我有兴趣将一些文本设置为 a UILabel，并根据语言的方向性（例如，希伯来语 - 从右到左 [RTL]、英语 - 从左到右 [LTR]）设置UILabel.
请注意，使用 iOS 6NSTextAlignmentNatural并不能解决问题，因为它会根据当前的语言环境选择对齐方式，实验表明。
问问题
4051 次
5 回答
11
最终遵循此 SO 答案中给出的建议：编写一个简短的脚本来解析此处公开可用的 Unicode 数据，并生成代码以识别代码点是否具有强 R 或 AL 方向属性。然后，在字符串中搜索第一个这样的字符。这正是ICU 包中的ubidi_getBaseDirection所做的。
由于其内部表示NSString为UTF16（即变长编码），为了简化扫码，首先将其转换为UTF32。另一种方法是动态解码字符串，这需要处理 BOM 和 Unicode 代理项。另一种方法是简单地忽略无法由 one 表示的字符unichar。有关更多详细信息，请参阅Wikipedia 的 UTF16 文章。
简答
@interface NSString (TextDirectionality)
/* Return 1 if the string is strongly LTR, -1 if strongly RTL, or 0 if neutral. */
/* See http://icu-project.org/apiref/icu4c/ubidi_8h.html#aeb1fd15743833278cc11906cd5a48aef */
-(int)getBaseDirection;
@end
@implementation NSString (TextDirectionality)
// Function takes UTF32 character, and not a unichar (=UTF16 character),
// because some Unicode characters need full 32 bits to represent.
BOOL isCodePointStrongRTL(UTF32Char c) {
return ((c == 0x5BE) || (c == 0x5C0) || (c == 0x5C3) || (c == 0x5C6) || (c >= 0x5D0 && c <= 0x5EA) || (c >= 0x5F0 && c <= 0x5F4) || (c == 0x608) || (c == 0x60B) || (c == 0x60D) || (c == 0x61B) || (c >= 0x61E && c <= 0x64A) || (c >= 0x66D && c <= 0x66F) || (c >= 0x671 && c <= 0x6D5) || (c >= 0x6E5 && c <= 0x6E6) || (c >= 0x6EE && c <= 0x6EF) || (c >= 0x6FA && c <= 0x70D) || (c >= 0x70F && c <= 0x710) || (c >= 0x712 && c <= 0x72F) || (c >= 0x74D && c <= 0x7A5) || (c == 0x7B1) || (c >= 0x7C0 && c <= 0x7EA) || (c >= 0x7F4 && c <= 0x7F5) || (c == 0x7FA) || (c >= 0x800 && c <= 0x815) || (c == 0x81A) || (c == 0x824) || (c == 0x828) || (c >= 0x830 && c <= 0x83E) || (c >= 0x840 && c <= 0x858) || (c == 0x85E) || (c == 0x8A0) || (c >= 0x8A2 && c <= 0x8AC) || (c == 0x200F) || (c == 0xFB1D) || (c >= 0xFB1F && c <= 0xFB28) || (c >= 0xFB2A && c <= 0xFB36) || (c >= 0xFB38 && c <= 0xFB3C) || (c == 0xFB3E) || (c >= 0xFB40 && c <= 0xFB41) || (c >= 0xFB43 && c <= 0xFB44) || (c >= 0xFB46 && c <= 0xFBC1) || (c >= 0xFBD3 && c <= 0xFD3D) || (c >= 0xFD50 && c <= 0xFD8F) || (c >= 0xFD92 && c <= 0xFDC7) || (c >= 0xFDF0 && c <= 0xFDFC) || (c >= 0xFE70 && c <= 0xFE74) || (c >= 0xFE76 && c <= 0xFEFC) || (c >= 0x10800 && c <= 0x10805) || (c == 0x10808) || (c >= 0x1080A && c <= 0x10835) || (c >= 0x10837 && c <= 0x10838) || (c == 0x1083C) || (c >= 0x1083F && c <= 0x10855) || (c >= 0x10857 && c <= 0x1085F) || (c >= 0x10900 && c <= 0x1091B) || (c >= 0x10920 && c <= 0x10939) || (c == 0x1093F) || (c >= 0x10980 && c <= 0x109B7) || (c >= 0x109BE && c <= 0x109BF) || (c == 0x10A00) || (c >= 0x10A10 && c <= 0x10A13) || (c >= 0x10A15 && c <= 0x10A17) || (c >= 0x10A19 && c <= 0x10A33) || (c >= 0x10A40 && c <= 0x10A47) || (c >= 0x10A50 && c <= 0x10A58) || (c >= 0x10A60 && c <= 0x10A7F) || (c >= 0x10B00 && c <= 0x10B35) || (c >= 0x10B40 && c <= 0x10B55) || (c >= 0x10B58 && c <= 0x10B72) || (c >= 0x10B78 && c <= 0x10B7F) || (c >= 0x10C00 && c <= 0x10C48) || (c >= 0x1EE00 && c <= 0x1EE03) || (c >= 0x1EE05 && c <= 0x1EE1F) || (c >= 0x1EE21 && c <= 0x1EE22) || (c == 0x1EE24) || (c == 0x1EE27) || (c >= 0x1EE29 && c <= 0x1EE32) || (c >= 0x1EE34 && c <= 0x1EE37) || (c == 0x1EE39) || (c == 0x1EE3B) || (c == 0x1EE42) || (c == 0x1EE47) || (c == 0x1EE49) || (c == 0x1EE4B) || (c >= 0x1EE4D && c <= 0x1EE4F) || (c >= 0x1EE51 && c <= 0x1EE52) || (c == 0x1EE54) || (c == 0x1EE57) || (c == 0x1EE59) || (c == 0x1EE5B) || (c == 0x1EE5D) || (c == 0x1EE5F) || (c >= 0x1EE61 && c <= 0x1EE62) || (c == 0x1EE64) || (c >= 0x1EE67 && c <= 0x1EE6A) || (c >= 0x1EE6C && c <= 0x1EE72) || (c >= 0x1EE74 && c <= 0x1EE77) || (c >= 0x1EE79 && c <= 0x1EE7C) || (c == 0x1EE7E) || (c >= 0x1EE80 && c <= 0x1EE89) || (c >= 0x1EE8B && c <= 0x1EE9B) || (c >= 0x1EEA1 && c <= 0x1EEA3) || (c >= 0x1EEA5 && c <= 0x1EEA9) || (c >= 0x1EEAB && c <= 0x1EEBB));
}
BOOL isCodePointStrongLTR(UTF32Char c) {
return (c >= 0x41 && c <= 0x5A) || (c >= 0x61 && c <= 0x7A) || (c == 0xAA) || (c == 0xB5) || (c == 0xBA) || (c >= 0xC0 && c <= 0xD6) || (c >= 0xD8 && c <= 0xF6) || (c >= 0xF8 && c <= 0x2B8) || (c >= 0x2BB && c <= 0x2C1) || (c >= 0x2D0 && c <= 0x2D1) || (c >= 0x2E0 && c <= 0x2E4) || (c == 0x2EE) || (c >= 0x370 && c <= 0x373) || (c >= 0x376 && c <= 0x377) || (c >= 0x37A && c <= 0x37D) || (c == 0x386) || (c >= 0x388 && c <= 0x38A) || (c == 0x38C) || (c >= 0x38E && c <= 0x3A1) || (c >= 0x3A3 && c <= 0x3F5) || (c >= 0x3F7 && c <= 0x482) || (c >= 0x48A && c <= 0x527) || (c >= 0x531 && c <= 0x556) || (c >= 0x559 && c <= 0x55F) || (c >= 0x561 && c <= 0x587) || (c == 0x589) || (c >= 0x903 && c <= 0x939) || (c == 0x93B) || (c >= 0x93D && c <= 0x940) || (c >= 0x949 && c <= 0x94C) || (c >= 0x94E && c <= 0x950) || (c >= 0x958 && c <= 0x961) || (c >= 0x964 && c <= 0x977) || (c >= 0x979 && c <= 0x97F) || (c >= 0x982 && c <= 0x983) || (c >= 0x985 && c <= 0x98C) || (c >= 0x98F && c <= 0x990) || (c >= 0x993 && c <= 0x9A8) || (c >= 0x9AA && c <= 0x9B0) || (c == 0x9B2) || (c >= 0x9B6 && c <= 0x9B9) || (c >= 0x9BD && c <= 0x9C0) || (c >= 0x9C7 && c <= 0x9C8) || (c >= 0x9CB && c <= 0x9CC) || (c == 0x9CE) || (c == 0x9D7) || (c >= 0x9DC && c <= 0x9DD) || (c >= 0x9DF && c <= 0x9E1) || (c >= 0x9E6 && c <= 0x9F1) || (c >= 0x9F4 && c <= 0x9FA) || (c == 0xA03) || (c >= 0xA05 && c <= 0xA0A) || (c >= 0xA0F && c <= 0xA10) || (c >= 0xA13 && c <= 0xA28) || (c >= 0xA2A && c <= 0xA30) || (c >= 0xA32 && c <= 0xA33) || (c >= 0xA35 && c <= 0xA36) || (c >= 0xA38 && c <= 0xA39) || (c >= 0xA3E && c <= 0xA40) || (c >= 0xA59 && c <= 0xA5C) || (c == 0xA5E) || (c >= 0xA66 && c <= 0xA6F) || (c >= 0xA72 && c <= 0xA74) || (c == 0xA83) || (c >= 0xA85 && c <= 0xA8D) || (c >= 0xA8F && c <= 0xA91) || (c >= 0xA93 && c <= 0xAA8) || (c >= 0xAAA && c <= 0xAB0) || (c >= 0xAB2 && c <= 0xAB3) || (c >= 0xAB5 && c <= 0xAB9) || (c >= 0xABD && c <= 0xAC0) || (c == 0xAC9) || (c >= 0xACB && c <= 0xACC) || (c == 0xAD0) || (c >= 0xAE0 && c <= 0xAE1) || (c >= 0xAE6 && c <= 0xAF0) || (c >= 0xB02 && c <= 0xB03) || (c >= 0xB05 && c <= 0xB0C) || (c >= 0xB0F && c <= 0xB10) || (c >= 0xB13 && c <= 0xB28) || (c >= 0xB2A && c <= 0xB30) || (c >= 0xB32 && c <= 0xB33) || (c >= 0xB35 && c <= 0xB39) || (c >= 0xB3D && c <= 0xB3E) || (c == 0xB40) || (c >= 0xB47 && c <= 0xB48) || (c >= 0xB4B && c <= 0xB4C) || (c == 0xB57) || (c >= 0xB5C && c <= 0xB5D) || (c >= 0xB5F && c <= 0xB61) || (c >= 0xB66 && c <= 0xB77) || (c == 0xB83) || (c >= 0xB85 && c <= 0xB8A) || (c >= 0xB8E && c <= 0xB90) || (c >= 0xB92 && c <= 0xB95) || (c >= 0xB99 && c <= 0xB9A) || (c == 0xB9C) || (c >= 0xB9E && c <= 0xB9F) || (c >= 0xBA3 && c <= 0xBA4) || (c >= 0xBA8 && c <= 0xBAA) || (c >= 0xBAE && c <= 0xBB9) || (c >= 0xBBE && c <= 0xBBF) || (c >= 0xBC1 && c <= 0xBC2) || (c >= 0xBC6 && c <= 0xBC8) || (c >= 0xBCA && c <= 0xBCC) || (c == 0xBD0) || (c == 0xBD7) || (c >= 0xBE6 && c <= 0xBF2) || (c >= 0xC01 && c <= 0xC03) || (c >= 0xC05 && c <= 0xC0C) || (c >= 0xC0E && c <= 0xC10) || (c >= 0xC12 && c <= 0xC28) || (c >= 0xC2A && c <= 0xC33) || (c >= 0xC35 && c <= 0xC39) || (c == 0xC3D) || (c >= 0xC41 && c <= 0xC44) || (c >= 0xC58 && c <= 0xC59) || (c >= 0xC60 && c <= 0xC61) || (c >= 0xC66 && c <= 0xC6F) || (c == 0xC7F) || (c >= 0xC82 && c <= 0xC83) || (c >= 0xC85 && c <= 0xC8C) || (c >= 0xC8E && c <= 0xC90) || (c >= 0xC92 && c <= 0xCA8) || (c >= 0xCAA && c <= 0xCB3) || (c >= 0xCB5 && c <= 0xCB9) || (c >= 0xCBD && c <= 0xCC4) || (c >= 0xCC6 && c <= 0xCC8) || (c >= 0xCCA && c <= 0xCCB) || (c >= 0xCD5 && c <= 0xCD6) || (c == 0xCDE) || (c >= 0xCE0 && c <= 0xCE1) || (c >= 0xCE6 && c <= 0xCEF) || (c >= 0xCF1 && c <= 0xCF2) || (c >= 0xD02 && c <= 0xD03) || (c >= 0xD05 && c <= 0xD0C) || (c >= 0xD0E && c <= 0xD10) || (c >= 0xD12 && c <= 0xD3A) || (c >= 0xD3D && c <= 0xD40) || (c >= 0xD46 && c <= 0xD48) || (c >= 0xD4A && c <= 0xD4C) || (c == 0xD4E) || (c == 0xD57) || (c >= 0xD60 && c <= 0xD61) || (c >= 0xD66 && c <= 0xD75) || (c >= 0xD79 && c <= 0xD7F) || (c >= 0xD82 && c <= 0xD83) || (c >= 0xD85 && c <= 0xD96) || (c >= 0xD9A && c <= 0xDB1) || (c >= 0xDB3 && c <= 0xDBB) || (c == 0xDBD) || (c >= 0xDC0 && c <= 0xDC6) || (c >= 0xDCF && c <= 0xDD1) || (c >= 0xDD8 && c <= 0xDDF) || (c >= 0xDF2 && c <= 0xDF4) || (c >= 0xE01 && c <= 0xE30) || (c >= 0xE32 && c <= 0xE33) || (c >= 0xE40 && c <= 0xE46) || (c >= 0xE4F && c <= 0xE5B) || (c >= 0xE81 && c <= 0xE82) || (c == 0xE84) || (c >= 0xE87 && c <= 0xE88) || (c == 0xE8A) || (c == 0xE8D) || (c >= 0xE94 && c <= 0xE97) || (c >= 0xE99 && c <= 0xE9F) || (c >= 0xEA1 && c <= 0xEA3) || (c == 0xEA5) || (c == 0xEA7) || (c >= 0xEAA && c <= 0xEAB) || (c >= 0xEAD && c <= 0xEB0) || (c >= 0xEB2 && c <= 0xEB3) || (c == 0xEBD) || (c >= 0xEC0 && c <= 0xEC4) || (c == 0xEC6) || (c >= 0xED0 && c <= 0xED9) || (c >= 0xEDC && c <= 0xEDF) || (c >= 0xF00 && c <= 0xF17) || (c >= 0xF1A && c <= 0xF34) || (c == 0xF36) || (c == 0xF38) || (c >= 0xF3E && c <= 0xF47) || (c >= 0xF49 && c <= 0xF6C) || (c == 0xF7F) || (c == 0xF85) || (c >= 0xF88 && c <= 0xF8C) || (c >= 0xFBE && c <= 0xFC5) || (c >= 0xFC7 && c <= 0xFCC) || (c >= 0xFCE && c <= 0xFDA) || (c >= 0x1000 && c <= 0x102C) || (c == 0x1031) || (c == 0x1038) || (c >= 0x103B && c <= 0x103C) || (c >= 0x103F && c <= 0x1057) || (c >= 0x105A && c <= 0x105D) || (c >= 0x1061 && c <= 0x1070) || (c >= 0x1075 && c <= 0x1081) || (c >= 0x1083 && c <= 0x1084) || (c >= 0x1087 && c <= 0x108C) || (c >= 0x108E && c <= 0x109C) || (c >= 0x109E && c <= 0x10C5) || (c == 0x10C7) || (c == 0x10CD) || (c >= 0x10D0 && c <= 0x1248) || (c >= 0x124A && c <= 0x124D) || (c >= 0x1250 && c <= 0x1256) || (c == 0x1258) || (c >= 0x125A && c <= 0x125D) || (c >= 0x1260 && c <= 0x1288) || (c >= 0x128A && c <= 0x128D) || (c >= 0x1290 && c <= 0x12B0) || (c >= 0x12B2 && c <= 0x12B5) || (c >= 0x12B8 && c <= 0x12BE) || (c == 0x12C0) || (c >= 0x12C2 && c <= 0x12C5) || (c >= 0x12C8 && c <= 0x12D6) || (c >= 0x12D8 && c <= 0x1310) || (c >= 0x1312 && c <= 0x1315) || (c >= 0x1318 && c <= 0x135A) || (c >= 0x1360 && c <= 0x137C) || (c >= 0x1380 && c <= 0x138F) || (c >= 0x13A0 && c <= 0x13F4) || (c >= 0x1401 && c <= 0x167F) || (c >= 0x1681 && c <= 0x169A) || (c >= 0x16A0 && c <= 0x16F0) || (c >= 0x1700 && c <= 0x170C) || (c >= 0x170E && c <= 0x1711) || (c >= 0x1720 && c <= 0x1731) || (c >= 0x1735 && c <= 0x1736) || (c >= 0x1740 && c <= 0x1751) || (c >= 0x1760 && c <= 0x176C) || (c >= 0x176E && c <= 0x1770) || (c >= 0x1780 && c <= 0x17B3) || (c == 0x17B6) || (c >= 0x17BE && c <= 0x17C5) || (c >= 0x17C7 && c <= 0x17C8) || (c >= 0x17D4 && c <= 0x17DA) || (c == 0x17DC) || (c >= 0x17E0 && c <= 0x17E9) || (c >= 0x1810 && c <= 0x1819) || (c >= 0x1820 && c <= 0x1877) || (c >= 0x1880 && c <= 0x18A8) || (c == 0x18AA) || (c >= 0x18B0 && c <= 0x18F5) || (c >= 0x1900 && c <= 0x191C) || (c >= 0x1923 && c <= 0x1926) || (c >= 0x1929 && c <= 0x192B) || (c >= 0x1930 && c <= 0x1931) || (c >= 0x1933 && c <= 0x1938) || (c >= 0x1946 && c <= 0x196D) || (c >= 0x1970 && c <= 0x1974) || (c >= 0x1980 && c <= 0x19AB) || (c >= 0x19B0 && c <= 0x19C9) || (c >= 0x19D0 && c <= 0x19DA) || (c >= 0x1A00 && c <= 0x1A16) || (c >= 0x1A19 && c <= 0x1A1B) || (c >= 0x1A1E && c <= 0x1A55) || (c == 0x1A57) || (c == 0x1A61) || (c >= 0x1A63 && c <= 0x1A64) || (c >= 0x1A6D && c <= 0x1A72) || (c >= 0x1A80 && c <= 0x1A89) || (c >= 0x1A90 && c <= 0x1A99) || (c >= 0x1AA0 && c <= 0x1AAD) || (c >= 0x1B04 && c <= 0x1B33) || (c == 0x1B35) || (c == 0x1B3B) || (c >= 0x1B3D && c <= 0x1B41) || (c >= 0x1B43 && c <= 0x1B4B) || (c >= 0x1B50 && c <= 0x1B6A) || (c >= 0x1B74 && c <= 0x1B7C) || (c >= 0x1B82 && c <= 0x1BA1) || (c >= 0x1BA6 && c <= 0x1BA7) || (c == 0x1BAA) || (c >= 0x1BAC && c <= 0x1BE5) || (c == 0x1BE7) || (c >= 0x1BEA && c <= 0x1BEC) || (c == 0x1BEE) || (c >= 0x1BF2 && c <= 0x1BF3) || (c >= 0x1BFC && c <= 0x1C2B) || (c >= 0x1C34 && c <= 0x1C35) || (c >= 0x1C3B && c <= 0x1C49) || (c >= 0x1C4D && c <= 0x1C7F) || (c >= 0x1CC0 && c <= 0x1CC7) || (c == 0x1CD3) || (c == 0x1CE1) || (c >= 0x1CE9 && c <= 0x1CEC) || (c >= 0x1CEE && c <= 0x1CF3) || (c >= 0x1CF5 && c <= 0x1CF6) || (c >= 0x1D00 && c <= 0x1DBF) || (c >= 0x1E00 && c <= 0x1F15) || (c >= 0x1F18 && c <= 0x1F1D) || (c >= 0x1F20 && c <= 0x1F45) || (c >= 0x1F48 && c <= 0x1F4D) || (c >= 0x1F50 && c <= 0x1F57) || (c == 0x1F59) || (c == 0x1F5B) || (c == 0x1F5D) || (c >= 0x1F5F && c <= 0x1F7D) || (c >= 0x1F80 && c <= 0x1FB4) || (c >= 0x1FB6 && c <= 0x1FBC) || (c == 0x1FBE) || (c >= 0x1FC2 && c <= 0x1FC4) || (c >= 0x1FC6 && c <= 0x1FCC) || (c >= 0x1FD0 && c <= 0x1FD3) || (c >= 0x1FD6 && c <= 0x1FDB) || (c >= 0x1FE0 && c <= 0x1FEC) || (c >= 0x1FF2 && c <= 0x1FF4) || (c >= 0x1FF6 && c <= 0x1FFC) || (c == 0x200E) || (c == 0x2071) || (c == 0x207F) || (c >= 0x2090 && c <= 0x209C) || (c == 0x2102) || (c == 0x2107) || (c >= 0x210A && c <= 0x2113) || (c == 0x2115) || (c >= 0x2119 && c <= 0x211D) || (c == 0x2124) || (c == 0x2126) || (c == 0x2128) || (c >= 0x212A && c <= 0x212D) || (c >= 0x212F && c <= 0x2139) || (c >= 0x213C && c <= 0x213F) || (c >= 0x2145 && c <= 0x2149) || (c >= 0x214E && c <= 0x214F) || (c >= 0x2160 && c <= 0x2188) || (c >= 0x2336 && c <= 0x237A) || (c == 0x2395) || (c >= 0x249C && c <= 0x24E9) || (c == 0x26AC) || (c >= 0x2800 && c <= 0x28FF) || (c >= 0x2C00 && c <= 0x2C2E) || (c >= 0x2C30 && c <= 0x2C5E) || (c >= 0x2C60 && c <= 0x2CE4) || (c >= 0x2CEB && c <= 0x2CEE) || (c >= 0x2CF2 && c <= 0x2CF3) || (c >= 0x2D00 && c <= 0x2D25) || (c == 0x2D27) || (c == 0x2D2D) || (c >= 0x2D30 && c <= 0x2D67) || (c >= 0x2D6F && c <= 0x2D70) || (c >= 0x2D80 && c <= 0x2D96) || (c >= 0x2DA0 && c <= 0x2DA6) || (c >= 0x2DA8 && c <= 0x2DAE) || (c >= 0x2DB0 && c <= 0x2DB6) || (c >= 0x2DB8 && c <= 0x2DBE) || (c >= 0x2DC0 && c <= 0x2DC6) || (c >= 0x2DC8 && c <= 0x2DCE) || (c >= 0x2DD0 && c <= 0x2DD6) || (c >= 0x2DD8 && c <= 0x2DDE) || (c >= 0x3005 && c <= 0x3007) || (c >= 0x3021 && c <= 0x3029) || (c >= 0x302E && c <= 0x302F) || (c >= 0x3031 && c <= 0x3035) || (c >= 0x3038 && c <= 0x303C) || (c >= 0x3041 && c <= 0x3096) || (c >= 0x309D && c <= 0x309F) || (c >= 0x30A1 && c <= 0x30FA) || (c >= 0x30FC && c <= 0x30FF) || (c >= 0x3105 && c <= 0x312D) || (c >= 0x3131 && c <= 0x318E) || (c >= 0x3190 && c <= 0x31BA) || (c >= 0x31F0 && c <= 0x321C) || (c >= 0x3220 && c <= 0x324F) || (c >= 0x3260 && c <= 0x327B) || (c >= 0x327F && c <= 0x32B0) || (c >= 0x32C0 && c <= 0x32CB) || (c >= 0x32D0 && c <= 0x32FE) || (c >= 0x3300 && c <= 0x3376) || (c >= 0x337B && c <= 0x33DD) || (c >= 0x33E0 && c <= 0x33FE) || (c == 0x3400) || (c == 0x4DB5) || (c == 0x4E00) || (c == 0x9FCC) || (c >= 0xA000 && c <= 0xA48C) || (c >= 0xA4D0 && c <= 0xA60C) || (c >= 0xA610 && c <= 0xA62B) || (c >= 0xA640 && c <= 0xA66E) || (c >= 0xA680 && c <= 0xA697) || (c >= 0xA6A0 && c <= 0xA6EF) || (c >= 0xA6F2 && c <= 0xA6F7) || (c >= 0xA722 && c <= 0xA787) || (c >= 0xA789 && c <= 0xA78E) || (c >= 0xA790 && c <= 0xA793) || (c >= 0xA7A0 && c <= 0xA7AA) || (c >= 0xA7F8 && c <= 0xA801) || (c >= 0xA803 && c <= 0xA805) || (c >= 0xA807 && c <= 0xA80A) || (c >= 0xA80C && c <= 0xA824) || (c == 0xA827) || (c >= 0xA830 && c <= 0xA837) || (c >= 0xA840 && c <= 0xA873) || (c >= 0xA880 && c <= 0xA8C3) || (c >= 0xA8CE && c <= 0xA8D9) || (c >= 0xA8F2 && c <= 0xA8FB) || (c >= 0xA900 && c <= 0xA925) || (c >= 0xA92E && c <= 0xA946) || (c >= 0xA952 && c <= 0xA953) || (c >= 0xA95F && c <= 0xA97C) || (c >= 0xA983 && c <= 0xA9B2) || (c >= 0xA9B4 && c <= 0xA9B5) || (c >= 0xA9BA && c <= 0xA9BB) || (c >= 0xA9BD && c <= 0xA9CD) || (c >= 0xA9CF && c <= 0xA9D9) || (c >= 0xA9DE && c <= 0xA9DF) || (c >= 0xAA00 && c <= 0xAA28) || (c >= 0xAA2F && c <= 