기울기 센서 값 가지고 오기

import android.app.Activity;
import android.content.Context;
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 test extends Activity implements SensorEventListener {
   
    private SensorManager sensorManager;
    private Sensor sensor;
    private TextView a , b, c;
  
   
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
  
        sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        sensor = sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
       
        setContentView(R.layout.main);
       
        a = (TextView)findViewById(R.id.h);
        b = (TextView)findViewById(R.id.p);
        c = (TextView)findViewById(R.id.r);
       
        a.setText("onCreate");
  
    }
  
    @Override
    public void onStart() {
        super.onStart();
  
        if (sensor != null)
            sensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_GAME);
    }
  
    @Override
    public void onStop() {
        super.onStop();
  
        if (sensorManager != null)
            sensorManager.unregisterListener(this);
    }
  
    @Override
    protected void onDestroy() {
     super.onDestroy();
     
     if (sensorManager != null)
            sensorManager.unregisterListener(this);
    }
   
    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
    }
  
    @Override
    public void onSensorChanged(SensorEvent sensorEvent) {
     if(sensorEvent.sensor.getType()==Sensor.TYPE_ORIENTATION){
       float headingAngle = sensorEvent.values[0];
       float pitchAngle = sensorEvent.values[1];
       float rollAngle = sensorEvent.values[2];
       
       a.setText("x: "+headingAngle);
       b.setText("y: "+ pitchAngle);
       c.setText("z: "+rollAngle);
     }
    } 
}