如何从webView创建PDF（已隐藏）？

Question

In my android application, I've implemented generating pdf from html content, by displaying the html content in a WebView and then creating pdf document using PdfDocument . It works perfectly fine (code samples below), but I would like to know if it is possible to genereate pdf file from html content which is not visible on the screen? When I set visibility of mPdfPreviewWebView to GONE , then the created pdf is empty.

In other words, I need to generate pdf from html, but I don't want html to be visible (or take any space) on the screen.

Remark: I don't want to use iText library because of its license.

private void createPDF() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
        PdfDocument pdfDocument = new PdfDocument();

        PdfDocument.PageInfo pageInfo = new PdfDocument
                .PageInfo.Builder(A4_WIDTH, A4_HEIGHT, 1).create();

        PdfDocument.Page page = pdfDocument.startPage(pageInfo);

        Canvas canvas = page.getCanvas();
        int webViewWidth = mPdfPreviewWebView.getWidth();
        float scale = A4_WIDTH / (float) webViewWidth;
        canvas.save();
        canvas.scale(scale, scale);

        mPdfPreviewWebView.draw(canvas);
        canvas.restore();
        pdfDocument.finishPage(page);

        String dir = Environment.getExternalStorageDirectory()
                + getString(R.string.three_clicks_folder);

        try {
            FileOutputStream fileOutputStream = null;
            try {
                File file = (new File(dir, "share.pdf"));
                if (!file.exists()) {
                    file.createNewFile();
                }

                fileOutputStream = new FileOutputStream(file);

                pdfDocument.writeTo(fileOutputStream);

                pdfDocument.close();
                Log.i(TAG, "PDF created");
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } finally {
                if (fileOutputStream != null) {
                    fileOutputStream.close();
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Answer 1

It is possible. Simply make a fragment on top of your activity and call the code in your activity that handles your pdf routine from the fragment. Once the conversion is finished, dismiss the fragment. The fragment can be a "processing...." message, and when done, dismiss it, then do whatever you like to do in your fragment. Or may be you want to do something with your converted pdf before you dismiss the fragment.