FlutterBlue is a bluetooth plugin for Flutter, a new app SDK to help developers build modern multi-platform apps.
This library is actively developed alongside production apps, and the API will evolve as we continue our way to version 1.0.
Please be fully prepared to deal with breaking changes. This package must be tested on a real device.
Having trouble adapting to the latest API? I'd love to hear your use-case, please contact me.
FlutterBlue aims to offer the most from both platforms (iOS and Android).
Using the FlutterBlue instance, you can scan for and connect to nearby devices (BluetoothDevice). Once connected to a device, the BluetoothDevice object can discover services (BluetoothService), characteristics (BluetoothCharacteristic), and descriptors (BluetoothDescriptor). The BluetoothDevice object is then used to directly interact with characteristics and descriptors.
FlutterBlue flutterBlue = FlutterBlue.instance;
// Start scanning
flutterBlue.startScan(timeout: Duration(seconds: 4));
// Listen to scan results
var subscription = flutterBlue.scanResults.listen((results) {
// do something with scan results
for (ScanResult r in results) {
print('${r.device.name} found! rssi: ${r.rssi}');
}
});
// Stop scanning
flutterBlue.stopScan();
// Connect to the device
await device.connect();
// Disconnect from device
device.disconnect();
List<BluetoothService> services = await device.discoverServices();
services.forEach((service) {
// do something with service
});
// Reads all characteristics
var characteristics = service.characteristics;
for(BluetoothCharacteristic c in characteristics) {
List<int> value = await c.read();
print(value);
}
// Writes to a characteristic
await c.write([0x12, 0x34])
// Reads all descriptors
var descriptors = characteristic.descriptors;
for(BluetoothDescriptor d in descriptors) {
List<int> value = await d.read();
print(value);
}
// Writes to a descriptor
await d.write([0x12, 0x34])
await characteristic.setNotifyValue(true);
characteristic.value.listen((value) {
// do something with new value
});
final mtu = await device.mtu.first;
await device.requestMtu(512);
Note that iOS will not allow requests of MTU size, and will always try to negotiate the highest possible MTU (iOS supports up to MTU size 185)
Flutter_blue is compatible only from version 19 of Android SDK so you should change this in android/app/build.gradle:
Android {
defaultConfig {
minSdkVersion: 19
We need to add the permission to use Bluetooth and access location:
In the android/app/src/main/AndroidManifest.xml let’s add:
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<application
In the ios/Runner/Info.plist let’s add:
<dict>
<key>NSBluetoothAlwaysUsageDescription</key>
<string>Need BLE permission</string>
<key>NSBluetoothPeripheralUsageDescription</key>
<string>Need BLE permission</string>
<key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
<string>Need Location permission</string>
<key>NSLocationAlwaysUsageDescription</key>
<string>Need Location permission</string>
<key>NSLocationWhenInUseUsageDescription</key>
<string>Need Location permission</string>
For location permissions on iOS see more at: https://developer.apple.com/documentation/corelocation/requesting_authorization_for_location_services
Android | iOS | Description | |
---|---|---|---|
scan | ✅ | ✅ | Starts a scan for Bluetooth Low Energy devices. |
state | ✅ | ✅ | Stream of state changes for the Bluetooth Adapter. |
isAvailable | ✅ | ✅ | Checks whether the device supports Bluetooth. |
isOn | ✅ | ✅ | Checks if Bluetooth functionality is turned on. |
Android | iOS | Description | |
---|---|---|---|
connect | ✅ | ✅ | Establishes a connection to the device. |
disconnect | ✅ | ✅ | Cancels an active or pending connection to the device. |
discoverServices | ✅ | ✅ | Discovers services offered by the remote device as well as their characteristics and descriptors. |
services | ✅ | ✅ | Gets a list of services. Requires that discoverServices() has completed. |
state | ✅ | ✅ | Stream of state changes for the Bluetooth Device. |
mtu | ✅ | ✅ | Stream of mtu size changes. |
requestMtu | ✅ | Request to change the MTU for the device. |
Android | iOS | Description | |
---|---|---|---|
read | ✅ | ✅ | Retrieves the value of the characteristic. |
write | ✅ | ✅ | Writes the value of the characteristic. |
setNotifyValue | ✅ | ✅ | Sets notifications or indications on the characteristic. |
value | ✅ | ✅ | Stream of characteristic's value when changed. |
Android | iOS | Description | |
---|---|---|---|
read | ✅ | ✅ | Retrieves the value of the descriptor. |
write | ✅ | ✅ | Writes the value of the descriptor. |
Make sure the device is advertising which service UUID's it supports. This is found in the advertisement packet as UUID 16 bit complete list or UUID 128 bit complete list.