In Android there was one much needed missing area i.e., displaying a pdf document within an Android app which currently solves with the introduction of PdfRenderer api from Api level 21 onwards.  I have added the source code link at the bottom of the article to try it out.

API’s needed to render PDF

Below is the list of bare minimum api’s needed to display a pdf document.

• android.graphics.Bitmap
• android.graphics.pdf.PdfRenderer
• android.os.ParcelFileDescriptor
• java.io.InputStream
• java.io.File
• java.io.FileOutputStream

  Read also –

  • How To Use BottomSheet In Android
  • How To Use BottomSheetDialog In Android
  • Use Of Material Design Snackbar In Android Apps
  • Handling exif data for captured images in android

Steps to render PDF

There are three important steps to display a pdf document, these are as follows –

• Step 1 : Initialization of PdfRenderer

The first and foremost step is to initialize PdfRenderer by opening the pdf file and passing FileDescriptor object to PdfRenderer  constructor.

/**
     * Sets up a {@link android.graphics.pdf.PdfRenderer} and related resources.
     */
    private void openRenderer(Context context) throws IOException {
        // In this sample, we read a PDF from the assets directory.
        File file = new File(context.getCacheDir(), FILENAME);
        if (!file.exists()) {
            // Since PdfRenderer cannot handle the compressed asset file directly, we copy it into
            // the cache directory.
            InputStream asset = context.getAssets().open(FILENAME);
            FileOutputStream output = new FileOutputStream(file);
            final byte[] buffer = new byte[1024];
            int size;
            while ((size = asset.read(buffer)) != -1) {
                output.write(buffer, 0, size);
            }
            asset.close();
            output.close();
        }
        mFileDescriptor = ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY);
        // This is the PdfRenderer we use to render the PDF.
        if (mFileDescriptor != null) {
            mPdfRenderer = new PdfRenderer(mFileDescriptor);
        }
    }

• Step 2: Show a Page

Next step is to show a particular page by getting Bitmap for that page and showing in an ImageView.

/**
 * Shows the specified page of PDF to the screen.
 *
 * @param index The page index.
 */
private void showPage(int index) {
    if (mPdfRenderer.getPageCount() 

• Step 3: Closing PdfRenderer

This is the last step that is once your fragment or activity get killed, make sure the renderer and related objects also get released from the memory.

/**
 * Closes the {@link android.graphics.pdf.PdfRenderer} and related resources.
 *
 * @throws java.io.IOException When the PDF file cannot be closed.
 */
private void closeRenderer() throws IOException {
    if (null != mCurrentPage) {
        mCurrentPage.close();
    }
    mPdfRenderer.close();
    mFileDescriptor.close();
}

If you also want to try, Google has already created a sample for it.

I hope this will be useful to all of you for displaying a pdf document in your respective Android app. So do not forget to share this with Android developers in your circle.

Happy coding!

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