0xAA30) || (c >= 0xAA33 && c <= 0xAA34) || (c >= 0xAA40 && c <= 0xAA42) || (c >= 0xAA44 && c <= 0xAA4B) || (c == 0xAA4D) || (c >= 0xAA50 && c <= 0xAA59) || (c >= 0xAA5C && c <= 0xAA7B) || (c >= 0xAA80 && c <= 0xAAAF) || (c == 0xAAB1) || (c >= 0xAAB5 && c <= 0xAAB6) || (c >= 0xAAB9 && c <= 0xAABD) || (c == 0xAAC0) || (c == 0xAAC2) || (c >= 0xAADB && c <= 0xAAEB) || (c >= 0xAAEE && c <= 0xAAF5) || (c >= 0xAB01 && c <= 0xAB06) || (c >= 0xAB09 && c <= 0xAB0E) || (c >= 0xAB11 && c <= 0xAB16) || (c >= 0xAB20 && c <= 0xAB26) || (c >= 0xAB28 && c <= 0xAB2E) || (c >= 0xABC0 && c <= 0xABE4) || (c >= 0xABE6 && c <= 0xABE7) || (c >= 0xABE9 && c <= 0xABEC) || (c >= 0xABF0 && c <= 0xABF9) || (c == 0xAC00) || (c == 0xD7A3) || (c >= 0xD7B0 && c <= 0xD7C6) || (c >= 0xD7CB && c <= 0xD7FB) || (c == 0xD800) || (c >= 0xDB7F && c <= 0xDB80) || (c >= 0xDBFF && c <= 0xDC00) || (c >= 0xDFFF && c <= 0xE000) || (c >= 0xF8FF && c <= 0xFA6D) || (c >= 0xFA70 && c <= 0xFAD9) || (c >= 0xFB00 && c <= 0xFB06) || (c >= 0xFB13 && c <= 0xFB17) || (c >= 0xFF21 && c <= 0xFF3A) || (c >= 0xFF41 && c <= 0xFF5A) || (c >= 0xFF66 && c <= 0xFFBE) || (c >= 0xFFC2 && c <= 0xFFC7) || (c >= 0xFFCA && c <= 0xFFCF) || (c >= 0xFFD2 && c <= 0xFFD7) || (c >= 0xFFDA && c <= 0xFFDC) || (c >= 0x10000 && c <= 0x1000B) || (c >= 0x1000D && c <= 0x10026) || (c >= 0x10028 && c <= 0x1003A) || (c >= 0x1003C && c <= 0x1003D) || (c >= 0x1003F && c <= 0x1004D) || (c >= 0x10050 && c <= 0x1005D) || (c >= 0x10080 && c <= 0x100FA) || (c == 0x10100) || (c == 0x10102) || (c >= 0x10107 && c <= 0x10133) || (c >= 0x10137 && c <= 0x1013F) || (c >= 0x101D0 && c <= 0x101FC) || (c >= 0x10280 && c <= 0x1029C) || (c >= 0x102A0 && c <= 0x102D0) || (c >= 0x10300 && c <= 0x1031E) || (c >= 0x10320 && c <= 0x10323) || (c >= 0x10330 && c <= 0x1034A) || (c >= 0x10380 && c <= 0x1039D) || (c >= 0x1039F && c <= 0x103C3) || (c >= 0x103C8 && c <= 0x103D5) || (c >= 0x10400 && c <= 0x1049D) || (c >= 0x104A0 && c <= 0x104A9) || (c == 0x11000) || (c >= 0x11002 && c <= 0x11037) || (c >= 0x11047 && c <= 0x1104D) || (c >= 0x11066 && c <= 0x1106F) || (c >= 0x11082 && c <= 0x110B2) || (c >= 0x110B7 && c <= 0x110B8) || (c >= 0x110BB && c <= 0x110C1) || (c >= 0x110D0 && c <= 0x110E8) || (c >= 0x110F0 && c <= 0x110F9) || (c >= 0x11103 && c <= 0x11126) || (c == 0x1112C) || (c >= 0x11136 && c <= 0x11143) || (c >= 0x11182 && c <= 0x111B5) || (c >= 0x111BF && c <= 0x111C8) || (c >= 0x111D0 && c <= 0x111D9) || (c >= 0x11680 && c <= 0x116AA) || (c == 0x116AC) || (c >= 0x116AE && c <= 0x116AF) || (c == 0x116B6) || (c >= 0x116C0 && c <= 0x116C9) || (c >= 0x12000 && c <= 0x1236E) || (c >= 0x12400 && c <= 0x12462) || (c >= 0x12470 && c <= 0x12473) || (c >= 0x13000 && c <= 0x1342E) || (c >= 0x16800 && c <= 0x16A38) || (c >= 0x16F00 && c <= 0x16F44) || (c >= 0x16F50 && c <= 0x16F7E) || (c >= 0x16F93 && c <= 0x16F9F) || (c >= 0x1B000 && c <= 0x1B001) || (c >= 0x1D000 && c <= 0x1D0F5) || (c >= 0x1D100 && c <= 0x1D126) || (c >= 0x1D129 && c <= 0x1D166) || (c >= 0x1D16A && c <= 0x1D172) || (c >= 0x1D183 && c <= 0x1D184) || (c >= 0x1D18C && c <= 0x1D1A9) || (c >= 0x1D1AE && c <= 0x1D1DD) || (c >= 0x1D360 && c <= 0x1D371) || (c >= 0x1D400 && c <= 0x1D454) || (c >= 0x1D456 && c <= 0x1D49C) || (c >= 0x1D49E && c <= 0x1D49F) || (c == 0x1D4A2) || (c >= 0x1D4A5 && c <= 0x1D4A6) || (c >= 0x1D4A9 && c <= 0x1D4AC) || (c >= 0x1D4AE && c <= 0x1D4B9) || (c == 0x1D4BB) || (c >= 0x1D4BD && c <= 0x1D4C3) || (c >= 0x1D4C5 && c <= 0x1D505) || (c >= 0x1D507 && c <= 0x1D50A) || (c >= 0x1D50D && c <= 0x1D514) || (c >= 0x1D516 && c <= 0x1D51C) || (c >= 0x1D51E && c <= 0x1D539) || (c >= 0x1D53B && c <= 0x1D53E) || (c >= 0x1D540 && c <= 0x1D544) || (c == 0x1D546) || (c >= 0x1D54A && c <= 0x1D550) || (c >= 0x1D552 && c <= 0x1D6A5) || (c >= 0x1D6A8 && c <= 0x1D6DA) || (c >= 0x1D6DC && c <= 0x1D714) || (c >= 0x1D716 && c <= 0x1D74E) || (c >= 0x1D750 && c <= 0x1D788) || (c >= 0x1D78A && c <= 0x1D7C2) || (c >= 0x1D7C4 && c <= 0x1D7CB) || (c >= 0x1F110 && c <= 0x1F12E) || (c >= 0x1F130 && c <= 0x1F169) || (c >= 0x1F170 && c <= 0x1F19A) || (c >= 0x1F1E6 && c <= 0x1F202) || (c >= 0x1F210 && c <= 0x1F23A) || (c >= 0x1F240 && c <= 0x1F248) || (c >= 0x1F250 && c <= 0x1F251) || (c == 0x20000) || (c == 0x2A6D6) || (c == 0x2A700) || (c == 0x2B734) || (c == 0x2B740) || (c == 0x2B81D) || (c >= 0x2F800 && c <= 0x2FA1D) || (c == 0xF0000) || (c == 0xFFFFD) || (c == 0x100000) || (c == 0x10FFFD);
}
-(int)getBaseDirection {
// Decode string into UTF32.
NSData *utf32data = [self dataUsingEncoding:NSUTF32StringEncoding];
// NSUTF32StringEncoding has the platform's byte-order, which should
// be the same as UTF32Char's.
UTF32Char *utf32chars = (UTF32Char *)[utf32data bytes];
for (NSUInteger i = 0; i < self.length; i++) {
// UTF32 is a fixed-length encoding, so utf32chars[i] will
// always give us the i'th character.
if (isCodePointStrongRTL(utf32chars[i]))
return -1;
if (isCodePointStrongLTR(utf32chars[i]))
return 1;
}
return 0;
}
@end
更长的答案：生成函数isCodePointStrong{RTL,LTR}
创建一个脚本
hex_numbers_to_dec_ranges_py，import sys from itertools import groupby, count numberlist = [] for line in sys.stdin: numberlist.append(int(line, 16)); def as_range(iterable): # not sure how to do this part elegantly l = list(iterable) if len(l) > 1: return '(c >= 0x{0:X} && c <= 0x{1:X})'.format(l[0], l[-1]) else: return '(c == 0x{0:X})'.format(l[0]) print ' || '.join(as_range(g) for _, g in groupby(numberlist, lambda n, c=count(): n-next(c)))（代码在 StackExhange 的代码审查中从这个出色的答案中无耻地窃取）。
从终端运行：
curl http://www.unicode.org/Public/UNIDATA/UnicodeData.txt > /tmp/UnicodeData.txt cat /tmp/UnicodeData.txt | awk -F';' '$5 == "R" || $5 == "AL"' | cut -d';' -f1 | python hex_numbers_to_dec_ranges.py > rtl.m cat /tmp/UnicodeData.txt | awk -F';' '$5 == "L"' | cut -d';' -f1 | python hex_numbers_to_dec_ranges.py > ltr.m rm /tmp/UnicodeData.txt
EDIT: As @masmor correctly noted, the for loop in getBaseDirection scans characters, and not bytes. Therefore, it should terminate after "character" number of iterations, and not "bytes" number of iterations. In other words, self.length times and not utf32data.length times. The code is now corrected.
