从 Android 上的 Webview 创建 PDF

Question

So I am trying to create a PDF from a Webview. Right now I can create an image from the webview, but I am having some problems to split my document in many pages.

First, I create a Bitmap from the webview:

public static Bitmap screenShot(View view) {
        Bitmap bitmap = Bitmap.createBitmap(view.getWidth(),
                view.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        canvas.drawColor(Color.WHITE);
        view.draw(canvas);
        return bitmap;
    }

Second, I create and I show the PDF:

public void criaPdf(){
        Bitmap bitmap = Utils.screenShot(mContratoWebview);

        Document doc = new Document();


        File dir = new File(getFilesDir(), "app_imageDir");

        if(!dir.exists()) {
            dir.mkdirs();
        }

        File file = new File(dir, "contratoPdf.pdf");

        try {
            FileOutputStream fOut = new FileOutputStream(file);

            PdfWriter.getInstance(doc, fOut);

            //open the document
            doc.open();

            ByteArrayOutputStream stream = new ByteArrayOutputStream();
            bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);

            byte[] byteArray = stream.toByteArray();
            Image image = Image.getInstance(byteArray);
            image.scaleToFit(PageSize.A4.getHeight(), PageSize.A4.getWidth());

            doc.newPage();
            doc.add(image);
        } catch (DocumentException de) {
            Log.e("PDFCreator", "DocumentException:" + de);
        } catch (IOException e) {
            Log.e("PDFCreator", "ioException:" + e);
        }
        finally {
            doc.close();
        }

        mPdfView.fromFile(file)
                .pages(0, 1) // all pages are displayed by default
                .enableSwipe(true)
                .load();
        mPdfView.setVisibility(View.VISIBLE);
}

This is what I got so far:

So my problem is: The content of the Webview is too big to fit in the PDF. How can I solve this?

Answer 1

WebView has built-in functionality to generate PDF's which is made available by using PrintManager Service specifically for the purpose of printing. But for your specific usecase I would suggest you to write(store) the final output of WebView's PrintAdapter which is a PDF file to a local file and go from there.

This link will walk you through the details and implementation. http://www.annalytics.co.uk/android/pdf/2017/04/06/Save-PDF-From-An-Android-WebView/

You can achieve API level 19(KitKat) compatibility with small tweaks for the above solution.

This should solve your problem but incase you face any issue with the implementation let me know.

Answer 2

to create pdf from webview you need android>kitkat -> sdk>=19

  btnSave.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            if (Build.VERSION.SDK_INT > Build.VERSION_CODES.KITKAT) {

                createWebPrintJob(webView);
            } else {



            }

        }
    });

//// Function:

private void createWebPrintJob(WebView webView) {

    PrintManager printManager = (PrintManager) this
            .getSystemService(Context.PRINT_SERVICE);

    PrintDocumentAdapter printAdapter =
            webView.createPrintDocumentAdapter();

    String jobName = getString(R.string.app_name) + " Print Test";

    if (printManager != null) {
        printManager.print(jobName, printAdapter,
                new PrintAttributes.Builder().build());
    }
}

I have problem in create image from webview :))))

Answer 3

In my case, I solved this by firstly converting the webview into a bitmap, then scaling the bitmap to fit into the pdf page.

As for the printing part, I think it was more flexible to simply share the pdf and ask the user to select his printer software, as it's more useful than simply saving as pdf.

If you want to print several pages, I think it is more manageable to create different bitmaps and assign them to different pdf pages.

Here is the code to converting the webview into a single pdf page and then sharing it:

public static void sharePdfFile(WebView webView, Context context)
{
    Bitmap bitmap = webviewToBitmap( webView );
    PrintedPdfDocument pdf =  bitmapToPdf( bitmap, context );
    File file = pdfToFile( pdf, context );
    shareFile( file,"application/pdf", context );
}

private static void shareFile(File file, String contentType, Context context)
{
    Uri uri = FileProvider.getUriForFile(
        context,
        context.getPackageName() + ".fileprovider",
        file);
    Intent shareIntent = new Intent(android.content.Intent.ACTION_SEND);
    shareIntent.setType(contentType);
    shareIntent.putExtra(Intent.EXTRA_STREAM, uri);
    shareIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    Toast.makeText(
        context,
        "Choose your printer app",
        Toast.LENGTH_LONG
    ).show();
    context.startActivity( shareIntent );
}

private static File pdfToFile(PrintedPdfDocument printedPdfDocument, Context context)
{
    File file = new File(context.getFilesDir(), "share.pdf");
    try {
        FileOutputStream outputStream = new FileOutputStream(file);
        printedPdfDocument.writeTo(outputStream);
        outputStream.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
    printedPdfDocument.close();
    return file;
}


private static PrintedPdfDocument bitmapToPdf(Bitmap bitmap, Context context)
{
    PrintAttributes printAttributes = new PrintAttributes.Builder()
        .setColorMode(PrintAttributes.COLOR_MODE_COLOR)
        .setMediaSize(PrintAttributes.MediaSize.ISO_A4)
        .setMinMargins(PrintAttributes.Margins.NO_MARGINS)
        .setResolution(new PrintAttributes.Resolution("1", "label", 300, 300))
        .build();
    PrintedPdfDocument printedPdfDocument = new PrintedPdfDocument(context, printAttributes);
    PdfDocument.Page pdfDocumentPage = printedPdfDocument.startPage(1);
    Canvas pdfCanvas = pdfDocumentPage.getCanvas();
    bitmap = scaleBitmapToHeight(bitmap, pdfCanvas.getHeight());
    pdfCanvas.drawBitmap(bitmap, 0f, 0f, null);
    printedPdfDocument.finishPage(pdfDocumentPage);
    return printedPdfDocument;
}

private static Bitmap webviewToBitmap(WebView webView) {
    webView.measure(
        View.MeasureSpec.makeMeasureSpec(
            0,
            View.MeasureSpec.UNSPECIFIED
        ),
        View.MeasureSpec.makeMeasureSpec(
            0,
            View.MeasureSpec.UNSPECIFIED
        )
    );
    int webViewWidth = webView.getMeasuredWidth();
    int webViewHeight = webView.getMeasuredHeight();
    webView.layout(0,0, webViewWidth, webViewHeight );
    Bitmap bitmap = Bitmap.createBitmap(webViewWidth, webViewHeight, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    canvas.drawBitmap(bitmap, 0, bitmap.getHeight(), new Paint());
    webView.draw(canvas);
    return bitmap;
}

private static Bitmap scaleBitmapToHeight(Bitmap bitmap, int maxHeight) {
    int height = bitmap.getHeight();
    if(height > maxHeight) {
        int width = bitmap.getWidth();
        float scalePercentage = ((float)maxHeight) / height;
        return Bitmap.createScaledBitmap(bitmap, (int) (width * scalePercentage), maxHeight, false);
    }
    return bitmap;
}