了解如何使用低功耗蓝牙
通过本节,你将学会:
为了使用蓝牙功能,你需要先初始化蓝牙模块。除了设置状态监听以外,所有的蓝牙接口都需要在初始化完成以后才能正常使用。
//初始化蓝牙模块
bluetooth.openAdapter({
//是否打开系统蓝牙开关,默认false
operateAdapter: true,
success: function() {
console.log('success')
},
fail: function(data, code) {
console.log(`handling fail, code = ${code}`)
if (code === 10001) {
//蓝牙未打开,提示用户打开蓝牙
}
},
complete: function() {
console.log('complete')
}
})
你可以通过搜索操作,发现周围的低功耗蓝牙设备。在进行扫描前,你需要注册设备发现回调以及时接收搜索结果
//在扫描之前先注册设备发现回调
bluetooth.ondevicefound = function (data) {
console.log("new device list has founded");
data.devices.forEach(device => {
//发现所需设备后停止扫描
bluetooth.stopDevicesDiscovery();
_this.deviceId = device.deviceId;
console.log(`handling find new devive:${JSON.stringify(device)}`);
console.log(`handling advertisData = ${_this.ab2hex(device.advertisData)}`);
for (let key in device.serviceData) {
console.log(
`handling serviceData: uuid = ${key}, serviceData = ${_this.ab2hex(device.serviceData[key])}`
);
}
});
};
//开始扫描
bluetooth.startDevicesDiscovery({
//指定设备uuid,支持16-bit,32-bit,128-bit uuid,不填则扫描周围所有设备
services: ["1105"],
//是否允许重复设备上报,如果不需要监听广播包数据,建议不设置此项,默认值为false
allowDuplicatesKey: false,
//上报间隔,单位毫秒,为0则立即上报,默认值为0
interval: 1000,
success: function () {
console.log("success");
}
});
在操作设备前,你需要先连接设备,连接操作可以通过deviceId直接进行,扫描并不是必要的操作。在连接前,你可以注册设备连接状态接口来监听设备断连状态
//注册设备连接状态监听
bluetooth.onbleconnectionstatechange = function (data) {
console.log(`handling device state change: deviceId = ${data.deviceId}, connected = ${data.connected}`)
//更新设备连接状态
_this.connected = data.connected
if (data.connected) {
//目标设备连接后,获取服务列表
_this.getServices()
} else {
//做断开连接的相关操作,比如重新连接,或者重新扫描等
}
}
//连接设备
bluetooth.createBLEConnection({
deviceId: _this.deviceId,
success: function () {
console.log("success")
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`)
},
complete: function () {
console.log("complete")
}
})
每个设备都会定义若干个服务,你可以从中获取需要操作的服务信息
bluetooth.getBLEDeviceServices({
deviceId: _this.deviceId,
success: function (data) {
data.services.forEach(service => {
console.log(`handling device services: uuid = ${service.uuid}, isPrimary = ${service.isPrimary}`)
//获取需要的服务,可以根据设备定义的uuid筛选
if (service.isPrimary) {
_this.serviceId = service.uuid
//获取特征值列表
_this.getCharacteristics()
}
})
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`)
},
complete: function () {
console.log("complete")
}
})
每个服务内会定义若干个特征值,你可以从中获取需要操作的特征值信息
bluetooth.getBLEDeviceCharacteristics({
deviceId: _this.deviceId,
serviceId: _this.serviceId,
success: function (data) {
data.characteristics.forEach(characteristic => {
console.log(`handling device characteristic : ${JSON.stringify(characteristic)}`)
//获取需要的特征值,可以根据设备定义的uuid筛选
if (characteristic.properties.write) {
_this.writeCharacteristicId = characteristic.uuid
} else if (characteristic.properties.read) {
_this.readCharacteristicId = characteristic.uuid
} else if (characteristic.properties.notify || characteristic.properties.indicate) {
_this.notifyCharacteristicId = characteristic.uuid
}
})
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`)
},
complete: function () {
console.log("complete")
}
})
通过获取到的服务与特征值信息,可以向设备对应的特征值写入数据,需要该特征值支持 write
let buffer = new ArrayBuffer(2)
let dataView = new DataView(buffer)
dataView.setUint8(0, 0)
dataView.setUint8(1, 0xf)
bluetooth.writeBLECharacteristicValue({
// 这里的 deviceId 需要在 getBluetoothDevices 或 onBluetoothDeviceFound接口中获取