于 2012-12-04T06:29:02.633 回答
2
I think the scan loop in -getBaseDirection should be for self.length times instead of utf32data.length in the accepted answer.
utf32data.length is the size in bytes while sizeof(UTF32Char) == 4, which would result in an overrun.
In action, the current code sporadically returns false positives for identical input, depending on what it overruns onto (maybe it'll segfault on a sufficiently bad day). Everything else seems to be working perfectly with the fix.
于 2013-10-15T19:32:14.437 回答
1
在 HTML5 中，这可以通过将 dir="auto" 应用于元素来完成。它是在 WebKit 中实现的，尽管我不完全确定它在 iOS 中是否可用。
dir="auto" 很简单，大概可以自己实现——只要搜索第一个方向性强的字符，把它的方向性应用到整个东西上。
如果你在 iOS 中找不到任何东西，你可以尝试从 StatusNet 实现它的方式中获取一些更聪明的想法：http: //status.net/sites/default/files/issues/1346_jquery.directionDetector.js
于 2012-11-16T13:35:03.410 回答
0
There is a solution that is based on the language detection of the string.
Method returns NSTextAlignmentNatural if direction can not be identified.
@implementation NSString (StringAlignmentDetection)
- (NSTextAlignment)naturalTextAligment
{
NSArray *tagschemes = [NSArray arrayWithObjects:NSLinguisticTagSchemeLanguage, nil];
NSLinguisticTagger *tagger = [[NSLinguisticTagger alloc] initWithTagSchemes:tagschemes options:0];
[tagger setString:self];
NSString *language = [tagger tagAtIndex:0 scheme:NSLinguisticTagSchemeLanguage tokenRange:NULL sentenceRange:NULL];
NSTextAlignment alignment = NSTextAlignmentNatural;
if(!language)
{
return alignment;
}
NSLocaleLanguageDirection direction = [NSLocale characterDirectionForLanguage: language];
switch (direction)
{
case NSLocaleLanguageDirectionLeftToRight:
alignment = NSTextAlignmentLeft;
break;
case NSLocaleLanguageDirectionRightToLeft:
alignment = NSTextAlignmentRight;
break;
default:
alignment = NSTextAlignmentNatural;
break;
}
return alignment;
}
@end
于 2018-07-09T09:46:41.097 回答
0
The ICU Project offers methods for what you are trying to achieve and on Xcode 11 it is possible to link the ICU library into an iOS application or iOS framework target. To do so, open your target and on the "General" tab under "Frameworks and Libraries" add libicucore.tbd.
It might happen that Xcode chooses the macOS variant of the library if you do that in which case you'll see something like this in your project file.
ABCDEFGHIJKLMNOPQRSTUVWX /* libicucore.tbd */ = {isa = PBXFileReference; lastKnownFileType = "sourcecode.text-based-dylib-definition"; name = libicucore.tbd; path = Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/usr/lib/libicucore.tbd; sourceTree = DEVELOPER_DIR; };
To force the iOS variant, simply edit the project file with a text editor to make the line look something like this
ABCDEFGHIJKLMNOPQRSTUVWX /* libicucore.tbd */ = {isa = PBXFileReference; lastKnownFileType = "sourcecode.text-based-dylib-definition"; name = libicucore.tbd; path = usr/lib/libicucore.tbd; sourceTree = SDKROOT; };
Unfortunately, the version of the library that ships with iOS is a bit older and doesn't include ubidi_getBaseDirection. There is, however, a method u_charDirection that you can use to rebuilt ubidi_getBaseDirection. Simply walk the characters in the string and return the direction of the first character with strong directionality. Below is an example of how to do this in Swift (Objective-C port should be straightforward).
enum Direction {
case leftToRight
case rightToLeft
case neutral
}
func ubidi_getBaseDirection(of string: String) -> Direction {
guard let data = string.data(using: .utf32) else {
return .leftToRight
}
let chars = data.withUnsafeBytes { $0.bindMemory(to: UChar32.self) }
for c in chars {
let direction = u_charDirection(c)
if direction == U_RIGHT_TO_LEFT || direction == U_RIGHT_TO_LEFT_ARABIC {
return .rightToLeft
} else if direction == U_LEFT_TO_RIGHT {
return .leftToRight
}
}
return .neutral
}
Note that since libicucore is a pure C library, you'll need to add it to your bridging header / umbrella header if you're working in Swift. I've found the following to be enough.
#include "unicode/utypes.h"
于 2020-04-06T12:20:59.670 回答