原生 iOS 应用程序中的断字

Question

如何在 iOS 中激活自动断字？

我尝试在 UILabel 的属性文本选项中将连字符因子设置为 1，但是我没有得到任何连字符。

Answer 1

1. iOS 7 方式。使用UITextView 而不是UILabel。然后hyphenationFactor（作为NSParagraphStyle 属性或NSLayoutManager 属性）应该可以工作（感谢新的TextKit）。
2. 网络方式。使用 UIWebView 和 -webkit-hyphens CSS 属性。
3. 核心文本或艰难的方式。使用您在评论中提到的 CFStringGetHyphenationLocationBeforeIndex() 函数。此函数仅提示您在特定语言的字符串中放置连字符的位置。然后你必须使用核心文本函数（如CTLineCreateWithAttributedString() 和所有）自己打破你的文本行。参见Getting to Know TextKit（名为Hyphenation 的段落解释了Core Text 过程的逻辑，没有代码）和Hyphenation with Core Text on the iPad（给出了一些代码示例，但该网站现在似乎已关闭）。工作量可能会超出您的预期！

Answer 2

CoreText 或 TextKit

您需要在字符串中添加“软连字符”。这些是“-”，在渲染时不可见，而只是排队等待 CoreText 或 UITextKit 知道如何分解单词。

您应该在文本中放置的软连字符是：

unichar const kTextDrawingSoftHyphenUniChar = 0x00AD;
NSString * const kTextDrawingSoftHyphenToken = @"­"; // NOTE: UTF-8 soft hyphen!

示例代码

NSString *string = @"accessibility tests and frameworks checking";
NSLocale *locale = [NSLocale localeWithLocaleIdentifier:@"en_US"];
NSString *hyphenatedString = [string softHyphenatedStringWithLocale:locale error:nil];
NSLog(@"%@", hyphenatedString);

输出ac-ces-si-bil-i-ty tests and frame-works check-ing

---

NSString+SoftHyphenation.h

typedef enum {
    NSStringSoftHyphenationErrorNotAvailableForLocale
} NSStringSoftHyphenationError;

extern NSString * const NSStringSoftHyphenationErrorDomain;

@interface NSString (SoftHyphenation)

- (NSString *)softHyphenatedStringWithLocale:(NSLocale *)locale error:(out NSError **)error;

@end

NSString+SoftHyphenation.m

NSString * const NSStringSoftHyphenationErrorDomain = @"NSStringSoftHyphenationErrorDomain";

@implementation NSString (SoftHyphenation)

- (NSError *)hyphen_createOnlyError
{
    NSDictionary *userInfo = @{
                               NSLocalizedDescriptionKey: @"Hyphenation is not available for given locale",
                               NSLocalizedFailureReasonErrorKey: @"Hyphenation is not available for given locale",
                               NSLocalizedRecoverySuggestionErrorKey: @"You could try using a different locale even though it might not be 100% correct"
                               };
    return [NSError errorWithDomain:NSStringSoftHyphenationErrorDomain code:NSStringSoftHyphenationErrorNotAvailableForLocale userInfo:userInfo];
}

- (NSString *)softHyphenatedStringWithLocale:(NSLocale *)locale error:(out NSError **)error
{
    CFLocaleRef localeRef = (__bridge CFLocaleRef)(locale);
    if(!CFStringIsHyphenationAvailableForLocale(localeRef))
    {
        if(error != NULL)
        {
            *error = [self hyphen_createOnlyError];
        }
        return [self copy];
    }
    else
    {
        NSMutableString *string = [self mutableCopy];
        unsigned char hyphenationLocations[string.length];
        memset(hyphenationLocations, 0, string.length);
        CFRange range = CFRangeMake(0, string.length);

        for(int i = 0; i < string.length; i++)
        {
            CFIndex location = CFStringGetHyphenationLocationBeforeIndex((CFStringRef)string,
                                                                         i,
                                                                         range,
                                                                         0,
                                                                         localeRef,
                                                                         NULL);

            if(location >= 0 && location < string.length)
            {
                hyphenationLocations[location] = 1;
            }
        }

        for(int i = string.length - 1; i > 0; i--)
        {
            if(hyphenationLocations[i])
            {
                [string insertString:@"-" atIndex:i];
            }
        }

        if(error != NULL) { *error = nil;}

        return string;
    }
}

@end

Answer 3

Swift 版本：

let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.hyphenationFactor = 1
paragraphStyle.alignment = .center

let string = NSAttributedString(string: "wyindywidualizowany indywidualista".uppercased(),
                                attributes: [NSParagraphStyleAttributeName : paragraphStyle])

myLabel.attributedText = string