App is a simple memory/guessing game with a grid of squares. Floating action button triggers a "New game" dialog, and a Yes response triggers setState() on the main widget. The print() calls show it is building all the Tile widgets in the grid, but as it returns, the old grid values are still showing. Probably done something stupid but not seeing it. Basic code is below. TIA if anyone can see what is missing/invalid/broken/etc.
Main.dart is the usual main() that creates a stateless HomePage which creates a stateful widget which uses this State:
class MemHomePageState extends State<MemHomePage> {
GameBoard gameBoard = GameBoard();
GameController? gameController;
int gameCount = 0, winCount = 0;
#override
void initState() {
super.initState();
gameController = GameController(gameBoard, this);
}
#override
Widget build(BuildContext context) {
if (kDebugMode) {
print("MemHomepageState::build");
}
gameBoard.newGame(); // Resets secrets and grids
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: GridView.count(
crossAxisCount: Globals.num_columns,
children: List.generate(Globals.num_columns * Globals.num_rows, (index) {
int x = index~/Globals.NR, y = index%Globals.NR;
int secret = gameBoard.secretsGrid![x][y];
var t = Tile(x, y, Text('$secret'), gameController!);
gameBoard.tilesGrid![x].add(t);
if (kDebugMode) {
print("Row $x is ${gameBoard.secretsGrid![x]} ${gameBoard.tilesGrid![x][y].secret}");
}
return t;
}),
),
// Text("You have played $gameCount games and won $winCount."),
),
floatingActionButton: FloatingActionButton(
onPressed: () => newGameDialog("Start a new game?"),
tooltip: 'New game?',
child: const Icon(Icons.refresh_outlined),
),
);
}
/** Called from the FAB and also from GameController "won" logic */
void newGameDialog(String message) {
showDialog<void>(
context: context,
barrierDismissible: false, // means the user must tap a button to exit the Alert Dialog
builder: (BuildContext context) {
return AlertDialog(
title: Text("New game?"),
content: Text(message),
//),
actions: <Widget>[
TextButton(
child: const Text('Yes'),
onPressed: () {
setState(() {
gameCount++;
});
Navigator.of(context).pop();
},
),
TextButton(
child: const Text('No'),
onPressed: () {
Navigator.of(context).pop();
},
),
],
);
}
);
}
The Tile class is a StatefulWidget whose state determines what that particular tile should show:
import 'package:flutter/material.dart';
import 'gamecontroller.dart';
enum TileMode {
SHOWN,
HIDDEN,
CLEARED,
}
/// Represents one Tile in the game
class Tile extends StatefulWidget {
final int x, y;
final Widget secret;
final GameController gameController;
TileState? tileState;
Tile(this.x, this.y, this.secret, this.gameController, {super.key});
#override
State<Tile> createState() => TileState(x, y, secret);
setCleared() {
tileState!.setCleared();
}
}
class TileState extends State<Tile> {
final int x, y;
final Widget secret;
TileMode tileMode = TileMode.HIDDEN;
TileState(this.x, this.y, this.secret);
_unHide() {
setState(() => tileMode = TileMode.SHOWN);
widget.gameController.clicked(widget);
}
reHide() {
print("rehiding");
setState(() => tileMode = TileMode.HIDDEN);
}
setCleared() {
print("Clearing");
setState(() => tileMode = TileMode.CLEARED);
}
_doNothing() {
//
}
#override
Widget build(BuildContext context) {
switch(tileMode) {
case TileMode.HIDDEN:
return ElevatedButton(
style: ElevatedButton.styleFrom(
backgroundColor: Colors.teal,
),
onPressed: _unHide,
child: Text(''));
case TileMode.SHOWN:
return ElevatedButton(
onPressed: _doNothing,
style: ElevatedButton.styleFrom(
backgroundColor: Colors.green,
),
child: secret);
case TileMode.CLEARED:
return ElevatedButton(
onPressed: _doNothing,
style: ElevatedButton.styleFrom(
backgroundColor: Colors.black12,
),
child: const Icon(Icons.check));
}
}
}
it looks like you are calling the following in your build function. That would cause everything to reset everytime it builds. Perhaps it belongs in init instead?
