Question

可能重复：
UITextView : get text with wrap info

我一直在寻找NSString库和众多库，以获取一个可以采用这样长字符串的函数：

Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Vestibulum tortor quam, feugiat vitae, ultricies eget, tempor sit amet, ante. Donec eu libero sit amet quam egestas semper. Aenean ultricies mi vitae est. Mauris placerat eleifend leo. Quisque sit amet est et sapien ullamcorper pharetra. Vestibulum erat wisi, condimentum sed, commodo vitae, ornare sit amet, wisi. Aenean fermentum, elit eget tincidunt condimentum, eros ipsum rutrum orci, sagittis tempus lacus enim ac dui.

并与CGSize或float一起指示宽度和正在使用的字体，并返回一个字符串，其中包含\ n \ break和单词包装。

结果（粗略地）：

Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac\n
egestas. Vestibulum tortor quam, feugiat vitae, ultricies eget, tempor sit amet.\n
 Donec eu libero sit amet quam egestas semper. Aenean ultricies mi vitae est. \n
placerat eleifend leo. Quisque sit amet est et sapien ullamcorper pharetra.\n
 Vestibulum erat wisi, condimentum sed, commodo vitae, ornare sit amet, wisi.\n
 Aenean fermentum, elit eget tincidunt condimentum, eros ipsum rutrum orci,\n
 sagittis tempus lacus enim ac dui.

我已经知道UITextViews等会这样做，但这没有用，因为我需要在原始的OpenGL环境中渲染文本，所以我没有使用常规的UI元素。

我知道这既存在于框架中，也存在于某个公共类中。我只是简单地找不到任何统一的处理方法。

我想它接近[NSString sizeWithFont：forWidth：lineBreakMode：]，但我不需要大小，我需要字符串本身。

Answer 1

确实没有必要重新发明这个轮子，因为它正是文本引擎每次包装文本时为你做的。什么是文本引擎？它是核心文本。如果您下拉到Core Text的级别并让CTFramesetter为您布置文本，您可以通过询问生成的CTLines来了解换行符的位置。

文档将帮助您入门：

http://developer.apple.com/library/ios/#documentation/StringsTextFonts/Conceptual/CoreText_Programming/Operations/Operations.html

网上有很多很好的教程。

简单示例：

NSString* s = @"Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do "
@"eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut "
@"enim ad minim veniam, quis nostrud exercitation ullamco laboris "
@"nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor "
@"in reprehenderit in voluptate velit esse cillum dolore eu fugiat "
@"nulla pariatur. Excepteur sint occaecat cupidatat non proident, "
@"sunt in culpa qui officia deserunt mollit.";
NSAttributedString* text = [[NSAttributedString alloc] initWithString:s];

CTFramesetterRef fs =
CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)text);
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, CGRectMake(0,0,200,100000));
CTFrameRef f = CTFramesetterCreateFrame(fs, CFRangeMake(0, 0), path, NULL);
CTFrameDraw(f, NULL);

NSArray* lines = (__bridge NSArray*)CTFrameGetLines(f);
for (id aLine in lines) {
    CTLineRef theLine = (__bridge CTLineRef)aLine;
    CFRange range = CTLineGetStringRange(theLine);
    NSLog(@"%ld %ld", range.location, range.length);
}
CGPathRelease(path);
CFRelease(f);
CFRelease(fs);

正如您将看到的，输出显示了每行包装文本的范围。这不是你想要的那种东西吗？

Answer 2

似乎没有工厂方式这样做，所以已经开始构建一个类函数来处理这个问题，基于this closely related stack引入的解决方案：

+ (NSString*)wrappedString:(NSString*)string withFont:(UIFont*)font andWidth:(float)width {
    NSMutableString *resultString = [[NSMutableString alloc] initWithString:@""];

    CGSize textSize = [string sizeWithFont:font];
    float textWidth = textSize.width;
    if (textWidth < width) {
        return string;
    }
    float wordLength;
    float lineLength;
    NSUInteger length = [string length];
    unichar buffer[length];
    [string getCharacters:buffer range:NSMakeRange(0, length)];

    NSString *singleLine = @"";
    NSString *word = @"";
    NSString *longWord = @"";

    for (NSUInteger i = 0; i < length; i++) {

        unichar character = buffer[i];
        if (character != '\n') {
            word = [NSString stringWithFormat:@"%@%c", word, character];
        }

        if (character == '\n') {
            float wordLength = [word sizeWithFont:font].width;
            float lineLength = [singleLine sizeWithFont:font].width;
            if ((lineLength + wordLength) > width) {
                [resultString appendString:singleLine];
                [resultString appendString:@"\n"];
                singleLine = @"";
                singleLine = [singleLine stringByAppendingFormat:@"%@\n",word];
                word = @"";
            } else {
                singleLine = [singleLine stringByAppendingString: word];
                word = @"";
                [resultString appendString:singleLine];
                [resultString appendString:@"\n"];
                singleLine = @"";
            }
        }

        else if (character == ' ') {
            float wordLength = [word sizeWithFont:font].width;
            float lineLength = [singleLine sizeWithFont:font].width;

            if ((lineLength + wordLength) > width) {
                if (wordLength > textWidth) {
                    [resultString appendString:singleLine];
                    [resultString appendString:@"\n"];
                    singleLine = @"";
                    int j = 0;
                    for (; j < [word length]; j++) {
                        unichar longChar = [word characterAtIndex:j];
                        longWord = [NSString stringWithFormat:@"%@%c", longWord, longChar];
                        float longwordLength = [longWord sizeWithFont:font].width;
                        float longlineLength = [singleLine sizeWithFont:font].width;
                        if ((longlineLength + longwordLength) >= width) {
                            singleLine = [singleLine stringByAppendingString:longWord];
                            word = @"";
                            longWord = @"";
                            break;
                        }
                    }

                }
                [resultString appendString:singleLine];
                [resultString appendString:@"\n"];
                singleLine = @"";
            }
            singleLine = [singleLine stringByAppendingString: word];
            word = @"";
        }
    }

    wordLength = [word sizeWithFont:font].width;
    lineLength = [singleLine sizeWithFont:font].width;

    if (wordLength > 0) {
        if ((lineLength + wordLength) > width) {
            [resultString appendString:singleLine];
            [resultString appendString:@"\n"];
            singleLine = @"";
        }
        singleLine = [singleLine stringByAppendingString:word];
    }


    if (lineLength > 0) {
        [resultString appendString:singleLine];
        [resultString appendString:@"\n"];
    }
    return resultString;
}

从较长的NSString返回一个包含字的NSString

2 个答案: