The named parameter 'title' is required, but there's no corresponding argument

Question

So I face an error when using webview_flutter and I am not sure how to fix it:

In my Page.dart I have the below onTap actions:

Navigator.pushNamed(context, WebView.routeName,
   arguments:
      MyPageArguments("Page Title1", "https://example1.com"));
    
Navigator.pushNamed(context, WebView.routeName,
   arguments:
      MyPageArguments("Page Title2", "https://example2.com"));

class MyPageArguments {
  final String title;
  final String url;
  MyPageArguments(this.title, this.url);
}

Then in my WebView.dart I do the following:

class WebView extends StatefulWidget {
  static const routeName = '/myRoute';
  final String title;
  final String url;

  const WebView({
    super.key,
    required this.title,
    required this.url,
  });

  @override
  _WebViewState createState() => _WebViewState();
}

class _WebViewState extends State<WebView> {
     //Remaining code
}

And in my main.dart I try to define the route:

  '/myRoute': (context) => WebView(),

But I get the following error:

The named parameter 'title' is required, but there's no corresponding argument. (Documentation)

Try adding the required argument.

So I should do something like the example below, however I am not sure how to pass the dynamic title and url parameters to main.dart:

'/myRoute': (context) => WebView(title: "Page Title1", url: "https://example1.com"),

You need to pass the parameters through the route, check at this article: https://docs.flutter.dev/cookbook/navigation/navigate-with-arguments — Wilson Toribio, May 30 '23 at 20:16
Hi, this is exactly the resource I was looking at but for some reason I get the mentioned error and I can't figure out why. Any idea what I am doing wrong? — BradG, May 30 '23 at 20:27

score 0 · Answer 1 · answered May 30 '23 at 22:02

While you are already using route arguments, you can remove WebView 's constructor parameters or make them option(with nullable dataType).

Your WebView state class will access the route arguments.

class WebView extends StatefulWidget {
  static const routeName = '/myRoute';
  const WebView({super.key});
  @override
  _WebViewState createState() => _WebViewState();
}

class _WebViewState extends State<WebView> {
  @override
  Widget build(BuildContext context) {
    final routeArguments = ModalRoute.of(context)?.settings.arguments as MyPageArguments?;

    final url = routeArguments?.url;
    final title = routeArguments?.title;
    return SizedBox();
  }
}

You can check my another answer with more example code.

score 0 · Answer 2 · answered May 31 '23 at 13:01

0

You can use onGenerateRoute in MaterialApp

Route<dynamic> onGenerateRoute(RouteSettings settings) {
switch (settings.name) {
  case WebView.routeName:
    return MaterialPageRoute(
        settings: settings, builder: (_) => const WebView(
          args: settings.arguments as MyPageArguments
        ))
        }}

in WebView you should declare MyPageArguments

final MyPageArguments args;

answered May 31 '23 at 13:01

Roman Maydana

56
2

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The named parameter 'title' is required, but there's no corresponding argument

2 Answers2