flutter - 如何在颤动中填充 2 个圆圈之间的空间？

Question

我的圈画师：

    CircleWavePainter(this.animationValue) {
//add some property to paint
  wavePaint = Paint()
    ..color = Colors.black.withAlpha(100)
    ..style = PaintingStyle.stroke
    ..strokeWidth = 1
    ..isAntiAlias = true;
}

我的油漆画了 2 个圆圈，需要一些帮助来填充空间：

void paint(Canvas canvas, Size size) {
//circle 1
canvas.drawCircle(Offset(size.height / 2, size.width / 2),
80 * (1.4 - animationValue / 2), wavePaint);
//circle 2    
canvas.drawCircle(Offset(size.height / 2, size.width / 2),
80 * (1.8 - animationValue / 2), wavePaint);
}

Answer 1

你可以使用堆栈小部件我在我的课程中没有达到动画但我可以给你一个提示

Stack(
        alignment: AlignmentDirectional.bottomEnd,
        children: [
          CircleAvatar(
            radius: 30,
            backgroundImage: NetworkImage(
              'https://thispersondoesnotexist.com/image',
            ),
          ), //photo
          CircleAvatar(
            radius: 7,
            backgroundColor: Colors.white,
          ), // active or not
          CircleAvatar(
            radius: 6,
            backgroundColor: Colors.green,
          ), // active circle space
        ],
      )

Answer 2

使用“Stack”小部件而不是“Paint”，实现了您的设计。

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: _buildBody(),
    );
  }

  Widget _buildBody() {
    return Container(
      height: 400,
      width: 400,
      child: Stack(
        alignment: AlignmentDirectional.center,
        children: [
          Container(
            width: 280,
            height: 280,
            decoration: BoxDecoration(
              shape: BoxShape.circle,
              color: Color(0xFF4C4D4F),
            ),
          ),
          Container(
            width: 200,
            height: 200,
            decoration: BoxDecoration(
              shape: BoxShape.circle,
              color: Colors.white,
            ),
          ),
          Container(
            width: 140,
            height: 140,
            child: Icon(
              Icons.access_alarm,
              color: Colors.white,
              size: 30,
            ),
            decoration: BoxDecoration(
              shape: BoxShape.circle,
              color: Color(0xFF5EA2EB),
            ),
          )
        ],
      ),
    );
  }
}