Dart 动态更改AlertDialog标题(showDialog())
我正在向用户显示一个对话框,我想在单击对话框的正面按钮时更改对话框的标题,但我如何才能做到这一点 因为对话框在屏幕上已经可见,并且Dart 动态更改AlertDialog标题(showDialog()),dart,flutter,flutter-layout,Dart,Flutter,Flutter Layout,我正在向用户显示一个对话框,我想在单击对话框的正面按钮时更改对话框的标题,但我如何才能做到这一点 因为对话框在屏幕上已经可见,并且setState()将无法执行任何操作 代码: String title=“旧标题”//member变量 升起按钮(按下时:(){ showDialog(上下文:上下文,生成器:(上下文){ 返回警报对话框(标题:文本(标题),操作:[FlatButton(按下时)(){ 设置状态(()=>title=“新标题”); },子项:文本(“更改”)],); }); },子
setState()
将无法执行任何操作
代码:
String title=“旧标题”//member变量
升起按钮(按下时:(){
showDialog(上下文:上下文,生成器:(上下文){
返回警报对话框(标题:文本(标题),操作:[FlatButton(按下时)(){
设置状态(()=>title=“新标题”);
},子项:文本(“更改”)],);
});
},子项:文本(“更改”),)
您可以创建一个StatefulWidget
,返回警报对话框
。点击更改按钮时,setState
将更新对话框的文本值
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Dynamic Dialog',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Dynamic Dialog'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'Press the FAB to present the dialog!',
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: () {
showDialog(
context: context,
builder: ((BuildContext context) {
return DynamicDialog(title: 'Original Title');
}));
},
tooltip: 'Show Dialog',
child: Icon(Icons.add),
),
);
}
}
class DynamicDialog extends StatefulWidget {
DynamicDialog({this.title});
final String title;
@override
_DynamicDialogState createState() => _DynamicDialogState();
}
class _DynamicDialogState extends State<DynamicDialog> {
String _title;
@override
void initState() {
_title = widget.title;
super.initState();
}
@override
Widget build(BuildContext context) {
return AlertDialog(
title: Text(_title),
actions: <Widget>[
FlatButton(
onPressed: () {
final newText = 'Updated Title!';
setState(() {
_title = newText;
});
},
child: Text('Change'))
],
);
}
}
导入“包装:颤振/材料.省道”;
void main()=>runApp(MyApp());
类MyApp扩展了无状态小部件{
@凌驾
小部件构建(构建上下文){
返回材料PP(
标题:“颤振动态对话框”,
主题:主题数据(
主样本:颜色。蓝色,
),
主页:MyHomePage(标题:“颤振动态对话框”),
);
}
}
类MyHomePage扩展StatefulWidget{
MyHomePage({Key,this.title}):超级(Key:Key);
最后的字符串标题;
@凌驾
_MyHomePageState createState()=>\u MyHomePageState();
}
类_MyHomePageState扩展状态{
@凌驾
小部件构建(构建上下文){
返回脚手架(
appBar:appBar(
标题:文本(widget.title),
),
正文:中(
子:列(
mainAxisAlignment:mainAxisAlignment.center,
儿童:[
正文(
'按FAB以显示对话框!',
),
],
),
),
浮动操作按钮:浮动操作按钮(
已按下:(){
显示对话框(
上下文:上下文,
生成器:((构建上下文){
返回DynamicDialog(标题:“原始标题”);
}));
},
工具提示:“显示对话框”,
子:图标(Icons.add),
),
);
}
}
类DynamicDialog扩展StatefulWidget{
动态对话框({this.title});
最后的字符串标题;
@凌驾
_DynamicDialogState createState()=>\u DynamicDialogState();
}
类_DynamicDialogState扩展状态{
字符串标题;
@凌驾
void initState(){
_title=widget.title;
super.initState();
}
@凌驾
小部件构建(构建上下文){
返回警报对话框(
标题:文本(_标题),
行动:[
扁平按钮(
已按下:(){
最终新文本='更新标题!';
设置状态(){
_标题=新文本;
});
},
子项:文本('Change'))
],
);
}
}
您可以这样做-无需创建其他小部件
RaisedButton(
onPressed: () {
showDialog(
context: context,
builder: (context) {
StreamController<String> controller = StreamController<String>.broadcast();
return AlertDialog(
title: StreamBuilder(
stream: controller.stream,
builder: (BuildContext context, AsyncSnapshot<String> snapshot){
return Text(snapshot.hasData ? snapshot.data : 'Title');
}),
actions: [
FlatButton(
onPressed: () {
controller.add('New Title');
},
child: Text('Change'))
],
);
});
},
child: Text('Change'),
);
RaisedButton(
已按下:(){
显示对话框(
上下文:上下文,
生成器:(上下文){
StreamController=StreamController.broadcast();
返回警报对话框(
标题:StreamBuilder(
stream:controller.stream,
生成器:(BuildContext上下文,异步快照){
返回文本(snapshot.hasData?snapshot.data:'Title');
}),
行动:[
扁平按钮(
已按下:(){
控制器。添加(“新标题”);
},
子项:文本('Change'))
],
);
});
},
子项:文本('Change'),
);
显示对话框(
禁止:错误,
上下文:上下文,
生成器:(上下文){
返回状态生成器(
生成器:(上下文,设置状态){
返回警报对话框(
标题:文本(标题),
行动:[
扁平按钮(
已按下:(){
设置状态(()=>title=“新标题”);
},
子项:文本(“更改”))
],
);
},
);
},
);
简短甜美,当然有效,谢谢。
RaisedButton(
onPressed: () {
showDialog(
context: context,
builder: (context) {
StreamController<String> controller = StreamController<String>.broadcast();
return AlertDialog(
title: StreamBuilder(
stream: controller.stream,
builder: (BuildContext context, AsyncSnapshot<String> snapshot){
return Text(snapshot.hasData ? snapshot.data : 'Title');
}),
actions: [
FlatButton(
onPressed: () {
controller.add('New Title');
},
child: Text('Change'))
],
);
});
},
child: Text('Change'),
);
showDialog(
barrierDismissible: false,
context: context,
builder: (context) {
return StatefulBuilder(
builder: (context, setState) {
return AlertDialog(
title: Text(title),
actions: <Widget>[
FlatButton(
onPressed: () {
setState(() => title = "New Title");
},
child: Text("Change"))
],
);
},
);
},
);