android中如何使用方向传感器Sensor

传感器：方向 、重力、磁场、温度、近距离、压力、光线、加速度

下面是如何使用方向传感器（指南针）：

使用自定义view画出指南针

public class MainActivity extends Activity
{
    private SensorManager manager;
    private Sensor mSensor;
    float[] mValues;
    private SampleView mView;
    @SuppressWarnings("deprecation")
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        mView = new SampleView(this);//使用自定义view
        setContentView(mView);
    //得到传感器管理器
        manager = (SensorManager)                         getSystemService(Context.SENSOR_SERVICE);
    //得到方向传感器
        mSensor = manager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
    }
    SensorEventListener mListener = new SensorEventListener()
    {
        @Override
        public void onSensorChanged(SensorEvent event)
        {
            mValues = event.values;
            if (mView != null)
            {
                mView.invalidate();//event发生改变时，重绘
            }
        }
        @Override
        public void onAccuracyChanged(Sensor sensor, int accuracy)
        {
        //精确改变，适用游戏
        }
    };
    @Override
    protected void onStart()
    {
        super.onStart();
        //在onstart()或onresume()里,管理器注册监听事件
        manager.registerListener(mListener, mSensor,             SensorManager.SENSOR_DELAY_GAME);
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu)
    {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    private class SampleView extends View
    {
        private Paint   mPaint = new Paint();
        private Path    mPath = new Path();
        private boolean mAnimate;
        private long    mNextTime;
        public SampleView(Context context)
        {
            super(context);
            // Construct a wedge-shaped path
            mPath.moveTo(0, -50);
            mPath.lineTo(-20, 60);
            mPath.lineTo(0, 50);
            mPath.lineTo(20, 60);
            mPath.close();
        }
        @Override protected void onDraw(Canvas canvas)
        {
            Paint paint = mPaint;
            canvas.drawColor(Color.WHITE);
            paint.setAntiAlias(true);
            paint.setColor(Color.BLACK);
            paint.setStyle(Paint.Style.FILL);
            int w = canvas.getWidth();
            int h = canvas.getHeight();
            int cx = w / 2;
            int cy = h / 2;
            canvas.translate(cx, cy);
            if (mValues != null)
            {
                canvas.rotate(-mValues[0]);
            }
            canvas.drawPath(mPath, mPaint);
        }
        @Override
        protected void onAttachedToWindow()
        {
        mAnimate = true;
        super.onAttachedToWindow();
        }
        @Override
        protected void onDetachedFromWindow()
        {
            mAnimate = false;
            super.onDetachedFromWindow();
        }
    }
}