"NoSuchMethodError: The method '>=' " Flutter

"NoSuchMethodError: The method '>=' " Flutter - android

i have the NoSuchMethodError by simulation my App.
NoSuchMethodError (NoSuchMethodError: The method '>=' was called on null.
Receiver: null
Tried calling: >=(55))
The Error is schowing when I simulation my app.
Can someone help me?
my full code in this file:
class GameEN extends StatefulWidget {
//Game({Key key}) : super(key: key);
#override
_GameENState createState() => _GameENState();
}
class _GameENState extends State<GameEN> {
int _counterK;
int _pktK;
#override
void initState() {
_subscription =
super.initState();
_loadCounterK();
}
#override
void dispose() {
_subscription.cancel();
super.dispose();
}
//Loading counter value on start (load)
_loadCounterK() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
setState(() {
_counterK = (prefs.getInt('counterK') ?? 1);
_pktK = (prefs.getInt('pktK') ?? 0);
print(Text("Load number is: $_counterK"));
print(Text("Load pkt is: $_pktK"));
});
}
#override
Widget build(BuildContext context) {
return new WillPopScope(
onWillPop: () async => false,
child: Scaffold(
appBar: AppBar(
backgroundColor: Colors.white,
centerTitle: true,
title: Text(
'ToolQuiz',
style: TextStyle(
fontStyle: FontStyle.italic,
color: Colors.black,
),
),
actions: <Widget>[
Padding(
padding: EdgeInsets.only(right: 15.0),
child: IconButton(
padding: EdgeInsets.all(0),
icon: Icon(
Icons.settings,
color: Colors.black,
),
onPressed: () {
Navigator.push(
context,
PageRouteBuilder(
pageBuilder: (context, animation1, animation2) {
return Einstellungen();
},
),
);
}),
)
],
),
body: Center(
child: Container(
decoration: BoxDecoration(),
child: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
//Küchenutensilien
GestureDetector(
onTap: () {
_interstitialAd.show();
_interstitialAd.dispose();
// _incrementCounterRightAnsK();
Navigator.push(
context,
PageRouteBuilder(
pageBuilder: (context, animation1, animation2) {
if (56 <= _counterK)
return KuechenutensilienEnd();
else
return KuechenutensilienStart();
},
transitionsBuilder:
(context, animation1, animation2, child) {
return FadeTransition(
opacity: animation1,
child: child,
);
},
transitionDuration: Duration(milliseconds: 500),
),
);
},
child: Container(
decoration: BoxDecoration(
gradient: LinearGradient(
colors: [
Colors.brown[600],
Colors.brown[700]
],
begin: Alignment.bottomLeft,
end: Alignment.topRight,
),
border:
Border.all(width: 2, color: Colors.black54),
borderRadius: const BorderRadius.all(
const Radius.circular(20))),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceAround,
children: <Widget>[
Container(
child: Column(
children: <Widget>[
Container(
alignment: Alignment.center,
child: Text('Küchenutensilien',
style: Theme.of(context)
.textTheme
.headline5
.copyWith(color: Colors.black)),
),
Container(
alignment: Alignment.center,
child: Text(
_pktK.toString() + ' ' + 'Punkte',
),
),
Container(
alignment: Alignment.center,
child: Text(() {
if (_counterK >= 55) {
return 'Level ' + '55' + '/55';
}
return 'Level ' +
_counterK.toString() +
'/55';
}()),
),
],
),
),
],
))),
],
),
),
))));
}
}
The error is showing me by all: if....>=
I dont find my problem :(
Thanks for your help

Please make sure that _counterK is properly initialized, do so by initializing it when declaring it
Int _counterK = 0

