如何将 Android 视图转换为 PDF

Question

我创建了一个 Android 发票应用。生成的发票是带有嵌套视图的标准 Android 布局。我正在寻找可用于将此视图转换为 pdf 文档的库。

我很惊讶在我的搜索中没有直接的选项，或者也许我最后做了第一件事。或者也许我正在寻找的东西是不可能的。

请有人帮我指出一个可以帮助我从 Android 视图转换或生成 PDF 的工具。我愿意接受免费和适度的付费选择。或者让我知道如果我正在寻找的东西是不可能的。

Answer 1

在您的设备上截屏：

Bitmap screen;
View v1 = MyView.getRootView();
v1.setDrawingCacheEnabled(true);
screen= Bitmap.createBitmap(v1.getDrawingCache());
v1.setDrawingCacheEnabled(false);

如果您将 ScrollView 作为根视图，则：

LayoutInflater inflater = (LayoutInflater) this.getSystemService(LAYOUT_INFLATER_SERVICE);
RelativeLayout root = (RelativeLayout) inflater.inflate(R.layout.activity_main, null); //RelativeLayout is root view of my UI(xml) file.
root.setDrawingCacheEnabled(true);
Bitmap screen= getBitmapFromView(this.getWindow().findViewById(R.id.relativelayout)); // here give id of our root layout (here its my RelativeLayout's id)

这里是getBitmapFromView() 方法：

public static Bitmap getBitmapFromView(View view) {
    //Define a bitmap with the same size as the view
    Bitmap returnedBitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(),Bitmap.Config.ARGB_8888);
    //Bind a canvas to it
    Canvas canvas = new Canvas(returnedBitmap);
    //Get the view's background
    Drawable bgDrawable =view.getBackground();
    if (bgDrawable!=null) 
        //has background drawable, then draw it on the canvas
        bgDrawable.draw(canvas);
    else 
        //does not have background drawable, then draw white background on the canvas
        canvas.drawColor(Color.WHITE);
    // draw the view on the canvas
    view.draw(canvas);
    //return the bitmap
    return returnedBitmap;
}

它将显示整个屏幕，包括隐藏在您的ScrollView 中的内容。 现在我们有了位图屏幕，让我们将其保存为 pdf（您必须下载 itextpdf-5.3.2.jar 文件并附加到您的项目中......）

private static String FILE = "mnt/sdcard/invoice.pdf"; // add permission in your manifest...

try 
{
    Document document = new Document();

    PdfWriter.getInstance(document, new FileOutputStream(FILE));
    document.open();
    ByteArrayOutputStream stream = new ByteArrayOutputStream();
    screen.compress(Bitmap.CompressFormat.PNG, 100, stream);
    byte[] byteArray = stream.toByteArray();
    addImage(document,byteArray);
    document.close();
}

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

private static void addImage(Document document,byte[] byteArray) 
{
    try 
    {
        image = Image.getInstance(byteArray);  
    } 
    catch (BadElementException e) 
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    catch (MalformedURLException e) 
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    catch (IOException e) 
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
     // image.scaleAbsolute(150f, 150f);
      try 
      {
        document.add(image);
    } catch (DocumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

没有测试任何东西。以下是我使用的所有来源：source1、source2、source3。

Answer 2

您可以使用自定义库，例如 https://github.com/HendrixString/Android-PdfMyXml。我比任何其他方法更喜欢这个库。只需通过这些。

但还有另一种方法 - 如何将 Android View 转换为 PDF - 生成包含布局位图的 pdf

Answer 3

我创建了一个library 来实现这个目标（Getting PDF from Java View objects）。

主要代码sn-p是-

 PdfGenerator.getBuilder()
                        .setContext(context)
                        .fromViewSource()
                        .fromView(targetView) /* "targetView" is the view ,you want to convert PDF */
            /* "fromLayoutXML()" takes array of layout resources.
             * You can also invoke "fromLayoutXMLList()" method here which takes list of layout resources instead of array. */
                        .setDefaultPageSize(PdfGenerator.PageSize.A4)
            /* It takes default page size like A4,A5. You can also set custom page size in pixel
             * by calling ".setCustomPageSize(int widthInPX, int heightInPX)" here. */
                        .setFileName("Test-PDF")
            /* It is file name */
                        .setFolderName("FolderA/FolderB/FolderC")
            /* It is folder name. If you set the folder name like this pattern (FolderA/FolderB/FolderC), then
             * FolderA creates first.Then FolderB inside FolderB and also FolderC inside the FolderB and finally
             * the pdf file named "Test-PDF.pdf" will be store inside the FolderB. */
                        .openPDFafterGeneration(true)
            /* It true then the generated pdf will be shown after generated. */
                        .build(new PdfGeneratorListener() {
                            @Override
                            public void onFailure(FailureResponse failureResponse) {
                                super.onFailure(failureResponse);
                /* If pdf is not generated by an error then you will findout the reason behind it
                 * from this FailureResponse. */
                            }

                            @Override
                            public void showLog(String log) {
                                super.showLog(log);
                /*It shows logs of events inside the pdf generation process*/ 
                            }

                            @Override
                            public void onSuccess(SuccessResponse response) {
                                super.onSuccess(response);
                /* If PDF is generated successfully then you will find SuccessResponse 
                 * which holds the PdfDocument,File and path (where generated pdf is stored)*/
                
                            }
                        });

Answer 4

不使用第三方库，您可以使用在 Android API 19 中引入的PdfDocument。但是请记住，pdf 文件的尺寸将以 postscript 点（1/72 英寸）为单位。因此，在绘制到画布之前，您必须转换视图的尺寸以匹配要求。