如何检测UILabel在Cocoa Touch中包含从右到左的语言？ [英] How do you detect that a UILabel contains a right-to-left language in Cocoa Touch?

问题描述

我在两个，但以下函数对于每个字符串总是返回false，包括阿拉伯语。

  @implementation UILabel（位置）
 
  - （BOOL）containsArabic 
 {
 NSError * error; 
 NSRegularExpression * regex = [NSRegularExpression 
 regularExpressionWithPattern：@\p {Arabic}
选项：0 
错误：&错误
] 
 return error == nil 
&& [regex 
 numberOfMatchesInString：self.text 
 options：0 
 range：NSMakeRange（0，self.text.length）]> 0; 
} 
 
 @end 
  

尝试失败2：NSLocale

   - （BOOL）containsArabic 
 {
 NSString * isoLangCode =（NSString *）CFStringTokenizerCopyBestStringLanguage b（CFStringRef）self.text，
 CFRangeMake（
 0，
 self.text.length 
）
）; 
 NSLocaleLanguageDirection direction = [NSLocale lineDirectionForLanguage：isoLangCode]; 
 NSLog（@++++++）; 
 NSLog（@％@，self.text）; 
 NSLog（@％d，direction）; 
 return direction == NSLocaleLanguageDirectionRightToLeft; 
} 
  

输出无用：

  2012-05-28 10：59：11.454 [2110：707]曼彻斯特城与曼彻斯特联合高清
 2012-05-28 10：59：11.461 [2110 ：707] 0 
 2012-05-28 10：59：11.474 [2110：707] ++++++ 
 2012-05-28 10：59：11.477 [2110：707] tak 
 2012-05-28 10：59：11.484 [2110：707] 0 
 2012-05-28 10：59：11.511 [2110：707] ++++++ 
 2012- 05-28 10：59：11.513 [2110：707]ŸàŸÜŸáÿßÿ±ÉÉÿÿÿÿŸÿÿ
 2012-05-28 10：59：11.520 [2110：707] 3 
 2012-05-28 10： 59：11.704 [2110：707] ++++++ 
 2012-05-28 10：59：11.712 [2110：707]ŸÜŸáÿßÿ±ŸÉÿ≧ÿÿŸÿÿØ
 2012-05-28 10： 59：11.740 [2110：707] 3 
 2012-05-28 10：59：11.763 [2110：707] ++++++ 
 2012-05-28 10：59：11.767 [2110 ：707]我想我很近
 2012-05-28 10：59：11.772 [2110：707] 3 
  

解决方案

此回答假设您使用ARC：

  NSString * stringToTest = @一些外语; 
 
 NSString * isoLangCode =（__bridge_transfer NSString *）CFStringTokenizerCopyBestStringLanguage（（__ bridge CFStringRef）stringToTest，CFRangeMake（0，stringToTest.length））; 
 
 NSLocaleLanguageDirection direction = [NSLocale characterDirectionForLangauge：isoLangCode]; 
 

然后可以使用NSLocale API的lineDirectionForLanguage：方法来确定语言的行方向。

I am displaying user comments in two UILabels - one for the username and one for the message. Both labels have the same X,Y coordinate, but the message label is prepended with spaces equaling the width of the username. This technique helps me easily support multiline messages.

A problem arises when users write Arabic messages. Arabic is a right to left language. This means, I must add spaces to the end of an Arabic string, not the beginning. As you can see in the screenshot below, I didn't make that distinction and the Arabic message ran into the username. So how do I detect that the text property (NSString) of a UILabel was written in a right-to-left language?

Fail attempt 1: Regex

I've tried using regexes, but the following function always returns false for every string, including Arabic.

@implementation UILabel (position)

- (BOOL) containsArabic
{
    NSError* error;
    NSRegularExpression* regex = [NSRegularExpression
        regularExpressionWithPattern:@"\p{Arabic}" 
        options:0
        error:&error
    ];
    return error == nil 
        && [regex 
            numberOfMatchesInString:self.text 
            options:0 
            range:NSMakeRange(0, self.text.length)] > 0;
}

@end

Fail attempt 2: NSLocale

- (BOOL) containsArabic
{
    NSString *isoLangCode = (NSString*)CFStringTokenizerCopyBestStringLanguage(
       (CFStringRef)self.text, 
       CFRangeMake(
           0, 
           self.text.length
       )
    );
    NSLocaleLanguageDirection direction = [NSLocale lineDirectionForLanguage:isoLangCode];
    NSLog(@"++++++");
    NSLog(@"%@", self.text);
    NSLog(@"%d", direction);
    return direction == NSLocaleLanguageDirectionRightToLeft;
}

Output is useless:

2012-05-28 10:59:11.454 [2110:707] MANCHESTER CITY VS MANCHESTER UNITED LIVE HD
2012-05-28 10:59:11.461 [2110:707] 0
2012-05-28 10:59:11.474 [2110:707] ++++++
2012-05-28 10:59:11.477 [2110:707] tak
2012-05-28 10:59:11.484 [2110:707] 0
2012-05-28 10:59:11.511 [2110:707] ++++++
2012-05-28 10:59:11.513 [2110:707] ونهارك سعيد
2012-05-28 10:59:11.520 [2110:707] 3
2012-05-28 10:59:11.704 [2110:707] ++++++
2012-05-28 10:59:11.712 [2110:707] نهارك سعيد
2012-05-28 10:59:11.740 [2110:707] 3
2012-05-28 10:59:11.763 [2110:707] ++++++
2012-05-28 10:59:11.767 [2110:707] i think i am close
2012-05-28 10:59:11.772 [2110:707] 3

解决方案

This answer assumes that you are using ARC:

NSString *stringToTest = @"Some Foreign Language";

NSString *isoLangCode = (__bridge_transfer NSString*)CFStringTokenizerCopyBestStringLanguage((__bridge CFStringRef)stringToTest, CFRangeMake(0, stringToTest.length));

NSLocaleLanguageDirection direction = [NSLocale characterDirectionForLangauge:isoLangCode];

You can then use the NSLocale API's lineDirectionForLanguage: method to determine the languages line direction.

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