中文排序问题

- (void)viewDidLoad
{
    [super viewDidLoad];
    NSArray* array = @[ @"北京", @"广州", @"上海", @"西安", @"安徽" ];
    NSArray* sortArray = [array sortedArrayUsingComparator:^NSComparisonResult(NSString* obj1, NSString* obj2) {

        CFMutableStringRef string1 = CFStringCreateMutableCopy(NULL, 0,  (__bridge CFStringRef)obj1);

        CFStringTransform(string1, NULL, kCFStringTransformMandarinLatin, NO);
        CFStringTransform(string1, NULL, kCFStringTransformStripDiacritics, NO);

        CFMutableStringRef string2 = CFStringCreateMutableCopy(NULL, 0, (__bridge CFStringRef)obj2);
        CFStringTransform(string2, NULL, kCFStringTransformMandarinLatin, NO);
        CFStringTransform(string2, NULL, kCFStringTransformStripDiacritics, NO);

        NSString *str1 = (__bridge NSString *)string1;
        NSString *str2 = (__bridge NSString *)string2;

        NSComparisonResult  result =  [str1 compare:str2 ];
        CFRelease(string1);
        CFRelease(string2);
        return result;

    }];

    NSLog(@"%@",sortArray);
}