为什么表情符号在UITextField中无法正确显示？ [英] Why can't Emoji display correctly in a UITextField?

问题描述

使用以下代码设置表情符号字符时：

When an Emoji character is set using the code below:

self.textField.text = @"\ue415";

它只显示为正方形。但是当我从键盘输入表情符号时，它会正确显示。有什么问题？

It just display as a square. But when I input an Emoji from the keyboard it displays correctly. What's the problem?

PS：我正在使用IOS 5.1

< img src =https://i.stack.imgur.com/SOgKh.pngalt =带表情符号文字视图>

推荐答案

在旧版本的iOS中，表情符号字符都在Unicode专用区域中，顾名思义就是一组明确没有任何关联字符的Unicode代码点。但是，Unicode标准已更新为包含大量表情符号字符，因此iOS现在使用这些字符，Mac OS X也是如此。

In older versions of iOS the Emoji characters were all in the Unicode Private Use Area, which as the name suggests is a set of Unicode code points that explicitly don't have any associated characters. However, the Unicode standard has been updated to include a large number of Emoji characters, so iOS now uses these ones, as does Mac OS X.

您可以看到一个列表www.unicode.org/charts中代码表中所有Unicode表情符号的例子 http://www.unicode.org/charts/PDF/U1F600.pdf 这些也告诉你每个表情符号实际上代表什么。

You can see a list of all the Unicode Emoji in the code charts at www.unicode.org/charts e.g. http://www.unicode.org/charts/PDF/U1F600.pdf and these also tell you what each Emoji is actually meant to represent.

Unicode规范的基本多语言平面中没有任何Unicode表情符号，这意味着它们'太大了，不适合单一的iOS unichar。因此，当它们存储在NSString中时，每个表情符号将覆盖多个unichars - 如果您尝试迭代字符串中的字符，则需要注意。

None of the Unicode Emoji are in the Basic Multilingual Plane of the Unicode spec, which means that they're all too big to fit in a single iOS unichar. So when they're stored in an NSString each emoji will cover multiple unichars — something to be aware of if you try to iterate over the characters in a string.

如果你有类似的代码

NSString *emoji =@"\U0001F604";
NSString *ascii = @"A";
NSLog(@"emoji.length %d, ascii.length %d", emoji.length, ascii.length);

你会在输出中看到这个

2013-03-08 14:42:22.841 test[23980:c07] emoji.length 2, ascii.length 1

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