flutter - 如何将传递的值分配给构造函数中的最终字段？

Question

代码：

class MyColor {
  final Color one;
  final Color two;

  MyColor({
    this.one = Colors.black,
    this.two = one.withOpacity(0.5), // error
  });
}

有没有办法在构造函数本身中分配 to 的值one，two我希望所有字段都是final.

标签： flutterdart

Answer 1

class MyColor {
  final Color one;
  final Color two;

  MyColor({
    this.one = Colors.black,
    Color two,
  }) : two = two ?? one.withOpacity(0.5);
}