做了一个类似于浏览器标签的功能，取出主色调，选取标题第一个字，这里标题是可以编辑的，遇到表情符号就出现了以下状况：
很尴尬对不对。
Stack Overflow了一下，代码如下：
nsssting *string = @"?????"；
NSRange range = [string rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, 1)];
NSString * result = [string substringWithRange:range];
复制代码这里用到了rangeOfComposedCharacterSequencesForRange方法，把解释翻译一下：
Returns the range in the string of the composed character sequences for a given range.
This method provides a convenient way to grow a range to include all composed character sequences it overlaps.
返回给定范围内组合字符序列的字符串范围。此方法提供了一种方便的方法来扩展，使其包含所有与其重叠的字符序列。
@parameters range
A range in the receiver. The range must not exceed the bounds of the receiver.
接收机中的一个量程。范围不得超过接收机的范围。
@parameters return
The range in the receiver that includes the composed character sequences in range.
接收机中包括组合字符序列的范围
复制代码效果如下: