本文介绍了如何在屏幕中央的所有小部件顶部显示CircularProgressIndicator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
我想在所有小部件顶部的屏幕中央显示 CircularProgressIndicator .它应该像叠加层.
Hi I want to display the CircularProgressIndicator in centre of my screen on top of all widget. it should be like overlay.
现在，当 CircularProgressIndicator 可见时，所有小部件都会向下移动一点以显示 CircularProgressIndicator .我希望它应该覆盖.有人知道怎么做吗?
Right now when CircularProgressIndicator is visible all widgets move down a bit to display CircularProgressIndicator . I want it should be overlay. Does anyone know how to do that ?
import 'package:flutter/material.dart';
import 'package:roomie/auth/Auth.dart';
class ForgotPasswordScreen extends StatefulWidget {
@override
State<StatefulWidget> createState() {
return ForgotPasswordScreenState();
}
}
class ForgotPasswordScreenState extends State<ForgotPasswordScreen> {
var emailController = new TextEditingController();
var authHandler = new Auth();
bool isLoading = false;
@override
Widget build(BuildContext context) {
return new Scaffold(
body: Container(
height: MediaQuery.of(context).size.height,
decoration: BoxDecoration(
color: Colors.white,
),
child: new Column(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisSize: MainAxisSize.max,
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Row(
children: <Widget>[
new Expanded(
child: isLoading
? Center(child: CircularProgressIndicator())
: new Container()),
],
),
new Row(
children: <Widget>[
new Expanded(
child: new Padding(
padding: const EdgeInsets.only(left: 40.0),
child: new Text(
"EMAIL",
style: TextStyle(
fontWeight: FontWeight.bold,
color: Colors.redAccent,
fontSize: 15.0,
),
),
),
),
],
),
new Container(
width: MediaQuery.of(context).size.width,
margin:
const EdgeInsets.only(left: 40.0, right: 40.0, top: 10.0),
alignment: Alignment.center,
decoration: BoxDecoration(
border: Border(
bottom: BorderSide(
color: Colors.redAccent,
width: 0.5,
style: BorderStyle.solid),
),
),
padding: const EdgeInsets.only(left: 0.0, right: 10.0),
child: new Row(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
new Expanded(
child: TextField(
controller: emailController,
textAlign: TextAlign.left,
decoration: InputDecoration(
border: InputBorder.none,
hintText: 'PLEASE ENTER YOUR EMAIL',
hintStyle: TextStyle(color: Colors.grey),
),
),
),
],
),
),
Divider(
height: 24.0,
),
new Container(
width: MediaQuery.of(context).size.width,
margin:
const EdgeInsets.only(left: 30.0, right: 30.0, top: 20.0),
alignment: Alignment.center,
child: new Row(
children: <Widget>[
new Expanded(
child: new FlatButton(
shape: new RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(30.0),
),
color: Colors.redAccent,
onPressed: () {
setState(() {
isLoading = true;
});
authHandler
.sendPasswordResetEmail(emailController.text)
.then((void nothing) async {
await showDialog(
context: context,
builder: (BuildContext context) {
// return object of type Dialog
return AlertDialog(
content: new Text(
"Password reset email has been sent."),
actions: <Widget>[
// usually buttons at the bottom of the dialog
new FlatButton(
child: new Text("OK"),
onPressed: () {
Navigator.pop(context);
},
),
],
);
},
);
Navigator.pop(context);
setState(() {
isLoading = false;
});
}).catchError((e) => print(e));
},
child: new Container(
padding: const EdgeInsets.symmetric(
vertical: 20.0,
horizontal: 20.0,
),
child: new Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Expanded(
child: Text(
"FORGOT PASSWORD",
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.white,
fontWeight: FontWeight.bold),
),
),
],
),
),
),
),
],
),
),
],
)));
}
}
推荐答案
堆栈是您想要的:
https://docs.flutter.io/flutter/widgets/Stack-class.html
@override
Widget build(BuildContext context) {
return new Scaffold(
body: Stack(
children:<Widget>[ Container(
height: MediaQuery.of(context).size.height,
decoration: BoxDecoration(
color: Colors.white,
),
child: new Column(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisSize: MainAxisSize.max,
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Row(
children: <Widget>[
new Expanded(
child: new Padding(
padding: const EdgeInsets.only(left: 40.0),
child: new Text(
"EMAIL",
style: TextStyle(
fontWeight: FontWeight.bold,
color: Colors.redAccent,
fontSize: 15.0,
),
),
),
),
],
),
new Container(
width: MediaQuery.of(context).size.width,
margin:
const EdgeInsets.only(left: 40.0, right: 40.0, top: 10.0),
alignment: Alignment.center,
decoration: BoxDecoration(
border: Border(
bottom: BorderSide(
color: Colors.redAccent,
width: 0.5,
style: BorderStyle.solid),
),
),
padding: const EdgeInsets.only(left: 0.0, right: 10.0),
child: new Row(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
new Expanded(
child: TextField(
controller: emailController,
textAlign: TextAlign.left,
decoration: InputDecoration(
border: InputBorder.none,
hintText: 'PLEASE ENTER YOUR EMAIL',
hintStyle: TextStyle(color: Colors.grey),
),
),
),
],
),
),
Divider(
height: 24.0,
),
new Container(
width: MediaQuery.of(context).size.width,
margin:
const EdgeInsets.only(left: 30.0, right: 30.0, top: 20.0),
alignment: Alignment.center,
child: new Row(
children: <Widget>[
new Expanded(
child: new FlatButton(
shape: new RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(30.0),
),
color: Colors.redAccent,
onPressed: () {
setState(() {
isLoading = true;
});
authHandler
.sendPasswordResetEmail(emailController.text)
.then((void nothing) async {
await showDialog(
context: context,
builder: (BuildContext context) {
// return object of type Dialog
return AlertDialog(
content: new Text(
"Password reset email has been sent."),
actions: <Widget>[
// usually buttons at the bottom of the dialog
new FlatButton(
child: new Text("OK"),
onPressed: () {
Navigator.pop(context);
},
),
],
);
},
);
Navigator.pop(context);
setState(() {
isLoading = false;
});
}).catchError((e) => print(e));
},
child: new Container(
padding: const EdgeInsets.symmetric(
vertical: 20.0,
horizontal: 20.0,
),
child: new Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Expanded(
child: Text(
"FORGOT PASSWORD",
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.white,
fontWeight: FontWeight.bold),
),
),
],
),
),
),
),
],
),
),
],
)),
isLoading ? Container(
color: Colors.black.withOpacity(0.5),
child: Center(
child: CircularProgressIndicator(),
),
) : Container()
],
));
}
这篇关于如何在屏幕中央的所有小部件顶部显示CircularProgressIndicator的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！