wx.openBluetoothAdapter({
 success (res) {
 console.log(res)//res:{errMsg: "openBluetoothAdapter:ok"}
 }
})

wx.startBluetoothDevicesDiscovery({
 //services: ['FEE7'],只搜索主服務(wù) UUID 為 FEE7 的設(shè)備，如果明確知道主服務(wù)UUID可以用此項(xiàng)做篩選
 success (res) {
 console.log(res)//res:{errCode: 0, errMsg: "startBluetoothDevicesDiscovery:ok", isDiscovering: true}
 }
})

wx.getBluetoothDevices({
 success: function (res) {
 console.log(res)//res:{errMsg: "getBluetoothDevices:ok", devices: Array(3)}
 }
})

wx.onBluetoothDeviceFound(function(res) {
 console.log(res)//res:{devices: Array(1)}
})

wx.createBLEConnection({
 deviceId,//上面選擇藍(lán)牙設(shè)備的deviceId,例：連接第一個(gè)設(shè)備devices[0].deviceId
 success (res) {
 console.log(res)//{errCode: 0, errMsg: "createBLEConnection:ok"}
 }
})

onUnload（）函數(shù)里）
wx.stopBluetoothDevicesDiscovery({
 success (res) {
 console.log(res)
 }
})

wx.getBLEDeviceServices({
 deviceId,//已連接的藍(lán)牙設(shè)備ID
 success (res) {
 console.log(res)//{errMsg: "getBLEDeviceServices:ok", services: Array(5), errCode: 0}
 }
})
//這邊獲取到了5個(gè)服務(wù)

var characteristics="";
wx.getBLEDeviceCharacteristics({
 deviceId,
 serviceId,//第七步的服務(wù)ID，
 success (res) {
 //res:{errMsg: "getBLEDeviceCharacteristics:ok", characteristics: Array(4), errCode: 0}
 //characteristics[0].properties: {read: true, write: false, notify: false, indicate: false}
 //特征值有好幾種類型，我們這邊打印需要的是item.properties.write為true的特征值
 for (var i = 0; i < res.characteristics.length; i++) {
 var item = res.characteristics[i];
 if (item.properties.write) {
 characteristics = item.uuid;
 }
 }
 //保存特征值
 }
})

wx.writeBLECharacteristicValue({
 deviceId,
 serviceId,
 characteristicId,//上面保存的特征值
 value: buffer, // 這里的value是ArrayBuffer類型，中間層傳過來的打印數(shù)據(jù)前端自己做轉(zhuǎn)換，轉(zhuǎn)換過程我這邊就不描述了；
 success (res) {
 console.log('writeBLECharacteristicValue success', res.errMsg)
 }
})
//特別提醒建議每次寫入的buffer不超過20字節(jié)，超過會有寫入錯(cuò)誤的風(fēng)險(xiǎn)，所以一個(gè)打印的內(nèi)容可能要拆成N個(gè)20字節(jié)的buffer去循環(huán)writeBLECharacteristicValue，這樣就能打印成功啦。