英文:
Flutter ColorScheme CopyWith brightness not working
问题
在我的Flutter项目的app_theme.dart文件中，我有以下代码：
class AppTheme {
static const primaryColor = Color.fromARGB(255, 106, 49, 185);
static ThemeData lightTheme() {
return ThemeData(
useMaterial3: true,
colorScheme: ColorScheme.fromSeed(
seedColor: primaryColor,
brightness: Brightness.light,
),
);
}
static ThemeData darkTheme() {
return ThemeData(
useMaterial3: true,
colorScheme: ColorScheme.fromSeed(
seedColor: primaryColor,
brightness: Brightness.dark,
),
);
}
}
然后在main.dart中，我的Material App小部件像这样实现：
theme: AppTheme.lightTheme(),
darkTheme: AppTheme.darkTheme(),
这样可以正常工作，在Android模拟器中，在设置中切换暗黑模式时，应用会自动更改。
但是我想要单独声明ColorScheme（这样我可以覆盖某些颜色等），然后只需使用copyWith在ThemeData中声明亮度：
class AppTheme {
static const primaryColor = Color.fromARGB(255, 106, 49, 185);
static ColorScheme colorScheme = ColorScheme.fromSeed(
seedColor: primaryColor,
// 这里进行自定义
);
static ThemeData lightTheme() {
return ThemeData(
useMaterial3: true,
colorScheme: colorScheme.copyWith(
brightness: Brightness.light,
),
);
}
static ThemeData darkTheme() {
return ThemeData(
useMaterial3: true,
colorScheme: colorScheme.copyWith(
brightness: Brightness.dark,
),
);
}
}
但是这并不起作用。它一直保持在亮度模式下，尽管没有抛出错误。
有没有什么想法我做错了？
英文:
In my Flutter project app_theme.dart file I have this code:
class AppTheme {
static const primaryColor = Color.fromARGB(255, 106, 49, 185);
static ThemeData lightTheme() {
return ThemeData(
useMaterial3: true,
colorScheme: ColorScheme.fromSeed(
seedColor: primaryColor,
brightness: Brightness.light,
),
);
}
static ThemeData darkTheme() {
return ThemeData(
useMaterial3: true,
colorScheme: ColorScheme.fromSeed(
seedColor: primaryColor,
brightness: Brightness.dark,
),
);
}
Then in main.dart, my Material App widget implements this like so:
theme: AppTheme.lightTheme(),
darkTheme: AppTheme.darkTheme(),
This works correctly, so that in the Android emulator, when I switch between dark and light mode (within settings), the app automatically changes.
But what I wanted to do was declare the ColorScheme separately (so I can override certain colors etc) and then just use copyWith to declare the brightness in the ThemeData:
class AppTheme {
static const primaryColor = Color.fromARGB(255, 106, 49, 185);
static ColorScheme colorScheme = ColorScheme.fromSeed(
seedColor: primaryColor,
// Customisation goes here
);
static ThemeData lightTheme() {
return ThemeData(
useMaterial3: true,
colorScheme: colorScheme.copyWith(
brightness: Brightness.light,
),
);
}
static ThemeData darkTheme() {
return ThemeData(
useMaterial3: true,
colorScheme: colorScheme.copyWith(
brightness: Brightness.dark,
),
);
}
But this does not work. It just stays in light mode all the time, although no errors are thrown.
Any ideas what I'm doing wrong?
答案1
得分: 3
[ColorScheme.fromSeed][1] 构造函数基于给定的 seedColor 生成一个 `ColorScheme`。显然，复制生成的对象并不会再次生成颜色。类似这样的方法可以运行：
class AppTheme {
static const primaryColor = Color.fromARGB(255, 106, 49, 185);
static ColorScheme fromBrightness({required Brightness brightness}) {
return ColorScheme.fromSeed(
brightness: brightness,
seedColor: primaryColor,
// 在这里进行自定义
);
}
static ThemeData lightTheme() {
return ThemeData(
useMaterial3: true,
colorScheme: AppTheme.fromBrightness(
brightness: Brightness.light,
),
);
}
static ThemeData darkTheme() {
return ThemeData(
useMaterial3: true,
colorScheme: AppTheme.fromBrightness(
brightness: Brightness.dark,
),
);
}
}
英文:
ColorScheme.fromSeed constructor generates a ColorScheme derived from the given seedColor. Copying the generated object obviously does not generate colours again. Something like this would work:
class AppTheme {
static const primaryColor = Color.fromARGB(255, 106, 49, 185);
static ColorScheme fromBrightness({required Brightness brightness}) {
return ColorScheme.fromSeed(
brightness: brightness,
seedColor: primaryColor,
// Customisation goes here
);
}
static ThemeData lightTheme() {
return ThemeData(
useMaterial3: true,
colorScheme: AppTheme.fromBrightness(
brightness: Brightness.light,
),
);
}
static ThemeData darkTheme() {
return ThemeData(
useMaterial3: true,
colorScheme: AppTheme.fromBrightness(
brightness: Brightness.dark,
),
);
}
}
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