Flutter - 自定义警报对话框未显示
Flutter - custom alert dialog not showing
我正在使用 flutter/Dart 和从 Github 获得的 Custom Show Dialog class 构建一个 custom alert dialog，出于某种原因，对话框是没有显示。
问：如何让对话框正常显示？
PS resultsDialog(a,b) 在别处单击按钮时被调用。
这是我的警报对话框代码：
Future<void> resultsDialog(String sq, String sl) async {
BuildContext ctx;
CustomAlertDialog dialog = new CustomAlertDialog(
content: Material(
type: MaterialType.card,
child: new Container(
margin: EdgeInsets.only(left: 26.0, right: 26.0),
decoration: new BoxDecoration(
shape: BoxShape.rectangle,
color: const Color(0xFFFFFF),
borderRadius:
new BorderRadius.all(new Radius.circular(32.0)),
),
child: new Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
// dialog top
new Expanded(
//...
),
// dialog center row
new Expanded(
//...
),
// dialog bottom row
new Expanded(
//...
),
],
),
),
),
);
customShowDialog(context: ctx, child: dialog);
}
预期结果：
PS 我处理了内部行，所以这里的问题只是让对话框显示并防止它被关闭，仅此而已
您需要从父窗口小部件传递上下文
并在您的 resultsDialog 中添加一个参数 BuildContext ctx
您可以复制粘贴 运行 完整代码
代码片段
void _incrementCounter() {
resultsDialog(context, "a", "b");
setState(() {
Future<void> resultsDialog(BuildContext ctx, String sq, String sl) async {
//BuildContext ctx;
CustomAlertDialog dialog = new CustomAlertDialog(
content: Material(
type: MaterialType.card,
child: new Container(
margin: EdgeInsets.only(left: 26.0, right: 26.0),
decoration: new BoxDecoration(
shape: BoxShape.rectangle,
color: const Color(0xFFFFFF),
borderRadius:
new BorderRadius.all(new Radius.circular(32.0)),
),
child: new Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
// dialog top
Text('Dialog OK'),
Text('${sq}'),
Text('${sl}'),
],
),
),
),
);
customShowDialog(context: ctx, child: dialog);
}
工作演示
完整代码
import 'package:flutter/material.dart';
import 'dart:async';
import 'dart:ui';
import 'package:flutter/foundation.dart';
import 'package:flutter/widgets.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
resultsDialog(context, "a", "b");
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Invoke "debug painting" (press "p" in the console, choose the
// "Toggle Debug Paint" action from the Flutter Inspector in Android
// Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
// to see the wireframe for each widget.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.display1,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
Future<void> resultsDialog(BuildContext ctx, String sq, String sl) async {
//BuildContext ctx;
CustomAlertDialog dialog = new CustomAlertDialog(
content: Material(
type: MaterialType.card,
child: new Container(
margin: EdgeInsets.only(left: 26.0, right: 26.0),
decoration: new BoxDecoration(
shape: BoxShape.rectangle,
color: const Color(0xFFFFFF),
borderRadius:
new BorderRadius.all(new Radius.circular(32.0)),
),
child: new Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
// dialog top
Text('Dialog OK'),
Text('${sq}'),
Text('${sl}'),
],
),
),
),
);
customShowDialog(context: ctx, child: dialog);
}
// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Examples can assume:
// enum Department { treasury, state }
/// A material design dialog.
///
/// This dialog widget does not have any opinion about the contents of the
/// dialog. Rather than using this widget directly, consider using [AlertDialog]
/// or [SimpleDialog], which implement specific kinds of material design
/// dialogs.
///
/// See also:
///
/// * [AlertDialog], for dialogs that have a message and some buttons.
/// * [SimpleDialog], for dialogs that offer a variety of options.
/// * [showDialog], which actually displays the dialog and returns its result.
/// * <https://material.google.com/components/dialogs.html>
class Dialog extends StatelessWidget {
/// Creates a dialog.