I solve the problem by changing to the flutter stable channel

Related

Can't solve problem with FloatingActionButton

I want the dialog to open when a button is clicked, but an error occurs due to BLoC. Previously, there was such an error with the class itself, but I successfully solved it, and in this case, the complexity already arises. I've already tried a couple of options but couldn't solve it. I tried to make the event in onPressed as a separate widget, and the same error did not work either.
home_page
class HomePage extends StatelessWidget {
final todoRepository = TodoRepository();
#override
Widget build(BuildContext context) {
// final TodoBloc todoBloc = context.read<TodoBloc>();
return BlocProvider<TodoBloc>(
create: (context) => TodoBloc(todoRepository),
child: Scaffold(
appBar: AppBar(
title: const Text('Flutter Todos'),
),
// floatingActionButton: FloatingActionButton(
// onPressed: () {
// // _addTodo(context);
// final newTodo = Todo(description: 'Todo 1');
// BlocProvider.of<TodoBloc>(context).add(CreateTodos(newTodo));
// },
// child: const Icon(Icons.add),
// ),
body: SingleChildScrollView(
child: Column(
// crossAxisAlignment: CrossAxisAlignment.center,
children: [
// ActionButton(),
TodoList(),
],
),
),
floatingActionButton: FloatingActionButton(
child: const Icon(Icons.add, size: 32, color: Colors.black),
onPressed: () {
// showAddTodoSheet(context);
// showAddTodoSheet(BuildContext context) {
final TodoBloc todoBloc = context.read<TodoBloc>();
final _todoDescriptionFromController = TextEditingController();
showModalBottomSheet(
context: context,
builder: (builder) {
return BlocBuilder<TodoBloc, TodoState>(
builder: (context, state) {
return Padding(
padding: EdgeInsets.only(
bottom: MediaQuery.of(context).viewInsets.bottom),
child: Container(
color: Colors.transparent,
child: Container(
height: 230,
decoration: const BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.only(
topLeft: Radius.circular(10.0),
topRight: Radius.circular(10.0))),
child: Padding(
padding: const EdgeInsets.only(
left: 15, top: 25.0, right: 15, bottom: 30),
child: ListView(
children: <Widget>[
Row(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment:
CrossAxisAlignment.center,
children: <Widget>[
Expanded(
child: TextFormField(
controller:
_todoDescriptionFromController,
textInputAction:
TextInputAction.newline,
maxLines: 4,
style: const TextStyle(
fontSize: 21,
fontWeight: FontWeight.w400),
autofocus: true,
decoration: const InputDecoration(
hintText: 'I have to...',
labelText: 'New Todo',
labelStyle: TextStyle(
color: Colors.indigoAccent,
fontWeight: FontWeight.w500)),
validator: (value) {
if (value!.isEmpty) {
return 'Empty description!';
}
return value.contains('')
? 'Do not use the # char.'
: null;
},
),
),
Padding(
padding: const EdgeInsets.only(
left: 5, top: 15),
child: CircleAvatar(
backgroundColor: Colors.indigoAccent,
radius: 18,
child: IconButton(
icon: const Icon(
Icons.save,
size: 22,
color: Colors.white,
),
onPressed: () {
final newTodo = Todo(
description:
_todoDescriptionFromController
.value.text);
if (newTodo
.description.isNotEmpty) {
todoBloc
.add(CreateTodos(newTodo));
Navigator.pop(context);
}
},
),
),
)
],
),
],
),
),
),
),
);
});
});
},
),
));
}

You have to use MultiBlocProvider before MaterialApp.
just do like that
#override
Widget build(BuildContext context) => MultiBlocProvider(
providers: [
BlocProvider(create: (_) => TodoBloc()),
],
child: MaterialApp()
);

Dynamically Adding Widgets in list item on button’s on pressed function in Flutter

