Flutter-如何创建显示RenderBox组件的小部件？

Question

RenderBox提供了覆盖paint（）方法的机会。但是如何从该RenderBox构建（）小部件？

Answer 1

可以代替StatefulWidget或StatelessWidget的子类SingleChildRenderObjectWidget（或类似的子类）

class MyWidget extends SingleChildRenderObjectWidget {
  @override
  MyRenderBox createRenderObject(BuildContext context) {
    return new MyRenderBox(title: "bar");
  }

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

class MyRenderBox extends RenderBox {
  String title;

  MyRenderBox({this.title});
}

其他一些有趣的子类是LeafRenderObjectWidget和MultiChildRenderObjectWidget