終於實現了藍芽的功能，也找到了合適的硬體，記錄一下自己需要注意和總結的地方
具體的搜尋、連線、斷開、訊息傳輸都已經實現了，作為專案的一個頁面完成了

相應的程式碼地址，具體的藍芽程式碼在pages/bluetooth當中

一.硬體部分

1. HC-08 藍芽模組 4.0BLE主從一體 CC2540 無線串列埠透傳模組 BLE串列埠通訊
2. 硬體官網
   匯承官網
3. 基本連線教程
   
   注意：串列埠模組和usb to ttl的連線方式

二. Windows串列埠除錯助手

1. 下載串列埠除錯助手
2. 設定預設波特率為9600

三.手機App測試

1. LightBlue和Windows的除錯
   
   
   注意：由圖4可以看出串列埠通訊的serviceId的UUID為FFE0(讀寫UUID)

四.微信小程式初始化連線（重頭戲來了）

1. 初始化藍芽介面卡

        wx.openBluetoothAdapter({
          success: function (res) {
            console.log('初始化藍芽介面卡成功' + JSON.stringify(res))
            that.msg = '初始化藍芽介面卡成功'
            wx.showModal({
              title: '藍芽適配情況',
              content: '初始化藍芽介面卡成功'
            })
          },
          fail: function () {
            that.msg = '初始化藍芽介面卡失敗'
            wx.showModal({
              title: '藍芽適配情況',
              content: '藍芽適配失敗，請檢查手機藍芽和定位功能是否開啟'
            })
          },
          complete: function () {
            console.log('初始化藍芽介面卡完成')
          }
        })
 

2. 開啟藍芽搜尋,並獲取藍芽裝置列表 wx.getBluetoothAdapterState --> wx.onBluetoothAdapterStateChange --> wx.startBluetoothDevicesDiscovery --> wx.onBluetoothDeviceFound --> getBluetoothDevices
3. 選擇藍芽裝置獲取相應的deviceId
4. 連線藍芽裝置 wx.createBLEConnection --> wx.getBLEDeviceService(獲取裝置的ServiceId)

wx.createBLEConnection({
          deviceId: deviceId,
          success: function (res) {
            console.log('藍芽裝置連線成功')
            wx.hideLoading()
            wx.getBLEDeviceServices({
              deviceId: deviceId,
              success: function (res) {
                that.deviceService = res.services
                for (var t = 0; t < that.deviceService.length; t++) {
                  var service = that.deviceService[t]
                  var serviceId = service.uuid.substring(4, 8)
                  if (serviceId === 'FFE0') {                  //‘FFE0’為裝置定義的讀寫UUID
                    that.serviceId = service.uuid
                  }
                }
                that.nowDevice = !that.nowDevice
                that.nowService = !that.nowService
                console.log('獲取藍芽裝置Service' + res.errMsg)
              },
              fail: function (res) {
                wx.showModal({
                  title: '裝置Service資訊',
                  content: '藍芽裝置連線成功' + '\n' + '裝置資訊獲取錯誤' + res.errMsg
                })
              }
            })
          },
          fail: function (res) {
            console.log('藍芽裝置連線失敗，請稍後重試')
            wx.hideLoading()
            wx.showModal({
              title: '提示',
              content: '藍芽裝置連線失敗，請稍後重試',
              duration: 2000
            })
          },
          complete: function () {
            console.log('藍芽裝置連線完成')
            wx.hideLoading()
          }
        })
 

4. 連線裝置同時關閉藍芽搜尋 wx.stopBluetoothDevicesDiscovery
5. 向串列埠傳送資料（重要）
   wx.getBLEDeviceCharacteristics --> success: wx.notifyBLECharacteristicValueChang (啟用notify功能) --> success:wx.writeBLECharacteristicValue --> success:wx.readBLECharacteristicValue(必須讀取，否則Android裝置無法正常向串列埠傳送資料