i have list item on my screen ... All I want to know is, how to add dynamicaly a list item on pressing a floatingActionbutton....
here is a first screen on which i have a button (for adding one more item like above item)
in this picture after selecting suit id .. i want when i pressed add button a copy of naap widget displays from which i can select 2ndsuit id...
i read a tutorial from medium.com but there he used sijmply two text boxes whixh is very easy..whereas in my situation it is pretty difficult for me.... but the situation is same .. you can also visit https://medium.com/#anilpandey071999/dynamically-adding-widgets-on-buttons-on-pressed-function-in-flutter-4d9f139744c7
following is my code...
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/material.dart';
import 'package:flutter/material.dart';
import 'package:flutter_auth/Screens/Dashboard/DashboardScreen.dart';
import 'package:flutter_auth/Screens/SearchCustomer/SearchCustomerScreen.dart';
import 'package:flutter_auth/components/NavDrawer.dart';
import 'package:flutter_auth/components/bottombar.dart';
import 'package:flutter_auth/components/rounded_button.dart';
import 'package:flutter_auth/components/rounded_input_field.dart';
import 'package:flutter_auth/components/drop_down_list.dart';
import 'package:flutter_auth/Screens/Welcome/welcome_screen.dart';
import '../../constants.dart';
import 'components/inputtextfieldname.dart';
import 'components/inputtextfieldnumber.dart';
class AddCustomerScreen extends StatefulWidget {
#override
_AddCustomerScreenState createState() => _AddCustomerScreenState();
}
class _AddCustomerScreenState extends State<AddCustomerScreen> {
final CategoriesScroller categoriesScroller = CategoriesScroller();
ScrollController controller = ScrollController();
bool closeTopContainer = false;
double topContainer = 0;
List<Widget> itemsData = [];
void getPostsData() {
List<AddCustomerScreen> dynamicList = [];
List<dynamic> responseList = Customer_Data;
List<Widget> listItems = [];
responseList.forEach((post) {
listItems.add(GestureDetector(
onTap: () {
// _navigateAndDisplaySelection(context);
},
child: Container(
height: 200,
margin: const EdgeInsets.symmetric(horizontal: 20, vertical: 10),
decoration: BoxDecoration(borderRadius: BorderRadius.all(Radius.circular(20.0)), color: Colors.white, boxShadow: [
BoxShadow(color: Colors.black.withAlpha(100), blurRadius: 10.0),
]),
child: Padding(
padding: const EdgeInsets.symmetric(horizontal: 20.0, vertical: 10),
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
post["name"], textAlign: TextAlign.center,
style: const TextStyle( fontSize: 20, fontWeight: FontWeight.bold,color: kPrimaryColor),
),
// Expanded(child: drop_down_list())
],
),
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Padding(
padding:EdgeInsets.symmetric(horizontal:10.0),
child:Container(
height:2.0,
width:275.0,
color:kPrimaryColor),),
],),
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
IconButton(onPressed: (){}, icon: Icon(Icons.camera_alt_rounded), iconSize: 30,color: Color(0XFFc49864)),
IconButton(onPressed: (){}, icon: Icon(Icons.add_photo_alternate_outlined), iconSize: 30,color: Color(0XFFc49864))
],
),
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Expanded(child: drop_down_list())
])
],),
)),));
});
setState(() {
itemsData = listItems;
});
}
#override
void initState() {
super.initState();
getPostsData();
controller.addListener(() {
setState(() {
});
});
}
#override
Widget build(BuildContext context) {
final Size size = MediaQuery.of(context).size;
final double categoryHeight = size.height*0.30;
return SafeArea(
child: Scaffold(
backgroundColor: Colors.white,
appBar: AppBar(
title: Text('Add Customer'),
actions: <Widget>[
IconButton(
icon: Icon(Icons.home,),
onPressed: (){Navigator.push(
context,
MaterialPageRoute(
builder: (context) {
return WelcomeScreen();
},
),
);},
)
]
),
drawer: NavDrawer(),
body:Container(
height: size.height,
child: Column(
children: <Widget>[
const SizedBox(
height: 10,
),
AnimatedOpacity(
duration: const Duration(milliseconds: 200),
opacity: closeTopContainer?0:1,
child: AnimatedContainer(
duration: const Duration(milliseconds: 200),
width: size.width,
alignment: Alignment.topCenter,
height: closeTopContainer?0:categoryHeight,
child: categoriesScroller),
),
Expanded(
child: ListView.builder(
controller: controller,
itemCount: itemsData.length,
physics: BouncingScrollPhysics(),
itemBuilder: (context, index) {
return itemsData[index];
})),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: () {
// Add your onPressed code here!
},
child: const Icon(Icons.add),
backgroundColor: Color(0xFF6D4C41),
),
floatingActionButtonLocation: FloatingActionButtonLocation.centerFloat,
),
);
}
}
void _navigateAndDisplaySelection(BuildContext context) async {
// Navigator.push returns a Future that completes after calling
// Navigator.pop on the Selection Screen.
final result = await Navigator.push(
context,
MaterialPageRoute(builder: (context) => SearchCustomerScreen()),
);
}
class CategoriesScroller extends StatelessWidget {
const CategoriesScroller();
#override
Widget build(BuildContext context) {
final double categoryHeight = MediaQuery.of(context).size.height * 0.35 - 50;
return SingleChildScrollView(
physics: BouncingScrollPhysics(),
// scrollDirection: Axis.horizontal,
child: Container(
margin: const EdgeInsets.symmetric(vertical: 25, horizontal: 25),
child: FittedBox(
fit: BoxFit.fill,
alignment: Alignment.topCenter,
child: Row(
children: <Widget>[
Container(
width: 400,
margin: const EdgeInsets.symmetric(horizontal: 10, vertical: 10),
height: categoryHeight,
decoration: BoxDecoration(color: Color(0XFFc49864), borderRadius: BorderRadius.all(Radius.circular(20.0)),boxShadow: [
BoxShadow(color: Colors.black.withAlpha(100), blurRadius: 10.0),]),
child: Padding(
padding: const EdgeInsets.all(12.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
RoundInputField(
hintText: "Customer Name",
onChanged: (value) {},
),
RoundInputFieldNumber(
hintText: "Phone Number",
icon: Icons.phone,
onChanged: (value) {},
),
],
),
),
),
],
),
),
),
);
}
}
class bottombar extends StatelessWidget {
const bottombar();
#override
Widget build(BuildContext context) {
return Scaffold(
bottomNavigationBar: BottomAppBar(
child: Row(
children: [
IconButton(icon: Icon(Icons.menu), onPressed: () {}),
Spacer(),
IconButton(icon: Icon(Icons.search), onPressed: () {}),
IconButton(icon: Icon(Icons.more_vert), onPressed: () {}),
],
),
),
floatingActionButton:
FloatingActionButton(child: Icon(Icons.add), onPressed: () {}),
floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
);
}
}

The most straight forward way is imho:
embed the widget to be added with showWidgetA ? WidgetA() : Container();
in your button you toggle the value onPressed: () => showWidgetA = !showWidgetA (showWidgetA being bool)

Flutter : How to prevent rebuild of whole Reorderable Listview?

