我正在尝试为应用程序使用自定义颜色主题。
这是main.dart文件
import 'package:flutter/material.dart';
import 'pages/HomePage.dart';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Flutter Demo',
debugShowCheckedModeBanner: false,
theme: new ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or press Run > Flutter Hot Reload in IntelliJ). Notice that the
// counter didn't reset back to zero; the application is not restarted.
primarySwatch: MaterialColor(0xFF990000, {
50: Color(0xFF990001),
300: Color(0xFF990002),
900: Color(0xFF990003)
}),
),
home: new HomePage(),
);
}
}
我收到以下错误:
颤振:W小工具库引起的异常CA ═══════════════════════ 颤抖:构建MyApp(dirty)时引发以下NoSuchMethodError: flutter:方法'computeLuminance'在null上调用。 颤动:接收者:null 扑:尝试调用:computeLuminance()
我做错了什么?
答案 0 :(得分:0)
您不能将 MaterialColor 分配给 primaryswatch ,从而感染用于分配不同颜色类型(例如primaryColor,primaryColorLight / Dark,accentColor等)的primaryswatch。
您可以从类似的问题类型中获得更多详细信息。 How do I use the different shades of a color swatch in Flutter?
答案 1 :(得分:0)
如果要使用所有值,则应定义所有值,当我也仅定义一个或两个值时,也会遇到相同的错误。
从official documentation中我们发现
MaterialColor类 定义一种颜色以及具有十种颜色阴影的色板。
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),
});
答案 2 :(得分:0)
您需要整体创建一个MaterialColor
对象,为十个不同的亮度值提供所有颜色值。请考虑使用此解决方案以获得更好的方法。