///
/// Typically used in conjunction with [showDialog].
const Dialog({
Key key,
this.child,
this.insetAnimationDuration: const Duration(milliseconds: 100),
this.insetAnimationCurve: Curves.decelerate,
}) : super(key: key);
/// The widget below this widget in the tree.
///
/// {@macro flutter.widgets.child}
final Widget child;
/// The duration of the animation to show when the system keyboard intrudes
/// into the space that the dialog is placed in.
///
/// Defaults to 100 milliseconds.
final Duration insetAnimationDuration;
/// The curve to use for the animation shown when the system keyboard intrudes
/// into the space that the dialog is placed in.
///
/// Defaults to [Curves.fastOutSlowIn].
final Curve insetAnimationCurve;
Color _getColor(BuildContext context) {
return Theme.of(context).dialogBackgroundColor;
}
@override
Widget build(BuildContext context) {
return new AnimatedPadding(
padding: MediaQuery.of(context).viewInsets +
const EdgeInsets.symmetric(horizontal: 40.0, vertical: 24.0),
duration: insetAnimationDuration,
curve: insetAnimationCurve,
child: new MediaQuery.removeViewInsets(
removeLeft: true,
removeTop: true,
removeRight: true,
removeBottom: true,
context: context,
child: new Center(
child: new ConstrainedBox(
constraints: const BoxConstraints(minWidth: 280.0),
child: new Material(
borderRadius: BorderRadius.all(Radius.circular(20.0)),
elevation: 30.0,
color: _getColor(context),
type: MaterialType.card,
child: child,
),
),
),
),
);
}
}
/// A material design alert dialog.
///
/// An alert dialog informs the user about situations that require
/// acknowledgement. An alert dialog has an optional title and an optional list
/// of actions. The title is displayed above the content and the actions are
/// displayed below the content.
///
/// If the content is too large to fit on the screen vertically, the dialog will
/// display the title and the actions and let the content overflow. Consider
/// using a scrolling widget, such as [ListView], for [content] to avoid
/// overflow.
///
/// For dialogs that offer the user a choice between several options, consider
/// using a [SimpleDialog].
///
/// Typically passed as the child widget to [showDialog], which displays the
/// dialog.
///
/// ## Sample code
///
/// This snippet shows a method in a [State] which, when called, displays a dialog box
/// and returns a [Future] that completes when the dialog is dismissed.
///
/// ```dart
/// Future<Null> _neverSatisfied() async {
/// return showDialog<Null>(
/// context: context,
/// barrierDismissible: false, // user must tap button!
/// builder: (BuildContext context) {
/// return new AlertDialog(
/// title: new Text('Rewind and remember'),
/// content: new SingleChildScrollView(
/// child: new ListBody(
/// children: <Widget>[
/// new Text('You will never be satisfied.'),
/// new Text('You\’re like me. I’m never satisfied.'),
/// ],
/// ),
/// ),
/// actions: <Widget>[
/// new FlatButton(
/// child: new Text('Regret'),
/// onPressed: () {
/// Navigator.of(context).pop();
/// },
/// ),
/// ],
/// );
/// },
/// );
/// }
/// ```
///
/// See also:
///
/// * [SimpleDialog], which handles the scrolling of the contents but has no [actions].
/// * [Dialog], on which [AlertDialog] and [SimpleDialog] are based.
/// * [showDialog], which actually displays the dialog and returns its result.
/// * <https://material.google.com/components/dialogs.html#dialogs-alerts>
class CustomAlertDialog extends StatelessWidget {
/// Creates an alert dialog.
///
/// Typically used in conjunction with [showDialog].
