wx.notifyBLECharacteristicValueChange({                   state: true, // 启用 notify 功能                   deviceId: that.data.deviceId,                   serviceId: that.data.serviceId,                   characteristicId: that.data.charaId,                   success(res) {                     console.log('notifyBLECharacteristicValueChange success', res.errMsg)                   }                 })                     function ab2hex(buffer) {                       let hexArr = Array.prototype.map.call(                         new Uint8Array(buffer),                         function (bit) {                           return ('00' + bit.toString(16)).slice(-2)                         }                       )                       return hexArr.join('');                       }                     wx.onBLECharacteristicValueChange(function (res) {                       console.log(`characteristic ${res.characteristicId} has changed, now is ${res.value}`)                       console.log(ab2hex(res.value)) 之前代码的characteristic里的write,read都为true,但writeDefault:false   wirtenoresponse:true 我不知道跟这个有没有关系,导致我notify是success和ok,writeBLECharacteristicValue也可以正常实现,但onble这个函数却不执行