Controlar el sensor de proximidad en Android

Se necesitará tener un TextView con id proximityTextView en el layout para poderlo probar

package ud10.e2;

import android.app.Activity;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.TextView;

public class Main extends Activity implements SensorEventListener{
   ImageView proxImg;
   SensorManager sm;
   Sensor proxSensor;
   
   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);

      sm         = (SensorManager) getSystemService(SENSOR_SERVICE);
      proxSensor = sm.getDefaultSensor(Sensor.TYPE_PROXIMITY);
      proxText   = (TextView) findViewById(R.id.proximityTextView);

      sm.registerListener(this, proxSensor, SensorManager.SENSOR_DELAY_NORMAL);
   }
   
   @Override
   public void onAccuracyChanged(Sensor sensor, int accuracy) {}
   
   @Override
   public void onSensorChanged(SensorEvent event) {
      proxText.setText(String.valueOf(event.values[0]));
   }
}