'Looking up a deactivated widget's ancestor is unsafe
I am new in Flutter and I am trying receive data with a Dialog. When a click in textField the error of image2 appear...
show(BuildContext context){
var dialog = Dialog(
child: Container(
margin: EdgeInsets.all(8.0),
child: Form(
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
TextFormField(
decoration: InputDecoration(
labelText: "Insira o número de telefone",
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(2.0)))),
),
Row(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
FlatButton(
onPressed: () {
Navigator.of(context).pop();
},
child: Text("Cancelar")),
FlatButton(
onPressed: () {
Navigator.of(context).pop();
},
child: Text("Aceitar"))
],
)
],
),
),
),
);
showDialog(context: context,builder: (context){
return dialog;
});
}
This is my code.
I/flutter (31032): Looking up a deactivated widget's ancestor is unsafe.
I/flutter (31032): At this point the state of the widget's element tree is no longer stable. To safely refer to a
I/flutter (31032): widget's ancestor in its dispose() method, save a reference to the ancestor by calling
I/flutter (31032): inheritFromWidgetOfExactType() in the widget's didChangeDependencies() method.
I/flutter (31032):
Solution 1:[1]
Declare a global variable
final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
then register the key on your widget build's scaffold eg
@override
Widget build(BuildContext context) {
return Scaffold(
key: _scaffoldKey,
...
then on the dialog
show(BuildContext context){
var dialog = Dialog(
child: Container(
margin: EdgeInsets.all(8.0),
child: Form(
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
TextFormField(
decoration: InputDecoration(
labelText: "Insira o número de telefone",
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(2.0)))),
),
Row(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
FlatButton(
onPressed: () {
Navigator.of(context).pop();
},
child: Text("Cancelar")),
FlatButton(
onPressed: () {
Navigator.of(context).pop();
},
child: Text("Aceitar"))
],
)
],
),
),
),
);
Pass that scaffold context to the showDialog method
showDialog(context: _scaffoldKey.currentContext ,builder: (context){
return dialog;
});
}
Solution 2:[2]
Try This
Give different context name for dialog
showDialog(context: context,builder: (dialogContex){
return Dialog(
child: Container(
margin: EdgeInsets.all(8.0),
child: Form(
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
TextFormField(
decoration: InputDecoration(
labelText: "Insira o número de telefone",
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(2.0)))),
),
Row(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
FlatButton(
onPressed: () {
Navigator.of(dialogContex).pop();
},
child: Text("Cancelar")),
FlatButton(
onPressed: () {
Navigator.of(context).pop();
},
child: Text("Aceitar"))
],
)
],
),
),
),
);
});
Solution 3:[3]
I got the same error when attempting to open a dialog and I found a solution here: github flutter issues. Specifically, I followed the poster's recommendation, which was to create a GlobalKey and associate it with the Scaffold widget, and use the context from that key when creating the dialog. In my case, I have a globally accessible object which holds the GlobalKey:
MyGlobals myGlobals = MyGlobals();
class MyGlobals {
GlobalKey _scaffoldKey;
MyGlobals() {
_scaffoldKey = GlobalKey();
}
GlobalKey get scaffoldKey => _scaffoldKey;
}
In the Scaffold widget constructor call:
Scaffold(
appBar: ...,
body: ...,
drawer: ...,
key: myGlobals.scaffoldKey,
)
And in the showDialog call:
showDialog<String>(
barrierDismissible: ...,
builder: ...,
context: myGlobals.scaffoldKey.currentContext,
);
Solution 4:[4]
You’re trying to access a context that isn’t probably available. That happens because you’ve assigned your Dialog to a var and afterwards use a different context (the one from your dialog builder).
Either create your dialog directly after your return in the builder or make it a method instead that returns a Dialog and pass it a BuildContext parameter.
Widget myDialog(BuildContext context) => Dialog(/*your dialog here*/);
This is also a more convenient Flutter practice. You should use methods that return widgets instead of assigning it to variables.
Solution 5:[5]
use this:
Navigator.of(context,rootNavigator: true).pop();
instead of
Navigator.of(context).pop();
Solution 6:[6]
This might happen while you are popping from the context and trying to open new content on the context you are popping.
()async{
Navigator.of(context).pop();
_alertPopUp(); // shows a dialog
// might do some work after
}
if alert dialog is created on current context then it throws an error because context doesn't exist anymore
Solution 7:[7]
My problem was that I was using hot reload for pretty long time, I think at some point everything got messed up, doing a normal run of the app fixed the problem.
Solution 8:[8]
Try this:
Future<AlertDialog> myDialog(BuildContext context) {
return showDialog<AlertDialog>(
context: context,
builder: (BuildContext context) {
return AlertDialog(
content: Container(
margin: EdgeInsets.all(8.0),
child: Form(
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
TextFormField(
decoration: InputDecoration(
labelText: "Insira o número de telefone",
border: OutlineInputBorder(
borderRadius:
BorderRadius.all(Radius.circular(2.0)))),
),
],
),
),
),
actions: <Widget>[
FlatButton(
onPressed: () {
Navigator.of(context).pop();
},
child: Text("Cancelar")),
FlatButton(
onPressed: () {
Navigator.of(context).pop();
},
child: Text("Aceitar"))
],
);
},
);
}
Solution 9:[9]
declare dialog and set in initState
late Dialog dialog;
@override
void initState() {
super.initState();
dialog = Dialog(
...
);
}
Solution 10:[10]
first : declare a FormKey.
GlobalKey<FormState>myFormKey=GlobalKey<FormState>();
second : add the FormKey to your Form widget.
Form(
key:myFormKey,
child:child
)
Solution 11:[11]
removing application from emulator and run below commands
flutter clean
flutter pub get
works for me
Solution 12:[12]
In my case i was calling
setState(() {
Navigator.pop(context);
});
Solution 13:[13]
I simply solved this by wrapping the showDialog with a Builder widget, though for me the error came from a stream builder I simply wrap the stream builder with a builder widget and the remove the notify listeners from the a stream am calling in the stream builder, but in your case wrap the showDialog with a Builder widget and it will use the context from the builder, problem solved
Sources
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Source: Stack Overflow