1# Sensor Usage Guidelines<a name="EN-US_TOPIC_0000001077367158"></a> 2 3The following steps use the sensor whose **sensorTypeId** is **0** as an example. The guidelines for other sensor types are similar. 4 5## How to Use<a name="section18816105182315"></a> 6 71. Import the required header files. 8 9``` 10#include "sensor_agent.h" 11#include "sensor_agent_type.h" 12``` 13 141. Create a sensor callback. 15 16``` 17void SensorDataCallbackImpl(SensorEvent *event) 18{ 19 if(event == NULL){ 20 return; 21 } 22 float *sensorData=(float *)event->data; 23} 24``` 25 26> **NOTE:** 27>The callback must be of the RecordSensorCallback type. 28 291. Obtain the list of sensors supported by the device. 30 31``` 32SensorInfo *sensorInfo = (SensorInfo *)NULL; 33int32_t count = 0; 34int32_t ret = GetAllSensors(&sensorInfo, &count); 35``` 36 371. Create a sensor user. 38 39``` 40SensorUser sensorUser; 41sensorUser.callback = SensorDataCallbackImpl; // Assign the created callback SensorDataCallbackImpl to the member variable callback. 42``` 43 441. Enable the sensor. 45 46``` 47int32_t ret = ActivateSensor(0, &sensorUser); 48``` 49 501. Subscribe to sensor data. 51 52``` 53int32_t ret = SubscribeSensor(0, &sensorUser); 54``` 55 56> **NOTE:** 57>Till now, you can obtain the sensor data via the callback. 58 591. Unsubscribe from the sensor data. 60 61``` 62int32_t ret = UnsubscribeSensor(0, &sensorUser); 63``` 64 651. Disable the sensor. 66 67``` 68int32_t ret = DeactivateSensor(0, &sensorUser); 69``` 70 71