///
/// The [contentPadding] must not be null. The [titlePadding] defaults to
/// null, which implies a default that depends on the values of the other
/// properties. See the documentation of [titlePadding] for details.
const CustomAlertDialog({
Key key,
this.title,
this.titlePadding,
this.content,
this.contentPadding: const EdgeInsets.fromLTRB(24.0, 20.0, 24.0, 24.0),
this.actions,
this.semanticLabel,
}) : assert(contentPadding != null),
super(key: key);
/// The (optional) title of the dialog is displayed in a large font at the top
/// of the dialog.
///
/// Typically a [Text] widget.
final Widget title;
/// Padding around the title.
///
/// If there is no title, no padding will be provided. Otherwise, this padding
/// is used.
///
/// This property defaults to providing 24 pixels on the top, left, and right
/// of the title. If the [content] is not null, then no bottom padding is
/// provided (but see [contentPadding]). If it _is_ null, then an extra 20
/// pixels of bottom padding is added to separate the [title] from the
/// [actions].
final EdgeInsetsGeometry titlePadding;
/// The (optional) content of the dialog is displayed in the center of the
/// dialog in a lighter font.
///
/// Typically, this is a [ListView] containing the contents of the dialog.
/// Using a [ListView] ensures that the contents can scroll if they are too
/// big to fit on the display.
final Widget content;
/// Padding around the content.
///
/// If there is no content, no padding will be provided. Otherwise, padding of
/// 20 pixels is provided above the content to separate the content from the
/// title, and padding of 24 pixels is provided on the left, right, and bottom
/// to separate the content from the other edges of the dialog.
final EdgeInsetsGeometry contentPadding;
/// The (optional) set of actions that are displayed at the bottom of the
/// dialog.
///
/// Typically this is a list of [FlatButton] widgets.
///
/// These widgets will be wrapped in a [ButtonBar], which introduces 8 pixels
/// of padding on each side.
///
/// If the [title] is not null but the [content] _is_ null, then an extra 20
/// pixels of padding is added above the [ButtonBar] to separate the [title]
/// from the [actions].
final List<Widget> actions;
/// The semantic label of the dialog used by accessibility frameworks to
/// announce screen transitions when the dialog is opened and closed.
///
/// If this label is not provided, a semantic label will be infered from the
/// [title] if it is not null. If there is no title, the label will be taken
/// from [MaterialLocalizations.alertDialogLabel].
///
/// See also:
///
/// * [SemanticsConfiguration.isRouteName], for a description of how this
/// value is used.
final String semanticLabel;
@override
Widget build(BuildContext context) {
final List<Widget> children = <Widget>[];
String label = semanticLabel;
if (title != null) {
children.add(new Padding(
padding: titlePadding ??
new EdgeInsets.fromLTRB(
24.0, 24.0, 24.0, content == null ? 20.0 : 0.0),
child: new DefaultTextStyle(
style: Theme.of(context).textTheme.title,
child: new Semantics(child: title, namesRoute: true),
),
));
} else {
switch (defaultTargetPlatform) {
case TargetPlatform.iOS:
label = semanticLabel;
break;
case TargetPlatform.android:
case TargetPlatform.fuchsia:
label = semanticLabel ??
MaterialLocalizations.of(context)?.alertDialogLabel;
}
}
if (content != null) {
children.add(new Flexible(
child: new Padding(
padding: contentPadding,
child: new DefaultTextStyle(
style: Theme.of(context).textTheme.subhead,
child: content,
),
),
));
}
if (actions != null) {
children.add(new ButtonTheme.bar(
child: new ButtonBar(
children: actions,
),
));
}
Widget dialogChild = new IntrinsicWidth(
child: new Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: children,
),
);
if (label != null)
dialogChild =
new Semantics(namesRoute: true, label: label, child: dialogChild);
return new Dialog(child: dialogChild);
}
}
/// An option used in a [SimpleDialog].
///
/// A simple dialog offers the user a choice between several options. This
/// widget is commonly used to represent each of the options. If the user
/// selects this option, the widget will call the [onPressed] callback, which
/// typically uses [Navigator.pop] to close the dialog.
