中文字符串比较

// 获取拼音首字母(传入汉字字符串, 返回大写拼音首字母)
- (NSString *)stringCharactors:(NSString *)aString{   
    //转成了可变字符串    
    NSMutableString *str = [NSMutableString stringWithString:aString];    
    //先转换为带声调的拼音    
    CFStringTransform((CFMutableStringRef)str,NULL,   kCFStringTransformMandarinLatin,NO);    
    //再转换为不带声调的拼音    
    CFStringTransform((CFMutableStringRef)str,NULL, kCFStringTransformStripDiacritics,NO);    
    //转化为大写拼音   
    NSString *pinYin = [str capitalizedString];    
    //获取并返回首字母    
    return pinYin;
}

// 降序排列
NSArray *temp = [NSArrayarray];
 if (isDistrict) {              
    temp = [specificArray sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {                       
    NSComparisonResult compareResult = [[self stringCharactors:[obj1 district]] compare:[self stringCharactors:[obj2 district]]];                       
    if (compareResult == NSOrderedAscending) {                
        return NSOrderedDescending;           
    } else if (compareResult == NSOrderedDescending) {                
        return NSOrderedAscending;          
    } else {               
       return NSOrderedSame;          
    }       
 }];                
      return temp;
 }

 // 升序排列
 NSArray *temp = [NSArrayarray];
 if (isDistrict) {               
     temp = [specificArray sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {                       
     return [[self stringCharactors:[obj1 district]] compare:[self stringCharactors:[obj2 district]]];       
 }];              
     return temp;
 }