Navigator.pushNamed 返回黑屏

Question

我知道问题的根源，但我不知道如何解决。 当我单击转到另一个页面的按钮时，屏幕变黑了。

这里是调试控制台：

[38;5;248m════════ Exception caught by scheduler library ═════════════════════════════════[39;49m
There are multiple heroes that share the same tag within a subtree.
[38;5;248m════════════════════════════════════════════════════════════════════════════════[39;49m

这是主页：

class HomePage extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
  appBar: AppBar(
    title: Text('Compilación de Flutter'),
    ),
  body:Stack(children: <Widget>[
   _fondoApp(),
   _listView(context),

  ],) ,
  floatingActionButton: Container(),
);
}

Widget _texto(){
return Text('Hola, bienvenido a mi compilacion de apps que yo mismo hice por un curso en flutter por internet.', style: TextStyle(
  color: Colors.white, fontSize: 30
),);
}
Widget _fondoApp(){
return Container(
  height: double.infinity,
  width: double.infinity,
  color: Color.fromRGBO(67, 107, 116, 1),
  );
}
Widget _listView(BuildContext context){
return ListView(
  padding: EdgeInsets.symmetric(horizontal: 10, vertical:15),
  children: <Widget>[
  _texto(),
  SizedBox(height:20),
  _targetadeApps(context, 'app1', Colors.green, "1", "primera", "una app contadora")
],);
}
Widget _targetadeApps(BuildContext context, String route, Color color, String no, String text, String description){
return Card(
  child: Column(
    children:<Widget>[
      ListTile(
        leading: Icon(Icons.check_circle_outline, color: color,),
        title: Text("App $no", style: TextStyle(fontSize: 20.0,),),
        subtitle: Text("Esta fue la $text app que cree trata sobre $description", style: TextStyle(fontSize: 18.0,),),
        ),
        FlatButton(child: Text("Entrar", style: TextStyle(fontSize: 18.0,),), onPressed: (){

          Navigator.pushNamed(context, route);
        },)
    ]
  ),
);
}
} 

这里是导航器需要去的页面

class ContadorPage extends StatefulWidget {
 @override 
 createState() {
  return _ContadorPageState();
}

}

class _ContadorPageState extends State<ContadorPage> {

final _estiloTexto=new TextStyle( fontSize: 27);
 int _conteo = 0;

@override
Widget build(BuildContext context) {
   return Scaffold(
      appBar: AppBar(
        title: Text('AppContadora(app1)'),
        centerTitle: true,
      ) ,
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text('Contador:', style: _estiloTexto,),
            Text('$_conteo', style: _estiloTexto),
          ],
          ) ,
        ),
      floatingActionButton: _crearbotones()

   );
 }
 Widget _crearbotones() {

  return Stack(
      children:<Widget>[ Row(
      mainAxisAlignment: MainAxisAlignment.end,
      children: <Widget>[
        SizedBox(width: 30.0,),
        FloatingActionButton(
          child: Icon(Icons.remove), 
        onPressed: () {
         _sustraer();
        },

        ),
        Expanded(
          child: SizedBox(),
          ),
              FloatingActionButton(
          child: Icon(Icons.exposure_zero), 
        onPressed: () {
         _reset();
        },

        ),
        Expanded(
          child: SizedBox(),
          ),
              FloatingActionButton(
          child: Icon(Icons.add), 
        onPressed: () {
        _agregar();
        },
        )
        ],

    ),
      ]);
 }
 void _agregar(){
   setState(() {
      _conteo++;
   });
 }

void _sustraer(){
  setState(() {
    _conteo--;
  });
}

void _reset(){
setState(() {
  _conteo = _conteo -_conteo;
});


