public class MainActivity extends Activity {
 private Preview mPreview;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mPreview = new Preview(this);
        setContentView(mPreview);
    }
    class Preview extends SurfaceView implements SurfaceHolder.Callback {
        SurfaceHolder mHolder;
        Camera mCamera;
        Context mCtx;
       
        Preview(Context context) {
            super(context);
            mCtx = context;
            mHolder = getHolder();
            mHolder.addCallback(this);
            mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        }

        public void surfaceCreated(SurfaceHolder holder) {
            mCamera = Camera.open();
            try {
               mCamera.setPreviewDisplay(holder);
            } catch (IOException exception) {
                mCamera.release();
                mCamera = null;
            }
        }
       
        public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
            Camera.Parameters parameters = mCamera.getParameters();
            parameters.setPreviewSize(w, h);
            mCamera.setParameters(parameters);
            mCamera.startPreview();
        }

        public void surfaceDestroyed(SurfaceHolder holder) {
            mCamera.stopPreview();
            mCamera.release();
            mCamera = null;
        }

    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
}

이런식으로 책에있는데로 코딩을 해봐는데 왜 카메라가 왼쪽으로 90도 돌아간 상태로 화면이 보여질까요?????

다른걸 해줘야하는건가요?????