删除Flutter中最后绘制的元素

Question

我正在尝试删除Flutter中的最后绘制的元素。只有一些示例可以删除整个草图。 removeLast（）函数无法按预期运行。希望有所帮助。

class Sketcher extends CustomPainter {
  final List<Offset> points;

  Sketcher(this.points);

  var color = Colors.black;

  @override
  void paint(Canvas canvas, Size size) {
    Paint paint = Paint()
      ..color = color
      ..strokeCap = StrokeCap.round
      ..strokeWidth = 4.0;

    for (int i = 0; i < points.length - 1; i++) {
      if (points[i] != null && points[i + 1] != null) {
        canvas.drawLine(points[i], points[i + 1], paint);
      }
    }
  }

  @override
  bool shouldRepaint(Sketcher oldDelegate) {
    return oldDelegate.points != points;
  }
}