如何在 Flutter 中定义自定义 BorderRadius 类？答案

【问题标题】：How to define Custom BorderRadius class in flutter?如何在 Flutter 中定义自定义 BorderRadius 类？
【发布时间】：2021-01-20 21:00:48
【问题描述】：

标准化设计并避免错误并减少构建时间，我正在尝试定义一个以double corner 值作为参数的 BorderRadius 类，因此它可以在整个应用程序的许多地方使用

我在定义类构造函数时遇到很多错误，在这里无法真正找到解决方案

import 'package:flutter/material.dart';

class Borderz extends BorderRadius{
  final BorderRadius enBorderz;
  final double corner;
  static const double zeroCorner =  0.0,

 const Borderz({
    @required this.corner,
    this.enBorderz = BorderRadius.only(
              topLeft: Radius.circular(corner),
              topRight: Radius.circular(corner),
              bottomLeft: Radius.circular(corner),
              bottomRight: Radius.circular(zeroCorner),
            )
}) : super(zeroCorner : zeroCorner)
}

这段代码中的一些严重的基本错误让我感到尴尬，感谢您的帮助

【问题讨论】：

标签： flutter dart border-radius

【解决方案1】：

您可以在下面复制粘贴运行完整代码
可以直接拨打super.only，不用enBorderz

class Borderz extends BorderRadius {
  final double corner;
  static const double zeroCorner = 0.0;

  Borderz({
    @required this.corner,
  }) : super.only(
          topLeft: Radius.circular(corner),
          topRight: Radius.circular(corner),
          bottomLeft: Radius.circular(corner),
          bottomRight: Radius.circular(zeroCorner),
        );
}
...
Container(
      width: 100,
      height: 100,
      child: Center(
        child: Text(
          'test',
        ),
      ),
      decoration: BoxDecoration(
        borderRadius: Borderz(corner: 10.0),
        color: Colors.blue,
      ),
    ),

工作演示

完整代码

import 'package:flutter/material.dart';

class Borderz extends BorderRadius {
  final double corner;
  static const double zeroCorner = 0.0;

  Borderz({
    @required this.corner,
  }) : super.only(
          topLeft: Radius.circular(corner),
          topRight: Radius.circular(corner),
          bottomLeft: Radius.circular(corner),
          bottomRight: Radius.circular(zeroCorner),
        );
}

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> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Container(
              width: 100,
              height: 100,
              child: Center(
                child: Text(
                  'test',
                ),
              ),
              decoration: BoxDecoration(
                borderRadius: Borderz(corner: 10.0),
                color: Colors.blue,
              ),
            ),
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

【讨论】：