gameBoard.newGame(); // Resets secrets and grids
The original problem is that the Tile objects, although correctly created and connected to the returned main widget, did not have distinct 'key' values so they were not replacing the originals. Adding 'key' to the Tile constructor and 'key: UniqueKey()' to each Tile() in the loop, solved this problem. It exposed a related problem but is out of scope for this question. See the github link in the OP for the latest version.
i am trying to use CurveBottomNavigatorBar in my flutter project...
i used my Curve... in the main dart like this:
class _BottomNavigatorBarState extends State<BottomNavigatorBar> {
int selectedIndex = 0;
final screen = [
HomeScreen(),
CartScreen(),
MyStore(),
SettingScreen(),
];
#override
Widget build(BuildContext context) {
int args = ModalRoute.of(context).settings.arguments;
return Scaffold(
body: screen[selectedIndex],
bottomNavigationBar: CurvedNavigationBar(
height: 55,
backgroundColor: Colors.transparent,
buttonBackgroundColor: Theme.of(context).accentColor,
color: Theme.of(context).primaryColor,
animationCurve: Curves.easeOutCubic,
index: selectedIndex,
items: <Widget>[
// code here
],
onTap: (index) {
setState(() {
args = selectedIndex;
selectedIndex = index;
});
},
),
);
}
}
when i go to my store screen there is an add button that take me to a Form to complete it but when i go back it doesn't show me the BOTNAVBAR on my screen so i though that if i can pass arguments so when i pushback to my main it open my my stores automatically
this is the adding store page:
#override
Widget build(BuildContext context) {
int index = 2;
_onBackPressed() {
Navigator.of(context).pushReplacementNamed(
'/myStore',
arguments: index,
);
}
return WillPopScope(
onWillPop: () {
return _onBackPressed();
},
child: Scaffold(
appBar: AppBar(
title: Text('Add Store'),
leading: IconButton(
onPressed: () {
Navigator.of(context).pushReplacementNamed(
'/myStore',
arguments: index,
);
},
icon: Icon(Icons.arrow_back),
),
),
sp i did it like that and i know its wrong cause its not working
anyhelp please and excuse my bad english :(
Please refer this : https://flutter.dev/docs/cookbook/navigation/navigate-with-arguments
Navigator.pushNamed(
context,
ExtractArgumentsScreen.routeName,
arguments: MyStore(index),
);
Make your MyStore() widget that accepts argument like,
int Index;
MyStore(this.Index)
and use in that screen like,
widget.Index
Please go through above link once.
You have a parameters arguments which you can pass to pushReplacementName:
Future<T?> pushReplacementNamed <T extends Object?, TO extends Object?>(
BuildContext context,
String routeName,
{
TO? result,
Object? arguments,
}
)
You can call it like this:
// Considering a variable named my_args_obj
Navigator.of(context).pushReplacementNamed('/myStore', arguments: my_args_obj);
Then to get it from your page:
final args = ModalRoute.of(context).settings.arguments;
For applying app's setting configuration to take effect around app i need to trigger main's setState from appSettings file, how to do so?
Files code:
for main.dart
class _MyAppState extends State<MyApp> {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Builder(
builder: (context) => Scaffold(
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(isVibrationEnabled
? "Vibration is enabled"
: "Vibration is disabled"),
MaterialButton(
color: Colors.grey,
child: Text("Open app setting"),
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => AppSettings(),
),
);
},
)
],
),
),
),
),
);
for globalVariables.dart
bool isVibrationEnabled = false;
for appSettings.dart
class _AppSettingsState extends State<AppSettings> {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
body: Center(
child: FlatButton(
color: Colors.grey,
child: Text(
isVibrationEnabled ? "Disable Vibration" : "Enable Vibration"),
onPressed: () {
setState(() {
isVibrationEnabled
? isVibrationEnabled = false
: isVibrationEnabled = true;
});
//What to do here to trigger setState() in main.dart flie
//for displaying "Vibration is enabled" or "Vibration is disabled"
//acording to the value of bool variable which is in globalVariable.dart file.