///
/// The padding on a [SimpleDialogOption] is configured to combine with the
/// default [SimpleDialog.contentPadding] so that each option ends up 8 pixels
/// from the other vertically, with 20 pixels of spacing between the dialog's
/// title and the first option, and 24 pixels of spacing between the last option
/// and the bottom of the dialog.
///
/// ## Sample code
///
/// ```dart
/// new SimpleDialogOption(
/// onPressed: () { Navigator.pop(context, Department.treasury); },
/// child: const Text('Treasury department'),
/// )
/// ```
///
/// See also:
///
/// * [SimpleDialog], for a dialog in which to use this widget.
/// * [showDialog], which actually displays the dialog and returns its result.
/// * [FlatButton], which are commonly used as actions in other kinds of
/// dialogs, such as [AlertDialog]s.
/// * <https://material.google.com/components/dialogs.html#dialogs-simple-dialogs>
class SimpleDialogOption extends StatelessWidget {
/// Creates an option for a [SimpleDialog].
const SimpleDialogOption({
Key key,
this.onPressed,
this.child,
}) : super(key: key);
/// The callback that is called when this option is selected.
///
/// If this is set to null, the option cannot be selected.
///
/// When used in a [SimpleDialog], this will typically call [Navigator.pop]
/// with a value for [showDialog] to complete its future with.
final VoidCallback onPressed;
/// The widget below this widget in the tree.
///
/// Typically a [Text] widget.
final Widget child;
@override
Widget build(BuildContext context) {
return new InkWell(
onTap: onPressed,
child: new Padding(
padding: const EdgeInsets.symmetric(vertical: 8.0, horizontal: 24.0),
child: child),
);
}
}
/// A simple material design dialog.
///
/// A simple dialog offers the user a choice between several options. A simple
/// dialog has an optional title that is displayed above the choices.
///
/// Choices are normally represented using [SimpleDialogOption] widgets. If
/// other widgets are used, see [contentPadding] for notes regarding the
/// conventions for obtaining the spacing expected by Material Design.
///
/// For dialogs that inform the user about a situation, consider using an
/// [AlertDialog].
///
/// Typically passed as the child widget to [showDialog], which displays the
/// dialog.
///
/// ## Sample code
///
/// In this example, the user is asked to select between two options. These
/// options are represented as an enum. The [showDialog] method here returns
/// a [Future] that completes to a value of that enum. If the user cancels
/// the dialog (e.g. by hitting the back button on Android, or tapping on the
/// mask behind the dialog) then the future completes with the null value.
///
/// The return value in this example is used as the index for a switch statement.
/// One advantage of using an enum as the return value and then using that to
/// drive a switch statement is that the analyzer will flag any switch statement
/// that doesn't mention every value in the enum.
///
/// ```dart
/// Future<Null> _askedToLead() async {
/// switch (await showDialog<Department>(
/// context: context,
/// builder: (BuildContext context) {
/// return new SimpleDialog(
/// title: const Text('Select assignment'),
/// children: <Widget>[
/// new SimpleDialogOption(
/// onPressed: () { Navigator.pop(context, Department.treasury); },
/// child: const Text('Treasury department'),
/// ),
/// new SimpleDialogOption(
/// onPressed: () { Navigator.pop(context, Department.state); },
/// child: const Text('State department'),
/// ),
/// ],
/// );
/// }
/// )) {
/// case Department.treasury:
/// // Let's go.
/// // ...
/// break;
/// case Department.state:
/// // ...
/// break;
/// }
/// }
/// ```
///
/// See also:
///
/// * [SimpleDialogOption], which are options used in this type of dialog.
/// * [AlertDialog], for dialogs that have a row of buttons below the body.
/// * [Dialog], on which [SimpleDialog] and [AlertDialog] are based.
/// * [showDialog], which actually displays the dialog and returns its result.
