Flutter自定义绘制Widget初探

import 'package:flutter/material.dart';
 
void main() => runApp(MyApp());
 
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}
 
class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('自定义绘制Widget'),
      ),
      body: Center(
        child: CustomPaint(
          size: Size(200, 200),
          painter: MyPainter(),
        ),
      ),
    );
  }
}
 
class MyPainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()
      ..color = Colors.blue
      ..style = PaintingStyle.fill;
 
    canvas.drawCircle(Offset(100, 100), 50, paint);
  }
 
  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    return false;
  }
}

这段代码创建了一个简单的自定义绘制Widget，它在一个200x200像素的圆形中心绘制了一个蓝色的圆。这个例子展示了如何使用CustomPaint Widget和CustomPainter类来实现自定义绘制逻辑。