Currently I'm using flutter package 'Reorderables' to show a reorderable listview which contains several images.These images can be deleted from listview through a button , everything works fine. But the listview rebuild everytime when I delete an image. I'm using a class called 'ReorderableListviewManager' with ChangeNotifier to update images and Provider.of<ReorderableListviewManager>(context) to get latest images . The problem now is that using Provider.of<ReorderableListviewManager>(context) makes build() called everytime I delete an image , so the listview rebuid. I koow I
can use consumer to only rebuild part of widget tree, but it seems like that there's no place to put consumer in children of this Listview. Is there a way to rebuild only image but not whole ReorderableListview ? Thanks very much!
Below is my code:
class NotePicturesEditScreen extends StatefulWidget {
final List<Page> notePictures;
final NotePicturesEditBloc bloc;
NotePicturesEditScreen({#required this.notePictures, #required this.bloc});
static Widget create(BuildContext context, List<Page> notePictures) {
return Provider<NotePicturesEditBloc>(
create: (context) => NotePicturesEditBloc(),
child: Consumer<NotePicturesEditBloc>(
builder: (context, bloc, _) =>
ChangeNotifierProvider<ReorderableListviewManager>(
create: (context) => ReorderableListviewManager(),
child: NotePicturesEditScreen(
bloc: bloc,
notePictures: notePictures,
),
)),
dispose: (context, bloc) => bloc.dispose(),
);
}
#override
_NotePicturesEditScreenState createState() => _NotePicturesEditScreenState();
}
class _NotePicturesEditScreenState extends State<NotePicturesEditScreen> {
PreloadPageController _pageController;
ScrollController _reorderableScrollController;
List<Page> notePicturesCopy;
int longPressIndex;
List<double> smallImagesWidth;
double scrollOffset = 0;
_reorderableScrollListener() {
scrollOffset = _reorderableScrollController.offset;
}
#override
void initState() {
Provider.of<ReorderableListviewManager>(context, listen: false)
.notePictures = widget.notePictures;
notePicturesCopy = widget.notePictures;
_reorderableScrollController = ScrollController();
_pageController = PreloadPageController();
_reorderableScrollController.addListener(_reorderableScrollListener);
Provider.of<ReorderableListviewManager>(context, listen: false)
.getSmallImagesWidth(notePicturesCopy, context)
.then((imagesWidth) {
smallImagesWidth = imagesWidth;
});
super.initState();
}
#override
void dispose() {
_pageController.dispose();
_reorderableScrollController.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
ReorderableListviewManager reorderableManager =
Provider.of<ReorderableListviewManager>(context, listen: false);
return SafeArea(
child: Scaffold(
appBar: AppBar(
backgroundColor: Colors.white,
shape: Border(bottom: BorderSide(color: Colors.black12)),
iconTheme: IconThemeData(color: Colors.black87),
elevation: 0,
automaticallyImplyLeading: false,
titleSpacing: 0,
centerTitle: true,
title: Row(
mainAxisAlignment: MainAxisAlignment.start,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Container(
child: IconButton(
padding: EdgeInsets.only(left: 20, right: 12),
onPressed: () => Navigator.of(context).pop(),
icon: Icon(Icons.close),
),
),
Text('編輯',
style: TextStyle(color: Colors.black87, fontSize: 18))
],
),
actions: <Widget>[
FlatButton(
onPressed: () {},
child: Text(
'下一步',
),
)
],
),
backgroundColor: Color(0xffeeeeee),
body: Column(
mainAxisAlignment: MainAxisAlignment.start,
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Spacer(),
StreamBuilder<List<Page>>(
initialData: widget.notePictures,
stream: widget.bloc.notePicturesStream,
builder: (context, snapshot) {
notePicturesCopy = snapshot.data;
return Container(
margin: EdgeInsets.symmetric(horizontal: 20),
height: MediaQuery.of(context).size.height * 0.65,
child: PreloadPageView.builder(
preloadPagesCount: snapshot.data.length,
controller: _pageController,
itemCount: snapshot.data.length,
onPageChanged: (index) {
reorderableManager.updateCurrentIndex(index);
reorderableManager.scrollToCenter(
smallImagesWidth,
index,
scrollOffset,
_reorderableScrollController,
context);
},
itemBuilder: (context, index) {
return Container(
child: Image.memory(
File.fromUri(
snapshot.data[index].polygon.isNotEmpty
? snapshot.data[index]
.documentPreviewImageFileUri
: snapshot.data[index]
.originalPreviewImageFileUri)
.readAsBytesSync(),
gaplessPlayback: true,
alignment: Alignment.center,
),
);
}),
);
},
),
Spacer(),
Container(
height: MediaQuery.of(context).size.height * 0.1,
margin: EdgeInsets.symmetric(horizontal: 20),
child: SingleChildScrollView(
scrollDirection: Axis.horizontal,
child: ReorderableRow(
scrollController: _reorderableScrollController,
buildDraggableFeedback: (context, constraints, __) =>
Container(
width: constraints.maxWidth,
height: constraints.maxHeight,
child: Image.memory(File.fromUri(
notePicturesCopy[longPressIndex]
.polygon
.isNotEmpty
? notePicturesCopy[longPressIndex]
.documentPreviewImageFileUri
: notePicturesCopy[longPressIndex]
.originalPreviewImageFileUri)
.readAsBytesSync()),
),
onReorder: (oldIndex, newIndex) async {
List<Page> result = await widget.bloc.reorderPictures(
oldIndex,
newIndex,
reorderableManager.notePictures);
_pageController.jumpToPage(newIndex);
reorderableManager.updateNotePictures(result);
reorderableManager
.getSmallImagesWidth(result, context)
.then((imagesWidth) {
smallImagesWidth = imagesWidth;
});
},
footer: Container(
width: 32,
height: 32,
margin: EdgeInsets.only(left: 16),
child: SizedBox(
child: FloatingActionButton(
backgroundColor: Colors.white,
elevation: 1,
disabledElevation: 0,
highlightElevation: 1,
child: Icon(Icons.add, color: Colors.blueAccent),
onPressed: notePicturesCopy.length >= 20
? () {
Scaffold.of(context)
.showSnackBar(SnackBar(
content: Text('筆記上限為20頁 !'),
));
}
: () async {
List<Page> notePictures =
await widget.bloc.addPicture(
reorderableManager.notePictures);
List<double> imagesWidth =
await reorderableManager
.getSmallImagesWidth(
notePictures, context);
smallImagesWidth = imagesWidth;
reorderableManager.updateCurrentIndex(
notePictures.length - 1);
reorderableManager
.updateNotePictures(notePictures);
_pageController
.jumpToPage(notePictures.length - 1);
},
),
),
),
children: Provider.of<ReorderableListviewManager>(
context)
.notePictures
.asMap()
.map((index, page) {
return MapEntry(
index,
Consumer<ReorderableListviewManager>(
key: ValueKey('value$index'),
builder: (context, manager, _) =>
GestureDetector(
onTapDown: (_) {
longPressIndex = index;
},
onTap: () {
reorderableManager.scrollToCenter(
smallImagesWidth,
index,
scrollOffset,
_reorderableScrollController,
context);
_pageController.jumpToPage(index);
},
child: Container(
margin: EdgeInsets.only(
left: index == 0 ? 0 : 12),
decoration: BoxDecoration(
border: Border.all(
width: 1.5,
color: index ==
manager
.getCurrentIndex
? Colors.blueAccent
: Colors.transparent)),
child: index + 1 <=
manager.notePictures.length
? Image.memory(
File.fromUri(manager
.notePictures[
index]
.polygon
.isNotEmpty
? manager
.notePictures[
index]
.documentPreviewImageFileUri
: manager
.notePictures[
index]
.originalPreviewImageFileUri)
.readAsBytesSync(),
gaplessPlayback: true,
)
: null),
),
));
})
.values
.toList()),
)),
Spacer(),
Container(
decoration: BoxDecoration(
color: Colors.white,
border: Border(top: BorderSide(color: Colors.black12))),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
FlatButton(
onPressed: () async => await widget.bloc
.cropNotePicture(reorderableManager.notePictures,
_pageController.page.round())
.then((notePictures) {
reorderableManager.updateNotePictures(notePictures);
reorderableManager
.getSmallImagesWidth(notePictures, context)
.then((imagesWidth) {
smallImagesWidth = imagesWidth;
});
}),
child: Column(
children: <Widget>[
Icon(
Icons.crop,
color: Colors.blueAccent,
),
Container(
margin: EdgeInsets.only(top: 1),
child: Text(
'裁切',
style: TextStyle(color: Colors.blueAccent),
),
)
],
),
),
FlatButton(
onPressed: () {
int deleteIndex = _pageController.page.round();
widget.bloc
.deletePicture(
reorderableManager.notePictures, deleteIndex)
.then((notePictures) {
if (deleteIndex == notePictures.length) {
reorderableManager
.updateCurrentIndex(notePictures.length - 1);
}
reorderableManager.updateNotePictures(notePictures);
reorderableManager
.getSmallImagesWidth(notePictures, context)
.then((imagesWidth) {
smallImagesWidth = imagesWidth;
});
if (reorderableManager.notePictures.length == 0) {
Navigator.pop(context);
}
});
},
child: Column(
children: <Widget>[
Icon(
Icons.delete_outline,
color: Colors.blueAccent,
),
Container(
margin: EdgeInsets.only(top: 1),
child: Text(
'刪除',
style: TextStyle(color: Colors.blueAccent),
),
),
],
),
)
],
),
)
],
)),
);
}
}

