Dart如何获得“价值”一个枚举

本文介绍了Dart如何获得“价值”一个枚举的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

在Dart中提供枚举之前，我编写了一些麻烦且难以维护的代码来模拟枚举，现在想简化它。我需要以字符串形式获取枚举的值，例如可以用Java完成但不能。

Before enums were available in Dart I wrote some cumbersome and hard to maintain code to simulate enums and now want to simplify it. I need to get the value of the enum as a string such as can be done with Java but cannot.

例如，很少的测试代码片段在其中返回 day.MONDAY每种情况下我想要的是'MONDAY'

For instance little test code snippet returns 'day.MONDAY' in each case when what I want is 'MONDAY"

enum day {MONDAY, TUESDAY}
print( 'Today is $day.MONDAY');
print( 'Today is $day.MONDAY.toString()');

我是否纠正为仅获取'MONDAY'，我需要解析字符串？

Am I correct that to get just 'MONDAY' I will need to parse the string?

推荐答案

遗憾的是，您正确地认为toString方法返回 day.MONDAY ，而不是更有用的MONDAY 。您可以通过以下方式获取字符串的其余部分：

Sadly, you are correct that the toString method returns "day.MONDAY", and not the more useful "MONDAY".You can get the rest of the string as:

day theDay = day.MONDAY;      
print(theDay.toString().substring(theDay.toString().indexOf('.') + 1));

诚然，这很方便。

如果要迭代所有值，可以使用 day.values ：

If you want to iterate all the values, you can do it using day.values:

for (day theDay in day.values) {
  print(theDay);
}

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Monday