我是 Flutter 的初學者,我正在創建一個演示應用程式,但在該應用程式中,我想在串列小部件中添加另一張卡片(代碼如下所述),但不知何故它顯示了一個錯誤。
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
class Intro extends StatefulWidget {
const Intro({Key? key}) : super(key: key);
@override
_IntroState createState() => _IntroState();
}
class _IntroState extends State<Intro> {
@override
Widget build(BuildContext context) {
return Scaffold(
body: Column(
children:
List<Widget>[
Container(
child: Padding(
padding: const EdgeInsets.all(36.0),
child: Center(
child: Card(
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
const ListTile(
title: Text('Goal'),
),
Row(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
TextButton(
child: const Text('>'),
onPressed: () {
showAlertDialog(context);
},
),
const SizedBox(width: 8),
],
),
],
),
),
),
),
),
Container(
child: Padding(
padding: const EdgeInsets.all(36.0),
child: Center(
child: Card(
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
const ListTile(
title: Text('objective'),
),
Row(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
TextButton(
child: const Text('>'),
onPressed: () {
showAlertDialog1(context);
},
),
const SizedBox(width: 8),
],
),
],
),
),
),
),
),
]
)
);
}
}
showAlertDialog(BuildContext context) {
// Create button
Widget okButton = FlatButton(
child: Text("OK"),
onPressed: () {
Navigator.of(context).pop(MaterialPageRoute(builder: (context) => Intro()));
},
);
// Create AlertDialog
AlertDialog alert = AlertDialog(
title: Text("Simple Alert"),
content: Text("This is an alert message."),
actions: [
okButton,
],
);
// show the dialog
showDialog(
context: context,
builder: (BuildContext context) {
return alert;
},
);
}
showAlertDialog1(BuildContext context) {
// Create button
Widget okButton = FlatButton(
child: Text("OK"),
onPressed: () {
Navigator.of(context).pop(MaterialPageRoute(builder: (context) => Intro()));
},
);
// Create AlertDialog
AlertDialog alert = AlertDialog(
title: Text("Simple Alert"),
content: Text("This is an alert message."),
actions: [
okButton,
],
);
// show the dialog
showDialog(
context: context,
builder: (BuildContext context) {
return alert;
},
);
}
另外,我嘗試創建一個小部件回圈,但它仍然在小部件構建(BuildContext 背景關系)中顯示錯誤!
所以告訴我一個成功運行這段代碼的方法!
uj5u.com熱心網友回復:
洗掉List<widget>后Column( children:
試試這個代碼:
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
class Intro extends StatefulWidget {
const Intro({Key? key}) : super(key: key);
@override
_IntroState createState() => _IntroState();
}
class _IntroState extends State<Intro> {
@override
Widget build(BuildContext context) {
return Scaffold(
body: Column(
children:[
Container(
child: Padding(
padding: const EdgeInsets.all(36.0),
child: Center(
child: Card(
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
const ListTile(
title: Text('Goal'),
),
Row(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
TextButton(
child: const Text('>'),
onPressed: () {
showAlertDialog(context);
},
),
const SizedBox(width: 8),
],
),
],
),
),
),
),
),
Container(
child: Padding(
padding: const EdgeInsets.all(36.0),
child: Center(
child: Card(
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
const ListTile(
title: Text('objective'),
),
Row(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
TextButton(
child: const Text('>'),
onPressed: () {
showAlertDialog1(context);
},
),
const SizedBox(width: 8),
],
),
],
),
),
),
),
),
]
)
);
}}}
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標籤:安卓 扑 列表显示 小部件 android-cardview