You can't prevent a rebuild on your ReorderableListView widget because it will be rebuild every time there's an update on the Provider. What you can do here is to keep track the current index of all visible ListView items. When new data should be displayed coming from the Provider, you can retain the current indices of previous ListView items, and add the newly added items at the end of the list, or wherever you like.

I am trying to put gesture dectector in the alert dialog to navigate to next page but the alert box overflows

I am not using any button in alert dialog, so in action how can we prevent the overflow the alert dialog, if am using gesture detector or inkwell to get ontap or onpress function or is there any other method to do it
_showDialog(BuildContext context) {
showDialog(
context: context,
builder: (context) {
return UnicornAlertDialog(
title: Column(
children: <Widget>[
Container(
child: Image.asset('images/done.png'),
),
const SizedBox(height: 15.0),
Container(
child: Text(
'Verify',
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.white,
fontSize: 20.0,
),
),
)
],
),
content: Text('You have successfully verified your mobile number',
textAlign: TextAlign.center,
style: TextStyle(color: Colors.white, fontSize: 15.0)),
gradient: LinearGradient(
colors: <Color>[
Color(0xDD4a00e0),
Color(0xFF8e2de2),
],
begin: Alignment.topCenter,
end: Alignment.bottomCenter,
),
actions: <Widget>[
Container(
child: new GestureDetector(
onTap:(){
Navigator.push(context,
MaterialPageRoute(builder: (context) => ThirdRoute()));
} ,
),
),
]
);
});
}

You are getting overflow error due to GestureDetector used inside actions property of the dialog. If you just want user to tap anywhere on the alertDialog, you can wrap the AlertDialog with GestureDetector. With this, when user taps anywhere on the dialog, it will navigate them to thirdRoute. Working code below:
_showDialog(BuildContext context) {
showDialog(
context: context,
builder: (context) {
return GestureDetector(
child: AlertDialog(
title:
Column(
children: <Widget>[
Container(
child: Image.asset('images/done.png'),
),
const SizedBox(height: 15.0),
Container(
child: Text(
'Verify',
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.black,
fontSize: 20.0,
),
),
)
],
),
content:
Text('You have successfully verified your mobile number',
textAlign: TextAlign.center,
style: TextStyle(color: Colors.black, fontSize: 15.0)),
// gradient: LinearGradient(
// colors: <Color>[
// Color(0xDD4a00e0),
// Color(0xFF8e2de2),
// ],
// begin: Alignment.topCenter,
// end: Alignment.bottomCenter,
// ),
actions: <Widget>[]
),
onTap: () {
Navigator.push(context, MaterialPageRoute(builder: (context) => NextScreen()));
}
);
});
}
Hope this answers your question.

_showDialog(BuildContext context) {
showDialog(
context: context,
builder: (context) {
return GestureDetector(
child: UnicornAlertDialog(
title: Column(
children: <Widget>[
Container(
child: Image.asset('images/done.png'),
),
const SizedBox(height: 15.0),
Container(
child: Text(
'Verify',
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.white,
fontSize: 20.0,
),
),
)
],
),
content: Text(
'You have successfully verified your mobile number',
textAlign: TextAlign.center,
style: TextStyle(color: Colors.white, fontSize: 15.0)),
gradient: LinearGradient(
colors: <Color>[
Color(0xDD4a00e0),
Color(0xFF8e2de2),
],
begin: Alignment.topCenter,
end: Alignment.bottomCenter,
),
actions: <Widget>[ ]),
onTap: () {
Navigator.push(context,
MaterialPageRoute(builder: (context) => ThirdRoute()));
},
);
});
}
Unicorn alert dialog is used for background-color decoration, and since you cannot have gradient color in normal alert dialog, I used this.

