[英]Unhandled Exception: Bad state: Future already completed in flutter
你好,當我導航到我的應用程序中的另一個頁面時出現此錯誤
我不知道為什么會出現這個錯誤
#0 _AsyncCompleter.complete (dart:async/future_impl.dart:39:31)
#1 Route.didComplete
package:flutter/…/widgets/navigator.dart:203
#2 NavigatorState.pushReplacement.<anonymous closure>
package:flutter/…/widgets/navigator.dart:1861
#3 TickerFuture.whenCompleteOrCancel.thunk
package:flutter/…/scheduler/ticker.dart:389
#4 _rootRunUnary (dart:async/zone.dart:1132:38)
#5 _CustomZone.runUnary (dart:async/zone.dart:1029:19)
#6 _FutureListener.handleValue (dart:async/future_impl.dart:137:18)
#7 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:678:45)
#8 Future._propagateToListeners (dart:async/future_impl.dart:707:32)
#9 Future._completeWithValue (dart:async/future_impl.dart:522:5)
#10 Future._asyncComplete.<anonymous closure> (dart:async/future_impl.dart:552:7)
#11 _rootRun (dart:async/zone.dart:1124:13)
#12 <…>
導航代碼是
Navigator.pop(context);
Navigator.pushReplacementNamed(context, '/NavigationBar');
路線是這樣的
routes: {
"/": (BuildContext context) => LoginPage(),
"/NavigationBar": (BuildContext context) => NavigationBarPage(),
},
我已經用官方示例重現了這個錯誤
刪除Navigator.pop(context);
工作正常
在演示中,第一個屏幕單擊按鈕轉到第二個屏幕。
你不需要Navigator.pop(context);
只是Navigator.pushReplacementNamed(context, '/second');
將工作
代碼片段
onPressed: () {
//Navigator.pop(context); remove this line
// Navigate to the second screen using a named route.
Navigator.pushReplacementNamed(context, '/second');
},
完整代碼
import 'package:flutter/material.dart';
void main() {
runApp(MaterialApp(
title: 'Named Routes Demo',
// Start the app with the "/" named route. In this case, the app starts
// on the FirstScreen widget.
initialRoute: '/',
routes: {
// When navigating to the "/" route, build the FirstScreen widget.
'/': (context) => FirstScreen(),
// When navigating to the "/second" route, build the SecondScreen widget.
'/second': (context) => SecondScreen(),
},
));
}
class FirstScreen extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('First Screen'),
),
body: Center(
child: RaisedButton(
child: Text('Launch screen'),
onPressed: () {
//Navigator.pop(context); remove this line
// Navigate to the second screen using a named route.
Navigator.pushReplacementNamed(context, '/second');
},
),
),
);
}
}
class SecondScreen extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Second Screen"),
),
body: Center(
child: RaisedButton(
onPressed: () {
// Navigate back to the first screen by popping the current route
// off the stack.
Navigator.pop(context);
},
child: Text('Go back!'),
),
),
);
}
}
如果有 Navigator.pop(context) 則出現錯誤信息; 在 Navigator.pushReplacementNamed 之前
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