在flutter中创建可调整大小的视图

import 'package:flutter/material.dart';

class ResizableWidget extends StatefulWidget {
  @override
  _ResizableWidgetState createState() => _ResizableWidgetState();
}

class _ResizableWidgetState extends State<ResizableWidget> {
  double _width = 200;
  double _height = 200;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Resizable Widget'),
      ),
      body: Center(
        child: LayoutBuilder(
          builder: (context, constraints) {
            return ConstrainedBox(
              constraints: BoxConstraints(
                minWidth: 100,
                maxWidth: constraints.maxWidth,
                minHeight: 100,
                maxHeight: constraints.maxHeight,
              ),
              child: GestureDetector(
                onPanUpdate: (details) {
                  setState(() {
                    _width += details.delta.dx;
                    _height += details.delta.dy;
                  });
                },
                child: Container(
                  width: _width,
                  height: _height,
                  color: Colors.blue,
                ),
              ),
            );
          },
        ),
      ),
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: ResizableWidget(),
  ));
}