/// * <https://material.google.com/components/dialogs.html#dialogs-simple-dialogs>
class SimpleDialog extends StatelessWidget {
/// Creates a simple dialog.
///
/// Typically used in conjunction with [showDialog].
///
/// The [titlePadding] and [contentPadding] arguments must not be null.
const SimpleDialog({
Key key,
this.title,
this.titlePadding: const EdgeInsets.fromLTRB(24.0, 24.0, 24.0, 0.0),
this.children,
this.contentPadding: const EdgeInsets.fromLTRB(0.0, 12.0, 0.0, 16.0),
this.semanticLabel,
}) : assert(titlePadding != null),
assert(contentPadding != null),
super(key: key);
/// The (optional) title of the dialog is displayed in a large font at the top
/// of the dialog.
///
/// Typically a [Text] widget.
final Widget title;
/// Padding around the title.
///
/// If there is no title, no padding will be provided.
///
/// By default, this provides the recommend Material Design padding of 24
/// pixels around the left, top, and right edges of the title.
///
/// See [contentPadding] for the conventions regarding padding between the
/// [title] and the [children].
final EdgeInsetsGeometry titlePadding;
/// The (optional) content of the dialog is displayed in a
/// [SingleChildScrollView] underneath the title.
///
/// Typically a list of [SimpleDialogOption]s.
final List<Widget> children;
/// Padding around the content.
///
/// By default, this is 12 pixels on the top and 16 pixels on the bottom. This
/// is intended to be combined with children that have 24 pixels of padding on
/// the left and right, and 8 pixels of padding on the top and bottom, so that
/// the content ends up being indented 20 pixels from the title, 24 pixels
/// from the bottom, and 24 pixels from the sides.
///
/// The [SimpleDialogOption] widget uses such padding.
///
/// If there is no [title], the [contentPadding] should be adjusted so that
/// the top padding ends up being 24 pixels.
final EdgeInsetsGeometry contentPadding;
/// The semantic label of the dialog used by accessibility frameworks to
/// announce screen transitions when the dialog is opened and closed.
///
/// If this label is not provided, a semantic label will be infered from the
/// [title] if it is not null. If there is no title, the label will be taken
/// from [MaterialLocalizations.dialogLabel].
///
/// See also:
///
/// * [SemanticsConfiguration.isRouteName], for a description of how this
/// value is used.
final String semanticLabel;
@override
Widget build(BuildContext context) {
final List<Widget> body = <Widget>[];
String label = semanticLabel;
if (title != null) {
body.add(new Padding(
padding: titlePadding,
child: new DefaultTextStyle(
style: Theme.of(context).textTheme.title,
child: new Semantics(namesRoute: true, child: title),
)));
} else {
switch (defaultTargetPlatform) {
case TargetPlatform.iOS:
label = semanticLabel;
break;
case TargetPlatform.android:
case TargetPlatform.fuchsia:
label =
semanticLabel ?? MaterialLocalizations.of(context)?.dialogLabel;
}
}
if (children != null) {
body.add(new Flexible(
child: new SingleChildScrollView(
padding: contentPadding,
child: new ListBody(children: children),
)));
}
Widget dialogChild = new IntrinsicWidth(
stepWidth: 56.0,
child: new ConstrainedBox(
constraints: const BoxConstraints(minWidth: 280.0),
child: new Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: body,
),
),
);
if (label != null)
dialogChild = new Semantics(
namesRoute: true,
label: label,
child: dialogChild,
);
return new Dialog(child: dialogChild);
}
}
class _DialogRoute<T> extends PopupRoute<T> {
_DialogRoute({
@required this.theme,
bool barrierDismissible: true,
this.barrierLabel,
@required this.child,
RouteSettings settings,
}) : assert(barrierDismissible != null),
_barrierDismissible = barrierDismissible,
super(settings: settings);
final Widget child;
final ThemeData theme;
@override
Duration get transitionDuration => const Duration(milliseconds: 150);
@override
bool get barrierDismissible => _barrierDismissible;
final bool _barrierDismissible;
@override
Color get barrierColor => Colors.black54;
@override
final String barrierLabel;
@override
Widget buildPage(BuildContext context, Animation<double> animation,
Animation<double> secondaryAnimation) {
return new SafeArea(
child: new Builder(builder: (BuildContext context) {
final Widget annotatedChild = new Semantics(
child: child,
scopesRoute: true,
explicitChildNodes: true,
);
return theme != null
? new Theme(data: theme, child: annotatedChild)
: annotatedChild;
}),
);
}
@override
Widget buildTransitions(BuildContext context, Animation<double> animation,
Animation<double> secondaryAnimation, Widget child) {
return new FadeTransition(
opacity: new CurvedAnimation(parent: animation, curve: Curves.easeOut),
child: child);
}
}
/// Displays a dialog above the current contents of the app.
