import 'package:flutter/material.dart';
import 'package:webview_flutter/webview_flutter.dart';
 
void main() => runApp(MyApp());

class MyApp extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
    home: Scaffold(
        body: WebViewClass()
       )
      );
  }
}

class WebViewClass extends StatefulWidget {

  WebViewState createState() => WebViewState();

}

class WebViewState extends State<WebViewClass>{

  num position = 1 ;

  final key = UniqueKey();

  doneLoading(String A) {
    setState(() {
      position = 0;
    });
  }

  startLoading(String A){
    setState(() {
      position = 1;
    });
  }

  @override
  Widget build(BuildContext context) {
  return Scaffold(
     appBar: AppBar(
        title: Text('Show ProgressBar While Loading Webview')),
      body: IndexedStack(
      index: position,
      children: <Widget>[

      WebView(
        initialUrl: 'https://Google.com',
        javascriptMode: JavascriptMode.unrestricted,
        key: key ,
        onPageFinished: doneLoading,
        onPageStarted: startLoading,
        ),

       Container(
        color: Colors.white,
        child: Center(
          child: CircularProgressIndicator()),
        ),
        
      ])
  );
  }
}

Why is this error showing? Basically I want to add progress bar on flutter webview before loading the full website. After many searching I got this code but I also showing error. Is there any problem in this code or if you can, kindly help me with new code.

CodePudding user response：

Follow this,

1. Replace num with int?, at line no 26 -> like, int? position = 1 ;
2. Add !(Exclamation mark) after position, at line no 48 -> like, index: position!.

Happy codding!