有没有更好的方法将数据传递给没有状态的，继承的小部件的子代？

Question

我有一个如下所示的课程，

class DottedLine extends StatelessWidget{
  final double circleSize, space;
  final Color color;

  DottedLine({@required this.color, this.circleSize = 1.0, this.space = 5.0});

  @override
  Widget build(BuildContext context){
    return CustomPaint(painter: _DottedLinePainter(color: color, circleSize: circleSize, space: space),);
  }

}

还有另一个类，

class _DottedLinePainter extends CustomPainter{

  _DottedLinePainter({this.color, this.circleSize, this.space});

  final double circleSize, space;
  final Color color;

  @override
  void paint(Canvas canvas, Size size){
  ...
  }
  ...
}

这里，来自[[DottedLine，我将相同的三个参数传递给_ DottedLinePainter现在，如果我想为类_ DottedLinePainter添加新参数，则必须创建它也适用于[[DottedLine ...

那么如何只能在一个地方定义参数名称？但是我不想扩展Inherited Widgets导致的情况，因此我不得不更改DottedLine StatefulWidget，这是不必要的。

Answer 1

class DottedLine extends StatelessWidget{
  final double circleSize, space;
  final Color color;

  DottedLine({@required this.color, this.circleSize = 1.0, this.space = 5.0});

  @override
  Widget build(BuildContext context){
    return CustomPaint(painter: _DottedLinePainter(this),);
  }
}

class _DottedLinePainter extends CustomPainter{

  _DottedLinePainter(this.data);

  final DottedLine data;

  @override
  void paint(Canvas canvas, Size size){
  ...
  }
  ...
}