android - Flutter:如何使用Navigator PushNamed发送屏幕构造器所需的参数

Question

我有一个路线图，从该路线图中我可以快速看到屏幕。我需要将三个参数传递给下一个屏幕的构造方法。我想使用Navigator.pushNamed()，但是当我使用arguments属性时，它似乎不起作用。

//Screen to build 
class ResultPage extends StatelessWidget{
ResultPage(
  {@required this.calc1Result,
  @required this.calc2Text,
  @required this.interpretation});

  final String calc1Result;
  final String calc2Text;
  final String interpretation;

   @override
   Widget build(BuildContext context) {  //etc.. etc... }

  --------------------------------------------------------------------------

然后，我需要从另一个页面调用此屏幕:

  //Call to ResultPage from another screen
  Calculator calculator = Calculator(param1: param1, param2: param2);


   Navigator.pushNamed(context, 'resultPage', arguments: 
       {
       'calc1Result': calculator.getCalc1Result(),
       'calc2Text': calculator.getCalc2Text()
       'interpretation': calculator.getInterpretation(),           
       });

它根本不起作用，结果始终为Null。

如果我使用Navigator.push()做同样的事情，它将起作用。

//Working alternative - I don't want to use this:
Navigator.push(
              context,
              MaterialPageRoute(
                builder: (context) => ResultPage(
                  calc1Result: calculator.getCalc1Result(),
                  calc2Text: calculator.getCalc2Text(),
                  interpretation: calculator.getInterpretation(),                      
                ),
              ),
            );

Answer 1

您是否已将命名路线添加到MaterialApp小部件？

MaterialApp(
  routes: {
    ExtractArgumentsScreen.routeName: (context) => ExtractArgumentsScreen(),
  },
);

看这里:
https://flutter.dev/docs/cookbook/navigation/navigate-with-arguments

然后在ResultPage中，您必须使用以下命令提取参数:

@override
  Widget build(BuildContext context) {
    // Extract the arguments from the current ModalRoute settings and cast
    // them as ScreenArguments.
    final args = ModalRoute.of(context).settings.arguments;

...
}