wx.getBLEDeviceCharacteristics({
          deviceId: that.deviceId,
          serviceId: that.serviceId,
          success: function (res) {
            console.log(res.characteristics)
            that.deviceCharacteristics = res.characteristics
            for (var i = 0; i < that.deviceCharacteristics.length; i++) {
              that.characteristic = that.deviceCharacteristics[i]
              that.characteristicProperties = that.characteristic.properties
              if (that.characteristicProperties.notify === true) {
                that.characteristicId = that.characteristic.uuid
                wx.notifyBLECharacteristicValueChange({
                  state: true, // 啟用 notify 功能
                  deviceId: that.deviceId,
                  serviceId: that.serviceId,
                  characteristicId: that.characteristicId,
                  success: function (res) {
                    console.log('開啟notify成功' + that.characteristic.uuid)
                    for (let i = 0; i < dataView.byteLength; i++) {
                      var writeData = '0x' + dataView.getUint8(i).toString(16)
                      that.writeDatas = that.writeDatas + '\n' + writeData
                    }
                    wx.writeBLECharacteristicValue({
                      deviceId: that.deviceId,
                      serviceId: that.serviceId,
                      characteristicId: that.characteristicId,
                      value: dataBuffer,
                      success: function (res) {
                        console.log('傳送的資料：' + that.writeDatas)
                        console.log('message傳送成功')
                        wx.showModal({
                          title: '資料傳送成功',
                          content: that.writeDatas
                        })
                        wx.readBLECharacteristicValue({
                          deviceId: that.deviceId,
                          serviceId: that.serviceId,
                          characteristicId: that.characteristicId,
                          success: function (res) {
                            console.log('讀取資料成功')
                          }
                        })
                      },
                      fail: function (res) {
                        // fail
                        console.log('message傳送失敗' + that.characteristicIdw)
                        wx.showToast({
                          title: '資料傳送失敗，請稍後重試',
                          icon: 'none'
                        })
                      },
                      complete: function (res) {
                        // fail
                        console.log('message傳送完成')
                      }
                    })
                  },
                  fail: function () {
                    console.log('開啟notify失敗' + that.characteristicId)
                  }
                })
                // that.writeMessage(that.deviceId, that.serviceId, that.characteristicIdw, that.characteristicIdr, that.characteristicIdn)
              }
            }
          },
          fail: function () {
            console.log('獲取characteristic失敗')
          }
        })

5. 讀取串列埠傳送的資料 （重要）
   wx.getBLEDeviceCharacteristics --> success:wx.notifyBLECharacteristicValueChange --> success:wx.readBLECharacteristicValue --> wx.onBLECharacteristicValueChange

五.微信小程式藍芽未啟動，離開小程式開啟藍芽後再啟動小程式

1. 在onLoad中wx.openBluetoothAdapter
2. 在onShow中判斷當前藍芽介面卡的狀態wx.onBluetoothAdapterStateChange --> 若更改成功，則wx.openBluetoothAdapter

六.微信小程式開發注意

1. Android裝置在readBLECharacteristicValu後可能會出現顯示message傳輸成功但是串列埠除錯助手收不到資料的情況
   解決方法：在writeBLECharacteristicValu後新增readBLECharacteristicValue
2. 串列埠讀寫裝置的時候注意轉換資料格式，傳輸的資料格式為ArrayBuffer，需要轉換才可以顯示，直接console返回的res.value為空
   用到的轉換格式程式碼

let data = that.sendData.split(',')
        let dataBuffer = new ArrayBuffer(data.length)
        let dataView = new DataView(dataBuffer)
        for (let j = 0; j < data.length; j++) {
          dataView.setUint8(j, '0x' + data[j])
        }

var writeData = '0x' + dataView.getUint8(i).toString(16)

ab2hex: function (buffer) {
        var hexArr = Array.prototype.map.call(
          new Uint8Array(buffer), function (bit) {
            return ('00' + bit.toString(16)).slice(-2)
          }
        )
        return hexArr.join('')
      }

3. 根據serviceId獲取characteristicId時需要採用for迴圈獲取，不使用for迴圈會無法開啟notify，使用for迴圈會開啟兩遍，兩次開啟UUID相同，但是第一次顯示開啟成功，第二次顯示開啟失敗
4. 實際讀取串列埠傳送資料的位置為wx.onBLECharacteristicValueChang，wx.readBLECharacteristicValue返回的res中只有接受資訊是否成功的資訊
5. 問題：若手機藍芽未啟動，初始化頁面無法成功開啟藍芽介面卡，重新開啟藍芽後，頁面無法重新開啟藍芽介面卡
   解決：因為只在onLoad中定義了開始藍芽介面卡，沒有在onShow中定義，通過《六》中來解決
   注意：必須在onShow中先進行判斷，再選擇是否呼叫wx.openBluetoothAdapter，否則在第一次啟動頁面的時候呼叫兩次wx.openBluetoothAdapter，wx.showModal會顯示兩次（初始化頁面的時候onLoad後會呼叫onShow）