I am try pass context to second widget tree (in function) but I get error:
Tried to use Provider with a subtype of Listenable/Stream (Model2).
This is likely a mistake, as Provider will not automatically update
dependents when Model2 is updated. Instead, consider changing Provider
for more specific implementation that handles the update mecanism,
such as:
- ListenableProvider
- ChangeNotifierProvider
- ValueListenableProvider
- StreamProvider
Future<void> _neverSatisfied({Key key, #required BuildContext context}) async {
final model2 = Provider.of<Model2>(context, listen: false);
return showDialog<void>(
context: context,
barrierDismissible: false,
builder: (BuildContext context) {
return
Provider.value(value: model2, child:
AlertDialog(
title: Text('Rewind and remember'),
content: SingleChildScrollView(
child: ListBody(
children: <Widget>[
Text('You will never be satisfied.'),
Text('You\’re like me. I’m never satisfied.'),
],
),
),
actions: <Widget>[
FlatButton(
child: Text('Regret'),
onPressed: () async {
await model2.getData();
Navigator.of(context).pop();
},
),
],
),
);
},
);
}
First widget in same StatefulWidget:
#override
Widget build(BuildContext context) {
return ChangeNotifierProxyProvider<Model1, Model2>(
initialBuilder: (_) => Model2(),
builder: (_, model1, model2) => model2
..string = model1.string,
),
child: Consumer<Model2>(
builder: (context, model2, _) =>
Second (I pass context from here):
#override
Widget buildStep(BuildContext context) {
Consumer<Model2>(
builder: (context, model2, _) =>
...
_neverSatisfied(context: context); //**pass context**
Instead of Provider.value you should use ChangeNotifierProvider.value
Related
How to set global variable using OK button on AlertDialog in StatefulBuilder?
String stringMain = "My String";
Future<String?> dialogChangeMainContent(BuildContext context) {
return showDialog<String>(
context: context,
builder: (BuildContext context) {
return StatefulBuilder(builder: (context, setState) {
return AlertDialog(
title: const Text('AlertDialog Title'),
content: const Text('AlertDialog description'),
actions: <Widget>[
TextButton(
onPressed: () {
Navigator.pop(context, 'OK');
setState(() {
// setState2();
stringMain = "New String";
});
},
child: const Text('OK'),
),
],
);
});
});
}
I changed StatefulWidget from StatelessWidget, but nothing changes. What I know is the problem is because the button is in the StatefulBuilder. If using BLoC etc, it's too wasteful for only small applications.
I found a way to solve my problem, redrawing (refreshing) the Text (or other widget) in a Stateless Widget from an AlertDialog in a StatefulBuilder. By creating a setState with a different name, for example setStateTarget.
Without having to rebuild the entire page, or without state management like BLoC. My code:
String stringMain = "My String";
#override
Widget build(BuildContext context) {
return Column(
// ....
children: [
StatefulBuilder(builder: (BuildContext context, setStateTarget) {
return Column(children: [
Text(stringMain), // <--- target
TextButton(
onPressed: () => dialogChangeMainContent(context, setStateTarget),
child: const Text('Show Dialog'))
]);
})
],
);
}
Future<String?> dialogChangeMainContent(BuildContext context, StateSetter setStateTarget) {
return showDialog<String>(
context: context,
builder: (BuildContext context) {
return StatefulBuilder(builder: (context, setState) {
return AlertDialog(
title: const Text('AlertDialog Title'),
content: const Text('AlertDialog description'),
actions: <Widget>[
TextButton(
onPressed: () {
Navigator.pop(context, 'OK');
setStateTarget(() {
// setState2();
stringMain = "New String";
});
},
child: const Text('OK'),
),
],
);
});
});
}
I´m new in the bloc pattern. I want to show up an alert dialog when I press a button, but when I use showDialog func and showDialog I want to access Bloc from context or BlocListner doesn't contain bloc and throw error is there a way to access bloc in this situatuion
Error: Could not find the correct Provider above this BlocListener<TeacherFinancialCubit, TeacherFinancialState> Widget
#override
Widget build(BuildContext context) {
return BlocBuilder<UserBloc, UserState>(
builder: (context, state) {
if(state is! Authorize) {
return const BaBaFullScreenLoading();
}
return BlocProvider<TeacherFinancialCubit>(
lazy: false,
