Flutter-动态添加需要更改状态的小部件 [英] Flutter - Dynamically adding widget that needs to change state as well
本文介绍了Flutter-动态添加需要更改状态的小部件的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我要实现的目标解释如下:通过单击一个按钮显示几个小部件.动态显示的窗口小部件基本上是带有图标作为子元素的FlatButtons.因此,当我单击这些按钮时,我希望更改图标.但是,在测试时-我发现它们的状态没有改变.下面是示例代码
What I want to achieve is explained below:- To show several widgets by clicking a button. The dynamically displayed widgets are basically FlatButtons with Icons as child. So when I click these buttons, I want the icon to change. However, on testing it - I found that their state doesn't change. Below is a sample code
import 'package:flutter/material.dart';
class Test extends StatefulWidget {
@override
_TestState createState() => _TestState();
}
class _TestState extends State<Test> {
IconData icon;
List<Widget> w;
void initState() {
super.initState();
w = List();
}
Widget getWidget() {
icon = Icons.play_arrow;
return Center(
child: FlatButton(
child: Icon(
icon,
color: Colors.black,
),
onPressed: () {
setState(() {
icon = Icons.pause;
});
},
)
);
}
@override
Widget build(BuildContext context) {
//w = Widget();
return Scaffold(
appBar: AppBar(
title: Text('Speech Aid'),
),
body: Column(
children: <Widget>[
Center(
child: FlatButton(
child: Text('Text'),
onPressed: () {
setState(() {
List<Widget> w1 = List();
w1.add(getWidget());
w = w1;
});
},
)
),
...w,
],
),
);
}
}
推荐答案
这可能对您有帮助
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Test(),
);
}
}
class Test extends StatefulWidget {
@override
_TestState createState() => _TestState();
}
class _TestState extends State<Test> {
List<Widget> playButtonList;
void initState() {
playButtonList = <Widget>[];
super.initState();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Speech Aid'),
),
body: Column(
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
FlatButton(
child: Text('Add Play Button'),
color: Colors.black26,
onPressed: () {
setState(() {
playButtonList.add(PlayButton());
});
},
),
Expanded(
child: ListView.builder(
itemCount: playButtonList.length,
itemBuilder: (context, index) => playButtonList[index],
),
)
],
),
);
}
}
class PlayButton extends StatefulWidget {
@override
_PlayButtonState createState() => _PlayButtonState();
}
class _PlayButtonState extends State<PlayButton> {
IconData icon;
@override
void initState() {
icon = Icons.play_arrow;
super.initState();
}
@override
Widget build(BuildContext context) {
return Center(
child: FlatButton(
child: Icon(icon),
onPressed: () {
setState(() {
if (icon == Icons.play_arrow)
icon = Icons.pause;
else
icon = Icons.play_arrow;
});
},
),
);
}
}
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