flutter - flutter - 如何在 rflutter_alert 对话框中显示 CircularProgressIndicator
问题描述
我有以下代码。当用户单击“保存”按钮时,将运行 Web 服务。服务运行时,如何在 rflutter_alert 对话框中显示 CircularProgressIndicator?如果 Web 服务失败,我希望警报对话框保持打开状态,以便他们可以重试。
谢谢,
保罗
Future<bool> saveRequest({context, int rId}) {
String _reason = '';
GlobalKey<FormState> _formKey = GlobalKey<FormState>();
TextEditingController reasonController = TextEditingController();
TextStyle _style = TextStyle(
fontFamily: 'Montserrat', fontSize: 18.0, fontWeight: FontWeight.normal);
InputDecoration _textFormFieldDecoration({String hintText, double padding}) =>
InputDecoration(
//contentPadding: EdgeInsets.fromLTRB(8.0, 8.0, 8.0, 8.0),
contentPadding: EdgeInsets.all(padding),
isDense: true,
hintText: hintText,
hintStyle: TextStyle(color: kHintText),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(5)),
),
);
return Alert(
context: context,
title: 'New Request',
//desc: 'Reason',
content: Form(
key: _formKey,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
SizedBox(height: 20.0),
Text('Reason', textAlign: TextAlign.left, style: _style),
SizedBox(height: 10.0),
TextFormField(
validator: (value) {
if (value.isEmpty) {
return "please enter reason";
}
return null;
},
onSaved: (value) {
_reason = value;
},
decoration: _textFormFieldDecoration(
hintText: 'reason for request',
padding: 8.0,
),
controller: reasonController,
),
SizedBox(height: 10.0),
],
),
),
buttons: [
DialogButton(
child:
Text('Save', style: TextStyle(color: Colors.white, fontSize: 20)),
color: kMainColor,
onPressed: () async {
if (_formKey.currentState.validate()) {
_formKey.currentState.save();
var saved = await doSaveRequest(pReason: _reason);
Navigator.pop(context, false);
if (saved.savedOK) {
Navigator.of(context).pop();
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => UserRequests(
rId: rId,
),
),
);
} else {
Navigator.pop(context, false);
}
}
},
),
DialogButton(
child:
Text('Cancel', style: TextStyle(color: Colors.white, fontSize: 20)),
color: kMainColor,
onPressed: () {
Navigator.pop(context, false);
},
),
],
).show();
}
解决方案
您可以在下面复制粘贴运行完整代码
Step 1: 下面的代码使用 3 秒延迟来模拟doSaveRequest()
Step 2: 你可以使用StreamBuilder<bool>
and use _events.add(true);
beforedoSaveRequest()
来显示CircularProgressIndicator()
Step 3: back to Form screen with_events.add(false);
代码片段
Future<bool> doSaveRequest({String pReason}) async {
await Future.delayed(const Duration(seconds: 3), () {});
print("3 secs");
return false;
}
return Alert(
context: context,
title: 'New Request',
//desc: 'Reason',
content: StreamBuilder<bool>(
initialData: false,
stream: _events.stream,
builder: (BuildContext context, AsyncSnapshot<bool> snapshot) {
print(" ${snapshot.data.toString()}");
return snapshot.data
? CircularProgressIndicator()
: Form(
key: _formKey,
...
onPressed: () async {
if (_formKey.currentState.validate()) {
...
_events.add(true);
var saved = await doSaveRequest(pReason: _reason);
if (saved) {
Navigator.pop(context, false);
} else {
_events.add(false);
}
工作演示
完整代码
import 'package:flutter/material.dart';
import 'package:rflutter_alert/rflutter_alert.dart';
import 'dart:async';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
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;
Color kMainColor = Colors.blue;
Color kHintText = Colors.blue;
StreamController<bool> _events;
void _incrementCounter() {
setState(() {
_counter++;
});
}
@override
initState() {
super.initState();
_events = new StreamController<bool>();
}
Future<bool> doSaveRequest({String pReason}) async {
await Future.delayed(const Duration(seconds: 3), () {});
print("3 secs");
return false;
}
Future<bool> saveRequest({context, int rId}) {
String _reason = '';
GlobalKey<FormState> _formKey = GlobalKey<FormState>();
TextEditingController reasonController = TextEditingController();
TextStyle _style = TextStyle(
fontFamily: 'Montserrat',
fontSize: 18.0,
fontWeight: FontWeight.normal);
InputDecoration _textFormFieldDecoration(
{String hintText, double padding}) =>
InputDecoration(
//contentPadding: EdgeInsets.fromLTRB(8.0, 8.0, 8.0, 8.0),
contentPadding: EdgeInsets.all(padding),
isDense: true,
hintText: hintText,
hintStyle: TextStyle(color: kHintText),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(5)),
),
);
return Alert(
context: context,
title: 'New Request',
//desc: 'Reason',
content: StreamBuilder<bool>(
initialData: false,
stream: _events.stream,
builder: (BuildContext context, AsyncSnapshot<bool> snapshot) {
print(" ${snapshot.data.toString()}");
return snapshot.data
? CircularProgressIndicator()
: Form(
key: _formKey,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
SizedBox(height: 20.0),
Text('Reason',
textAlign: TextAlign.left, style: _style),
SizedBox(height: 10.0),
TextFormField(
validator: (value) {
if (value.isEmpty) {
return "please enter reason";
}
return null;
},
onSaved: (value) {
_reason = value;
},
decoration: _textFormFieldDecoration(
hintText: 'reason for request',
padding: 8.0,
),
controller: reasonController,
),
SizedBox(height: 10.0),
],
),
);
}),
buttons: [
DialogButton(
child:
Text('Save', style: TextStyle(color: Colors.white, fontSize: 20)),
color: kMainColor,
onPressed: () async {
if (_formKey.currentState.validate()) {
_formKey.currentState.save();
print(_reason);
_events.add(true);
var saved = await doSaveRequest(pReason: _reason);
if (saved) {
Navigator.pop(context, false);
} else {
_events.add(false);
}
/*if (saved.savedOK) {
Navigator.of(context).pop();
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => UserRequests(
rId: rId,
),
),
);
} else {
Navigator.pop(context, false);
}*/
}
},
),
DialogButton(
child: Text('Cancel',
style: TextStyle(color: Colors.white, fontSize: 20)),
color: kMainColor,
onPressed: () {
Navigator.pop(context, false);
},
),
],
).show();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
RaisedButton(
child: Text('Alert'),
onPressed: () {
saveRequest(context: context, rId: 123);
},
),
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
}
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