},
),
),
),
);
i have seen other answer on stackoverflow but none of them are easy to understand, if someone can answer in a easy way please
For your specific use case, I think best is to use a state management solution like Provider, BLoC, or GetX. Docs here:
https://flutter.dev/docs/development/data-and-backend/state-mgmt/options
If you want something quick and easy, you can pass the value you're listening to and a function containing setState to your new page. Normally you'd do this with a child widget rather than new page, so it might get a bit complicated -- you'll need to rebuild the entire page after the setState. Easiest way I can think of doing that is with Navigator.pushReplacement.
Some code (I wrote this in stackoverflow not my IDE so probably has errors):
class AppSettings extends StatefulWidget {
final Function callback;
final bool isVibrationEnabled;
AppSettings({
#required this.callback,
#required this.isVibrationEnabled,
});
}
...
In your AppSettingsState use:
FlatButton(
color: Colors.grey,
child: Text(
widget.isVibrationEnabled ? "Disable Vibration" : "Enable Vibration"),
onPressed: () => widget.callback(),
),
And in your main file, when creating your appsettings use something like:
MaterialButton(
color: Colors.grey,
child: Text("Open app setting"),
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => AppSettings(
isVibrationEnabled: isVibrationEnabled,
callback: callback,
),
),
);
},
)
void Function callback() {
setState(() => isVibrationEnabled = !isVibrationEnabled);
Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (context) => AppSettings(
isVibrationEnabled: isVibrationEnabled,
callback: callback,
),
),
);
}
Again, you should probably use a state management solution for this specific use case. Rebuilding a page from another page seems messy. But it should work.
And yes, you're using the callback within your callback. So you may need to put the callback near the top of your file, or outside the main function to make it work right.
I am trying to receive in my home the total lines that exist in my database. When I run the app for the first time in my text widget appears "null", it only changes if I go to another page and go back and the value is not updated. I add another line to bd and when I go back the value goes from null to 28 for example but there is already +1 line.
In home I am getting the value inside initState with setState. Any suggestion? Thank you!!
class HomePage extends StatefulWidget {
#override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
ContactHelper helper = ContactHelper();
List<Contact> listaSigilos = List();
int count;
#override
initState() {
super.initState();
setState(() {
helper.getAllContacts().then((list) {
listaSigilos = list;
count = listaSigilos.length;
print(list);
print("count: $count");
});
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
floatingActionButton: FloatingActionButton(
backgroundColor: Colors.black,
onPressed: () {
Navigator.push(
context, MaterialPageRoute(builder: (context) => NovoSigilo()));
},
child: Icon(Icons.add),
),
appBar: AppBar(
title: Text("Stuff to do"),
backgroundColor: Colors.black,
centerTitle: true,
actions: <Widget>[],
),
body: Container(
child: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text("Active"),
Text("$count",//Show row count here
...
First of all never use setState() directly inside initState() method. Second, you were only listening to the database inside initState() which gets called just once, I have created a new method called _fetchData(), which is put inside initState() as well as one you come back from your second page.
