#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(...);
});
Related
I use the following function to check and display the content either in Dialog or Bottom Sheet, but when executing it does not work properly, as it displays both together, what is the reason and how can the problem be solved?
Is it possible to suggest a better name for the function?
Content function:
content(BuildContext context, dynamic dialog, dynamic bottomSheet) {
(MediaQuery.of(context).orientation == Orientation.landscape) ? dialog : bottomSheet;
}
Implementation:
ElevatedButton(
child: Text('Button'),
onPressed: () {
content(context, dialog(context), bottomSheet(context));
},
),
How can this be solved?
In order to determine the Orientation of the screen, we can use the OrientationBuilder Widget. The OrientationBuilder will determine the current Orientation and rebuild when the Orientation changes.
void main() async {
runApp(const Home(
));
}
class Home extends StatefulWidget {
const Home({Key key}) : super(key: key);
#override
State<Home> createState() => _HomeState();
}
class _HomeState extends State<Home> {
#override
Widget build(BuildContext context) {
return MaterialApp(home: Scaffold(
body: Center(
child: OrientationBuilder(
builder: (context, orientation) {
return ElevatedButton(
child: Text('Button'),
onPressed: () {
revealContent(orientation,context);
},
);
},
)
),
));
}
revealContent(Orientation orientation, BuildContext context) {
orientation == Orientation.landscape ? dialog(context) : bottomSheet(context);
}
dialog(BuildContext context){
showDialog(
context: context,
builder: (context) => const Dialog(
child: Padding(
padding: EdgeInsets.all(20.0),
child: Text('test'),
),
)
);
}
bottomSheet(final BuildContext context) {
return showModalBottomSheet(
context: context,
isScrollControlled: true,
builder: (builder) => const Padding(
padding: EdgeInsets.all(20.0),
child: Text('test'),
),
);
}
}
here are screenshots:
happy coding...
The reason the function is not working properly is because you're not actually showing the dialog or bottom sheet. To show the dialog or bottom sheet, you need to call showDialog or showModalBottomSheet, respectively, and pass them the result of calling dialog or bottomSheet.
try this
void revealContent(BuildContext context, Widget dialog, Widget bottomSheet) {
(MediaQuery.of(context).orientation == Orientation.landscape)
? showDialog(context: context, builder: (context) => dialog)
: showModalBottomSheet(context: context, builder: (context) => bottomSheet);
}
You have a fundamental misunderstanding as to what your code is doing.
Take your "Implementation" and revealContent code, for example:
ElevatedButton(
child: Text('Button'),
onPressed: () {
revealContent(context, dialog(context), bottomSheet(context));
},
),
revealContent(BuildContext context, dynamic dialog, dynamic bottomSheet) {
(MediaQuery.of(context).orientation == Orientation.landscape) ? dialog : bottomSheet;
}
You think that revealContent will invoke either dialog or bottomSheet based on the orientation of the screen. What you are actually doing, however, is you are invoking both of them and then passing the result of the invocations to revealContent, which isn't actually doing anything with them.
What you need to be doing is passing the functions as callbacks to revealContent and then invoking the callbacks within the function:
ElevatedButton(
child: Text('Button'),
onPressed: () {
revealContent(context, () => dialog(context), () => bottomSheet(context));
},
),
revealContent(BuildContext context, void Function() dialog, void Function() bottomSheet) {
if (MediaQuery.of(context).orientation == Orientation.landscape) {
dialog()
} else {
bottomSheet();
}
}
You should be calling showDialog and showModalBottomSheet inside revealContent.
Dialog
dialog(BuildContext context){
return Dialog( //.. );
}
BottomSheet
bottomSheet(final BuildContext context) {
return Widget( /.. );
}
Reveal Content
void revealContent(BuildContext context, Widget dialog, Widget bottomSheet) {
if (MediaQuery.of(context).orientation == Orientation.landscape) {
return showDialog(context: context, builder: (context) => dialog);
} else {
return showModalBottomSheet(context: context, builder: (context) => bottomSheet);
}
}
I have this buildShowDialog that loads in initState and in my Text widget when I receive some data I want to close the buildShowDialog. How can I do this ?
