1：安卓手機呼叫wx.getBluetoothDevices方法獲取不到藍芽裝置時：

解決方法：Android藍芽除錯時，未開啟微信的定位服務會導致搜尋不到裝置，請到手機的設定裡面確認

2：wx.getBluetoothDevices(OBJECT)

存在呼叫該介面會返回之前的藍芽使用流程中搜索到的藍芽裝置，可能裝置已經不在使用者身邊，無法連線。

解決方法：每次呼叫前，需要呼叫wx.closeBluetoothAdapter(OBJECT)，然後wx.openBluetoothAdapter(OBJECT)

然後wx.startBluetoothDevicesDiscovery，最後再呼叫wx.getBluetoothDevices，參考程式碼如下

//搜尋獲取已發現裝置  
function searchBluetooth (that) {
  console.log('searchBluetooth')
  // 避免獲取到之前的裝置，每次獲取裝置前，先關閉藍芽介面卡，再開啟介面卡,設定延遲執行為了呼叫藍芽介面正常
  closeBluetoothAdapter(function(res){
    if ('success' == res){
      initializeBluetooth(function (res) {
        if ('success' == res) {
          setTimeout(function(){
            wx.startBluetoothDevicesDiscovery({//開始搜尋附近的藍芽外圍裝置
              services: ['00003900-842F-544F-5348-494241000001'], //只搜尋主服務 UUID 為 FEE7 的裝置
              success: function (res) {
                console.log('開始搜尋周邊藍芽裝置')
                console.log(res)
                setTimeout(function(){
                  wx.getBluetoothDevices({//sucess返回uuid 對應的的已連線裝置列表，Array型別
                    success: function (res) {
                      // 獲取到藍芽裝置成功之後停止搜尋周邊裝置
                      wx.stopBluetoothDevicesDiscovery({ //先停止搜尋周邊裝置
                        success: function (res) {
                          console.log('連線裝置前，先停止搜尋周邊裝置:')
                          console.log(res)
                        }
                      })
                      console.log('裝置：' + JSON.stringify(res.devices));
                      var devices = res.devices;
                      var length = devices.length;
                      if (null != devices && length > 0){
                        for (var i = 0; i < length; i++){
                          var device = devices[i];
                          if (device.name == '未知裝置' && device.localName){
                            device.name = device.localName;
                          }
                        }
                      }
                      that.setData({
                        devices: devices
                      })
                    }, fail: function (res) {
                      console.log("getBluetoothDevices fail:" + res);
                    }
                  })
                }, 500)
              }, fail: function (res) {
                console.log("searchBluetooth fail:" + res);
                wx.showToast({
                  title: '連線藍芽失敗',
                  icon: 'none',
                  image: '/images/my/
 
[email protected]',
                  mask: true
                })
              }
            })
          }, 100)
        }
      })
   }
  });
}

3：iOS平臺上，直接呼叫read、write、notify報如下錯誤

iOS平臺上後續對特徵值的read、write、notify，由於系統需要獲取特徵值例項，傳入的 serviceId 與 characteristicId 必須由 getBLEDeviceServices 與 getBLEDeviceCharacteristics 中獲取到後才能使用。建議雙平臺統一在建立連結後先執行 getBLEDeviceServices 與 getBLEDeviceCharacteristics 後再進行與藍芽裝置的資料互動

參考程式碼如下

// 密碼配對
function pair(password, newPassword, callback){
  var deviceId = app.globalData.localId;
  wx.getBLEDeviceServices({
    deviceId: deviceId,
    success: function (res) {
      wx.getBLEDeviceCharacteristics({
        deviceId: deviceId,
        serviceId: order.uuid,
        success: function (res) {
          pair1(password, newPassword, callback);
        }, fail: function (res) {
          return callback('裝置不支援密碼配對特徵值');
        }
      })
    }, fail: function (res) {
      return callback('裝置不支援密碼配對服務');
    }
  })
}
// 密碼配對-寫
function pair1(oldPassword, newPassword, callback){
  var deviceId = app.globalData.localId;
  var password = '123456';
  if (oldPassword){
    password = oldPassword;
  }
  var buf = stringToBytes(password)
  wx.writeBLECharacteristicValue({
    deviceId: deviceId,
    serviceId: order.uuid,
    characteristicId: order.pair,
    value: buf,
    success: function (res) {
      console.log('writeBLECharacteristicValue success', res)
      // 必須在這裡的回撥才能獲取
      wx.onBLECharacteristicValueChange(function (characteristic) {
        console.log('characteristic value comed:', characteristic)
        var ret = byteToDecString(characteristic.value)
        console.log(ret);
        if (ret === "1") {
          // 配對成功之後，獲取安全模式，以控制器的為準
          onConnected();
          if (newPassword && newPassword.length == 6){
            return changePassword(newPassword, callback);
          }else{
            return callback('配對成功');
          }
        } else {
          return callback('配對密碼錯誤');
        }
      })
      wx.readBLECharacteristicValue({
        deviceId: deviceId,
        serviceId: order.uuid,
        characteristicId: order.pair,
        success: function (res) {
          console.log('readBLECharacteristicValue:', res.errCode)
        },
        fail: function (res) {
          return callback('裝置不支援密碼配對讀取');
        }
      })
    },
    fail: function (res) {
      return callback('裝置不支援密碼配對寫入');
    }
  })
}

4：小程式藍芽常用轉換api

function byteToDecString(buffer) {
  return new Uint8Array(buffer)[0].toString(10)
}

function hexToBytes(hexs) {
  var array = new Uint8Array(hexs.length);
  for (var i = 0, l = hexs.length; i < l; i++) {
    array[i] = hexs[i]
  }
  return array.buffer;
}

function stringToBytes(str) {
  var array = new Uint8Array(str.length);
  for (var i = 0, l = str.length; i < l; i++) {
    array[i] = str.charCodeAt(i);
  }
  console.log(array);
  return array.buffer;
}

function bytesToString(buffer) {
  return String.fromCharCode.apply(null, new Uint8Array(buffer))
}

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