android - 使用 pushNamed() 从屏幕错误中 flutter 返回数据

Question

我使用 pushNamed() 从屏幕获取返回数据，如下所示:

_pushToPage2() async {
    String result = await Navigator.pushNamed(context, "/page2");
    print("$tag $result");
}

但是代码有问题，这是完整的错误堆栈跟踪:

E/flutter: [ERROR:flutter/shell/common/shell.cc(181)] Dart Error: Unhandled exception:
type 'MaterialPageRoute' is not a subtype of type 'Route'
0 NavigatorState._routeNamed (package:flutter/src/widgets/navigator.dart:1408:14)
1 NavigatorState.pushNamed (package:flutter/src/widgets/navigator.dart:1454:20)
2 _MyHomePageState._pushToPage2 (file:///Users/wang/flutter_project/flutter_navigation/lib/main.dart:113:50)
3 _MyHomePageState.build. (file:///Users/wang/flutter_project/flutter_navigation/lib/main.dart:58:19)
4 _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:507:14)
5 _InkResponseState.build. (package:flutter/src/material/ink_well.dart:562:30)
6 GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:102:24)
7 TapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:242:9)
8 TapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:175:7)
9 PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:315:9)
10 PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:73:12)
11 PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:101:11)
12 _WidgetsFlutterBinding&BindingBase&GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:143:19)
13 _WidgetsFlutterBinding&BindingBase&GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:121:22)
14 _WidgetsFlutterBinding&BindingBase&GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:101:7)
15 _WidgetsFlutterBinding&BindingBase&GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:64:7)
16 _WidgetsFlutterBinding&BindingBase&GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:48:7)
17 _invoke1 (dart:ui/hooks.dart:153:13)
18 _dispatchPointerDataPacket (dart:ui/hooks.dart:107:5)

但以下代码运行正常:

_pushToPage2() async {
    String result = await Navigator.push(
         context, MaterialPageRoute(builder: (context) => Page2()));
    print("$tag $result");
}

Answer 1

对我来说，错误是另一个错误 (type 'MaterialPageRoute<dynamic>' is not a subtype of type 'Route<String>')，我通过将返回值声明为动态类型来解决它:

dynamic result = await Navigator.of(context).pushNamed("/page");

虽然这会失去一些类型安全性，但它对我来说很好。