これはあなたを助けるかもしれません...
public class SensorActivity extends Activity implements SensorEventListener,
        CompoundButton.OnCheckedChangeListener {
    private ToggleButton toggleButton;
    private SensorManager sensorManager;
    private Sensor proximitySensor;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        toggleButton = (ToggleButton) findViewById(R.id.toggleButton);
        toggleButton.setOnCheckedChangeListener(this);
        sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        proximitySensor = sensorManager
                .getDefaultSensor(Sensor.TYPE_PROXIMITY);
    }
    @Override
    protected void onResume() {
        super.onResume();
        if (proximitySensor != null) {
            sensorManager.registerListener(this, proximitySensor,
                    SensorManager.SENSOR_DELAY_NORMAL);
        }
    }
    @Override
    protected void onPause() {
        super.onPause();
        sensorManager.unregisterListener(this);
    }
    @Override
    public void onSensorChanged(SensorEvent event) {
    }
    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
    }
    @Override
    public void onCheckedChanged(CompoundButton buttonView,
            boolean isChecked) {
        if (isChecked && proximitySensor != null) {
            sensorManager.registerListener(this, proximitySensor,
                    SensorManager.SENSOR_DELAY_NORMAL);
        } else {
            sensorManager.unregisterListener(this);
        }
    }
}