dart - 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 RenderBox 构建()小部件？

Answer 1

除了 StatefulWidget 或 StatelessWidget 你可以继承 SingleChildRenderObjectWidget (或类似的)

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