写一个微信小程序实习蓝牙连接和数据传输

首先，需要在微信开发者工具中新建一个小程序项目。然后，按照以下步骤实现蓝牙连接和数据传输：

1. 在 app.json 文件中添加以下代码：

"permission": {
    "scope.userLocation": {
      "desc": "你的位置信息将用于蓝牙设备连接"
    },
    "scope.bluetooth": {
      "desc": "你的蓝牙信息将用于连接蓝牙设备"
    }
}

这样可以获取用户的位置和蓝牙权限。

2. 在 index.wxml 文件中添加以下代码：

<view class='container'>
  <view class='devices'>
    <view class='device' wx:for="{{devices}}" wx:key="{{index}}" bindtap='connect'>
      <text>{{item.name}}</text>
      <text>{{item.deviceId}}</text>
    </view>
  </view>
  <view class='data'>
    <form bindsubmit='sendData'>
      <input type='text' placeholder='请输入发送内容' bindinput='inputData' value='{{inputValue}}' />
      <button type='submit'>发送</button>
    </form>
  </view>
</view>

这个代码主要是用来显示蓝牙设备和发送数据。

3. 在 index.js 文件中添加以下代码：

const app = getApp()

Page({
  data: {
    devices: [],
    connectedDeviceId: '',
    inputValue: '',
    characteristics: [],
    connected: false
  },
  onReady() {
    wx.onBluetoothAdapterStateChange(function (res) {
      console.log('蓝牙适配器状态变化', res)
    })
    wx.onBluetoothDeviceFound((devices) => {
      devices.forEach(device => {
        if (!device.name && !device.localName) {
          return
        }
        const foundDevices = this.data.devices
        const idx = app.globalData.devices.findIndex(item => item.deviceId === device.deviceId)
        if (idx === -1) {
          foundDevices.push(device)
        } else {
          foundDevices[idx] = device
        }
        this.setData({
          devices: foundDevices
        })
      })
    })
    wx.onBLEConnectionStateChange((res) => {
      console.log(`device ${res.deviceId} state has changed, connected: ${res.connected}`)
      this.setData({
        connected: res.connected
      })
    })
  },
  openBluetoothAdapter() {
    wx.openBluetoothAdapter({
      success: (res) => {
        console.log('初始化蓝牙适配器成功', res)
        this.startBluetoothDevicesDiscovery()
      },
      fail: (res) => {
        wx.showToast({
          title: '请开启蓝牙',
          icon: 'none'
        })
      }
    })
  },
  startBluetoothDevicesDiscovery() {
    if (this._discoveryStarted) {
      return
    }
    this._discoveryStarted = true
    wx.startBluetoothDevicesDiscovery({
      allowDuplicatesKey: false,
      success: (res) => {
        console.log('开始搜索附近的蓝牙设备', res)
      },
      fail: (res) => {
        console.log('搜索附近的蓝牙设备失败', res)
        this._discoveryStarted = false
      }
    })
  },
  connect(e) {
    const deviceId = e.currentTarget.dataset.deviceId
    wx.createBLEConnection({
      deviceId,
      success: (res) => {
        console.log('连接成功', res)
        this.setData({
          connectedDeviceId: deviceId,
          connected: true
        })
        this.getBLEDeviceServices(deviceId)
      },
      fail: (res) => {
        console.log('连接失败', res)
      }
    })
  },
  getBLEDeviceServices(deviceId) {
    wx.getBLEDeviceServices({
      deviceId,
      success: (res) => {
        console.log('获取服务成功', res)
        this.getBLEDeviceCharacteristics(deviceId, res.services[0].uuid)
      }
    })
  },
  getBLEDeviceCharacteristics(deviceId, serviceId) {
    wx.getBLEDeviceCharacteristics({
      deviceId,
      serviceId,
      success: (res) => {
        console.log('获取特征值成功', res)
        this.setData({
          characteristics: res.characteristics
        })
        this.notifyBLECharacteristicValueChange(deviceId, res.characteristics[0].uuid)
      }
    })
  },
  notifyBLECharacteristicValueChange(deviceId, characteristicId) {
    wx.notifyBLECharacteristicValueChange({
      state: true,
      deviceId,
      serviceId: '0000ffe0-0000-1000-8000-00805f9b34fb',
      characteristicId,
      success: (res) => {
        console.log('开启notify成功', res)
      },
      fail: (res) => {
        console.log('开启notify失败', res)
      }
    })
    wx.onBLECharacteristicValueChange((res) => {
      console.log(`characteristic ${res.characteristicId} has changed, now is ${res.value}`)
    })
  },
  sendData(e) {
    const { connectedDeviceId, characteristics, inputValue } = this.data
    const buffer = new ArrayBuffer(inputValue.length)
    const dataView = new DataView(buffer)
    for (let i = 0; i < inputValue.length; i++) {
      dataView.setUint8(i, inputValue.charAt(i).charCodeAt())
    }
    wx.writeBLECharacteristicValue({
      deviceId: connectedDeviceId,
      serviceId: '0000ffe0-0000-1000-8000-00805f9b34fb',
      characteristicId: characteristics[0].uuid,
      value: buffer,
      success: (res) => {
        console.log('发送数据成功', res)
        this.setData({
          inputValue: ''
        })
      },
      fail: (res) => {
        console.log('发送数据失败', res)
      }
    })
  },
  inputData(e) {
    this.setData({
      inputValue: e.detail.value
    })
  },
  onShow() {
    wx.getSystemInfo({
      success: (res) => {
        if (res.platform === 'ios') {
          this.setData({
            isIos: true
          })
        }
      }
    })
    this.openBluetoothAdapter()
  }
})

这段代码主要实现了一些功能，包括搜索蓝牙设备、连接蓝牙设备、获取服务、获取特征值、开启notify、发送数据等。

以上是一个简单的微信小程序实现蓝牙连接和数据传输的代码，可根据实际需要进行修改和完善。