Итак, я смотрел учебник YouTube по созданию приложения-календаря в дартс / флаттер. Код, который написан на видео, похоже, не работает для меня. Это как-то связано с созданием одного из виджетов, но я не писал этот конкретный код или не имел большого опыта работы с дротиками или трепетанием. Вот сообщение об ошибке.
I/flutter (10952): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (10952): The following assertion was thrown building HomePage(dirty, dependencies:
I/flutter (10952): [_LocalizationsScope-[GlobalKey#2a61b], _InheritedTheme], state: _HomePageState#6701d):
I/flutter (10952): setState() or markNeedsBuild() called during build.
I/flutter (10952): This Overlay widget cannot be marked as needing to build because the framework is already in the
I/flutter (10952): process of building widgets. A widget can be marked as needing to be built during the build phase
I/flutter (10952): only if one of its ancestors is currently building. This exception is allowed because the framework
I/flutter (10952): builds parent widgets before children, which means a dirty descendant will always be built.
I/flutter (10952): Otherwise, the framework might not visit this widget during this build phase.
I/flutter (10952): The widget on which setState() or markNeedsBuild() was called was:
I/flutter (10952): Overlay-[LabeledGlobalKey<OverlayState>#6d6f2]
I/flutter (10952): The widget which was currently being built when the offending call was made was:
I/flutter (10952): HomePage
I/flutter (10952):
I/flutter (10952): The relevant error-causing widget was:
I/flutter (10952): HomePage
package:hello_world/main.dart:15
I/flutter (10952):
I/flutter (10952): When the exception was thrown, this was the stack:
I/flutter (10952): #0 Element.markNeedsBuild.<anonymous closure>
package:flutter/…/widgets/framework.dart:3896
I/flutter (10952): #1 Element.markNeedsBuild
package:flutter/…/widgets/framework.dart:3911
I/flutter (10952): #2 State.setState
package:flutter/…/widgets/framework.dart:1168
I/flutter (10952): #3 OverlayState.insertAll
package:flutter/…/widgets/overlay.dart:344
I/flutter (10952): #4 OverlayRoute.install
package:flutter/…/widgets/routes.dart:44
I/flutter (10952): #5 TransitionRoute.install
package:flutter/…/widgets/routes.dart:181
I/flutter (10952): #6 ModalRoute.install
package:flutter/…/widgets/routes.dart:959
I/flutter (10952): #7 NavigatorState.push
package:flutter/…/widgets/navigator.dart:1791
I/flutter (10952): #8 showGeneralDialog
package:flutter/…/widgets/routes.dart:1634
I/flutter (10952): #9 showDialog
package:flutter/…/material/dialog.dart:711
I/flutter (10952): #10 _HomePageState._showAddDialog
А вот и сам код:
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:table_calendar/table_calendar.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Calendar',
theme: ThemeData(
primarySwatch: Colors.grey,
),
home: HomePage(),
);
}
}
class HomePage extends StatefulWidget {
@override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
CalendarController _controller;
Map<DateTime,List<dynamic>> _events;
TextEditingController _eventController;
@override
void initState() {
// TODO: implement initState
super.initState();
_controller = CalendarController();
_eventController = TextEditingController();
_events = {};
}
Map<String, dynamic> encodeMap(Map<DateTime, dynamic> map) {
Map<String, dynamic> newMap = {};
map.forEach((key, value) {
newMap[key.toString()] = map[key];
});
return newMap;
}
Map<DateTime, dynamic> decodeMap(Map<String, dynamic> map) {
Map<DateTime, dynamic> newMap = {};
map.forEach((key, value) {
newMap[DateTime.parse(key)] = map[key];
});
return newMap;
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Flutter Calendar'),
),
body: SingleChildScrollView(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
TableCalendar(
events: _events,
initialCalendarFormat: CalendarFormat.month,
calendarStyle: CalendarStyle(
todayColor: Colors.blue,
selectedColor: Theme.of(context).primaryColor,
todayStyle: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 18.0,
color: Colors.white
)
),
calendarController: _controller,
)
],
),
),
floatingActionButton: FloatingActionButton(
child: Icon(Icons.add),
onPressed: _showAddDialog(),
),
);
}
_showAddDialog(){
showDialog(
context: context,
builder: (context) => AlertDialog(
content: TextField(
controller: _eventController,
),
actions: <Widget>[
FlatButton(
child: Text("Save"),
onPressed: (){
if(_eventController.text.isEmpty) return;
setState(() {
if(_events[_controller.selectedDay] != null){
_events[_controller.selectedDay].add
(_eventController.text);
}else{
_events[_controller.selectedDay] = [_eventController.text];
}
});
},
)
]
)
);
}
}