将表情符号从十六进制代码转换为 unicode

Question

我想在我的 iOS 和 Android 应用程序中使用表情符号。我在这里检查了表情符号列表，它列出了表情符号的十六进制代码。当我尝试直接使用十六进制代码时U+1F600，我在应用程序中看不到表情符号。我发现了另一种表示表情符号的方式，看起来像\uD83D\uDE00. 使用此表示法时，无需任何额外代码即可在应用程序中看到表情符号。我认为这是表情符号的 Unicode 字符串。我认为这更像是一个针对表情符号的普遍问题。如何将表情符号十六进制代码转换为如上所示的 Unicode 字符串。我没有找到任何列出表情符号 Unicode 的列表。

Answer 1

看来你的问题实际上是“如何显示一个字符，知道它的代码点？”

This question turns out to be rather language-dependent! Modern languages have little trouble with this. In Swift, we do this:

$ swift
Welcome to Apple Swift version 3.0.2 (swiftlang-800.0.63 clang-800.0.42.1). Type :help for assistance.
  1> "\u{1f600}"
$R0: String = ""

In JavaScript, it is the same:

$ node
> "\u{1f600}"
''

In Java, you have to do a little more work. If you want to use the code point directly you can say:

new StringBuilder().appendCodePoint(0x1f600).toString();

The sequence "\uD83D\uDE00" also works in all three languages. This is because those "characters" are actually what Unicode calls surrogates and when they are combined together a certain way they stand for a single character. The details of how this all works can be found on the web in many places (look for UTF-16 encoding). The algorithm is there. In a nutshell you take the code point, subtract 10000 hex, and spread out the 20 bits of that difference like this: 110110xxxxxxxxxx110111xxxxxxxxxx.

But rather than worrying about this translation, you should use the code point directly if your language supports it well. You might also be able to copy-paste the emoji character into a good text editor (make sure the encoding is set to UTF-8). If you need to use the surrogates, your best best is to look up a Unicode chart that shows you something called the "UTF-16 encoding."