蓝牙部分知识
- 关于Service:
每个设备包含有多个Service，每个Service对应一个uuid
- 关于Characteristic
每个Service包含多个Characteristic，每个Characteristic对应一个uuid
- 如何得到数据
我们想要的数据是包含在每一个Characteristic
微信小程序目前提供的蓝牙API：详细参数请见小程序开发文档
1.操作蓝牙适配器的4个API
wx.openBluetoothAdapter //初始化蓝牙适配器
wx.closeBluetoothAdapter //关闭蓝牙模块
wx.getBluetoothAdapterState //获取本机蓝牙适配器状态
wx.onBluetoothAdapterStateChange //监听蓝牙适配器状态变化事件
2.连接前使用的共有4个，分别是
wx.startBluetoothDevicesDiscovery //开始搜寻附近的蓝牙外围设备
wx.stopBluetoothDevicesDiscovery //停止搜寻附近的蓝牙外围设备
wx.getBluetoothDevices //获取所有已发现的蓝牙设备
wx.onBluetoothDeviceFound //监听寻找到新设备的事件3.连接和断开时使用的共有2个，分别是
wx.createBLEConnection //连接低功耗蓝牙设备
wx.closeBLEConnection //断开与低功耗蓝牙设备的连接4.连接成功后使用的共有8个，分别是
wx.getConnectedBluetoothDevices //根据 uuid 获取处于已连接状态的设备
wx.getBLEDeviceServices //获取蓝牙设备所有 service（服务）
wx.getBLEDeviceCharacteristics //获取蓝牙设备所有 characteristic（特征值）
wx.readBLECharacteristicValue //读取低功耗蓝牙设备的特征值的二进制数据值
wx.writeBLECharacteristicValue //向低功耗蓝牙设备特征值中写入二进制数据
wx.notifyBLECharacteristicValueChange //启用低功耗蓝牙设备特征值变化时的 notify 功能
wx.onBLECharacteristicValueChange //监听低功耗蓝牙设备的特征值变化
wx.onBLEConnectionStateChange //监听低功耗蓝牙连接的错误事件
基本操作流程
1.初始化蓝牙适配器
2.开始搜寻附近的蓝牙外围设备
3.监听寻找到新设备的事件
4.连接低功耗蓝牙设备
5获取蓝牙设备所有 service 和 characteristic
6.读取或写入低功耗蓝牙设备的特征值的二进制数据值。
示例：
<!--index.wxml-->
<view class="container">
<view class="content">
<text class="status">适配器状态：{{ status }}</text>
<text class="sousuo">是否搜索：{{ sousuo }}</text>
<text class="msg">消息：{{ msg }} </text>
<button type="default" class="button" bindtap="initializeBluetooth">初始化蓝牙适配器</button>
<button type="default" class="button" bindtap="searchBluetooth">搜索蓝牙设备 </button>
<button type="default" class="button" bindtap="getServices">获取连接设备所有service</button>
<button type="default" class="button" bindtap="sendMessages">发送消息</button>
<button type="default" class="button" bindtap="startBletNotify">启用设备特征值变化时的notify</button>
<button type="default" class="button" bindtap="receiveMessages">接收消息</button>
<button type="default" class="button" bindtap="closeBluetooth">断开蓝牙连接</button>
<view class="section">
<text class="status">接收到消息：{{ jieshou }}</text>
</view>
</view>
<view class="venues_list" >
<block wx:for="{{devices}}" wx:key="{{test}}">
<view class="venues_item">
<text class="status1">设备名称: {{item.name}} </text>
<text class="status">设备ID: {{item.deviceId}} </text>
<text class='status'>广播数据: {{item.advertisData}} </text>
<text class='status'>信号强度RSSI: {{item.RSSI}} </text>
<text class="status">连接状态:{{connectedDeviceId == item.deviceId?"已连接":"未连接"}} </text>
<view class="section">
</view>
<view class="section">
<button type="warn" class="button" id="{{item.deviceId}}" bindtap="connectTO">连接</button>
</view>
</view>
</block>
</view>
</view>
//index.js
//获取应用实例
//index.js
//获取应用实例
const app = getApp()
Page({
data: {
status: "",
sousuo: "",
connectedDeviceId: "", //已连接设备uuid
services: [], // 连接设备的服务
serviceId: "",
characteristics: "", // 连接设备的状态值
writeServicweId: "", // 可写服务uuid
writeCharacteristicsId: "",//可写特征值uuid
readServicweId: "", // 可读服务uuid
readCharacteristicsId: "",//可读特征值uuid
notifyServicweId: "", //通知服务UUid
notifyCharacteristicsId: "", //通知特征值UUID
inputValue: "",
characteristics1: "", // 连接设备的状态值
},
onLoad: function () {
},
// 初始化蓝牙适配器
initializeBluetooth: function () {
var that = this;
if (!wx.openBluetoothAdapter) {
console.log('蓝牙适配器打开失败，请检查微信版本或手机是否支持小程序蓝牙模块！')
} else {
wx.openBluetoothAdapter({
success: function (res) {
that.setData({
msg: "初始化蓝牙适配器成功！"
})
wx.getBluetoothAdapterState({//获取本机蓝牙适配器状态
success: function (res) {
console.log('本机蓝牙适配器状态：')
console.log(res)
}
})
}
})
}
},
//搜索获取已发现设备
searchBluetooth: function () {
var that = this;
wx.startBluetoothDevicesDiscovery({//开始搜寻附近的蓝牙外围设备
success: function (res) {
console.log('开始搜索周边蓝牙设备')
console.log(res)
wx.getBluetoothDevices({//sucess返回uuid 对应的的已连接设备列表，Array类型
success: function (res) {
//是否有已连接设备
wx.getConnectedBluetoothDevices({////根据 uuid 获取处于已连接状态的设备
success: function (res) {
console.log('已连接的蓝牙设备:')
console.log(JSON.stringify(res.devices));
that.setData({
connectedDeviceId: res.deviceId
})
}
})
that.setData({
devices: res.devices,
})
}
})
}
})
},
//连接设备
connectTO: function (e) {
var that = this;
wx.stopBluetoothDevicesDiscovery({ //先停止搜索周边设备
success: function (res) {
console.log('连接设备前，先停止搜索周边设备:')
console.log(res)
}
})
wx.showLoading({
title: '连接蓝牙设备中...',
})
wx.createBLEConnection({//若小程序在之前已有搜索过某个蓝牙设备，并成功建立链接，可直接传入之前搜索获取的deviceId直接尝试连接该设备，无需进行搜索操作。
deviceId: e.currentTarget.id,
success: function (res) {
console.log('连接成功:')
console.log(res)
wx.hideLoading()
that.setData({
connectedDeviceId: e.currentTarget.id, //currentTarget: 事件绑定的元素
msg: "已连接" + e.currentTarget.id,
})
},
fail: function () {
console.log("调用失败");
},
complete: function () {
console.log('已连接设备ID：' + that.data.connectedDeviceId);
console.log("调用结束");
}
})
},
// 获取连接设备的service服务
getServices: function () {
var that = this;
wx.getBLEDeviceServices({//获取在小程序蓝牙模块生效期间所有已发现的蓝牙设备，包括已经和本机处于连接状态的设备
// 这里的 deviceId 需要在上面的 getBluetoothDevices 或 onBluetoothDeviceFound 接口中获取
deviceId: that.data.connectedDeviceId,
success: function (res) {
//console.log('获取蓝牙设备所有服务成功：', res);
that.data.services = res.services
console.log('获取蓝牙设备所有服务成功：', that.data.services);
that.setData({
serviceId: that.data.services[0].uuid,
})
console.log("服务uuid:", that.data.serviceId)
wx.getBLEDeviceCharacteristics({
// 这里的 deviceId 需要在上面的 getBluetoothDevices 或 onBluetoothDeviceFound 接口中获取
deviceId: that.data.connectedDeviceId,
// 这里的 serviceId 需要在上面的 getBLEDeviceServices 接口中获取
serviceId: that.data.serviceId, //-----注意是that.data.services[0].uuid
success: function (res) {
console.log('serviceId: that.data.services[0].uuid: ', that.data.serviceId)
console.log(res)
for (var i = 0; i < res.characteristics.length; i++) {
if (res.characteristics[i].properties.notify) { //注意characteristic(特征值)信息,properties对象
that.setData({
notifyServicweId: that.data.services[0].uuid,
notifyCharacteristicsId: res.characteristics[i].uuid,
})
