微信小程序蓝牙模块

2023-12-03 12:02:34

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
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(that.data.services)
                that.setData({
                    serviceId: that.data.services[0].uuid,
                })
                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
                                console.log("11111111", that.data.services[0].uuid);
                                console.log("22222222222222222", res.characteristics[i].uuid);
                                that.setData({
                                    notifyServicweId: that.data.services[0].uuid,
                                    notifyCharacteristicsId: res.characteristics[i].uuid,
                                })
                            }
                            if (res.characteristics[i].properties.write) {
                                that.setData({
                                    writeServicweId: that.data.services[0].uuid,
                                    writeCharacteristicsId: res.characteristics[i].uuid,
                                })
                            } else if (res.characteristics[i].properties.read) {
                                that.setData({
                                    readServicweId: that.data.services[0].uuid,
                                    readCharacteristicsId: res.characteristics[i].uuid,
                                })
                            }
                        }
                    },
                    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, 0)
        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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