#override
initState() {
super.initState();
_fetchData(); // fetch data in the start
}
void _fetchData() {
helper.getAllContacts().then((list) {
listaSigilos = list;
count = listaSigilos.length;
print(list);
print("count: $count");
setState(() {});
});
}
Update your floatingActionButton to
floatingActionButton: FloatingActionButton(
backgroundColor: Colors.black,
onPressed: () {
Navigator.push(context, MaterialPageRoute(builder: (context) => NovoSigilo())).then((value) {
_fetchData(); // fetch data after coming back to this page
});
},
child: Icon(Icons.add),
)
I have one StatefulWidget in Flutter with button, which navigates me to another StatefulWidget using Navigator.push(). On second widget I'm changing global state (some user preferences). When I get back from second widget to first, using Navigator.pop() the first widget is in old state, but I want to force it's reload. Any idea how to do this? I have one idea but it looks ugly:
pop to remove second widget (current one)
pop again to remove first widget (previous one)
push first widget (it should force redraw)
There's a couple of things you could do here. #Mahi's answer while correct could be a little more succinct and actually use push rather than showDialog as the OP was asking about. This is an example that uses Navigator.push:
import 'package:flutter/material.dart';
class SecondPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container(
color: Colors.green,
child: Column(
children: <Widget>[
RaisedButton(
onPressed: () => Navigator.pop(context),
child: Text('back'),
),
],
),
);
}
}
class FirstPage extends StatefulWidget {
#override
State<StatefulWidget> createState() => new FirstPageState();
}
class FirstPageState extends State<FirstPage> {
Color color = Colors.white;
#override
Widget build(BuildContext context) {
return new Container(
color: color,
child: Column(
children: <Widget>[
RaisedButton(
child: Text("next"),
onPressed: () async {
final value = await Navigator.push(
context,
MaterialPageRoute(
builder: (context) => SecondPage()),
),
);
setState(() {
color = color == Colors.white ? Colors.grey : Colors.white;
});
},
),
],
),
);
}
}
void main() => runApp(
MaterialApp(
builder: (context, child) => SafeArea(child: child),
home: FirstPage(),
),
);
However, there's another way to do this that might fit your use-case well. If you're using the global as something that affects the build of your first page, you could use an InheritedWidget to define your global user preferences, and each time they are changed your FirstPage will rebuild. This even works within a stateless widget as shown below (but should work in a stateful widget as well).
An example of inheritedWidget in flutter is the app's Theme, although they define it within a widget instead of having it directly building as I have here.
import 'package:flutter/material.dart';
import 'package:meta/meta.dart';
class SecondPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container(
color: Colors.green,
child: Column(
children: <Widget>[
RaisedButton(
onPressed: () {
ColorDefinition.of(context).toggleColor();
Navigator.pop(context);
},
child: new Text("back"),
),
],
),
);
}
}
class ColorDefinition extends InheritedWidget {
ColorDefinition({
Key key,
#required Widget child,
}): super(key: key, child: child);
Color color = Colors.white;
static ColorDefinition of(BuildContext context) {
return context.inheritFromWidgetOfExactType(ColorDefinition);
}
void toggleColor() {
color = color == Colors.white ? Colors.grey : Colors.white;
print("color set to $color");
}
#override
bool updateShouldNotify(ColorDefinition oldWidget) =>
color != oldWidget.color;
}
class FirstPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
var color = ColorDefinition.of(context).color;
return new Container(
color: color,
child: new Column(
children: <Widget>[
new RaisedButton(
child: new Text("next"),
onPressed: () {
Navigator.push(
context,
new MaterialPageRoute(builder: (context) => new SecondPage()),
);
}),
],
),
);
}
}
void main() => runApp(
new MaterialApp(
builder: (context, child) => new SafeArea(
child: new ColorDefinition(child: child),
),
home: new FirstPage(),
),
);
If you use inherited widget you don't have to worry about watching for the pop of the page you pushed, which will work for basic use-cases but may end up having problems in a more complex scenario.
Short answer:
Use this in 1st page:
Navigator.pushNamed(context, '/page2').then((_) => setState(() {}));
and this in 2nd page:
Navigator.pop(context);
There are 2 things, passing data from
1st Page to 2nd
Use this in 1st page
// sending "Foo" from 1st
Navigator.push(context, MaterialPageRoute(builder: (_) => Page2("Foo")));
Use this in 2nd page.
class Page2 extends StatelessWidget {
final String string;
Page2(this.string); // receiving "Foo" in 2nd
...
}
2nd Page to 1st
Use this in 2nd page
// sending "Bar" from 2nd
Navigator.pop(context, "Bar");
Use this in 1st page, it is the same which was used earlier but with little modification.
// receiving "Bar" in 1st
String received = await Navigator.push(context, MaterialPageRoute(builder: (_) => Page2("Foo")));
For me this seems to work:
Navigator.of(context).pushNamed("/myRoute").then((value) => setState(() {}));
Then simply call Navigator.pop() in the child.
