手机找不到适用于Sensor的传感器。TYPE_LINEAR_ACCELERATION

Question

I'm trying to use the linear acceleration fusion sensor on my android app. However, it cannot find the sensor for Sensor.TYPE_LINEAR_ACCELERATION.

I perform these calls:

mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
mLinearAcceleration = mSensorManager.getDefaultSensor(Sensor.TYPE_LINEAR_ACCELERATION);

After the above, mAccelerometer is defined, but mLinearAcceleration is null. I know that TYPE_LINEAR_ACCELERATION was not added until API level 9, but I think I am running in at least API level 9. Here is a snippet of my manifest file:

<uses-sdk
android:minSdkVersion="9"
android:targetSdkVersion="17" />

So I believe I am working under the correct API level.

However, when I try listing all sensors that are available, I do not find all sensors that should be available for this API level.

When I call...

List<Sensor> l = mSensorManager.getSensorList(Sensor.TYPE_ALL);
for(Sensor s : l)
    System.out.println(s.getName());

I get

Goldfish 3-axis Accelerometer
Goldfish 3-axis Magnetic field sensor
Goldfish Orientation sensor
Goldfish Temperature sensor
Goldfish Proximity sensor

None of these are linear acceleration, and one is Orientation, a deprecated sensor. It appears my sensors are operating as though they were from before API level 9, but I don't know why that would be. Is there some field in my project that could be forcing the app to act as an older API? (other than the minimum supported API field in the AndroidManifest.xml file, which is already set to 9)

Answer 1

put this in your manifest

<uses-permission android:name=”android.permission.SET_ORIENTATION” />

Is for access to your accelerometer

try this:

     /* put this into your activity class */
  private SensorManager mSensorManager;
  private float mAccel; // acceleration apart from gravity
  private float mAccelCurrent; // current acceleration including gravity
  private float mAccelLast; // last acceleration including gravity

  private final SensorEventListener mSensorListener = new SensorEventListener() {
public void onSensorChanged(SensorEvent se) {
  float x = se.values[0];
  float y = se.values[1];
  float z = se.values[2];
  mAccelLast = mAccelCurrent;
  mAccelCurrent = (float) Math.sqrt((double) (x*x + y*y + z*z));
  float delta = mAccelCurrent - mAccelLast;
  mAccel = mAccel * 0.9f + delta; // perform low-cut filter
}

public void onAccuracyChanged(Sensor sensor, int accuracy) {
    }
  };

  @Override
  protected void onResume() {
    super.onResume();
    mSensorManager.registerListener(mSensorListener, mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL);
  }

  @Override
  protected void onPause() {
    mSensorManager.unregisterListener(mSensorListener);
    super.onPause();
  }

And this:

 /* do this in onCreate */
mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
mSensorManager.registerListener(mSensorListener, mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL);
mAccel = 0.00f;
mAccelCurrent = SensorManager.GRAVITY_EARTH;
mAccelLast = SensorManager.GRAVITY_EARTH;