///
/// This function takes a `builder` which typically builds a [Dialog] widget.
/// Content below the dialog is dimmed with a [ModalBarrier]. This widget does
/// not share a context with the location that `showDialog` is originally
/// called from. Use a [StatefulBuilder] or a custom [StatefulWidget] if the
/// dialog needs to update dynamically.
///
/// The `context` argument is used to look up the [Navigator] and [Theme] for
/// the dialog. It is only used when the method is called. Its corresponding
/// widget can be safely removed from the tree before the dialog is closed.
///
/// The `child` argument is deprecated, and should be replaced with `builder`.
///
/// Returns a [Future] that resolves to the value (if any) that was passed to
/// [Navigator.pop] when the dialog was closed.
///
/// The dialog route created by this method is pushed to the root navigator.
/// If the application has multiple [Navigator] objects, it may be necessary to
/// call `Navigator.of(context, rootNavigator: true).pop(result)` to close the
/// dialog rather just 'Navigator.pop(context, result)`.
///
/// See also:
/// * [AlertDialog], for dialogs that have a row of buttons below a body.
/// * [SimpleDialog], which handles the scrolling of the contents and does
/// not show buttons below its body.
/// * [Dialog], on which [SimpleDialog] and [AlertDialog] are based.
/// * <https://material.google.com/components/dialogs.html>
Future<T> customShowDialog<T>({
@required
BuildContext context,
bool barrierDismissible: true,
@Deprecated(
'Instead of using the "child" argument, return the child from a closure '
'provided to the "builder" argument. This will ensure that the BuildContext '
'is appropriate for widgets built in the dialog.')
Widget child,
WidgetBuilder builder,
}) {
assert(child == null || builder == null);
return Navigator.of(context, rootNavigator: true).push(new _DialogRoute<T>(
child: child ?? new Builder(builder: builder),
theme: Theme.of(context, shadowThemeOnly: true),
barrierDismissible: barrierDismissible,
barrierLabel:
MaterialLocalizations.of(context).modalBarrierDismissLabel,
));
}
我正在使用 flutter/Dart 和从 Github 获得的 Custom Show Dialog class 构建一个 custom alert dialog，出于某种原因，对话框是没有显示。
问：如何让对话框正常显示？
PS resultsDialog(a,b) 在别处单击按钮时被调用。
这是我的警报对话框代码：
Future<void> resultsDialog(String sq, String sl) async {
BuildContext ctx;
CustomAlertDialog dialog = new CustomAlertDialog(
content: Material(
type: MaterialType.card,
child: new Container(
margin: EdgeInsets.only(left: 26.0, right: 26.0),
decoration: new BoxDecoration(
shape: BoxShape.rectangle,
color: const Color(0xFFFFFF),
borderRadius:
new BorderRadius.all(new Radius.circular(32.0)),
),
child: new Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
// dialog top
new Expanded(
//...
),
// dialog center row
new Expanded(
//...
