如何在 iOS 中将 UIView 转换为 PDF? [英] How to Convert UIView to PDF within iOS?

问题描述

有很多关于如何在应用程序的UIView 中显示 PDF 的资源.我现在正在做的是从 UIViews 创建一个 PDF.

There are a lot of resources about how to display a PDF in an App's UIView. What I am working on now is to create a PDF from UIViews.

例如，我有一个 UIView，带有 Textviews、UILabels、UIImages 等子视图，那么我如何转换 big UIView 作为一个整体，包括它的所有子视图和子视图到 PDF?

For example, I have a UIView, with subviews like Textviews, UILabels, UIImages, so how can I convert a big UIView as a whole including all its subviews and subsubviews to a PDF?

我检查了 Apple 的 iOS 参考.但是，它只讨论将文本/图像片段写入 PDF 文件.

I have checked Apple's iOS reference. However, it only talks about writing pieces of text/image to a PDF file.

我面临的问题是我想以 PDF 格式写入文件的内容很多.如果我将它们逐个写入 PDF，那将是一项艰巨的工作.这就是为什么我正在寻找一种将 UIViews 写入 PDF 甚至位图的方法.

The problem I am facing is that the content I want to write to a file as PDF is a lot. If I write them to the PDF piece by piece, it is going to be huge work to do. That's why I am looking for a way to write UIViews to PDFs or even bitmaps.

我尝试了从 Stack Overflow 中的其他问答中复制的源代码.但它只给了我一个带有 UIView 边界大小的空白 PDF.

I have tried the source code I copied from other Q/A within Stack Overflow. But it only gives me a blank PDF with the UIView bounds size.

-(void)createPDFfromUIView:(UIView*)aView saveToDocumentsWithFileName:(NSString*)aFilename
{
    // Creates a mutable data object for updating with binary data, like a byte array
    NSMutableData *pdfData = [NSMutableData data];

    // Points the pdf converter to the mutable data object and to the UIView to be converted
    UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
    UIGraphicsBeginPDFPage();

    // draws rect to the view and thus this is captured by UIGraphicsBeginPDFContextToData
    [aView drawRect:aView.bounds];

    // remove PDF rendering context
    UIGraphicsEndPDFContext();

    // Retrieves the document directories from the iOS device
    NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);

    NSString* documentDirectory = [documentDirectories objectAtIndex:0];
    NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];

    // instructs the mutable data object to write its context to a file on disk
    [pdfData writeToFile:documentDirectoryFilename atomically:YES];
    NSLog(@"documentDirectoryFileName: %@",documentDirectoryFilename);
}

推荐答案

注意下面的方法创建只是一个位图的视图；它不会创建实际的排版.

Note that the following method creates just a bitmap of the view; it does not create actual typography.

(void)createPDFfromUIView:(UIView*)aView saveToDocumentsWithFileName:(NSString*)aFilename
{
    // Creates a mutable data object for updating with binary data, like a byte array
    NSMutableData *pdfData = [NSMutableData data];

    // Points the pdf converter to the mutable data object and to the UIView to be converted
    UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
    UIGraphicsBeginPDFPage();
    CGContextRef pdfContext = UIGraphicsGetCurrentContext();


    // draws rect to the view and thus this is captured by UIGraphicsBeginPDFContextToData

    [aView.layer renderInContext:pdfContext];

    // remove PDF rendering context
    UIGraphicsEndPDFContext();

    // Retrieves the document directories from the iOS device
    NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);

    NSString* documentDirectory = [documentDirectories objectAtIndex:0];
    NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];

    // instructs the mutable data object to write its context to a file on disk
    [pdfData writeToFile:documentDirectoryFilename atomically:YES];
    NSLog(@"documentDirectoryFileName: %@",documentDirectoryFilename);
}

还要确保您导入:QuartzCore/QuartzCore.h

Also make sure you import: QuartzCore/QuartzCore.h

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