Opening pdf in android webview

[priyanshi bhardwaj]

Hello, I have a very simple use case a pdf is already downloaded in the device of my app user. That pdf has to be rendered in webview using file protocol.

Things which I have tried :

webView = binding.linkOpeningWithinAppWebview;
        webView.invalidate();
        webView.getSettings().setJavaScriptEnabled(true);
        webView.setVerticalScrollBarEnabled(true);
        webView.setWebChromeClient(new WebChromeClient());
        webView.setWebViewClient(new WebViewClient() {
            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon) {

                super.onPageStarted(view, url, favicon);
                binding.linkOpeningWithinAppProgressBar.setVisibility(View.VISIBLE);
            }

            @Override
            public void onPageFinished(WebView view, String url) {
                binding.linkOpeningWithinAppProgressBar.setVisibility(View.GONE);
            }

            @Override
            public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
                super.onReceivedError(view, request, error);
            }

            @Override
            public void onReceivedHttpError(WebView view, WebResourceRequest request, WebResourceResponse errorResponse) {
                super.onReceivedHttpError(view, request, errorResponse);
            }

            @Override
            public void onReceivedSslError(WebView view, SslErrorHandler handler, SslError error) {
                super.onReceivedSslError(view, handler, error);
            }

            @Override
            public boolean shouldOverrideKeyEvent(WebView view, KeyEvent event) {
                return super.shouldOverrideKeyEvent(view, event);
            }
        });



      
            webView.getSettings().setLoadsImagesAutomatically(true);
            webView.getSettings().setAllowFileAccess(true);
            webView.getSettings().setAllowFileAccessFromFileURLs(true);
            webView.getSettings().setAllowUniversalAccessFromFileURLs(true);
            webView.getSettings().setLoadWithOverviewMode(true);
            webView.getSettings().setUseWideViewPort(true);
            webView.getSettings().setDomStorageEnabled(true);
            webView.getSettings().setAllowContentAccess(true);
            webView.getSettings().setBuiltInZoomControls(true);
            webView.getSettings().setDisplayZoomControls(false);
            webView.getSettings().setAllowFileAccess(true);
            webView.getSettings().setPluginState(WebSettings.PluginState.OFF);
            webView.setScrollbarFadingEnabled(false);
            webView.getSettings().setCacheMode(WebSettings.LOAD_NO_CACHE);
            webView.getSettings().setDefaultZoom(WebSettings.ZoomDensity.FAR);
            webView.getSettings().setRenderPriority(WebSettings.RenderPriority.HIGH);
            webView.setInitialScale(1);
            webView.setHorizontalScrollBarEnabled(false);
            webView.getSettings().setAppCacheEnabled(true);
            webView.getSettings().setDatabaseEnabled(true);

            webView.loadUrl("file:///"+ getWebviewUrl());
or 
   webView.loadData("file:///"+ getWebviewUrl(),"application/pdf", "UTF-8");

Problem: I have tried with loadData and loadurl but it never gets loaded just a blank screen. No Error is getting logged. Any suggestions will be appreciated.

[Tim Moores]

I'm fairly certain webview can't do that. What's wrong with letting an app open it? At least Google Drive is likely to be installed everywhere.

[priyanshi bhardwaj]

Tim Moores wrote:I'm fairly certain webview can't do that. What's wrong with letting an app open it? At least Google Drive is likely to be installed everywhere.

I really don't know about its possibility with webview. But the reason for not using Gdrive app for opening pdf is, recently a very weird problem I am facing with drive i.e. in some devices, mainly Android 10 (Not sure yet) pdf opens for a while and then comes back to my app.

I am not able to figure out any reason (any exception, and no problem with the response code of intent)

Here: https://support.google.com/drive/thread/44585950?hl=en

[Tim Moores]

Well, we don't know what you tried to display PDFs using an external viewer app, so we can't advise on that.

WebView likely won't help, although you can try https://inducesmile.com/android-programming/how-to-display-a-pdf-in-webview-in-android/

You could also render the PDF as a Bitmap using the PDFRenderer class: https://developer.android.com/reference/android/graphics/pdf/PdfRenderer.html

[priyanshi bhardwaj]

Tim Moores wrote:Well, we don't know what you tried to display PDFs using an external viewer app, so we can't advise on that.

WebView likely won't help, although you can try https://inducesmile.com/android-programming/how-to-display-a-pdf-in-webview-in-android/

You could also render the PDF as a Bitmap using the PDFRenderer class: https://developer.android.com/reference/android/graphics/pdf/PdfRenderer.html

Thanks Tim Moores for help. I have opened another thread related to the issue I am facing with another app. You can check this out : Problem with Gdrive

[priyanshi bhardwaj]

Tim Moores wrote:
WebView likely won't help, although you can try https://inducesmile.com/android-programming/how-to-display-a-pdf-in-webview-in-android/

Regarding this, I have already tried opening using google docs in webview. In this Pdf was opening fine but it was hampering the experience like :
1. Pdf used to load late and slow.
2. And sometimes pdf does not even loads. i.e on pdf loading finishes then a white screen comes.


And Regarding the pdf Renderer class is supported for API level 21+. But my app minimum sdk is 19. So I can't use it.

Adding to the above solution I have also tried adding a third-party library for rendering it was increasing app size up to 16mb.Just for sake of rendering a pdf increasing app size or adding a complete library I don't find it efficient enough.

It would be great if we could solve the root cause which I have mentioned in my last comment/another thread. Just as a quick hack I was trying to shift to webview. I have tried adding each and every details of my issue. Please check it. I am already stuck with this issue for a month now.

[priyanshi bhardwaj]

And I have also asked the same questions in another community too like gdrive. But got no response yet.

[Tim Moores]

Regarding the pdf Renderer class is supported for API level 21+. But my app minimum sdk is 19. So I can't use it.

Then use the PdfRenderer class on Android 10, and have the earlier versions open it externally via Intent. That would be a quick improvement until you figure out the actual problem with Android 10. Just make sure to wrap all calls to PdfRenderer inside of

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.L) {
        // do PdfRenderer stuff here
}

Also, seriously consider dropping support for Android 4.4 - it's 7 years old, and upping that to Lollipop lets you drop the pre-Material Design UI stuff. (Unless there are contractual obligations, obviously.)

[priyanshi bhardwaj]

Tim Moores wrote:

Regarding the pdf Renderer class is supported for API level 21+. But my app minimum sdk is 19. So I can't use it.

Then use the PdfRenderer class on Android 10, and have the earlier versions open it externally via Intent. That would be a quick improvement until you figure out the actual problem with Android 10. Just make sure to wrap all calls to PdfRenderer inside of

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.L) {
        // do PdfRenderer stuff here
}

This is something that I can use. Thanks, Tim Moores

Also, seriously consider dropping support for Android 4.4 - it's 7 years old, and upping that to Lollipop lets you drop the pre-Material Design UI stuff. (Unless there are contractual obligations, obviously.)

I understand it's 7 years old. I will be planning this also very soon.