flutter:renderObjects是在有状态的小部件的生命周期中重新创建的吗?

我有一个设置,其中 StatefulWidget 创建自定义(叶) RenderBox . 是否有可能 渲染器 在的生存期内释放并重新创建 State ?

背景。我想将大量计算/动画控制器的某些结果保存在 RenderObject 这就是为什么对我来说 渲染对象 只要 状态 封闭小部件的。

import 'package:flutter/widgets.dart';

class SquaredCircle extends StatefulWidget {
  const SquaredCircle({Key key, this.radius}) : super(key: key);

  final double radius;

  @override
  State<StatefulWidget> createState() => _SquaredCircleState();
}

class _SquaredCircleState extends State<SquaredCircle> {
  int _squareness = 42;

  @override
  Widget build(BuildContext context) {
    final foo = widget.radius * _squareness;
    return _SquaredCircleRenderObjectWidget(foo);
  }
}

class _SquaredCircleRenderObjectWidget extends LeafRenderObjectWidget {
  _SquaredCircleRenderObjectWidget(this.foo);

  final double foo;

  @override
  _RenderSquaredCircle createRenderObject(BuildContext context) {
    return _RenderSquaredCircle(foo: foo);
  }

  @override
  void updateRenderObject(BuildContext context, _RenderSquaredCircle renderObject) {
    renderObject..foo = foo;
  }
}

class _RenderSquaredCircle extends RenderBox {
  _RenderSquaredCircle({double foo})
      : assert(foo != null),
        _foo = foo;

  double get foo => _foo;
  double _foo;
  set foo(double value) {
    assert(value != null);
    if (_foo == value) return;
    _foo = value;
    markNeedsPaint();
  }

  // ...
}