BLE开发所需要的知识，通过官方demo，我们会发现很多service，点击service后，每个service下面是Characteristic，每个service和Characteristic都对应一个唯一的UUID。所以，在做BLE时候，首先你应该找出你的蓝牙外围设备uuid，不然会很头疼，这个UUID也可能是硬件给你的，也可以你自己试出来，当然自己试出来是个很烦的过程。自己试的方法就是根据demo，加上一份读写的协议，然后，排着点击，显示出来的蓝牙列表进行测试，看是否和协议对应。另外，BluetoothLeService类不用做太多的更改。(BLE develops the knowledge we need. Through official demo, we will find many service. After clicking service, every service is Characteristic, each service and Characteristic correspond to a unique UUID. So, when making BLE, first you should find out your Bluetooth peripheral device UUID, otherwise it will be very headache. This UUID may also be hardware for you, or you can try it out yourself, of course, trying out it yourself is a very boring process. The way to do it is to add a read and write protocol based on demo,then test the Bluetooth list displayed by clicking on it to see if it corresponds to the protocol. In addition, the BluetoothLeService class does not have to make too many changes.)