A Incredible Bluetooth Plugin For Flutter Applications



Bluetooth is a sort of capability that allows access to and from other electronic devices. In the app world, it is the most dependable wireless tool for connecting to other devices, and it also provides a free service because it is incorporated into most mobile and other electronic devices. However, some gadgets, such as mobile phones, are now available without Bluetooth because their developers choose to rely on the internet for all connectivity rather than Bluetooth. Bluetooth is still a dependable connectivity option in this day of digitalization, when the internet is cheaper than food and every electronic equipment is becoming an internet-processed device.
To incorporate Bluetooth capabilities in our app, we’ll utilize the flutter blue package in this blog.

FlutterBlue is a bluetooth plugin for Flutter, a new app SDK to help developers build modern multi-platform apps.

Alpha version

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.

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.


Obtain an instance

FlutterBlue flutterBlue = FlutterBlue.instance;

Scan for devices

// 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

Connect to a device

// Connect to the device
await device.connect();

// Disconnect from device

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 c.read();

// Writes to a characteristic
await c.write([0x12, 0x34])

Read and write descriptors

// Reads all descriptors
var descriptors = characteristic.descriptors;
for(BluetoothDescriptor d in descriptors) {
    List<int> value = await d.read();

// Writes to a descriptor
await d.write([0x12, 0x34])

Set notifications and listen to changes

await characteristic.setNotifyValue(true);
characteristic.value.listen((value) {
    // do something with new value

Read the MTU and request larger size

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)

Getting Started

Change the minSdkVersion for Android

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

Add permissions for Bluetooth

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"/>  


In the ios/Runner/Info.plist let’s add:

	    <string>Need BLE permission</string>  
	    <string>Need BLE permission</string>  
	    <string>Need Location permission</string>  
	    <string>Need Location permission</string>  
	    <string>Need Location permission</string>

For location permissions on iOS see more at: https://developer.apple.com/documentation/corelocation/requesting_authorization_for_location_services


FlutterBlue API

scanStarts a scan for Bluetooth Low Energy devices.
stateStream of state changes for the Bluetooth Adapter.
isAvailableChecks whether the device supports Bluetooth.
isOnChecks if Bluetooth functionality is turned on.

BluetoothDevice API

connectEstablishes a connection to the device.
disconnectCancels an active or pending connection to the device.
discoverServicesDiscovers services offered by the remote device as well as their characteristics and descriptors.
servicesGets a list of services. Requires that discoverServices() has completed.
stateStream of state changes for the Bluetooth Device.
mtuStream of mtu size changes.
requestMtuRequest to change the MTU for the device.

BluetoothCharacteristic API

readRetrieves the value of the characteristic.
writeWrites the value of the characteristic.
setNotifyValueSets notifications or indications on the characteristic.
valueStream of characteristic’s value when changed.

BluetoothDescriptor API

readRetrieves the value of the descriptor.
writeWrites the value of the descriptor.


When I scan using a service UUID filter, it doesn’t find any devices.

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.


Source Code: flutter_blue.

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