console.log("notifyServicweId:", that.data.notifyServicweId,"notifyCharacteristicsId", that.data.notifyCharacteristicsId)
}
if (res.characteristics[i].properties.write) {
that.setData({
writeServicweId: that.data.services[0].uuid,
writeCharacteristicsId: res.characteristics[i].uuid,
})
console.log("writeServicweId:", that.data.writeServicweId, "writeCharacteristicsId", that.data.writeCharacteristicsId)
} else if (res.characteristics[i].properties.read) {
that.setData({
readServicweId: that.data.services[0].uuid,
readCharacteristicsId: res.characteristics[i].uuid,
})
console.log("readServicweId:", that.data.readServicweId, "readCharacteristicsId", that.data.readCharacteristicsId)
}
}
},
fail: function () {
console.log("获取连接设备的所有特征值：", res);
},
complete: function () {
console.log("complete!");
}
})
}
})
},
//断开设备连接
closeBluetooth: function () {
var that = this;
wx.closeBLEConnection({
deviceId: that.data.connectedDeviceId,
success: function (res) {
console.log('断开设备连接: ', devicedId)
console.log(res)
}
})
},
//发送
sendMessages: function () {
var that = this;
// 这里的回调可以获取到 write 导致的特征值改变
wx.onBLECharacteristicValueChange(function (characteristic) {
console.log('characteristic value changed:1', characteristic)
})
var buf = new ArrayBuffer(16)
var dataView = new DataView(buf)
dataView.setUint8(0, 99)
wx.writeBLECharacteristicValue({
deviceId: that.data.connectedDeviceId,
serviceId: that.data.writeServicweId,
characteristicId: that.data.writeCharacteristicsId,
value: buf,
success: function (res) {
console.log('writeBLECharacteristicValue success', res)
}
})
},
//启用低功耗蓝牙设备特征值变化时的 notify 功能
startBletNotify: function () {
var that = this;
wx.notifyBLECharacteristicValueChange({
state: true, // 启用 notify 功能
deviceId: that.data.connectedDeviceId,
serviceId: that.data.notifyServicweId,
characteristicId: that.data.notifyCharacteristicsId,
success: function (res) {
console.log('notifyBLECharacteristicValueChange success', res.errMsg)
},
fail: function () {
console.log('启用notify功能失败！');
console.log(that.data.notifyServicweId);
console.log(that.data.notifyCharacteristicsId);
},
})
},
//接收消息
receiveMessages: function () {
var that = this;
// 必须在这里的回调才能获取
wx.onBLECharacteristicValueChange(function (characteristic) {
let hex = Array.prototype.map.call(new Uint8Array(characteristic.value), x => ('00' + x.toString(16)).slice(-2)).join('');
console.log(hex)
})
console.log(that.data.readServicweId);
console.log(that.data.readCharacteristicsId);
wx.readBLECharacteristicValue({
deviceId: that.data.connectedDeviceId,
serviceId: that.data.readServicweId,
characteristicId: that.data.readCharacteristicsId,
success: function (res) {
console.log('readBLECharacteristicValue:', res.errMsg);
}
})
},
onHide: function () {
var that = this
this.setData({
devices_list: []
})
if (this.data.searching) {
wx.stopBluetoothDevicesDiscovery({//隐藏界面是建议停止
success: function (res) {
console.log(res)
that.setData({
searching: false
})
}
})
}
}
})
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