readData method
使用设备的read特征值去向设备读取数据
Implementation
void readData(String serviceUuid, String characteristicUuid) {
if (_state != DeviceState.destroyed && _state == DeviceState.connected) {
//已连接才能去向设备写入数据
FlutterBlueElves.instance._channel.invokeMethod('readData', {
"id": _id,
"serviceUuid": serviceUuid,
"characteristicUuid": characteristicUuid
}); //去向设备读取数据
}
}