deviceId: _this.deviceId,
// 这里的 serviceId 需要在 getBLEDeviceServices 接口中获取
serviceId: _this.serviceId,
// 这里的 characteristicId 需要在 getBLEDeviceCharacteristics 接口中获取
characteristicId: _this.writeCharacteristicId,
// 这里的value是ArrayBuffer类型
value: buffer,
success: function () {
console.log("success")
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`)
},
complete: function () {
console.log("complete")
}
})
通过获取到的服务与特征值信息,可以读取设备对应特征值数据,需要该特征值支持 read,读取到的设备信息会通过onblecharacteristicvaluechange监听接口上报,此接口蓝牙模块通用,无需重复注册
//注册特征值改变监听
bluetooth.onblecharacteristicvaluechange = function (data) {
console.log(`handling characteristic value change: deviceId = ${data.deviceId}, serviceId = ${data.serviceId}, characteristicId = ${data.characteristicId}, value = ${_this.ab2hex(data.value)}`)
}
bluetooth.readBLECharacteristicValue({
// 这里的 deviceId 需要已经通过 createBLEConnection 与对应设备建立链接
deviceId: _this.deviceId,
// 这里的 serviceId 需要在 getBLEDeviceServices 接口中获取
serviceId: _this.serviceId,
// 这里的 characteristicId 需要在 getBLEDeviceCharacteristics 接口中获取
characteristicId: _this.readCharacteristicId,
success: function () {
// 执行操作成功,读取的值会在onblecharacteristicvaluechange 接口中上报
console.log("success")
}
})
通过获取到的服务与特征值信息,可以开启或者关闭设备相应的特征值变化时的通知功能,需要该特征值支持 notify 或者 indicate,读取到的设备信息会通过onblecharacteristicvaluechange监听接口上报,此接口蓝牙模块通用,无需重复注册
//注册特征值改变监听
bluetooth.onblecharacteristicvaluechange = function (data) {
console.log(`handling characteristic value change: deviceId = ${data.deviceId}, serviceId = ${data.serviceId}, characteristicId = ${data.characteristicId}, value = ${_this.ab2hex(data.value)}`)
}
bluetooth.notifyBLECharacteristicValueChange({
// 启用 notify 功能,为true则开启通知
state: enable,
// 这里的 deviceId 需要已经通过 createBLEConnection 与对应设备建立链接
deviceId: _this.deviceId,
// 这里的 serviceId 需要在 getBLEDeviceServices 接口中获取
serviceId: _this.serviceId,
// 这里的 characteristicId 需要在 getBLEDeviceCharacteristics 接口中获取
characteristicId: _this.notifyCharacteristicId,
success: function () {
// 执行操作成功,读取的值会在onblecharacteristicvaluechange 接口中上报
_this.notifyEnabled = enable
console.log("success")
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`)
},
complete: function () {
console.log("complete")
}
})
在不需要使用蓝牙时,需要注销蓝牙模块,以释放系统资源
//取消不需要的状态监听
bluetooth.onadapterstatechange = null
bluetooth.onbleconnectionstatechange = null
bluetooth.onblecharacteristicvaluechange = null
bluetooth.ondevicefound = null
//注销蓝牙模块
bluetooth.closeAdapter({
//是否关闭系统蓝牙开关,默认false,此操作会直接关闭系统蓝牙,为了不影响用户其他蓝牙设备的体验,不建议设置为true
operateAdapter: false,
success: function () {
console.log("success");
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`);
},
complete: function () {
console.log("complete");
}
});
示例代码如下:
<template>
<div class="doc-page">
<div class="item-container">
<text></text>
<input type="button" class="btn" onclick="startDiscovery" value="扫描设备" />
<input type="button" class="btn" onclick="createConnection" value="连接设备" />
<input type="button" class="btn" onclick="closeConnection" value="断开设备" />
</div>
<div class="item-container" if=false>
<input type="button" class="btn" onclick="write" value="写入数据" />
<input type="button" class="btn" onclick="read" value="读取数据" />
</div>
</div>
</template>
<style>
.doc-page {
flex: 1;
flex-direction: column;
}
.item-container {
flex - direction: column;
margin-bottom: 50px;
