目前，Android 平台支持的运动传感器包括以下内容 5 种：
TYPE_ACCELEROMETER。
TYPE_GRAVITY。
TYPE_GYROSCOPE。
TYPE_LINEAR_ACCELERATION。
TYPE_ROTATION_VECTOR。
本节教程将对这几种传感器的用法做简单介绍。
加速传感器
获取加速度传感器实例的代码如下：
private SensorManager mSensorManager; private Sensor mSensor; ... mSensorManager=(SensorManager)getSystemService(Context.SENSOR_SERVICE); mSensor=mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
代码从传感器获取数据并计算三个方向的加速度如下：
public void onSensorChanged(SensorEvent event) { // In this example, alpha is calculated as t / (t dT) , // where t is the low-pass filter's time-constant and // dT is the event delivery rate. final float alpha = 0.8; // Isolate the force of gravity with the low-pass filter. gravity[0] = alpha * gravity[0] (1 - alpha) * event.values[0]; gravity[1] = alpha * gravity[l] (1 - alpha) * event.values[1]; gravity[2] = alpha * gravity[2] (1 - alpha) * event.values[2]; // Remove the gravity contribution with the high-pass filter. linear_acceleration[0] = event.values[0] - gravity[0]; linear_acceleration[1] = event.values[1] - gravity[l]; linear_acceleration[2] = event.values[2] - gravity[2]; }
该计算方法仅用于例子，实际计算方法应根据应用程序确定。
重力传感器
重力传感器是一种加速度传感器，其数据处理方法也相似。重力传感器的数据计算方法在这里不再重复。获取重力传感器的代码如下：
private SensorManager mSensorManager; private Sensor mSensor; ... mSensorManager=(SensorManager)getSystemService(Context.SENSOR_SERVICE); mSensor=mSensorManager.getDefaultSensor(Sensor.TYPE_GRAVITY);
陀螺仪
陀螺仪可以在三个纬度上测量设备的旋转。获取陀螺仪传感器的代码如下：
private SensorManager mSensorManager; private Sensor mSensor; ... mSensorManager=(SensorManager)getSystemService(Context.SENSOR_SERVICE); mSensor=mSensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
陀螺仪数据计算三个纬度旋转的代码如下：
// Create a constant to convert nanoseconds to seconds. private static final float NS2S = 1.0f / 1000000000.0f; private final float[] deltaRotationVector = new float[4](); private float timestamp; public void onSensorChanged(SensorEvent event) { // This timestep's delta rotation to be multiplied by the current rotation // after computing it from the gyro sample data. if (timestamp != 0) { final float dT = (event.timestamp - timestamp) * NS2S; // Axis of the rotation sample, not normalized yet. float axisX = event.values[0]; float axisY = event.values[1]; float axisZ = event.values[2]; // Calculate the angular speed of the sample float omegaMagnitude = sqrt(axisX * axisX axisY * axisY axisZ * axisZ); // Normalize the rotation vector if it's big enough to get the axis // (that is, EPSILON should represent your maximum allowable margin of error) if (omegaMagnitude > EPSILON) { axisX /= omegaMagnitude; axisY /= omegaMagnitude; axisZ /= omegaMagnitude; } // Integrate around this axis with the angular speed by the timestep // in order to get a delta rotation from this sample over the timestep // We will convert this axis-angle representation of the delta rotation // into a quaternion before turning it into the rotation matrix. float thetaOverTwo = omegaMagnitude * dT / 2. Of; float sinThetaOverTwo = sin(thetaOverTwo); float cosThetaOverTwo = cos(thetaOverTwo); deltaRotationVector[0] = sinThetaOverTwo * axisX; deltaRotationVector[1] = sinThetaOverTwo * axisY; deltaRotationVector[2] = sinThetaOverTwo * axisZ; deltaRotationVector[3] = cosThetaOverTwo; } timestamp = event.timestamp; float[] deltaRotationMatrix = new float[9]; SensorManager.getRotationMatrixFromVector(deltaRotationMatrix, deltaRotationVector); // User code should concatenate the delta rotation we computed with the current rotation // in order to get the updated rotation. // rotationCurrent=rotationCurrent * deltaRotationMatrix; }
线性加速度传感器
线性加速度传感器是一种传感器。实例代码如下：
private SensorManager mSensorManager; private Sensor mSensor; ... mSensorManager=(SensorManager)getSystemService(Context.SENSOR_SERVICE); mSensor=mSensorManager.getDefaultSensor(Sensor.TYPE_LINEAR_ACCELERATION);
旋转向量传感器
旋转向量传感器可以反映当前设备的状态，其返回值是旋转角度和旋转轴的集合。获取旋转向量传感器实例的相关代码如下：
private SensorManager mSensorManager; private Sensor mSensor; ... mSensorManager=(SensorManager)getSystemService(Context.SENSOR_SERVICE); mSensor=mSensorManager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR);