Navigator.push通过async在onTap内部引发未处理的异常

Question

我有一个快速的问题，为什么当async存在时，我不能在onTap中使用Navigator.push。删除async和await功能效果良好。Navigator.push按预期工作。但由于onTap内部有未来的函数调用，我无法导航到新类。

onTap: () async {
String _courierOrderID = await model.placeCourierOrder(widget.orderInfoMap);
// placeCourierOrder is just a Future<String> type function and it works fine. Order get placed successfully.

print("------- Courier Order Placed  " + _courierOrderID.toString());
print("context: " + _courierOrderID.toString());

Navigator.push(context,
MaterialPageRoute(
builder: (context) => CourierOrderSummaryView(singleCourierDataID: _courierOrderID),
),
);
},

输出从下面的代码输出中，您可以看到我的订单成功下订单，但在Navigator.push行，它给出了未处理的异常

------- Courier Order Placed  501-1c614
I/flutter (16526): context: LayoutBuilder(renderObject: _RenderLayoutBuilder#f6291 relayoutBoundary=up1 NEEDS-LAYOUT DETACHED)
E/flutter (16526): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: Looking up a deactivated widget's ancestor is unsafe.
E/flutter (16526): At this point the state of the widget's element tree is no longer stable.
E/flutter (16526): To safely refer to a widget's ancestor in its dispose() method, save a reference to the ancestor by calling dependOnInheritedWidgetOfExactType() in the widget's didChangeDependencies() method.
E/flutter (16526): #0      Element._debugCheckStateIsActiveForAncestorLookup.<anonymous closure>
package:flutter/…/widgets/framework.dart:3864
E/flutter (16526): #1      Element._debugCheckStateIsActiveForAncestorLookup
package:flutter/…/widgets/framework.dart:3878
E/flutter (16526): #2      Element.findAncestorStateOfType
package:flutter/…/widgets/framework.dart:3926
E/flutter (16526): #3      Navigator.of
package:flutter/…/widgets/navigator.dart:2706
E/flutter (16526): #4      Navigator.push
package:flutter/…/widgets/navigator.dart:2116
E/flutter (16526): #5      _CourDelivReviewState.build.<anonymous closure>.<anonymous closure>.<anonymous closure>
package:storeifie/…/courierViews/courDelivReview.dart:560
E/flutter (16526): <asynchronous suspension>
E

Answer 1

也许这对你的有用

onTap: () async {
String _courierOrderID = await model.placeCourierOrder(widget.orderInfoMap);


await Navigator.push(context,
MaterialPageRoute(
builder: (context) => CourierOrderSummaryView(singleCourierDataID: _courierOrderID),
),
);
},

Answer 2

onTap: () async {
String _courierOrderID = await model.placeCourierOrder(widget.orderInfoMap);
// placeCourierOrder is just a Future<String> type function and it works fine. Order get placed successfully.

print("------- Courier Order Placed  " + _courierOrderID.toString());
print("context: " + _courierOrderID.toString());

if(!mounted){
print('you are not in this context anymore");
// you changed the page and now you can't use this context.
}
Navigator.push(context,
MaterialPageRoute(
builder: (context) => CourierOrderSummaryView(singleCourierDataID: _courierOrderID),
),
);
},