Points disappear when i rotate my device (Canvas)

Question

I'm developing an Android application, I have to implement a function that allow me to draw different points with canvas.

I have realized this function that works:

public class MainActivity extends AppCompatActivity {
    public Paint paint;
    public List<Point> coords;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new DrawingView(this));

        paint = new Paint();
        coords = new ArrayList();

        ImageView iv = new ImageView(getApplicationContext());
        iv.setImageResource(R.drawable.car);
        iv.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
        LinearLayout.LayoutParams parms = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,LinearLayout.LayoutParams.MATCH_PARENT);
        iv.setLayoutParams(parms);
    }

    class DrawingView extends SurfaceView {

        private final SurfaceHolder surfaceHolder;
        private final Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

        public DrawingView(Context context) {
            super(context);
            surfaceHolder = getHolder();
            paint.setColor(Color.BLACK);
            paint.setStyle(Paint.Style.FILL);
        }

        @Override
        public boolean onTouchEvent(MotionEvent event) {
            if(event.getAction() == MotionEvent.ACTION_DOWN) {
              addpoint(event.getX(), event.getY());
            }
            return false;
        }

        public void addpoint(float x, float y){

            Point point = new Point();
            point.x = Math.round(x);
            point.y = Math.round(y);
            coords.add(point);

            for(int i = 0; i< coords.size(); i++) {
                Canvas canvas = surfaceHolder.lockCanvas();
                canvas.drawColor(Color.WHITE);
                canvas.drawCircle(coords.get(i).x, coords.get(i).y, 20, paint);
                surfaceHolder.unlockCanvasAndPost(canvas);
            }
        }
    }
}

I have a problem, when i rotate my device the orientation change, and all points drawed disappear.

How i can keep all points ?