Flutter forEach typing: Unable to type a foreach callback (参数类型AND不能分配给参数类型'void Function(dynamic)')

Question

这里的菜鸟问题总数：

如果我没有指定类型，它会说Try adding an explicit type, or remove implicit-dynamic from your analysis options file.dart(implicit_dynamic_parameter)

当我在函数参数前面添加类型double时，它表示The argument type 'void Function(double)' can't be assigned to the parameter type 'void Function(dynamic)'

我也很不明白为什么不能从上面的数组声明推断出类型？

final List strengths = <double>[.05]; // type of array items in a forEach loop seems obvious

我尝试了很多在互联网上随处可见的不同的东西和语法，但解决我的问题的唯一方法是删除 analysis_options.yaml

我确定我真的错过了明显的...你能给我指明正确的方向吗？

其他我看到的不能适应我的相关问题：

真正的功能代码：

MaterialColor createMaterialColor(Color color) {
  final List strengths = <double>[.05];
  final swatch = <int, Color>{};
  final int r = color.red, g = color.green, b = color.blue;

  for (int i = 1; i < 10; i++) {
    strengths.add(0.1 * i);
  }
  strengths.forEach((double strength) {
    final double ds = 0.5 - strength;
    swatch[(strength * 1000).round()] = Color.fromRGBO(
      r + ((ds < 0 ? r : (255 - r)) * ds).round(),
      g + ((ds < 0 ? g : (255 - g)) * ds).round(),
      b + ((ds < 0 ? b : (255 - b)) * ds).round(),
      1,
    );
  });
  return MaterialColor(color.value, swatch);
}

Answer 1

只需删除第一行的 List 关键字

之前

final List strengths = <double>[.05];

之后

final strengths = <double>[.05];

Answer 2

像这样声明您的列表：

final List<double> strengths = <double>[.05];

Flutter forEach typing: Unable to type a foreach callback (参数类型AND不能分配给参数类型'void Function(dynamic)')

Flutter forEach typing: Unable to type a forach callback (The argument type N can't be assigned to the parameter type 'void Function(dynamic)')

foreach

typing

dart

flutter