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class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void initState(){
super.initState();
WidgetsBinding.instance.addPostFrameCallback(
(_) => _showStartDialog()
);
}
Future<void> _showStartDialog() async {
return showDialog<void>(
context: context,
barrierDismissible: false, // user must tap button!
builder: (BuildContext context) {
return AlertDialog(
title: Text('AlertDialog Title'),
content: SingleChildScrollView(
child: ListBody(
children: <Widget>[
Text('This is a demo alert dialog.'),
Text('Would you like to approve of this message?'),
],
),
),
actions: <Widget>[
TextButton(
child: Text('Approve'),
onPressed: () {
Navigator.of(context).pop();
},
),
],
);
},
);
}
void _incrementCounter() {
setState(() {
_counter++;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
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BuildContext dialogContext; // <<----
showDialog(
context: context, // <<----
barrierDismissible: false,
builder: (BuildContext context) {
dialogContext = context;
return Dialog(
child: new Row(
mainAxisSize: MainAxisSize.min,
children: [
new CircularProgressIndicator(),
new Text("Loading"),
],
),
);
},
);
await _longOperation();
Navigator.pop(dialogContext); // <<----
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@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text("Testing")),
body: Center(
child: RaisedButton(
child: Text("Show dialog"),
onPressed: () {
showDialog(
context: context,
builder: (context) {
return Dialog(
shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(40)),
elevation: 16,
child: Container(
height: 400.0,
width: 360.0,
child: ListView(
children: <Widget>[
SizedBox(height: 20),
Center(
child: Text(
"Leaderboard",
style: TextStyle(fontSize: 24, color: Colors.blue, fontWeight: FontWeight.bold),
),
),
SizedBox(height: 20),
_buildName(imageAsset: 'assets/chocolate.jpg', name: "Name 1", score: 1000),
_buildName(imageAsset: 'assets/chocolate.jpg', name: "Name 2", score: 2000),
_buildName(imageAsset: 'assets/chocolate.jpg', name: "Name 3", score: 3000),
_buildName(imageAsset: 'assets/chocolate.jpg', name: "Name 4", score: 4000),
_buildName(imageAsset: 'assets/chocolate.jpg', name: "Name 5", score: 5000),
_buildName(imageAsset: 'assets/chocolate.jpg', name: "Name 6", score: 6000),
],
),
),
);
},
);
},
),
),
);
}
Widget _buildName({String imageAsset, String name, double score}) {
return Padding(
padding: const EdgeInsets.symmetric(horizontal: 20.0),
child: Column(
children: <Widget>[
SizedBox(height: 12),
Container(height: 2, color: Colors.redAccent),
SizedBox(height: 12),
Row(
children: <Widget>[
CircleAvatar(
backgroundImage: AssetImage(imageAsset),
radius: 30,
),
SizedBox(width: 12),
Text(name),
Spacer(),
Container(
padding: EdgeInsets.symmetric(vertical: 8, horizontal: 20),
child: Text("${score}"),
decoration: BoxDecoration(
color: Colors.yellow[900],
borderRadius: BorderRadius.circular(20),
),
),
],
),
],
),
);
}
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import 'dart:async';
import 'package:flutter/material.dart';
void main() {
runApp(new MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Trial',
home: Scaffold(
appBar: AppBar(title: Text('List scroll')), body: new MyHome()));
}
}
class MyHome extends StatelessWidget { // Wrapper Widget
@override
Widget build(BuildContext context) {
Future.delayed(Duration.zero, () => showAlert(context));
return Container(
child: Text("Hello world"),
);
}
void showAlert(BuildContext context) {
showDialog(
context: context,
builder: (context) => AlertDialog(
content: Text("hi"),
));
}
}
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class XxxxxWidget extends StatelessWidget {
@override
Widget build(BuildContext context) {
// [NG]We want to show dialog on Container widget.
Future.delayed(Duration.zero, () => showMyDialog(context)); // import 'dart:async';
return Container(
child: FlatButton( . //same as question