code snippet
_showDialog(BuildContext context) {
showDialog(
context: context,
builder: (context) {
return UnicornAlertDialog(
title: GestureDetector(
onTap: () { print("on tap title");},
child: Column(
children: <Widget>[
Container(
child: Image.asset('assets/images/background.jpg'),
),
const SizedBox(height: 15.0),
Container(
child: Text(
'Verify',
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.white,
fontSize: 20.0,
),
),
)
],
),
),
content: GestureDetector(
onTap: () { print("on tap content");},
child: Text('You have successfully verified your mobile number',
textAlign: TextAlign.center,
style: TextStyle(color: Colors.white, fontSize: 15.0)),
),
gradient: LinearGradient(
colors: <Color>[
Color(0xDD4a00e0),
Color(0xFF8e2de2),
],
begin: Alignment.topCenter,
end: Alignment.bottomCenter,
),
actions: <Widget>[
]
);
});
}
full code
import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart';
class UnicornAlertDialog extends StatelessWidget {
const UnicornAlertDialog({
Key key,
#required this.gradient,
this.title,
this.titlePadding,
this.titleTextStyle,
this.content,
this.contentPadding = const EdgeInsets.fromLTRB(24.0, 20.0, 24.0, 24.0),
this.contentTextStyle,
this.actions,
this.backgroundColor,
this.elevation,
this.semanticLabel,
this.shape,
}) : assert(contentPadding != null),
super(key: key);
final Gradient gradient;
final Widget title;
final EdgeInsetsGeometry titlePadding;
final TextStyle titleTextStyle;
final Widget content;
final EdgeInsetsGeometry contentPadding;
final TextStyle contentTextStyle;
final List<Widget> actions;
final Color backgroundColor;
final double elevation;
final String semanticLabel;
final ShapeBorder shape;
#override
Widget build(BuildContext context) {
assert(debugCheckHasMaterialLocalizations(context));
final ThemeData theme = Theme.of(context);
final DialogTheme dialogTheme = DialogTheme.of(context);
final List<Widget> children = <Widget>[];
String label = semanticLabel;
if (title != null) {
children.add(Padding(
padding: titlePadding ?? EdgeInsets.fromLTRB(24.0, 24.0, 24.0, content == null ? 20.0 : 0.0),
child: DefaultTextStyle(
style: titleTextStyle ?? dialogTheme.titleTextStyle ?? theme.textTheme.title,
child: Semantics(
child: title,
namesRoute: true,
container: true,
),
),
));
} else {
switch (defaultTargetPlatform) {
case TargetPlatform.iOS:
label = semanticLabel;
break;
case TargetPlatform.android:
case TargetPlatform.fuchsia:
label = semanticLabel ?? MaterialLocalizations.of(context)?.alertDialogLabel;
}
}
if (content != null) {
children.add(Flexible(
child: Padding(
padding: contentPadding,
child: DefaultTextStyle(
style: contentTextStyle ?? dialogTheme.contentTextStyle ?? theme.textTheme.subhead,
child: content,
),
),
));
}
if (actions != null) {
children.add(ButtonTheme.bar(
child: ButtonBar(
children: actions,
),
));
}
Widget dialogChild = IntrinsicWidth(
child: Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: children,
),
);
if (label != null)
dialogChild = Semantics(
namesRoute: true,
label: label,
child: dialogChild,
);
return Dialog(
backgroundColor: backgroundColor,
gradient: gradient,
elevation: elevation,
shape: shape,
child: dialogChild,
);
}
}
class Dialog extends StatelessWidget {
const Dialog({
Key key,
this.gradient,
this.backgroundColor,
this.elevation,
this.insetAnimationDuration = const Duration(milliseconds: 100),
this.insetAnimationCurve = Curves.decelerate,
this.shape,
this.child,
}) : super(key: key);
final Color backgroundColor;
final double elevation;
final Duration insetAnimationDuration;
final Curve insetAnimationCurve;
final ShapeBorder shape;
final Widget child;
final Gradient gradient;
static const RoundedRectangleBorder _defaultDialogShape =
RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(4.0)));
static const double _defaultElevation = 24.0;
#override
Widget build(BuildContext context) {
final DialogTheme dialogTheme = DialogTheme.of(context);
return AnimatedPadding(
padding: MediaQuery.of(context).viewInsets + const EdgeInsets.symmetric(horizontal: 40.0, vertical: 24.0),
duration: insetAnimationDuration,
curve: insetAnimationCurve,
child: MediaQuery.removeViewInsets(
removeLeft: true,
removeTop: true,
removeRight: true,
removeBottom: true,
context: context,
child: Center(
child: ConstrainedBox(
constraints: const BoxConstraints(minWidth: 280.0),
child: Material(
color: backgroundColor ?? dialogTheme.backgroundColor ?? Theme.of(context).dialogBackgroundColor,
elevation: elevation ?? dialogTheme.elevation ?? _defaultElevation,
shape: shape ?? dialogTheme.shape ?? _defaultDialogShape,
type: MaterialType.card,
child: ClipRRect(