The buildshowDialog method
buildShowDialog(BuildContext context) {
return showDialog(
context: context,
barrierDismissible: false,
builder: (BuildContext context) {
return Center(
child: CircularProgressIndicator(),
);
});
}
calling it in initState
#override
void initState() {
super.initState();
buildShowDialog(context);
}
Now in my widget when I get some data in my text widget from the provider package I want to dismiss the dialog then
#override
Widget build(BuildContext context) {
\\\
return Scaffold(
body: Stack(
\\\
Consumer < AppData > (
builder: (ctx, prod, child) => dropOffText ?
Text(
prod.dropOffLocation != null ?
prod.dropOffLocation
***CALL NAVIGATOR.POP HERE! *** (close the dialog here)
:
"Pick your destination ",
style: TextStyle(fontSize: 12.0),
overflow: TextOverflow.ellipsis,
) :
Text("Pick your destination "),
you can do it in different ways like without showing the dialog in init state, You can use FutureBuilder Instead like below
FutureBuilder<String>(
future: _getData,
builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
if (snapshot.connectionState!=ConnectionState.done) {
return CircularProgressIndicator();
}
else Text(snapshot.data);
},
)
or you can use also this package instead
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
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();
}
Is there any limitation in BottomSheet that we cannot update the widget states? As you can see in the example below I'm using a Switch but its display is not changing, although the value update, it's just that it doesn't get re-render again.
This is part of StatefulWidget right now.
This same problem I'm experiencing with the DropdownButton widget. These both work in normal page fine.
Does anybody have the idea?
showModalBottomSheet(
context: context,
builder: (BuildContext context) {
return BottomSheet(
onClosing: () {},
builder: (BuildContext context) {
return Switch(
onChanged: (bool v) {
debugPrint('v is ${v.toString()}');
// b = v; <<-- This is also not working when using StatelessWidget
setState(() => b = v);
debugPrint(b.toString());
},
value: b,
);
},
);
},
);
The problem here is that the BottomSheet you are creating is not part of your StatefulWidget. If you only made your widget stateful for the purpose of using setState inside of showModalBottomSheet, you can revert that change now.
What you really want to do is set the state inside of your BottomSheet. You do that by either passing a StatefulWidget to the builder or by using a StatefulBuilder, which I will do for this example for the sake of simplicity:
showModalBottomSheet(
context: context,
builder: (BuildContext context) {
return BottomSheet(
onClosing: () {},
builder: (BuildContext context) {
bool b = false;
return StatefulBuilder(
builder: (BuildContext context, setState) => Switch(
onChanged: (bool v) {
setState(() => b = v);
},
value: b,
),
);
},
);
},
);
I also moved the b value inside the builder function of the BottomSheet.
If you want to use the value of b inside of your original StatefulWidget as well, you would move it out again and you probably want to call this.setState as well to also update the other widget (only if you need it to update).
I also faced the same problem. Its a small trick, you need to insert StatefulBuilder in the showModalBottomSheet. I will use a different code to make someone out there understand easily using checkbox now that the answer comes way late.
showModalBottomSheet(
context: context,
isScrollControlled: true,
builder: (BuildContext context) {
mpesachecked =false;
return StatefulBuilder(builder: (BuildContext context, StateSetter mystate) {
return Padding(
padding: const EdgeInsets.fromLTRB(10.0, 70.0, 20.0, 20.0),
child: Column(
children: <Widget>[
Checkbox(
value: mpesachecked,
activeColor: Colors.green,
onChanged: (value) {
mystate(() {
mpesachecked = value;
});
}),
])
));
});
)
NOTE: the new state within the showModalBottomSheet is mystate