iphone – 向NSString添加省略号

概述我有以下代码,我试图使用核心文本绘制,这就是为什么我不能像UILabel那样剪切文本.换句话说,我必须弄清楚我自己的省略号(‘…’). CGSize commentSize = [[self.sizeDictionary_ valueForKey:commentSizeKey] CGSizeValue]; CGSize actualSize = [[self.sizeDiction 我有以下代码,我试图使用核心文本绘制,这就是为什么我不能像UILabel那样剪切文本.换句话说,我必须弄清楚我自己的省略号(‘…’).

CGSize commentSize = [[self.sizeDictionary_ valueForKey:commentSizeKey] CGSizeValue];        CGSize actualSize = [[self.sizeDictionary_ valueForKey:actualCommentSizeKey] CGSizeValue]; Nsstring *actualComment = self.highlightItem_.comment;        if (actualSize.height > commentSize.height){            actualComment = [self.highlightItem_.comment stringByReplacingCharactersInRange:NSMakeRange(68,3) withString:@"..."];        }

我很难找到基于CGSize的’…’的范围.解决这个问题的最佳方法是什么？

这是我绘制它的方式：

CFStringRef string = CFBrIDgingRetain(actualComment);        CFMutableAttributedStringRef comment = CFAttributedStringCreateMutable(kcfAllocatorDefault,0);        CFAttributedStringReplaceString (comment,CFRangeMake(0,0),string);        CGcolorRef blue = CGcolorRetain([UIcolor colorWithRed:131/255.f green:204/255.f blue:253/255.f Alpha:1.0].CGcolor);        CGcolorRef gray = CGcolorRetain([UIcolor colorWithWhite:165/255.f Alpha:1.0].CGcolor);        CFAttributedStringSetAttribute(comment,[name length]),kCTForegroundcolorAttributename,blue);        CFAttributedStringSetAttribute(comment,CFRangeMake([name length],[self.highlightItem_.comment length] - [name length]),gray);        CGcolorRelease (blue);        CGcolorRelease (gray);        CTFontRef nameFont = CTFontCreateWithname(CFBrIDgingRetain(kProximaNovaBold),13.0f,nil);        CFAttributedStringSetAttribute(comment,kCTFontAttributename,nameFont);        CTFontRef commentFont = CTFontCreateWithname(CFBrIDgingRetain(kProximaNovaRegular),commentFont);        CGfloat commentYOffset = floorf((self.commentHeight_ - commentSize.height)/2);        CGContextSaveGState(context);        CGRect captionFrame = CGRectMake(0,rect.size.wIDth - 80,commentSize.height);        CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(comment);        CGMutablePathref captionFramePath = CGPathCreateMutable();        CGPathAddRect(captionFramePath,NulL,captionFrame);        CTFrameRef mainCaptionFrame = CTFramesetterCreateFrame(framesetter,captionFramePath,NulL);        CGContextRef context = UIGraphicsGetCurrentContext();        CGContextSetTextMatrix(context,CGAffinetransformIDentity);        CGContextTranslateCTM(context,self.buttonSize_ + 25,self.imageHeight_ + self.commentHeight_ + 6 - commentYOffset);        CGContextScaleCTM(context,1.0,-1.0);        CTFrameDraw(mainCaptionFrame,context);        CGContextRestoreGState(context);

解决方法 编辑

(我在这里的原始答案没有用;它没有处理多行.如果有人想看到它的历史兴趣,请查看编辑历史.我删除了它,因为它导致比它解决的更多混乱.答案是正确的代码.)

你需要做的是让CTFramesetter解决除最后一行之外的所有行.然后,如果需要,您可以手动截断最后一个.

- (voID)drawRect:(CGRect)rect{  CGContextRef context = UIGraphicsGetCurrentContext();  CGContextSetTextMatrix(context,CGAffinetransformIDentity);  CGRect pathRect = CGRectMake(50,200,40);  CGPathref path = CGPathCreateWithRect(pathRect,NulL);  CFAttributedStringRef attrString = (__brIDge CFTypeRef)[self attributedString];  // Create the framesetter using the attributed string  CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(attrString);  // Create a single frame using the entire string (CFRange(0,0))  // that fits insIDe of path.  CTFrameRef frame = CTFramesetterCreateFrame(framesetter,path,NulL);  // Draw the lines except the last one  CFArrayRef lines = CTFrameGetlines(frame);  CFIndex lineCount = CFArrayGetCount(lines);  CGPoint origins[lineCount]; // I'm assuming that a stack variable is safe here.                              // This would be bad if there were thousdands of lines,but that's unlikely.  CTFrameGetlineOrigins(frame,origins);  for (CFIndex i = 0; i < lineCount - 1; ++i) {    CGContextSetTextposition(context,pathRect.origin.x + origins[i].x,pathRect.origin.y + origins[i].y);    CTlineDraw(CFArrayGetValueAtIndex(lines,i),context);  }  ///  /// HERE'S THE INTERESTING PART  ///  // Make a new last line that includes the rest of the string.  // The last line is already truncated (just with no truncation mark),so we can't truncate it again  CTlineRef lastline = CFArrayGetValueAtIndex(lines,lineCount - 1);  CFIndex lastLocation = CTlineGetStringRange(lastline).location;  CFRange restRange = CFRangeMake(lastLocation,CFAttributedStringGetLength(attrString) - lastLocation);  CFAttributedStringRef restOfString = CFAttributedStringCreateWithSubstring(NulL,attrString,restRange);  CTlineRef restline = CTlineCreateWithAttributedString(restOfString);  // We need to provIDe the truncation mark. This is an ellipsis (Cmd-semicolon).  // You Could also use "\u2026". Don't use dot-dot-dot. It'll work,it's just not correct.  // ObvIoUsly you Could cache this…  CTlineRef ellipsis = CTlineCreateWithAttributedString((__brIDge CFTypeRef)                                                        [[NSAttributedString alloc] initWithString:@"…"]);  // OK,Now let's truncate it and draw it. I'm being a little sloppy here. If ellipsis Could possibly  // be wIDer than the path wIDth,then this will fail and truncateline will be NulL and we'll crash.  // Don't do that.  CTlineRef truncatedline = CTlineCreateTruncatedline(restline,CGRectGetWIDth(pathRect),kCTlineTruncationEnd,ellipsis);  CGContextSetTextposition(context,pathRect.origin.x + origins[lineCount - 1].x,pathRect.origin.y + origins[lineCount - 1].y);  CTlineDraw(truncatedline,context);  CFRelease(truncatedline);  CFRelease(ellipsis);  CFRelease(restline);  CFRelease(restOfString);  CFRelease(frame);  CFRelease(framesetter);  CGPathRelease(path);}

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