margin-right: 60px;
margin-left: 60px;
}
.text {
width: 100%;
margin-top: 5px;
background-color: white;
padding: 3px;
margin-top: 1px;
font-size: 28px;
color: black;
}
.btn {
height: 80px;
text-align: center;
border-radius: 5px;
margin-right: 60px;
margin-left: 60px;
margin-bottom: 50px;
color: #ffffff;
font-size: 30px;
background-color: #0faeff;
line-height: 80px;
}
</style>
<script>
import bluetooth from "@system.bluetooth";
export default {
private: {
connected: false,
notifyEnabled: false,
deviceId: '',
readCharacteristicId: '',
writeCharacteristicId: '',
notifyCharacteristicId: ''
},
//arrayBuffer转String
ab2hex(buffer) {
var hexArr = Array.prototype.map.call(
new Uint8Array(buffer),
function (bit) {
return ("00" + bit.toString(16)).slice(-2);
});
return hexArr.join("");
},
//在页面初始化时进行蓝牙模块初始化操作
onInit() {
let _this = this
//注册蓝牙适配器监听
bluetooth.onadapterstatechange = function (data) {
console.log("adapterState changed, now is", data.available);
};
//注册设备连接状态监听
bluetooth.onbleconnectionstatechange = function (data) {
console.log(`handling device state change: deviceId = ${data.deviceId}, connected = ${data.connected}`)
//更新设备连接状态
_this.connected = data.connected
if (data.connected) {
//目标设备连接后,获取服务列表
_this.getServices()
} else {
//做断开连接的相关操作,比如重新连接,或者重新扫描等
}
}
//注册特征值改变监听
bluetooth.onblecharacteristicvaluechange = function (data) {
console.log(`handling characteristic value change: deviceId = ${data.deviceId}, serviceId = ${data.serviceId}, characteristicId = ${data.characteristicId}, value = ${_this.ab2hex(data.value)}`)
}
//初始化蓝牙模块
bluetooth.openAdapter({
//是否打开系统蓝牙开关,默认false
operateAdapter: true,
success: function () {
console.log("success");
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`);
if (code === 10001) {
//蓝牙未打开,提示用户打开蓝牙
}
},
complete: function () {
console.log("complete");
}
});
},
//在结束时注销蓝牙模块
onDestroy() {
//取消不需要的状态监听
bluetooth.onadapterstatechange = null
bluetooth.onbleconnectionstatechange = null
bluetooth.onblecharacteristicvaluechange = null
bluetooth.ondevicefound = null
//注销蓝牙模块
bluetooth.closeAdapter({
//是否关闭系统蓝牙开关,默认false,此操作会直接关闭系统蓝牙,为了不影响用户其他蓝牙设备的体验,不建议设置为true
operateAdapter: false,
success: function () {
console.log("success");
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`);
},
complete: function () {
console.log("complete");
}
});
},
startDiscovery() {
let _this = this
//在扫描之前先注册设备发现回调
bluetooth.ondevicefound = function (data) {
console.log("new device list has founded");
data.devices.forEach(device => {
//发现所需设备后停止扫描
bluetooth.stopDevicesDiscovery();
_this.deviceId = device.deviceId;
console.log(`handling find new devive:${JSON.stringify(device)}`);
console.log(`handling advertisData = ${_this.ab2hex(device.advertisData)}`);
for (let key in device.serviceData) {
console.log(
`handling serviceData: uuid = ${key}, serviceData = ${_this.ab2hex(device.serviceData[key])}`
);
}
});
};
//开始扫描
bluetooth.startDevicesDiscovery({
//指定设备uuid,支持16-bit,32-bit,128-bit uuid,不填则扫描周围所有设备
services: ["1105"],
//是否允许重复设备上报,如果不需要监听广播包数据,建议不设置此项,默认值为false
allowDuplicatesKey: false,
success: function () {
console.log("success");
}
});
},
createConnection() {
let _this = this
//连接设备
bluetooth.createBLEConnection({
deviceId: _this.deviceId,
success: function () {
console.log("success")
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`)
