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我正在构建一个应用程序，它需要几个不同的文本文件并将它们串在一起，然后用它们构建一个 pdf。我需要添加文件的文本添加单独的时间，这样我就可以在每个文件的文本中添加超链接。我已经取得了一些进展，并且几乎可以准确地显示它，但是 CTFramesetterCreateWithAttributedString 的大小似乎不正确。

例如，三个文件中的第一个显示太多，换句话说，在文本结束后会有一个空白页出现。第二个文本文件显示得很好，但第三个从一开始就丢失了一大块。我不相信它与文件本身有任何关系，因为如果我颠倒文件的呈现顺序，我会遇到同样的问题。第一个文件（无论是哪个文件）最后都有一个空白页，第三个文件的第一页左右丢失了。有谁知道是什么导致了这种现象？

- (void)savePDFFile:(NSString *)file_Name
{ 
 NSString *homeDir = NSHomeDirectory();
 NSString *saveDirectory = [NSString stringWithFormat: @"%@/%@", homeDir, @"Documents/"]; 


 NSArray *fileAr = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:saveDirectory error:nil];
 NSMutableArray *textArray = [[NSMutableArray alloc] init];
 NSInteger currentPage = 0;
 NSInteger currentFile = 0;


 for (NSString *string in fileAr) {
    if([string hasSuffix:@"txt"]){
        NSString *file = [NSString stringWithFormat: @"%@/%@", saveDirectory, string];
        NSString *text =[NSString stringWithContentsOfFile:file encoding:NSUTF8StringEncoding error:nil];
        completeString = [NSString stringWithFormat:@"%@%@", completeString, text];
    }
 }

        NSString* pdfFileName = file_Name;

        // Create the PDF context using the default page size of 612 x 792.
        UIGraphicsBeginPDFContextToFile(pdfFileName, CGRectZero, nil);


        CFRange currentRange = CFRangeMake(0, 0);
        for (NSString *string in textArray){
        BOOL done = NO;
            NSString *thisText = [textArray objectAtIndex:currentFile];
            CFAttributedStringRef currentText = CFAttributedStringCreate(NULL, (CFStringRef)thisText, NULL);                                
            CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)currentText);
            currentPage = currentPage;
        do {
            // Mark the beginning of a new page.
            UIGraphicsBeginPDFPageWithInfo(CGRectMake(0, 0, 612, 792), nil);

            // Draw a page number at the bottom of each page
            currentPage++;
            [self drawPageNumber:currentPage];



            // Render the current page and update the current range to
            // point to the beginning of the next page.
            currentRange = [self renderPage:currentPage withTextRange:currentRange andFramesetter:framesetter];
            // If we're at the end of the text, exit the loop.
            if (currentRange.location == CFAttributedStringGetLength((CFAttributedStringRef)currentText))
                done = YES;

        } while (!done);
            currentFile ++;
            CFRelease(framesetter);
            CFRelease(currentText);
        }

        // Close the PDF context and write the contents out.
        UIGraphicsEndPDFContext();


}


// Use Core Text to draw the text in a frame on the page.
- (CFRange)renderPage:(NSInteger)pageNum withTextRange:(CFRange)currentRange
   andFramesetter:(CTFramesetterRef)framesetter
  {
 // Get the graphics context.
CGContextRef    currentContext = UIGraphicsGetCurrentContext();

// Put the text matrix into a known state. This ensures
// that no old scaling factors are left in place.
CGContextSetTextMatrix(currentContext, CGAffineTransformIdentity);

// Create a path object to enclose the text. Use 72 point
// margins all around the text.
CGRect    frameRect = CGRectMake(72, 72, 500, 648);
CGMutablePathRef framePath = CGPathCreateMutable();
CGPathAddRect(framePath, NULL, frameRect);

// Get the frame that will do the rendering.
// The currentRange variable specifies only the starting point. The framesetter
// lays out as much text as will fit into the frame.
CTFrameRef frameRef = CTFramesetterCreateFrame(framesetter, currentRange, framePath, NULL);
CGPathRelease(framePath);

// Core Text draws from the bottom-left corner up, so flip
// the current transform prior to drawing.
CGContextTranslateCTM(currentContext, 0, 792);
CGContextScaleCTM(currentContext, 1.0, -1.0);

// Draw the frame.
CTFrameDraw(frameRef, currentContext);

// Update the current range based on what was drawn.
currentRange = CTFrameGetVisibleStringRange(frameRef);
currentRange.location += currentRange.length;
currentRange.length = 0;
//    CFRelease(frameRef);

return currentRange;
}
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1 回答 1

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我已经想通了。

我放置了“currentPage = currentPage;” 在我的代码中只是为了在设置框架设置后有一个位置放置断点，以便我可以观看它。还没有完全掌握调试器。显然，这并没有引起问题，但是如果我用“currentRange.location = 0;”替换那行代码，则在每次循环后重置范围。问题解决了。奇怪的是，最初是重置 currentRange 导致了问题。

无论如何，通过我上面列出的更改，以及这个问题的第二个答案（减去最后四行），问题就解决了！

于 2012-06-13T16:25:32.633 回答