Error: [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: Looking up a deactivated widget's ancestor is unsafe. E/flutter ( 6342): At this point the state of the widget's element tree is no longer stable. E/flutter ( 6342): 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 ( 6342): #0 Element._debugCheckStateIsActiveForAncestorLookup. (package:flutter/src/widgets/framework.dart:3864:9) E/flutter ( 6342): #1 Element._debugCheckStateIsActiveForAncestorLookup (package:flutter/src/widgets/framework.dart:3878:6) E/flutter ( 6342): #2 Element.findAncestorStateOfType (package:flutter/src/widgets/framework.dart:3926:12) E/flutter ( 6342): #3 Navigator.of (package:flutter/src/widgets/navigator.dart:2706:40) E/flutter ( 6342): #4 Navigator.pop (package:flutter/src/widgets/navigator.dart:2592:15) E/flutter ( 6342): #5 NotificationDialog.checkAvailabilityOfRide (package:drivers_app/Notifications/notificationDialog.dart:240:20) E/flutter ( 6342):
Snippet of my code:
void checkAvailabilityOfRide(context) async {
var rideRequestId = await rideRequestRef.once();
...
var dataSnapShot2 = await newRequestsRef.child(rideRequestId.value).once();
...
Navigator.push(context, MaterialPageRoute(builder: (context)=>
NewRideScreen(rideDetails: rideDetails)));
...
}
Updated Code:
Widget build(BuildContext context) {
return Dialog(
shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12.0)),
backgroundColor: Colors.transparent,
elevation: 1.0,
child: Container(
margin: EdgeInsets.all(5.0),
width: double.infinity,
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.circular(5.0),
),
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
SizedBox(height: 30.0),
Image.asset("images/taxi.png", width: 120.0,),
SizedBox(height: 18.0,),
Text("New Ride Request", style: TextStyle(fontFamily: "Brand-Bold", fontSize: 18.0,),),
SizedBox(height: 30.0),
Padding(
padding: EdgeInsets.all(18.0),
child: Column(
children: [
Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Image.asset("images/pickicon.png", height: 16.0, width: 16.0,),
SizedBox(width: 20.0,),
Expanded(
child: Container(child: Text(rideDetails.pickup_address, style: TextStyle(fontSize: 18.0),)),
),
],
),
SizedBox(height: 15.0),
Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Image.asset("images/desticon.png", height: 16.0, width: 16.0,),
SizedBox(width: 20.0,),
Expanded(
child: Container(child: Text(rideDetails.dropOff_address, style: TextStyle(fontSize: 18.0),)),
)
],
),
SizedBox(height: 15.0),
],
),
),
SizedBox(height: 20.0),
Divider(height: 2.0,color: Colors.black, thickness: 2.0,),
SizedBox(height: 8.0),
Padding(
padding: EdgeInsets.all(20.0),
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
FlatButton(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(18.0),
side: BorderSide(color: Colors.red)),
color: Colors.white,
textColor: Colors.red,
padding: EdgeInsets.all(8.0),
onPressed: ()
{
assetsAudioPlayer.stop();
Navigator.pop(context);
},
child: Text(
"Cancel".toUpperCase(),
style: TextStyle(
fontSize: 14.0,
),
),
),
SizedBox(width: 25.0),
RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(18.0),
side: BorderSide(color: Colors.green)),
onPressed: ()
{
assetsAudioPlayer.stop();
checkAvailabilityOfRide0(context);
checkAvailabilityOfRide(context);
},
color: Colors.green,
textColor: Colors.white,
child: Text("Accept".toUpperCase(),
style: TextStyle(fontSize: 14)),
),
],
),
),
SizedBox(height: 10.0),
],
),
),
);
}
Future<void> checkAvailabilityOfRide(context) async {
var rideRequestId = await rideRequestRef.once();
Navigator.push(context);
String theRideId = "";
var dataSnapShot2 = await newRequestsRef.child( rideRequestId.value).once();
/*... process...*/
if(theRideId == rideDetails.ride_request_id && r2canShare) {
rideRequestRef.set("accepted");
AssistantMethods.disableHomeTabLiveLocationUpdates();
Navigator.push(context, MaterialPageRoute(builder: (context) =>
NewRideScreen(rideDetails: rideDetails)));
}
else if(theRideId == 'cancelled') {
displayToastMessage("Ride has been Cancelled.", context);
}
else if(theRideId == 'cancelled') {
displayToastMessage("Ride has been time out.", context);
}
else if(r2canShare == false) {
assetsAudioPlayer.stop();
displayToastMessage("Rider 2 cannot shared ride, out of range.", context);
}
else {
displayToastMessage("Ride not exists.", context);
}
}
altered code:
void checkAvailabilityOfRide(context)async{
var dataSnapShot2 = await newRequestsRef.child( (await
rideRequestRef.once()).value).once();
Navigator.pop(context);
String theRideId = "";
/*... process...*/
@Nin Yu, Past some days I got the same error I tried to fix using @Patrick answer, but that didn't work too sometimes. When I closely debug it I found I was calling method containing Navigator multiple times. So sometimes I got context and I pass safely to the next screen and some it throws an error. I would suggest debug method and check whether it occurence.