如何將pdf頁面轉換爲ios應用程序中的文本文件

Question

您可以幫助我將特定的PDF文件頁面轉換爲文本文件或提供鏈接來編輯PDF文件iOS應用程序。

在此先感謝

Answer 1

當加載自定義文檔類型（DOC，PPT，PDF等）轉換成一個UIWebView，web視圖返回零HTML字符串，即使是通過JavaScript。提取PDF文本here有幾點建議。

但是將字符串轉換回PDF是不同的。如果你想保留原始PDF的格式，我相當確定這是不可能的，因爲iOS上的NSAttributedString並沒有太大的作用。但是，如果可能的話，這將適用於純文本或NSAttributedString：

NSData *PDFDataFromString(NSString *str) { 
NSMutableData *data = [NSMutableData data]; 

//Create an NSAttributedString for CoreText. If you find a way to translate 
//PDF into an NSAttributedString, you can skip this step and simply use an 
//NSAttributedString for this method's argument. 

NSAttributedString* string = [[[NSAttributedString alloc] initWithString:str] autorelease]; 

//612 and 792 are the dimensions of the paper in pixels. (8.5" x 11") 
CGRect paperRect = CGRectMake(0.0, 0.0, 612, 792); 

CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef) string); 
CGSize requiredSize = CTFramesetterSuggestFrameSizeWithConstraints(framesetter, CFRangeMake(0, [string length]), NULL, CGSizeMake(paperRect.size.width - 144, 1e40), NULL); 

//Subtract the top and bottom margins (72 and 72), so they aren't factored in page count calculations. 
NSUInteger pageCount = ceill(requiredSize.height/(paperRect.size.height - 144)); 
CFIndex resumePageIndex = 0; 
UIGraphicsBeginPDFContextToData(data, paperRect, nil); 

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

//After calculating the required number of pages, break up the string and 
//draw them into sequential pages. 

    UIGraphicsBeginPDFPage(); 
    CGContextRef currentContext = UIGraphicsGetCurrentContext(); 
    CGContextSaveGState (currentContext); 
    CGContextSetTextMatrix(currentContext, CGAffineTransformIdentity); 
    CGMutablePathRef framePath = CGPathCreateMutable(); 

    //72 and 72 are the X and Y margins of the page in pixels. 
    CGPathAddRect(framePath, NULL, CGRectInset(paperRect, 72.0, 72.0)); 

    CTFrameRef frameRef = CTFramesetterCreateFrame(framesetter, CFRangeMake(resumePageIndex, 0), framePath, NULL); 
    resumePageIndex += CTFrameGetVisibleStringRange(frameRef).length; 
    CGPathRelease(framePath); 
    CGContextTranslateCTM(currentContext, 0, paperRect.size.height); 
    CGContextScaleCTM(currentContext, 1.0, -1.0); 
    CTFrameDraw(frameRef, currentContext); 
    CFRelease(frameRef);  
    CGContextRestoreGState (currentContext); 
} 
CFRelease(framesetter); 
UIGraphicsEndPDFContext(); 
return data; 
} 

快樂編碼！