borderRadius: _defaultDialogShape.borderRadius,
child: Container(
decoration: BoxDecoration(
gradient: gradient
),
child: child,
),
),
),
),
),
),
);
}
}
_showDialog(BuildContext context) {
showDialog(
context: context,
builder: (context) {
return UnicornAlertDialog(
title: GestureDetector(
onTap: () { print("on tap title");},
child: Column(
children: <Widget>[
Container(
child: Image.asset('assets/images/background.jpg'),
),
const SizedBox(height: 15.0),
Container(
child: Text(
'Verify',
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.white,
fontSize: 20.0,
),
),
)
],
),
),
content: GestureDetector(
onTap: () { print("on tap content");},
child: Text('You have successfully verified your mobile number',
textAlign: TextAlign.center,
style: TextStyle(color: Colors.white, fontSize: 15.0)),
),
gradient: LinearGradient(
colors: <Color>[
Color(0xDD4a00e0),
Color(0xFF8e2de2),
],
begin: Alignment.topCenter,
end: Alignment.bottomCenter,
),
actions: <Widget>[
]
);
});
}
Future<void> _ackAlert(BuildContext context) {
return showDialog<void>(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: Text('Not in stock'),
content: const Text('This item is no longer available'),
actions: <Widget>[
FlatButton(
child: Text('Ok'),
onPressed: () {
Navigator.of(context).pop();
},
),
],
);
},
);
}
enum ConfirmAction { CANCEL, ACCEPT }
Future<ConfirmAction> _asyncConfirmDialog(BuildContext context) async {
return showDialog<ConfirmAction>(
context: context,
barrierDismissible: false, // user must tap button for close dialog!
builder: (BuildContext context) {
return AlertDialog(
title: Text('Reset settings?'),
content: const Text(
'This will reset your device to its default factory settings.'),
actions: <Widget>[
FlatButton(
child: const Text('CANCEL'),
onPressed: () {
Navigator.of(context).pop(ConfirmAction.CANCEL);
},
),
FlatButton(
child: const Text('ACCEPT'),
onPressed: () {
Navigator.of(context).pop(ConfirmAction.ACCEPT);
},
)
],
);
},
);
}
Future<String> _asyncInputDialog(BuildContext context) async {
String teamName = '';
return showDialog<String>(
context: context,
barrierDismissible: false, // dialog is dismissible with a tap on the barrier
builder: (BuildContext context) {
return AlertDialog(
title: Text('Enter current team'),
content: new Row(
children: <Widget>[
new Expanded(
child: new TextField(
autofocus: true,
decoration: new InputDecoration(
labelText: 'Team Name', hintText: 'eg. Juventus F.C.'),
onChanged: (value) {
teamName = value;
},
))
],
),
actions: <Widget>[
FlatButton(
child: Text('Ok'),
onPressed: () {
Navigator.of(context).pop(teamName);
},
),
],
);
},
);
}
enum Departments { Production, Research, Purchasing, Marketing, Accounting }
Future<Departments> _asyncSimpleDialog(BuildContext context) async {
return await showDialog<Departments>(
context: context,
barrierDismissible: true,
builder: (BuildContext context) {
return SimpleDialog(
title: const Text('Select Departments '),
children: <Widget>[
SimpleDialogOption(
onPressed: () {
Navigator.pop(context, Departments.Production);
},
child: const Text('Production'),
),
SimpleDialogOption(
onPressed: () {
Navigator.pop(context, Departments.Research);
},
child: const Text('Research'),
),
SimpleDialogOption(
onPressed: () {
Navigator.pop(context, Departments.Purchasing);
},
child: const Text('Purchasing'),
),
SimpleDialogOption(
onPressed: () {
Navigator.pop(context, Departments.Marketing);
},
child: const Text('Marketing'),
),
SimpleDialogOption(
onPressed: () {
Navigator.pop(context, Departments.Accounting);
},
child: const Text('Accounting'),
)
],
);
});
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
// TODO: implement build
return new Scaffold(
appBar: AppBar(
title: Text("Dialog"),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new RaisedButton(
onPressed: () {
_showDialog(context);
},
child: const Text("Unicon Dialog"),
),
new RaisedButton(
onPressed: () {
_ackAlert(context);
},
child: const Text("Ack Dialog"),
),
new RaisedButton(
onPressed: () async {
final ConfirmAction action = await _asyncConfirmDialog(context);
print("Confirm Action $action" );
},
child: const Text("Confirm Dialog"),
),
new RaisedButton(
onPressed: () async {
final Departments deptName = await _asyncSimpleDialog(context);
print("Selected Departement is $deptName");
},
child: const Text("Simple dialog"),
),
new RaisedButton(
onPressed: () async {
final String currentTeam = await _asyncInputDialog(context);
print("Current team name is $currentTeam");
},
child: const Text("Input Dialog"),
),
],
),
),
);
}
}
void main() {
runApp(new MaterialApp(home: new MyApp()));
}

