Xamarin免费HTML或DOC到PDF转换

Question

我目前正在电话或标签页上寻找库或将HTML或DOCX文件转换为PDF的方法，主要是在Android或iOS idk上（如果使用PCL或特定于平台的方法）寻找方法。我可以为每个平台独立执行此操作，因为我们的应用程序需要iOS 8或android kitkat，它们都支持本机PDF转换，但我想为用户无缝进行此操作，所以问题是，是否有人以前曾经这样做过而不加载它？首先进入可见的Webview或了解开放的，未经GPL许可的API（无法发布代码），然后使用Xamarin进行操作。

我知道可以在线进行此操作，但是我不想依赖于此的在线服务。

帮助和想法表示赞赏。

Answer 1

Android解决方案：

通过类似的依赖项服务调用SafeHTMLToPDF（string html，string filename）

DependencyService.Get<YOURINTERFACE>().SafeHTMLToPDF(htmlString, "Invoice");


   public string SafeHTMLToPDF(string html, string filename)
    {

        var dir = new Java.IO.File(Android.OS.Environment.ExternalStorageDirectory.AbsolutePath + "/pay&go/");
        var file = new Java.IO.File(dir + "/" + filename + ".pdf");

        if (!dir.Exists())
            dir.Mkdirs();


        int x = 0;
        while (file.Exists())
        {
            x++;
            file= new Java.IO.File(dir + "/" + filename + "( " + x + " )" + ".pdf");
        }

        if (webpage == null)
            webpage = new Android.Webkit.WebView(GetApplicationContext());

        int width = 2102;
        int height = 2973;

        webpage.Layout(0, 0, width, height);
        webpage.LoadDataWithBaseURL("",html, "text/html", "UTF-8" , null);
        webpage.SetWebViewClient(new WebViewCallBack(file.ToString()));

        return file.ToString();
    }


    class WebViewCallBack : WebViewClient
    {

        string fileNameWithPath = null;

        public WebViewCallBack(string path)
        {
            this.fileNameWithPath = path;
        }


        public override void OnPageFinished(Android.Webkit.WebView myWebview, string url)
        {
            PdfDocument document = new PdfDocument();
            PdfDocument.Page page = document.StartPage(new PdfDocument.PageInfo.Builder(2120 ,3000, 1).Create());

            myWebview.Draw(page.Canvas);
            document.FinishPage(page);
            Stream filestream = new MemoryStream();
            FileOutputStream fos = new Java.IO.FileOutputStream(fileNameWithPath, false); ;
            try
            {
                document.WriteTo(filestream);
                fos.Write(((MemoryStream)filestream).ToArray(), 0, (int)filestream.Length);
                fos.Close();
            }
            catch
            {
            }
        }
    }

以及在iOS下的实现方式

public string SafeHTMLToPDF(string html, string filename)
    {
        UIWebView webView = new UIWebView(new CGRect(0, 0, 6.5 * 72, 9 * 72));


        var documents = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
        var file = Path.Combine(documents, "Invoice" + "_" + DateTime.Now.ToShortDateString() + "_" + DateTime.Now.ToShortTimeString() + ".pdf");

        webView.Delegate = new WebViewCallBack(file);
        webView.ScalesPageToFit = true;
        webView.UserInteractionEnabled = false;
        webView.BackgroundColor = UIColor.White;
        webView.LoadHtmlString(html, null);



        return file;
    }

    class WebViewCallBack : UIWebViewDelegate
    {

        string filename = null;
        public WebViewCallBack(string path)
        {
            this.filename = path;

        }
        public override void LoadingFinished(UIWebView webView)
        {
            double height, width;
            int header, sidespace;

            width = 595.2;
            height = 841.8;
            header = 10;
            sidespace = 10;


            UIEdgeInsets pageMargins = new UIEdgeInsets(header, sidespace, header, sidespace);
            webView.ViewPrintFormatter.ContentInsets = pageMargins;

            UIPrintPageRenderer renderer = new UIPrintPageRenderer();
            renderer.AddPrintFormatter(webView.ViewPrintFormatter, 0);

            CGSize pageSize = new CGSize(width, height);
            CGRect printableRect = new CGRect(sidespace,
                              header,
                              pageSize.Width - (sidespace * 2),
                              pageSize.Height - (header * 2));
            CGRect paperRect = new CGRect(0, 0, width, height);
            renderer.SetValueForKey(NSValue.FromObject(paperRect), (NSString)"paperRect");
            renderer.SetValueForKey(NSValue.FromObject(printableRect), (NSString)"printableRect");
            NSData file = PrintToPDFWithRenderer(renderer, paperRect);
            File.WriteAllBytes(filename, file.ToArray());
        }

        private NSData PrintToPDFWithRenderer(UIPrintPageRenderer renderer, CGRect paperRect)
        {
            NSMutableData pdfData = new NSMutableData();
            UIGraphics.BeginPDFContext(pdfData, paperRect, null);

            renderer.PrepareForDrawingPages(new NSRange(0, renderer.NumberOfPages));

            CGRect bounds = UIGraphics.PDFContextBounds;

            for (int i = 0; i < renderer.NumberOfPages; i++)
            {
                UIGraphics.BeginPDFPage();
                renderer.DrawPage(i, paperRect);
            }
            UIGraphics.EndPDFContent();

            return pdfData;
        }

    }