小程序连接和写入打印机的过程都ok，可是打印机就是没有相应！求解

代码贴出：

// 初始化蓝牙适配器  

initializeBluetooth: function () {

var that = this;

if (!wx.openBluetoothAdapter) {

console.log('蓝牙适配器打开失败，请检查微信版本或手机是否支持小程序蓝牙模块！')

} else {

wx.openBluetoothAdapter({

success: function (res) {

that.setData({

msg: "初始化蓝牙适配器成功！"

})

wx.getBluetoothAdapterState({//获取本机蓝牙适配器状态

success: function (res) {

console.log('本机蓝牙适配器状态：')

console.log(res)

}

})

}

})

}

},

//搜索获取已发现设备  

searchBluetooth: function () {

var that = this;

wx.startBluetoothDevicesDiscovery({//开始搜寻附近的蓝牙外围设备

success: function (res) {

console.log('开始搜索周边蓝牙设备')

console.log(res)

wx.getBluetoothDevices({//sucess返回uuid 对应的的已连接设备列表，Array类型

success: function (res) {

//是否有已连接设备

wx.getConnectedBluetoothDevices({////根据 uuid 获取处于已连接状态的设备

success: function (res) {

console.log('已连接的蓝牙设备:')

console.log(JSON.stringify(res.devices));

that.setData({

connectedDeviceId: res.deviceId

})

}

})

that.setData({

devices: res.devices,

})

}

})

}

})

},

//连接设备  

connectTO: function (e) {

var that = this;

wx.stopBluetoothDevicesDiscovery({ //先停止搜索周边设备

success: function (res) {

console.log('连接设备前，先停止搜索周边设备:')

console.log(res)

}

})

wx.showLoading({

title: '连接蓝牙设备中...',

})

wx.createBLEConnection({//若小程序在之前已有搜索过某个蓝牙设备，并成功建立链接，可直接传入之前搜索获取的deviceId直接尝试连接该设备，无需进行搜索操作。

deviceId: e.currentTarget.id,

success: function (res) {

console.log('连接成功:')

console.log(res)

wx.hideLoading()

that.setData({

connectedDeviceId: e.currentTarget.id,    //currentTarget: 事件绑定的元素

msg: "已连接" + e.currentTarget.id,

})

that.getServices();

that.startBletNotify();

that.receiveMessages();

},

fail: function () {

console.log("调用失败");

},

complete: function () {

console.log('已连接设备ID：' + that.data.connectedDeviceId);

console.log("调用结束");

}

})

},

// 获取连接设备的service服务  

getServices: function () {

var that = this;

wx.getBLEDeviceServices({//获取在小程序蓝牙模块生效期间所有已发现的蓝牙设备，包括已经和本机处于连接状态的设备

// 这里的 deviceId 需要在上面的 getBluetoothDevices 或 onBluetoothDeviceFound 接口中获取  

deviceId: that.data.connectedDeviceId,

success: function (res) {

//console.log('获取蓝牙设备所有服务成功：', res);

that.data.services = res.services

console.log('获取蓝牙设备所有服务成功：', that.data.services);

that.setData({

serviceId: that.data.services[0].uuid,

})

console.log("服务uuid:", that.data.serviceId)

wx.getBLEDeviceCharacteristics({

// 这里的 deviceId 需要在上面的 getBluetoothDevices 或 onBluetoothDeviceFound 接口中获取  

deviceId: that.data.connectedDeviceId,

// 这里的 serviceId 需要在上面的 getBLEDeviceServices 接口中获取  

serviceId: that.data.serviceId,   //-----注意是that.data.services[0].uuid

success: function (res) {

console.log('serviceId: that.data.services[0].uuid: ', that.data.serviceId)

console.log(res)

for (var i = 0; i < res.characteristics.length; i++) {

if (res.characteristics[i].properties.notify) {   //注意characteristic(特征值)信息,properties对象

that.setData({

notifyServicweId: that.data.services[0].uuid,

notifyCharacteristicsId: res.characteristics[i].uuid,

})

console.log("notifyServicweId:", that.data.notifyServicweId, "notifyCharacteristicsId", that.data.notifyCharacteristicsId)

}

if (res.characteristics[i].properties.write) {

that.setData({

writeServicweId: that.data.services[0].uuid,

writeCharacteristicsId: res.characteristics[i].uuid,

})

console.log("writeServicweId:", that.data.writeServicweId, "writeCharacteristicsId", that.data.writeCharacteristicsId)

} else if (res.characteristics[i].properties.read) {

that.setData({

readServicweId: that.data.services[0].uuid,

readCharacteristicsId: res.characteristics[i].uuid,

})

console.log("readServicweId:", that.data.readServicweId, "readCharacteristicsId", that.data.readCharacteristicsId)

}

}

},

fail: function () {

console.log("获取连接设备的所有特征值：", res);

},

complete: function () {

console.log("complete!");

}

})

}

})

},

//断开设备连接  

closeBluetooth: function () {

var that = this;

wx.closeBLEConnection({

deviceId: that.data.connectedDeviceId,

success: function (res) {

console.log('断开设备连接: ', res)

if (res.errCode==0){

}

}

})

},

Test:function(){

this.sendMessages();

},

//发送  

sendMessages: function () {

var that = this;

// 这里的回调可以获取到 write 导致的特征值改变  

wx.onBLECharacteristicValueChange(function (characteristic) {

console.log('characteristic value changed:1', characteristic)

})

var buf = new ArrayBuffer(16)

var dataView = new DataView(buf)

dataView.setUint8(0, 99)

wx.writeBLECharacteristicValue({

deviceId: that.data.connectedDeviceId,

serviceId: that.data.writeServicweId,

characteristicId: that.data.writeCharacteristicsId,

value: buf,

success: function (res) {

console.log('writeBLECharacteristicValue success', res)

}

})

},

//启用低功耗蓝牙设备特征值变化时的 notify 功能  

startBletNotify: function () {

var that = this;

wx.notifyBLECharacteristicValueChange({

state: true, // 启用 notify 功能  

deviceId: that.data.connectedDeviceId,

serviceId: that.data.notifyServicweId,

characteristicId: that.data.notifyCharacteristicsId,

success: function (res) {

console.log('notifyBLECharacteristicValueChange success', res.errMsg)

},

fail: function () {

console.log('启用notify功能失败！');

console.log(that.data.notifyServicweId);

console.log(that.data.notifyCharacteristicsId);

},

})

},

//接收消息  

receiveMessages: function () {

var that = this;

// 必须在这里的回调才能获取  

wx.onBLECharacteristicValueChange(function (characteristic) {

let hex = Array.prototype.map.call(new Uint8Array(characteristic.value), x => ('00' + x.toString(16)).slice(-2)).join('');

console.log(hex)

})

console.log(that.data.readServicweId);

console.log(that.data.readCharacteristicsId);

wx.readBLECharacteristicValue({

deviceId: that.data.connectedDeviceId,

serviceId: that.data.readServicweId,

characteristicId: that.data.readCharacteristicsId,

success: function (res) {

console.log('readBLECharacteristicValue:', res.errMsg);

}

})

},