The Easy Trick is to use the Navigator.pushReplacement method
Page 1
Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (context) => Page2(),
),
);
Page 2
Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (context) => Page1(),
),
);
Simply add .then((value) { setState(() {}); after Navigator.push on page1() just like below:
Navigator.push(context,MaterialPageRoute(builder: (context) => Page2())).then((value) { setState(() {});
Now when you use Navigator.pop(context) from page2 your page1 rebuild itself
You can use pushReplacement and specify the new Route
onTapFunction(BuildContext context) async {
final reLoadPage = await Navigator.push(
context,
MaterialPageRoute(builder: (context) => IdDetailsScreen()),
);
if (reLoadPage) {
setState(() {});
}
}
Now while doing Navigator.pop from second page to come back to first page just return some value which in my case is of bool type
onTap: () {
Navigator.pop(context, true);
}
my solution went by adding a function parameter on SecondPage, then received the reloading function which is being done from FirstPage, then executed the function before the Navigator.pop(context) line.
FirstPage
refresh() {
setState(() {
//all the reload processes
});
}
then on pushing to the next page...
Navigator.push(context, new MaterialPageRoute(builder: (context) => new SecondPage(refresh)),);
SecondPage
final Function refresh;
SecondPage(this.refresh); //constructor
then on before the navigator pop line,
widget.refresh(); // just refresh() if its statelesswidget
Navigator.pop(context);
Everything that needs to be reloaded from the previous page should be updated after the pop.
This work really good, i got from this doc from flutter page: flutter doc
I defined the method to control navigation from first page.
_navigateAndDisplaySelection(BuildContext context) async {
final result = await Navigator.push(
context,
MaterialPageRoute(builder: (context) => AddDirectionPage()),
);
//below you can get your result and update the view with setState
//changing the value if you want, i just wanted know if i have to
//update, and if is true, reload state
if (result) {
setState(() {});
}
}
So, i call it in a action method from a inkwell, but can be called also from a button:
onTap: () {
_navigateAndDisplaySelection(context);
},
And finally in the second page, to return something (i returned a bool, you can return whatever you want):
onTap: () {
Navigator.pop(context, true);
}
Put this where you're pushing to second screen (inside an async function)
Function f;
f= await Navigator.pushNamed(context, 'ScreenName');
f();
Put this where you are popping
Navigator.pop(context, () {
setState(() {});
});
The setState is called inside the pop closure to update the data.
I had a similar issue.
Please try this out:
In the First Page:
Navigator.push( context, MaterialPageRoute( builder: (context) => SecondPage()), ).then((value) => setState(() {}));
After you pop back from SecondPage() to FirstPage() the "then" statement will run and refresh the page.
You can pass back a dynamic result when you are popping the context and then call the setState((){}) when the value is true otherwise just leave the state as it is.
I have pasted some code snippets for your reference.
handleClear() async {
try {
var delete = await deleteLoanWarning(
context,
'Clear Notifications?',
'Are you sure you want to clear notifications. This action cannot be undone',
);
if (delete.toString() == 'true') {
//call setState here to rebuild your state.
}
} catch (error) {
print('error clearing notifications' + error.toString());
}
}
Future<bool> deleteLoanWarning(BuildContext context, String title, String msg) async {
return await showDialog<bool>(
context: context,
child: new AlertDialog(
title: new Text(
title,
style: new TextStyle(fontWeight: fontWeight, color: CustomColors.continueButton),
textAlign: TextAlign.center,
),
content: new Text(
msg,
textAlign: TextAlign.justify,
),
actions: <Widget>[
new Container(
decoration: boxDecoration(),
child: new MaterialButton(
child: new Text('NO',),
onPressed: () {
Navigator.of(context).pop(false);
},
),
),
new Container(
decoration: boxDecoration(),
child: new MaterialButton(
child: new Text('YES', ),
onPressed: () {
Navigator.of(context).pop(true);
},
),
),
],
),
) ??
false;
}
Regards,
Mahi
In flutter 2.5.2 this is worked for me also it works for updating a list
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => SecondPage()))
.then((value) => setState(() {}));
then in the second page I just code this
Navigator.pop(context);
I have a ListView in fist page which is display a list[] data, the second page was updating the data for my list[] so the above code works for me.
