Basic introduction to Android sensors

1 Overview

An Android sensor is a hardware device used to detect physical movement of the device and changes in the environment. They can provide information about the device's position, orientation, velocity, acceleration, light, temperature, humidity, and more. The Android Sensors API allows applications to access this sensor data for use within the application.

2. Sensor type

Android devices support a variety of sensor types, including:

• Acceleration sensor: used to detect the acceleration of the device, that is, the acceleration change of the device.
• Gyro Sensor: Used to detect the rotational speed and direction of the device.
• Magnetometer sensor: Used to detect the magnetic field around the device.
• Light sensor: used to detect the light intensity around the device.
• Temperature sensor: used to detect the temperature of the device.
• Humidity Sensor: Used to detect the humidity around the device.
• Pressure sensor: Used to detect the air pressure around the device.

3. Using the sensor API

Using the sensor API requires the following steps:

• Get Sensor Manager: Use the SensorManager class to get a sensor manager.
• Get a list of sensors: Use the getSensorList() method of the SensorManager class to get a list of sensors available on the device.
• Registering a sensor listener: Register a sensor listener using the registerListener() method of the SensorManager class.
• Implement the sensor listener: implement the SensorEventListener interface, rewrite the onSensorChanged() method and the onAccuracyChanged() method.
• Process sensor data: Process sensor data in the onSensorChanged() method.

4. Sample code

Here is a simple sample code that demonstrates how to use the accelerometer:

public class MainActivity extends AppCompatActivity implements SensorEventListener {

    private SensorManager sensorManager;
    private Sensor accelerometer;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    }

    @Override
    protected void onResume() {
        super.onResume();
        sensorManager.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
    }

    @Override
    protected void onPause() {
        super.onPause();
        sensorManager.unregisterListener(this);
    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
            float x = event.values[0];
            float y = event.values[1];
            float z = event.values[2];

            // 处理加速度传感器数据
        }
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        // 处理传感器精度变化
    }

5 Conclusion

The Android Sensors API provides a convenient way to access a device's physical movement and environmental change data. Developers can use the sensor API to create various applications such as games, fitness applications, navigation applications, etc.