前言

官方套件使用范例

想带大家认识 Flutter Blue 套件 怎麽使用。
了解里面的参数。

蓝牙中具体有些哪些：蓝牙名字（name）蓝芽装置（device）蓝牙信号强度（riss）蓝牙服务(service) 蓝牙服务下面又有小服务。

蓝芽物件介绍

BluetoothState 蓝芽状态

可以去监听 Stream = FlutterBlue.instance.state
BluetoothState

• unknown, // 未知状况，通常我设定这个为初始值
• unavailable, // 不存在蓝芽
• unauthorized, // 未授权
• turningOn, // 正在开启
• on, // 已经开启
• turningOff, // 正在关闭
• off // 已经关闭

ScanResult 蓝芽装置资讯

可以去监听 Stream = FlutterBlue.instance.scanResults

• rssi
• advertisementData
  发出广播封包的装置，其中广播封包包含装置的 MAC 位址也可以有其他额外的资料，像是 device name等...。
• device(BluetoothDevice)
  • name // 装置名称
  • id // 装置 id
  • type(BluetoothDeviceType) // 装置的状态
  • services // 装置服务
  • mtu // 监听 MTU (byte 为单位)
  • state // 监听装置的状态
  • isDiscoveringServices 监听搜寻服务
  • discoverServices() // 从新搜寻服务
  • disconnect() // 取消连接服务
  • connect() 连接服务
  • requestMtu() // 请求改变 Mtu 大小， (IOS 不支援)

BluetoothService

当搜寻到 ScanResult 拿到里面的 device 後。
stream: device.services,
BluetoothService

• uuid
• deviceId
• isPrimary
• characteristics
• includedServices

欢迎上官网了解GATT、参数

想要监听已经连蓝芽的状态

可以每 2 秒监听 Devices 这样子。
Stream.periodic(Duration(seconds: 2)).asyncMap((_) => FlutterBlue.instance.connectedDevices),

用法

初始化蓝芽

FlutterBlue flutterBlue = FlutterBlue.instance;

开始搜寻蓝芽

// 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();

连接、中断 蓝芽

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

// Disconnect from device
device.disconnect();

启用 BlueTooth Service

List<BluetoothService> services = await device.discoverServices();
services.forEach((service) {
    // do something with service
});

读写 characteristics

https://pub.dev/packages/flutter_blue#read-and-write-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])

读写 descriptors

https://pub.dev/packages/flutter_blue#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

https://pub.dev/packages/flutter_blue#set-notifications-and-listen-to-changes

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

读取 MTU and 请求更改 Mtu size

https://pub.dev/packages/flutter_blue#read-the-mtu-and-request-larger-size

final mtu = await device.mtu.first;
await device.requestMtu(512);

Refrence

flutter_blue 套件
GATT
参数