Needed to force rebuild of one of my stateless widgets. Did't want to use stateful. Came up with this solution:
await Navigator.of(context).pushNamed(...);
ModalRoute.of(enclosingWidgetContext);
Note that context and enclosingWidgetContext could be the same or different contexts. If, for example, you push from inside StreamBuilder, they would be different.
We don't do anything here with ModalRoute. The act of subscribing alone is enough to force rebuild.
If you are using an alert dialog then you can use a Future that completes when the dialog is dismissed. After the completion of the future you can force widget to reload the state.
First page
onPressed: () async {
await showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
....
);
}
);
setState(() {});
}
In Alert dialog
Navigator.of(context).pop();
This simple code worked for me to go to the root and reload the state:
...
onPressed: () {
Navigator.of(context).pushNamedAndRemoveUntil('/', ModalRoute.withName('/'));
},
...
In short, you should make the widget watch the state. You need state management for this.
My method is based on Provider explained in Flutter Architecture Samples as well as Flutter Docs. Please refer to them for more concise explanation but more or less the steps are :
Define your state model with states that the widget needs to observe.
You could have multiple states say data and isLoading, to wait for some API process. The model itself extends ChangeNotifier.
Wrap the widgets that depend on those states with watcher class.
This could be Consumer or Selector.
When you need to "reload", you basically update those states and broadcast the changes.
For state model the class would look more or less as follows. Pay attention to notifyListeners which broadcasts the changes.
class DataState extends ChangeNotifier{
bool isLoading;
Data data;
Future loadData(){
isLoading = true;
notifyListeners();
service.get().then((newData){
isLoading = false;
data = newData;
notifyListeners();
});
}
}
Now for the widget. This is going to be very much a skeleton code.
return ChangeNotifierProvider(
create: (_) => DataState()..loadData(),
child: ...{
Selector<DataState, bool>(
selector: (context, model) => model.isLoading,
builder: (context, isLoading, _) {
if (isLoading) {
return ProgressBar;
}
return Container(
child: Consumer<DataState>(builder: (context, dataState, child) {
return WidgetData(...);
}
));
},
),
}
);
Instance of the state model is provided by ChangeNotifierProvider. Selector and Consumer watch the states, each for isLoading and data respectively. There is not much difference between them but personally how you use them would depend on what their builders provide. Consumer provides access to the state model so calling loadData is simpler for any widgets directly underneath it.
If not then you can use Provider.of. If we'd like to refresh the page upon return from the second screen then we can do something like this:
await Navigator.push(context,
MaterialPageRoute(
builder: (_) {
return Screen2();
));
Provider.of<DataState>(context, listen: false).loadData();
For me worked:
...
onPressed: (){pushUpdate('/somePageName');}
...
pushUpdate (string pageName) async { //in the same class
await pushPage(context, pageName);
setState(() {});
}
//---------------------------------------------
//general sub
pushPage (context, namePage) async {
await Navigator.pushNamed(context, namePage);
}
In this case doesn't matter how you pop (with button in UI or "back" in android) the update will be done.
Very simply use "then" after you push, when navigator pops back it will fire setState and the view will refresh.
Navigator.push(blabla...).then((value) => setState(() {}))
// Push to second screen
await Navigator.push(
context,
CupertinoPageRoute(
builder: (context) => SecondScreen(),
),
);
// Call build method to update any changes
setState(() {});
Use setstate in your navigation push code.
Navigator.push(context, MaterialPageRoute(builder: (context) => YourPage())).then((value) {
setState(() {
// refresh state
});
});
This simple code goes to the root and reloads the state even without setState:
Navigator.pushAndRemoveUntil(context, MaterialPageRoute(builder: (context) => MainPage()), (Route<dynamic> route) => false,); //// this MainPage is your page to refresh