how to download/create pdf through webview in flutter

i have created a webviewscaffold and its worng good but

1- can't show a floating buton over it. 2- can't download anything from it (acutally i'm ttrying to use print command option that is in the website that i am browsing from the webview i made but when i click the button i do nothing. what do i need to do?

for solution 1: I have tried not using WebviewScaffold and using simple webView but in that keyboard don't popup so had to use WebviewScaffold

for solution 2: I don't know where to start. like in other browsers that can download and preview, i'm trying to achieve the same thing in here.

class AppState extends State<App> {


  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: <Widget>[
          Align(
            alignment: Alignment(1, 1),
            child: Container(
              child: Web(), // it is a statefulwidget that have WebviewScaffold, i have created it on a new page and imported/used here
            ),
          ),
          Column(
            mainAxisAlignment: MainAxisAlignment.end,
            children: <Widget>[
              Padding(
                padding: EdgeInsets.only(top: 20.0),
              )
            ],
          ),
          Align(
            alignment: Alignment(0.7, -0.93),
            child: FloatingActionButton(
                tooltip: "Share",
                child: Icon(
                  Icons.share,
                  color: Colors.amberAccent,
                ),
                onPressed: () {
                  _onShareTap();
                }),
          ),
        ],
      ),
    );
  }

for solution 1: I expect the floating button to show on the webview but it doesn't appear there but it shows on the app bar.

for solution 2: i expect, when i click the print or download button within the webview it should work like any other browser.