      }




}

当我退出 2 个按钮时，导航器工作正常。 有人知道如何在不退出 2 个按钮的情况下使其工作吗？

Answer 1

您可以在下面复制粘贴运行完整代码
您需要为每个FloatingActionButton 设置herTag

代码sn-p

FloatingActionButton(
                heroTag: "1",
                child: Icon(Icons.remove),
...     
FloatingActionButton(
                heroTag: "2",
                child: Icon(Icons.exposure_zero),
...         
FloatingActionButton(
                heroTag: "3",
                child: Icon(Icons.add),

工作演示

完整代码

import 'package:flutter/material.dart';

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Compilación de Flutter'),
      ),
      body: Stack(
        children: <Widget>[
          _fondoApp(),
          _listView(context),
        ],
      ),
      floatingActionButton: Container(),
    );
  }

  Widget _texto() {
    return Text(
      'Hola, bienvenido a mi compilacion de apps que yo mismo hice por un curso en flutter por internet.',
      style: TextStyle(color: Colors.white, fontSize: 30),
    );
  }

  Widget _fondoApp() {
    return Container(
      height: double.infinity,
      width: double.infinity,
      color: Color.fromRGBO(67, 107, 116, 1),
    );
  }

  Widget _listView(BuildContext context) {
    return ListView(
      padding: EdgeInsets.symmetric(horizontal: 10, vertical: 15),
      children: <Widget>[
        _texto(),
        SizedBox(height: 20),
        _targetadeApps(
            context, 'app1', Colors.green, "1", "primera", "una app contadora")
      ],
    );
  }

  Widget _targetadeApps(BuildContext context, String route, Color color,
      String no, String text, String description) {
    return Card(
      child: Column(children: <Widget>[
        ListTile(
          leading: Icon(
            Icons.check_circle_outline,
            color: color,
          ),
          title: Text(
            "App $no",
            style: TextStyle(
              fontSize: 20.0,
            ),
          ),
          subtitle: Text(
            "Esta fue la $text app que cree trata sobre $description",
            style: TextStyle(
              fontSize: 18.0,
            ),
          ),
        ),
        FlatButton(
          child: Text(
            "Entrar",
            style: TextStyle(
              fontSize: 18.0,
            ),
          ),
          onPressed: () {
            print(route);
            Navigator.pushNamed(context, route);
          },
        )
      ]),
    );
  }
}

class ContadorPage extends StatefulWidget {
  @override
  createState() {
    return _ContadorPageState();
  }
}

class _ContadorPageState extends State<ContadorPage> {
  final _estiloTexto = new TextStyle(fontSize: 27);
  int _conteo = 0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text('AppContadora(app1)'),
          centerTitle: true,
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text(
                'Contador:',
                style: _estiloTexto,
              ),
              Text('$_conteo', style: _estiloTexto),
            ],
          ),
        ),
        floatingActionButton: _crearbotones());
  }

  Widget _crearbotones() {
    return Stack(children: <Widget>[
      Row(
        mainAxisAlignment: MainAxisAlignment.end,
        children: <Widget>[
          SizedBox(
            width: 30.0,
          ),
          FloatingActionButton(
            heroTag: "1",
            child: Icon(Icons.remove),
            onPressed: () {
              _sustraer();
            },
          ),
          Expanded(
            child: SizedBox(),
          ),
          FloatingActionButton(
            heroTag: "2",
            child: Icon(Icons.exposure_zero),
            onPressed: () {
              _reset();
            },
          ),
          Expanded(
            child: SizedBox(),
          ),
          FloatingActionButton(
            heroTag: "3",
            child: Icon(Icons.add),
            onPressed: () {
              _agregar();
            },
          )
        ],
      ),
    ]);
  }

  void _agregar() {
    setState(() {
      _conteo++;
    });
  }

  void _sustraer() {
    setState(() {
      _conteo--;
    });
  }

  void _reset() {
    setState(() {
      _conteo = _conteo - _conteo;
    });
  }
}

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'Flutter Demo',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        initialRoute: '/',
        routes: {
          '/': (context) => HomePage(),
          'app1': (context) => ContadorPage(),
        });
  }
}