@Override public View onCreateView( LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_pdf, container, false); downloadBtn = (Button) rootView.findViewById(R.id.download); // Check if there is internet connection, if yes proceed, else return to previous fragment. if (!dbManager.checkInternetConnection(getActivity())) { Toast.makeText( getActivity(), "Internet connection is required to access this file.", Toast.LENGTH_SHORT) .show(); getFragmentManager().popBackStack(); } else { WebView webview = (WebView) rootView.findViewById(R.id.webView); webview.getSettings().setJavaScriptEnabled(true); webview.getSettings().setBuiltInZoomControls(true); webview.getSettings().setSupportZoom(true); webview.loadUrl("https://drive.google.com/viewerng/viewer?embedded=true&url=" + pdf); downloadBtn.setOnClickListener( new View.OnClickListener() { @Override public void onClick(View v) { if (!dbManager.checkInternetConnection(getActivity())) { Toast.makeText( getActivity(), "Internet connection is required to download file.", Toast.LENGTH_SHORT) .show(); } else { new DownloadFile().execute(); } } }); } return rootView; }