遇到的问题

在使用蓝牙的过程中，我们需要获取蓝牙设备的Mac地址。在Android设备上，onBluetoothDeviceFound方法中，deviceId是蓝牙设备的Mac地址。而在 iOS设备上，deviceId则是蓝牙设备的uuid。我们想要在iOS设备上获取Mac地址，就需要自己想办法。

解决的方法

通过查阅一些相关资料，发现有些蓝牙设备有180A这个服务id，该服务id中的2A23特征值可以获取蓝牙设备的Mac地址。具体操作参考下面的代码：

  function array2String(buffer) {    let hexArr = Array.prototype.map.call(      new Uint8Array(buffer),      function (bit) {        return ('00' + bit.toString(16)).slice(-2)      }    )    return `${hexArr[7]}:${hexArr[6]}:${hexArr[5]}:${hexArr[2]}:${hexArr[1]}:${hexArr[0]}`  }// 连接蓝牙wx.createBLEConnection({  deviceId,  success: res = {    // 获取服务id    wx.getBLEDeviceServices({      deviceId,      success: res = {        let serviceId = ''        for (let i = 0, len = res.services.length; i  len; i++) {          // 使用包含 180A 的服务id          if (~res.services[i].uuid.indexOf('180A')) {            serviceId = res.services[i].uuid            // 获取对应的特征值            wx.getBLEDeviceCharacteristics({              deviceId,              serviceId,              success: res = {                let characteristicId = ''                for (let i = 0, len = res.characteristics.length; i  len; i++) {                  // 使用含有 2A23 对应的特征值                  if (~res.characteristics[i].uuid.indexOf('2A23')) {                    characteristicId = res.characteristics[i].uuid                  }                }                wx.readBLECharacteristicValue({                  deviceId,                  serviceId,                  characteristicId,                  success: res = {                    console.log('mac read ----------', res)                  }                })                wx.notifyBLECharacteristicValueChange({                  deviceId,                  serviceId,                  characteristicId,                  state: true,                })                wx.onBLECharacteristicValueChange(function (characteristic) {                  // 当特征值是查询 Mac 地址时                  if (~characteristic.characteristicId.indexOf('2A23')) {                    let macInfo = (array2String(characteristic.value)).toUpperCase()                    console.log('mac info -----------', macInfo)                  }                })              }            })          }        }      }    })  }})复制代码

后续

当获取到蓝牙设备Mac地址后，我们一般还是要继续使用蓝牙的。这个时候需要重新获取蓝牙设备的服务id，以及新的特征值。

wx.getBLEDeviceCharacteristics({  deviceId,  // 新的服务id, 通过 getBLEDeviceServices 获取  serviceId: newServiceId,  success: res = {    wx.notifyBLECharacteristicValueChange({      state: true,      deviceId,      serviceId: newServiceId,      // 新的特征值      characteristicId: newCharacteristicId    })    // 监听低功耗蓝牙连接的错误事件    wx.onBLEConnectionStateChange(res = { })  }})复制代码