java - PDFBox 避免 关闭前是否要保存更改

Question

我目前正在尝试向现有 pdf 页面添加一个按钮，单击该按钮后将关闭当前选项卡。我已经使用 PDFbox 2.0.15 通过以下代码实现了这一点...

try {

            InputStream pdfInput = new FileInputStream(new File("C:\\Users\\justi\\Desktop\\test\\real.pdf"));
            PDDocument doc = PDDocument.load(pdfInput);
            PDPage page = doc.getPage(0);
//            PDDocument doc = new PDDocument();
//            PDPage page = new PDPage();
//            doc.addPage(page);

            COSDictionary acroFormDict = new COSDictionary();
            acroFormDict.setBoolean(COSName.getPDFName("NeedAppearances"), true);
            acroFormDict.setItem(COSName.getPDFName("Fields"), new COSArray());

//            PDDocumentCatalog pdCatalog = doc.getDocumentCatalog();
//            PDAcroForm acroForm = pdCatalog.getAcroForm();

            PDAcroForm acroForm = new PDAcroForm(doc, acroFormDict);
            doc.getDocumentCatalog().setAcroForm(acroForm);

            PDActionJavaScript javascript = new PDActionJavaScript("function validate(index){ app.alert(index); }");
            doc.getDocumentCatalog().setOpenAction( javascript );

            COSDictionary cosDict = new COSDictionary();
            PDPushButton button = new PDPushButton(acroForm);
            cosDict = button.getCOSObject();
            COSArray rect = new COSArray();
            rect.add(new COSFloat(100));
            rect.add(new COSFloat(10));
            rect.add(new COSFloat(200));
            rect.add(new COSFloat(60));


            cosDict.setItem(COSName.RECT, rect);
            cosDict.setItem(COSName.FT, COSName.getPDFName("Btn")); // Field Type
            cosDict.setItem(COSName.TYPE, COSName.ANNOT);
            cosDict.setItem(COSName.SUBTYPE, COSName.getPDFName("Widget"));
            cosDict.setItem(COSName.T, new COSString("Btn"+1));
            cosDict.setItem(COSName.V, new COSString("Validate"));
            cosDict.setItem(COSName.DA, new COSString("/Helv 7 Tf 0 g"));
            cosDict.setInt(COSName.FF, 65536);

//            button.setValue("Validate Button");

            PDActionJavaScript tfJs = new PDActionJavaScript("this.closeDoc();");
            PDAnnotationAdditionalActions tfAction = new PDAnnotationAdditionalActions();
            tfAction.setU(tfJs);
            button.getWidget().setActions(tfAction);

            PDColor colourBlack = new PDColor(new float[] { 0, 0, 0 }, PDDeviceRGB.INSTANCE);
            PDAppearanceCharacteristicsDictionary fieldAppearance =
                    new PDAppearanceCharacteristicsDictionary(new COSDictionary());
            fieldAppearance.setBorderColour(colourBlack);
            button.getWidget().setAppearanceCharacteristics(fieldAppearance);

            page.getAnnotations().add(button.getWidget());

            acroForm.getFields().add(button);

            doc.save("C:\\Users\\justi\\Desktop\\test\\test2.pdf");
            doc.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

我目前遇到的主要问题是，每次我打开文档并单击按钮时，它都会打开一个提示，显示“您想在关闭之前保存对 xyz.pdf 的更改吗？环顾四周，我发现设置将“NeedAppearances”设置为 false 会删除此提示，但不会显示要单击的框。有没有办法让它显示该框，但仍然在没有提示的情况下退出 pdf？

--更新--看来，如果您在打开文档后保存该文档，则可以单击该按钮将其关闭，没有问题。也许另一种解决方案是在生成它后正确保存它？不确定那会如何工作。

Answer 1

删除/NeedAppearances 条目是正确的，但您还需要创建一个外观，此处:黑色边框。我还添加了一段文字。

    PDAnnotationWidget widget = button.getWidgets().get(0);
    PDAppearanceDictionary appearanceDictionary = new PDAppearanceDictionary();
    PDAppearanceStream appearanceStream = new PDAppearanceStream(doc);
    appearanceStream.setResources(new PDResources());
    try (PDPageContentStream cs = new PDPageContentStream(doc, appearanceStream))
    {
        PDRectangle bbox = new PDRectangle(widget.getRectangle().getWidth(), widget.getRectangle().getHeight());
        appearanceStream.setBBox(bbox);
        cs.setNonStrokingColor(0, 0, 0); // black
        cs.addRect(bbox.getLowerLeftX() + 0.5f, bbox.getLowerLeftY() + 0.5f, bbox.getWidth() - 1, bbox.getHeight() - 1);
        cs.stroke();

        // put some useful text
        cs.setFont(PDType1Font.HELVETICA, 20);
        cs.beginText();
        cs.newLineAtOffset(20, 20);
        cs.showText("Close");
        cs.endText();
    }
    appearanceDictionary.setNormalAppearance(appearanceStream);
    widget.setAppearance(appearanceDictionary);