flutter_bluex 0.9.1

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THIS IS A FORK VERSION OF FLUTTER_BLUE #

Since the original flutter_blue is no longer maintained, I forked the original repository and continued to maintain it for newer versions of Flutter:

• Fixed the crash issue caused by the UUID class on higher Android versions.
• Fixed the issue with the example not running on higher Android versions.
• Added a method to retrieve already bonded devices.
• Added more intuitive functions for getting device connection status and MTU.
• Fixed the issue where the timeout setting in the original connect method would not throw in the current await process.

由于原先的flutter_blue不再维护，我fork了原仓库并针对新版本flutter继续维护：

• 修复了在高版本安卓上由于UUID类导致的闪退问题。
• 修复了示例在高版本安卓上运行的问题。
• 增加了获取已绑定设备的方法。
• 增加了更直观的获取设备连接状态和MTU的函数。
• 修复了原来的connect方法中的timeout设置并不会在当前的await流程中抛出异常的问题。

Introduction #

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.

Usage #

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
flutterBlue.stopScan();

Connect to a device #

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

// Disconnect from device
device.disconnect();

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();
    print(value);
}

// 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();
    print(value);
}

// 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:

Android

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

IOS

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

Reference #

FlutterBlue API #

BluetoothDevice API #

BluetoothCharacteristic API #

BluetoothDescriptor API #

Troubleshooting #

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.