Bluetooth plugin for Flutter

flutterblue

flutterblue is a bluetooth plugin for flutter, a new mobile sdk to help developers build modern apps for ios and android.

cross-platform bluetooth le

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.

usage for bluetooth plugin

obtain an instance

flutterblue flutterblue = flutterblue.instance;

scan for devices

/// start scanning
var scansubscription = flutterblue.scan().listen((scanresult) {
    // do something with scan result
});

/// stop scanning
scansubscription.cancel();

connect to a device

/// create a connection to the device
var deviceconnection = flutterblue.connect(device).listen((s) {
    if(s == bluetoothdevicestate.connected) {
        // device is connected, do something
    }
});

/// disconnect from device
deviceconnection.cancel();

discover services

list<bluetoothservice> services = await device.discoverservices();
services.foreach((service) {
    // do something with service
});

read and write characteristics

// reads all characteristics
var characteristics = service.characteristics;
for(bluetoothcharacteristic c in characteristics) {
    list<int> value = await device.readcharacteristic(c);
    print(value);
}

// writes to a characteristic
await device.writecharacteristic(c, [0x12, 0x34])

read and write descriptors

// reads all descriptors
var descriptors = characteristic.descriptors;
for(bluetoothdescriptor d in descriptors) {
    list<int> value = await device.readdescriptor(d);
    print(value);
}

// writes to a descriptor
await device.writedescriptor(d, [0x12, 0x34])

set notifications

await device.setnotifyvalue(characteristic, true);
device.onvaluechanged(characteristic).listen((value) {
    // do something with new value
});

reference

flutterblue api

bluetoothdevice api

troubleshooting

scanning for service uuid’s doesn’t return any results

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.