While upgrading to dart 2.2.1 on pressed is not working in icon button and raised button

If I pressed a button and open a empty page in flutter which will be locating in the same page but the on pressed is not working
Widget _cameraDisable(){
return Container(
alignment: Alignment.bottomRight,
margin: new EdgeInsets.fromLTRB(0, 0, 0, 30),
child: Visibility(
visible: cameraviewVisbility,
child: RawMaterialButton(
onPressed: () {
_videoOffPage();
setState(() => pressAttention = !pressAttention);
},
child: new Icon(IconData(0xe800, fontFamily: '_kFontFamiiiiiii',
),
color: Theme.Colors.bluecolor,
),
shape: new CircleBorder(),
elevation: 2.0,
fillColor: pressAttention ? Colors.transparent: Colors.white54,
padding: const EdgeInsets.all(15.0),
),
),
);
}
void _videoOffPage(){
setState(() {
Scaffold(
body: new Center(
child: Column(
children: <Widget>[
Container(
alignment: Alignment.center,
color: Colors.white,
child: Image(image: new AssetImage('assets/img/videologo.png')
),
),
],
),
),
);
});
}

For opening a page on button press try like this
on first page only
void _videoOffPage(){
Navigator.push(context, MaterialPageRoute(builder: (context) => secondPage()));}
class secondPage extends StatefulWidget {
#override
_secondPageState createState() => _secondPageState();
}
class _secondPageState extends State<secondPage> {
#override
Widget build(BuildContext context) {
// TODO: implement build
return Scaffold(
body: new Center(
child: Column(
children: <Widget>[
Container(
alignment: Alignment.center,
color: Colors.white,
child: Image(image: new AssetImage('assets/img/videologo.png')
),
),
],
),
),
);
}
}

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

"NoSuchMethodError: The method '>=' " Flutter - android

Please make sure that _counterK is properly initialized, do so by initializing it when declaring it Int _counterK = 0

I solve the problem by changing to the flutter stable channel

Related

Can't solve problem with FloatingActionButton

Dynamically Adding Widgets in list item on button’s on pressed function in Flutter

Flutter : How to prevent rebuild of whole Reorderable Listview?

I am trying to put gesture dectector in the alert dialog to navigate to next page but the alert box overflows

While upgrading to dart 2.2.1 on pressed is not working in icon button and raised button

Categories

Resources