},
complete: function () {
console.log("complete")
}
})
},
closeConnection() {
let _this = this
bluetooth.closeBLEConnection({
deviceId: _this.deviceId,
success: function () {
console.log("success")
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`)
},
complete: function () {
console.log("complete")
}
})
},
getServices() {
let _this = this
bluetooth.getBLEDeviceServices({
deviceId: _this.deviceId,
success: function (data) {
data.services.forEach(service => {
console.log(`handling device services: uuid = ${service.uuid}, isPrimary = ${service.isPrimary}`)
//获取需要的服务,可以根据设备定义的uuid筛选
if (service.isPrimary) {
_this.serviceId = service.uuid
//获取特征列表
_this.getCharacteristics()
}
})
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`)
},
complete: function () {
console.log("complete")
}
})
},
getCharacteristics() {
let _this = this
bluetooth.getBLEDeviceCharacteristics({
deviceId: _this.deviceId,
serviceId: _this.serviceId,
success: function (data) {
data.characteristics.forEach(characteristic => {
console.log(`handling device characteristic : ${JSON.stringify(characteristic)}`)
//获取需要的特征,可以根据设备定义的uuid筛选
if (characteristic.properties.write) {
_this.writeCharacteristicId = characteristic.uuid
} else if (characteristic.properties.read) {
_this.readCharacteristicId = characteristic.uuid
} else if (characteristic.properties.notify || characteristic.properties.indicate) {
_this.notifyCharacteristicId = characteristic.uuid
}
})
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`)
},
complete: function () {
console.log("complete")
}
})
},
write() {
let _this = this
let buffer = new ArrayBuffer(2)
let dataView = new DataView(buffer)
dataView.setUint8(0, 0)
dataView.setUint8(1, 0xf)
bluetooth.writeBLECharacteristicValue({
// 这里的 deviceId 需要在 getBluetoothDevices 或 onBluetoothDeviceFound接口中获取
deviceId: _this.deviceId,
// 这里的 serviceId 需要在 getBLEDeviceServices 接口中获取
serviceId: _this.serviceId,
// 这里的 characteristicId 需要在 getBLEDeviceCharacteristics 接口中获取
characteristicId: _this.writeCharacteristicId,
// 这里的value是ArrayBuffer类型
value: buffer,
success: function () {
console.log("success")
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`)
},
complete: function () {
console.log("complete")
}
})
},
read() {
let _this = this
bluetooth.readBLECharacteristicValue({
// 这里的 deviceId 需要已经通过 createBLEConnection 与对应设备建立链接
deviceId: _this.deviceId,
// 这里的 serviceId 需要在 getBLEDeviceServices 接口中获取
serviceId: _this.serviceId,
// 这里的 characteristicId 需要在 getBLEDeviceCharacteristics 接口中获取
characteristicId: _this.readCharacteristicId,
success: function () {
// 执行操作成功,读取的值会在onblecharacteristicvaluechange 接口中上报
console.log("success")
}
})
},
notifyDevice(enable) {
let _this = this
bluetooth.notifyBLECharacteristicValueChange({
// 启用 notify 功能
state: enable,
// 这里的 deviceId 需要已经通过 createBLEConnection 与对应设备建立链接
deviceId: _this.deviceId,
// 这里的 serviceId 需要在 getBLEDeviceServices 接口中获取
serviceId: _this.serviceId,
// 这里的 characteristicId 需要在 getBLEDeviceCharacteristics 接口中获取
characteristicId: _this.notifyCharacteristicId,
success: function () {
// 执行操作成功,读取的值会在onblecharacteristicvaluechange 接口中上报
_this.notifyEnabled = enable
console.log("success")
},
fail: function (data, code) {
console.log(`handling fail, code = ${code}`)
},
complete: function () {
console.log("complete")
}
})
}
};
</script>