android - toUpperCaseLocale() 与 toUpperCase() - 现在针对 Android 4.2

Question

由于我针对的是 Android 的较新 SDK 版本，因此我收到了关于这行代码的警告:

return getString(R.string.usertab1).toUpperCase()

当我将鼠标悬停在它上面时，它会说:

Implicitly using the default locale is a common source of bugs: Use toUpperCase(Locale) instead.

有谁知道如何消除这个错误？为什么现在是使用这种方法的首选方式？

我知道这就是答案，使用 toUpperCase(Locale) 但在实现时遇到了麻烦。 Locale 对象从何而来？

Answer 1

您可以显式使用默认语言环境:

return getString(R.string.usertab1).toUpperCase(Locale.getDefault());

基本上，您不希望隐式允许设备使用默认值，因为这可能意味着您只是忽略了它可能是一个问题的事实。对于机器可读的内容，您可能需要指定特定的语言环境(例如 Locale.ENGLISH)，以确保始终从数据中获得所需的可重用性。为了向用户展示，明确指定默认区域设置应该没问题。

更完整的阅读:

A common mistake is to implicitly use the default locale when producing output meant to be machine-readable. This tends to work on the developer's test devices (especially because so many developers use en_US), but fails when run on a device whose user is in a more complex locale.

For example, if you're formatting integers some locales will use non-ASCII decimal digits. As another example, if you're formatting floating-point numbers some locales will use ',' as the decimal point and '.' for digit grouping. That's correct for human-readable output, but likely to cause problems if presented to another computer (parseDouble(String) can't parse such a number, for example). You should also be wary of the toLowerCase() and toUpperCase() overloads that don't take a Locale: in Turkey, for example, the characters 'i' and 'I' won't be converted to 'I' and 'i'. This is the correct behavior for Turkish text (such as user input), but inappropriate for, say, HTTP headers.

-- Locale developer documentation