create: (context) => TeacherFinancialCubit(locator())..getTeacherFinancial(state.user, state.account, teacherId ?? 0),
child: _masterLayout(context),
);
},
);
}
Widget _masterLayout(BuildContext context) {
Authorize authorize = context.read<UserBloc>().state as Authorize;
return MasterLayout(
showBack: true,
floatingActionButton: authorize.account.type == master ? FloatingActionButton(
child: const Icon(Icons.add),
onPressed: () {
Future.microtask(() => _showAddPaymentDialog(context));
},
) : null,
title: const Text(""),
child: WillPopScope(
onWillPop: () => Future.value(false),
child: _showTeacherFinancials(context, authorize),
),
);
}
void _showAddPaymentDialog(BuildContext context) async {
return showDialog(
barrierDismissible: false,
context: context,
builder: (_) {
return BlocListener<TeacherFinancialCubit, TeacherFinancialState>(
listener: (context, state) {
if(state is TeacherFinancialLoading) {
EasyLoadingHelper.showLoading();
}
else {
EasyLoadingHelper.dismiss();
if(state is TeacherFinancialFailed) {
EasyLoadingHelper.showToastError(context, message: state.error);
}
else if(state is TeacherFinancialSuccess) {
EasyLoadingHelper.showToastSuccess(context, message: successMessage);
Navigator.pop(context);
}
}
},
child: AlertDialog(
title: const Text(''),
content: Form(
key: addPaymentFormKey,
child: Text(""),
),
actions: [],
),
);
}
);
}
Make sure to provide the bloc to the AlertDialog. You can do something like this:
return showDialog(
...
builder: (dialogContext) => BlocProvider.value(
value: BlocProvider.of<TeacherFinancialCubit>(context),
child: BlocListener<TeacherFinancialCubit, TeacherFinancialState>(
...
),
),
#override
Widget build(BuildContext context, WidgetRef ref) {
final provider = counterNotifierProviders(Counter.initialize());
final counter = ref.watch(provider);
return Scaffold(
body: ElevatedButton(
onPressed: () => showModalBottomSheet<void>(
context: context,
builder: (context) {
return Column(
children: [
Text(counter.count),
TextButton(child: 'Add' onPressed: () => ref.read(provider.notifier).add()),
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Text(counter.count) is not updated. But, I know counter.count was updating from log.
How I can resolve that problem?
You can solve your problem by using Consumer to use its ref and rebuild the widget for you:
Consumer(
builder: (BuildContext context, WidgetRef ref, Widget? child) {
return Scaffold(...);
});
Future<bool> show(BuildContext context) async {
return Platform.isIOS
? await showCupertinoDialog<bool>
(context: context, builder: (context)=>this)
:await showDialog<bool>(
context: context,
builder: (context) => this,
);
}
Can anyone help me to understand the term 'this',what does 'this' refer to and how does showDialog works that it returns Future.I tried to read documentation but still couldn't understand it?Is it the same as AlertDialog widget?
well, it's pretty much what the documentation said, it shows a material dialog above the current content of your app, as for this it passes the current widget as child for the dialog, as for the returned value is just like normal page navigation that when you call pop(context, {value}) method you can also return a value, so that value that inside pop will be returned from the dialog.
here is an example below:
class DialogTest extends StatefulWidget {
#override
_DialogTestState createState() => _DialogTestState();
}
class _DialogTestState extends State<DialogTest> {
// the value that will be typed to the dialog
String dialogText;
// the value that will be returned from the dialog
String returnedFromDialog;
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Sample Code'),
),
body: Center(
child:
Text('You got this value from the dialog => $returnedFromDialog'),
),
floatingActionButton: FloatingActionButton(
onPressed: () async {
returnedFromDialog = await showDialog<String>(
context: context,
builder: (context) {
return AlertDialog(
content: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
TextField(
onChanged: (value) => dialogText = value,
),
FlatButton(
onPressed: () {
setState(() => Navigator.pop(context, dialogText));
},
child: Text(
'Close dialog',
style: TextStyle(color: Colors.red),
),
)
],
),
);
});
},
child: Icon(Icons.open_in_browser),
),
);
}
}
I want to show a dialog if I receive an error in a futurebuilder.
