如下方法可以把汉字字符串转换成拼音，并且支持是否在拼音间插入空格

- (NSString *)chineseToPinyin:(NSString *)chinese withSpace:(BOOL)withSpace {
    CFStringRef hanzi = (__bridge CFStringRef)chinese;
    CFMutableStringRef string = CFStringCreateMutableCopy(NULL, 0, hanzi);
    CFStringTransform(string, NULL, kCFStringTransformMandarinLatin, NO);
    CFStringTransform(string, NULL, kCFStringTransformStripDiacritics, NO);
    NSString *pinyin = (NSString *)CFBridgingRelease(string);
    if (!withSpace) {
        pinyin = [pinyin stringByReplacingOccurrencesOfString:@" " withString:@""];
    }
    return pinyin;
}