only one characteristic with specified UUID.

peripheral.writeCharacteristic(
  "F000AA00-0451-4000-B000-000000000000",
  "F000AA02-0451-4000-B000-000000000000",
  Uint8List.fromList([0]),
  false); //returns Characteristic to chain operations more easily

service.writeCharacteristic(
  "F000AA02-0451-4000-B000-000000000000",
  Uint8List.fromList([0]),
  false); //returns Characteristic to chain operations more easily

characteristic.write(Uint8List.fromList([0]), false); //returns void

Monitoring or reading a characteristic from Peripheral/Service level return CharacteristicWithValue object, which is Characteristic with additional Uint8List value property.

Facilitated by Frontside #

Frontside provided architectural advice and financial support for this library on behalf of Resideo.

Maintained by #

This library is maintained by Polidea

Contact us

Learn more about Polidea's BLE services.

Maintainers #

TBD

License #

Copyright 2019 Polidea Sp. z o.o

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

More from Polidea #

Check out other Polidea's BLE libraries:

2.1.0 #

  • BREAKING ScanResult.AdvertisementData.ManufacturerData has changed type from Int8List to Uint8List
  • Fix issue with invalid value of manufacturer data in scan results
  • Fix issue with initialising plugin from a service without an active activity
  • Update README with information about permissions
  • Fix issue with default value of MTU when connecting to a peripheral on Android
  • Fix issue where first few notifications right after start of monitoring a characteristic could get lost

2.0.1 #

  • Fix issue with automatically generated transaction IDs.

2.0.0 #

  • Dart 2.0 support
  • BREAKING Completely new API. Consult README for instructions on how to use the new version.
  • Added BLEmulator support

example/README.md

flutter_ble_lib_example #

Demonstrates how to use the flutter_ble_lib plugin.

Getting Started #

This project is a starting point for a Flutter application.

A few resources to get you started if this is your first Flutter project:

For help getting started with Flutter, view our online documentation, which offers tutorials, samples, guidance on mobile development, and a full API reference.

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:


dependencies:
  flutter_ble_lib: ^2.1.0

2. Install it

You can install packages from the command line:

with Flutter:


$ flutter pub get

Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:


import 'package:flutter_ble_lib/flutter_ble_lib.dart';
  
Popularity:
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86
Health:
Code health derived from static analysis. [more]
100
Maintenance:
Reflects how tidy and up-to-date the package is. [more]
100
Overall:
Weighted score of the above. [more]
93
Learn more about scoring.

We analyzed this package on Jan 27, 2020, and provided a score, details, and suggestions below. Analysis was completed with status completed using:

  • Dart: 2.7.1
  • pana: 0.13.4
  • Flutter: 1.12.13+hotfix.5

Health issues and suggestions

Document public APIs. (-0.43 points)

407 out of 415 API elements have no dartdoc comment.Providing good documentation for libraries, classes, functions, and other API elements improves code readability and helps developers find and use your API.

Dependencies

Package Constraint Resolved Available
Direct dependencies
Dart SDK >=2.1.0 <3.0.0
async ^2.2.0 2.4.0
collection ^1.14.11 1.14.11 1.14.12
flutter 0.0.0
Transitive dependencies
meta 1.1.8
sky_engine 0.0.99
typed_data 1.1.6
vector_math 2.0.8
Dev dependencies
flutter_test
mockito ^4.0.0
test ^1.5.3