webview Android 6.0中的PDF

Question

我正在尝试从Android Marshmallow中的链接加载pdf文件。它始终显示空白屏幕，而代码工作正常，版本低于6.0。请帮忙。 感谢

以下是我正在使用的代码

webView = (WebView)findViewById(R.id.webView);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.setWebViewClient(new WebViewClient() {

            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                // TODO Auto-generated method stub
                webView.loadUrl ("http://drive.google.com/viewerng/viewer?embedded=true&url="+url);
                return super.shouldOverrideUrlLoading(view, url);
            }

            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon) {
                // TODO Auto-generated method stub
               // showProgress(LoadPageByUrlActivity.this,"Please wait...");
                super.onPageStarted(view, url, favicon);
            }

            @Override
            public void onPageFinished(WebView view, String url)
            {
                super.onPageFinished(view, url);
               // stopProgress();
            }
        });
        String url = getIntent().getExtras().getString("url");
        if(url.contains("pdf")){
            webView.loadUrl("http://drive.google.com/viewerng/viewer?embedded=true&url="+url);
        }else
            webView.loadUrl(url);
    }