If I receiver an error, I want to show a dialog and force the user to click on the button, so that he can be redirected to another page.
The problems seems to be that it is not possible to show a dialog while widget is being built.
FutureBuilder(
future: ApiService.getPosts(),
builder: (BuildContext context, AsyncSnapshot snapShot) {
if (snapShot.connectionState == ConnectionState.done) {
if (snapShot.data.runtimeType == http.Response) {
var message =
json.decode(utf8.decode(snapShot.data.bodyBytes));
showDialog(
context: context,
barrierDismissible: false,
builder: (context) {
return AlertDialog(
content: Text(message),
actions: <Widget>[
FlatButton(
child: Text("Ok"),
onPressed: () => null",
)
],
);
});
}
return ListView.separated(
separatorBuilder: (BuildContext context, int index) {
return Divider(
color: Colors.grey,
height: 1,
);
},
itemBuilder: (BuildContext context, int index) {
return _buildPostCard(index);
},
itemCount: snapShot.data.length,
);
return Center(
child: CircularProgressIndicator(),
);
},
)
If I return the AlertDialog alone, it works. But I need the showDialog because of the barrierDismissible property.
Does any one know if that is possible?
Also, is this a good way to handle what I want?
Thanks
UPDATE
For further reference, a friend at work had the solution.
In order to do what I was looking for, I had to decide which future I was going to pass to the futureBuilder.
Future<List<dynamic>> getPostsFuture() async {
try {
return await ApiService.getPosts();
} catch (e) {
await showDialog(
context: context,
barrierDismissible: false,
builder: (context) {
return AlertDialog(
content: Text(message),
actions: <Widget>[
FlatButton(
child: Text("Ok"),
onPressed: () => null",
)
],
);
});
}
}
}
Then in the futureBuilder I would just call
FutureBuilder(
future: getPostsFuture(),
Thanks
To avoid setState() or markNeedsBuild() called during build error when using showDialog wrap it into Future.delayed like this:
Future.delayed(Duration.zero, () => showDialog(...));
setState() or markNeedsBuild() called during build.
This exception is allowed because the framework builds parent widgets before its children, which means a dirty descendant will always be built. Otherwise, the framework might not visit this widget during this build phase.
So to avoid that Future Callback is used, which adds a call like this EventQueue.
class HomeScreen extends StatefulWidget {
#override
_HomeScreenState createState() => _HomeScreenState();
}
class _HomeScreenState extends State<HomeScreen> {
Future futureCall() async {
await Future.delayed(Duration(seconds: 2));
}
#override
Widget build(BuildContext context) {
return FutureBuilder(
future: futureCall(),
builder: (_, dataSnapshot) {
if (dataSnapshot.connectionState == ConnectionState.waiting) {
return Center(child: CircularProgressIndicator());
} else {
Future(() { // Future Callback
showDialog(
context: context,
builder: (context) => AlertDialog(
title: Text('Employee Data'),
content: Text('Do you want to show data?'),
actions: <Widget>[
FlatButton(
onPressed: () =>
Navigator.of(context).pop('No'),
child: Text('NO')),
FlatButton(
onPressed: () =>
Navigator.of(context).pop('Yes'),
child: Text('YES'))
],
));
});
return Container();
}
},
);
}
}
The builder param expects you to return a Widget. showDialog is a Future.
So you can't return that.
You show Dialog on top of other widgets, you can't return it from a build method that is expecting a widget.
What you want can be implemented the following way.
When you receive an error, show a dialog on the UI and return a Container for the builder. Modify your code to this:
if (snapShot.data.runtimeType == http.Response) {
var message =
json.decode(utf8.decode(snapShot.data.bodyBytes));
showDialog(
context: context,
barrierDismissible: false,
builder: (context) {
return AlertDialog(
content: Text(message),
actions: <Widget>[
FlatButton(
child: Text("Ok"),
onPressed: () => null",
)
],
);
});
return Container();
}