一、需求来源

当页面元素特别多，比较杂，又必须获取某个组件尺寸位置时，一个个加 GlobalKey 有太麻烦，这是使用一个封装好的组件就特别有用了。然后就有了 NRenderBox 组件，可以打印出子组件的位置及尺寸。

二、使用

NRenderBox(
  child: Container(
    padding: EdgeInsets.symmetric(horizontal: 8, vertical: 4),
    decoration: BoxDecoration(
      color: Colors.transparent,
      border: Border.all(color: Colors.blue),
      borderRadius: BorderRadius.all(Radius.circular(0)),
    ),
    child: Column(
      mainAxisSize: MainAxisSize.min,
      children: [
        NNetworkImage(
          width: 50,
          height: 60,
          url: AppRes.image.urls.random ?? '',
        ),
        Text("选项"),
      ],
    ),
  ),
)

flutter: NRenderBox rect: Rect.fromLTRB(88.5, 322.0, 157.5, 413.0)

三、NRenderBox源码

import 'package:flutter/material.dart';

/// 点击打印尺寸
class NRenderBox extends StatefulWidget {
  const NRenderBox({
    super.key,
    required this.child,
  });

  final Widget child;

  @override
  State<NRenderBox> createState() => _NRenderBoxState();
}

class _NRenderBoxState extends State<NRenderBox> {
  final renderKey = GlobalKey();

  RenderBox? get renderBox {
    final ctx = renderKey.currentContext;
    if (ctx == null) {
      return null;
    }
    final box = ctx.findRenderObject() as RenderBox?;
    return box;
  }

  Offset? get renderPosition {
    return renderBox?.localToGlobal(Offset.zero);
  }

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      key: renderKey,
      onTap: () {
        if (renderBox == null) {
          return;
        }
        final position = renderPosition;
        final size = renderBox!.size;
        final rect = Rect.fromLTWH(position!.dx, position.dy, size.width, size.height);
        debugPrint("$widget rect: $rect");
      },
      child: widget.child,
    );
  }
}

github