无法创建自定义颜色表

Question

我正在尝试为应用程序使用自定义颜色主题。

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这是 main.dart 文件

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import \'package:flutter/material.dart\';\n\nimport \'pages/HomePage.dart\';\n\nvoid main() => runApp(new MyApp());\n\nclass MyApp extends StatelessWidget {\n  // This widget is the root of your application.\n  @override\n  Widget build(BuildContext context) {\n    return new MaterialApp(\n      title: \'Flutter Demo\',\n      debugShowCheckedModeBanner: false,\n      theme: new ThemeData(\n        // This is the theme of your application.\n        //\n        // Try running your application with "flutter run". You\'ll see the\n        // application has a blue toolbar. Then, without quitting the app, try\n        // changing the primarySwatch below to Colors.green and then invoke\n        // "hot reload" (press "r" in the console where you ran "flutter run",\n        // or press Run > Flutter Hot Reload in IntelliJ). Notice that the\n        // counter didn\'t reset back to zero; the application is not restarted.\n        primarySwatch: MaterialColor(0xFF990000, {\n          50: Color(0xFF990001),\n          300: Color(0xFF990002),\n          900: Color(0xFF990003)\n        }),\n      ),\n      home: new HomePage(),\n    );\n  }\n}\n

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我收到以下错误：

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flutter: \xe2\x95\x90\xe2\x95\x90\xe2\x95\xa1 小部件库捕获异常 \xe2\x95\x9e\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\ xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\ x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\ x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\ xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\ x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\ x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\ xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\nflutter：构建 MyApp（脏）时抛出以下 NoSuchMethodError：\ nflutter：在 null 上调用了“computeLuminance”方法。\nflutter：接收器：null\nflutter：尝试调用：computeLuminance()

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我做错了什么？

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Answer 1

如果你想让它工作，你应该定义所有的值，当我只定义一两个值时，我也遇到了同样的错误。

从官方文档我们发现

MaterialColor 类 定义单一颜色以及具有十种颜色阴影的色样。

例如：

 primarySwatch: MaterialColor(0xFFFFFFFF, {
  50:  Color(0xFFFFFFFF),
  100: Color(0xFFFFFFFF),
  200: Color(0xFFFFFFFF),
  300: Color(0xFFFFFFFF),
  400: Color(0xFFFFFFFF),
  500: Color(0xFFFFFFFF),
  600: Color(0xFFFFFFFF),
  700: Color(0xFFFFFFFF),
  800: Color(0xFFFFFFFF),
  900: Color(0xFFFFFFFF),
    });