Android ItextG 图像标签未呈现

Question

我正在使用 iTextPdf（Android 的 iTextG）库将 Html 转换为我的 android 应用程序的 PDF 文档。除了收据上的徽标外，一切对我来说都很好。我的 html 包含 <img> 标签和图片的来源 http url

<img src="http...."></img>

创建的 pdf 没有图像。相同的代码和 html 运行在我的 Java 应用程序中显示带有创建的 PDF 的徽标（这表明访问图像没有问题）。我想知道此功能是否仅与 Java 兼容而不与 Android 兼容？我正在使用以下依赖项：

compile 'com.itextpdf:itextg:5.5.10'
compile 'com.itextpdf.tool:xmlworker:5.5.10'

Html代码：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="English">
<head>
    <title>Title</title>
    <meta http-equiv="content-type" content="text/html; charset=utf-8"/>
</head>

<body>
<img src="https://image.flaticon.com/teams/slug/google.jpg"></img>
<h1>Fischerstube</h1>
</body>
</html>

主要函数 Activity:

 private void htmlToPdf(String html) throws DocumentException, IOException {

    try {

        File file = new File(Environment.getExternalStorageDirectory() + File.separator + "logo.pdf");
        OutputStream fileOutputStream = new FileOutputStream(file);
        Document document = new Document();
        document.setPageSize(new Rectangle(201,720));
        PdfWriter writer = PdfWriter.getInstance(document, fileOutputStream);
        document.open();
        InputStream is = new ByteArrayInputStream(html.getBytes());
        XMLWorkerHelper.getInstance().parseXHtml(writer, document, is);
        document.close();
        fileOutputStream.close();

    } catch (Exception e) {
        e.printStackTrace();
    }
}

它只渲染 <h1> 标签并显示 Fischerstube 但在 ANDROIRD 设备上没有图像。谁能在这方面帮助我，将不胜感激。

Answer 1

查看提供的文档 here 为我解决了。

make sure you have Internet permission in the manifest.

创建 Base64ImageProvider class

class Base64ImageProvider extends AbstractImageProvider {

    @Override
    public Image retrieve(String src) {
        int pos = src.indexOf("base64,");
        try {
            if (src.startsWith("data") && pos > 0) {
                byte[] img = Base64.decode(src.substring(pos + 7));
                return Image.getInstance(img);
            }
            else {
                return Image.getInstance(src);
            }
        } catch (BadElementException ex) {
            return null;
        } catch (IOException ex) {
            return null;
        }
    }

    @Override
    public String getImageRootPath() {
        return null;
    }
}

然后调用create pdf方法将你的HTML转换成pdf

public void createPdf() throws IOException, DocumentException {
    String str = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +
            "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\">\n" +
            "<html xmlns=\"http://www.w3.org/1999/xhtml\" lang=\"English\">\n" +
            "<head>\n" +
            "    <title>Title</title>\n" +
            "    <meta http-equiv=\"content-type\" content=\"text/html; charset=utf-8\"/>\n" +
            "</head>\n" +
            "\n" +
            "<body>\n" +
            "<img src=\"https://image.flaticon.com/teams/slug/google.jpg\"></img>\n" +
            "<h1>Fischerstube</h1>\n" +
            "</body>\n" +
            "</html>";


    // step 1
    File file = new File(Environment.getExternalStorageDirectory() + File.separator + "logo.pdf");
    OutputStream fileOutputStream = new FileOutputStream(file);
    Document document = new Document();
    // step 2
    PdfWriter writer = PdfWriter.getInstance(document, fileOutputStream);
    // step 3
    document.open();
    // step 4

    // CSS
    CSSResolver cssResolver =
            XMLWorkerHelper.getInstance().getDefaultCssResolver(true);

    // HTML
    HtmlPipelineContext htmlContext = new HtmlPipelineContext(null);
    htmlContext.setTagFactory(Tags.getHtmlTagProcessorFactory());
    htmlContext.setImageProvider(new Base64ImageProvider());

    // Pipelines
    PdfWriterPipeline pdf = new PdfWriterPipeline(document, writer);
    HtmlPipeline html = new HtmlPipeline(htmlContext, pdf);
    CssResolverPipeline css = new CssResolverPipeline(cssResolver, html);

    // XML Worker
    XMLWorker worker = new XMLWorker(css, true);
    XMLParser p = new XMLParser(worker);
    p.parse(new ByteArrayInputStream(str.getBytes()));

    // step 5
    document.close();
}

Make sure you execute createPdf method on background thread. since you will be performing network operation.

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