),
// dialog bottom row
new Expanded(
//...
),
],
),
),
),
);
customShowDialog(context: ctx, child: dialog);
}
预期结果：
PS 我处理了内部行，所以这里的问题只是让对话框显示并防止它被关闭，仅此而已
您需要从父窗口小部件传递上下文
并在您的 resultsDialog 中添加一个参数 BuildContext ctx
您可以复制粘贴 运行 完整代码
代码片段
void _incrementCounter() {
resultsDialog(context, "a", "b");
setState(() {
Future<void> resultsDialog(BuildContext ctx, String sq, String sl) async {
//BuildContext ctx;
CustomAlertDialog dialog = new CustomAlertDialog(
content: Material(
type: MaterialType.card,
child: new Container(
margin: EdgeInsets.only(left: 26.0, right: 26.0),
decoration: new BoxDecoration(
shape: BoxShape.rectangle,
color: const Color(0xFFFFFF),
borderRadius:
new BorderRadius.all(new Radius.circular(32.0)),
),
child: new Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
// dialog top
Text('Dialog OK'),
Text('${sq}'),
Text('${sl}'),
],
),
),
),
);
customShowDialog(context: ctx, child: dialog);
}
工作演示
完整代码
import 'package:flutter/material.dart';
import 'dart:async';
import 'dart:ui';
import 'package:flutter/foundation.dart';
import 'package:flutter/widgets.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
resultsDialog(context, "a", "b");
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Invoke "debug painting" (press "p" in the console, choose the
// "Toggle Debug Paint" action from the Flutter Inspector in Android
// Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
// to see the wireframe for each widget.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.display1,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
Future<void> resultsDialog(BuildContext ctx, String sq, String sl) async {
//BuildContext ctx;
CustomAlertDialog dialog = new CustomAlertDialog(
content: Material(
type: MaterialType.card,
child: new Container(
margin: EdgeInsets.only(left: 26.0, right: 26.0),
decoration: new BoxDecoration(
shape: BoxShape.rectangle,
color: const Color(0xFFFFFF),
borderRadius:
new BorderRadius.all(new Radius.circular(32.0)),
),
child: new Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
// dialog top
Text('Dialog OK'),
Text('${sq}'),
Text('${sl}'),
],
),
),
),
);
customShowDialog(context: ctx, child: dialog);
}
// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Examples can assume:
// enum Department { treasury, state }
/// A material design dialog.
///
/// This dialog widget does not have any opinion about the contents of the
/// dialog. Rather than using this widget directly, consider using [AlertDialog]
/// or [SimpleDialog], which implement specific kinds of material design
/// dialogs.
///
/// See also:
///
/// * [AlertDialog], for dialogs that have a message and some buttons.
/// * [SimpleDialog], for dialogs that offer a variety of options.
/// * [showDialog], which actually displays the dialog and returns its result.
/// * <https://material.google.com/components/dialogs.html>
class Dialog extends StatelessWidget {
/// Creates a dialog.
///
/// Typically used in conjunction with [showDialog].
const Dialog({
Key key,
this.child,
this.insetAnimationDuration: const Duration(milliseconds: 100),
this.insetAnimationCurve: Curves.decelerate,
}) : super(key: key);
/// The widget below this widget in the tree.
///
/// {@macro flutter.widgets.child}
final Widget child;
/// The duration of the animation to show when the system keyboard intrudes
/// into the space that the dialog is placed in.
///
/// Defaults to 100 milliseconds.
final Duration insetAnimationDuration;
/// The curve to use for the animation shown when the system keyboard intrudes
/// into the space that the dialog is placed in.
///
/// Defaults to [Curves.fastOutSlowIn].
final Curve insetAnimationCurve;
Color _getColor(BuildContext context) {
return Theme.of(context).dialogBackgroundColor;
}
@override
Widget build(BuildContext context) {
return new AnimatedPadding(
padding: MediaQuery.of(context).viewInsets +
const EdgeInsets.symmetric(horizontal: 40.0, vertical: 24.0),
duration: insetAnimationDuration,
curve: insetAnimationCurve,
child: new MediaQuery.removeViewInsets(
removeLeft: true,
removeTop: true,
removeRight: true,
removeBottom: true,
context: context,
child: new Center(
child: new ConstrainedBox(
constraints: const BoxConstraints(minWidth: 280.0),
child: new Material(
borderRadius: BorderRadius.all(Radius.circular(20.0)),
elevation: 30.0,
color: _getColor(context),
type: MaterialType.card,
child: child,
),
),
),
),
);
}
}
/// A material design alert dialog.
///
/// An alert dialog informs the user about situations that require
/// acknowledgement. An alert dialog has an optional title and an optional list
/// of actions. The title is displayed above the content and the actions are
/// displayed below the content.
///
/// If the content is too large to fit on the screen vertically, the dialog will
/// display the title and the actions and let the content overflow. Consider
/// using a scrolling widget, such as [ListView], for [content] to avoid
/// overflow.
///
/// For dialogs that offer the user a choice between several options, consider
/// using a [SimpleDialog].
///
/// Typically passed as the child widget to [showDialog], which displays the
/// dialog.
///
/// ## Sample code
///
/// This snippet shows a method in a [State] which, when called, displays a dialog box
/// and returns a [Future] that completes when the dialog is dismissed.
///
/// ```dart
/// Future<Null> _neverSatisfied() async {
/// return showDialog<Null>(
/// context: context,
/// barrierDismissible: false, // user must tap button!
/// builder: (BuildContext context) {
/// return new AlertDialog(
/// title: new Text('Rewind and remember'),
/// content: new SingleChildScrollView(
/// child: new ListBody(
/// children: <Widget>[
/// new Text('You will never be satisfied.'),
/// new Text('You\’re like me. I’m never satisfied.'),
/// ],
/// ),
/// ),
/// actions: <Widget>[
/// new FlatButton(
/// child: new Text('Regret'),
/// onPressed: () {
/// Navigator.of(context).pop();
/// },
/// ),
/// ],
/// );
/// },
/// );
/// }
/// ```
///
/// See also:
///
/// * [SimpleDialog], which handles the scrolling of the contents but has no [actions].
/// * [Dialog], on which [AlertDialog] and [SimpleDialog] are based.
/// * [showDialog], which actually displays the dialog and returns its result.
/// * <https://material.google.com/components/dialogs.html#dialogs-alerts>
class CustomAlertDialog extends StatelessWidget {
/// Creates an alert dialog.
///
/// Typically used in conjunction with [showDialog].
///
/// The [contentPadding] must not be null. The [titlePadding] defaults to
/// null, which implies a default that depends on the values of the other
/// properties. See the documentation of [titlePadding] for details.
const CustomAlertDialog({
Key key,
this.title,
this.titlePadding,
this.content,
this.contentPadding: const EdgeInsets.fromLTRB(24.0, 20.0, 24.0, 24.0),
this.actions,
this.semanticLabel,
}) : assert(contentPadding != null),
super(key: key);
/// The (optional) title of the dialog is displayed in a large font at the top
/// of the dialog.
///
/// Typically a [Text] widget.
final Widget title;
/// Padding around the title.
///
/// If there is no title, no padding will be provided. Otherwise, this padding
/// is used.
///
/// This property defaults to providing 24 pixels on the top, left, and right
/// of the title. If the [content] is not null, then no bottom padding is
/// provided (but see [contentPadding]). If it _is_ null, then an extra 20
/// pixels of bottom padding is added to separate the [title] from the
/// [actions].
final EdgeInsetsGeometry titlePadding;
/// The (optional) content of the dialog is displayed in the center of the
/// dialog in a lighter font.
///
/// Typically, this is a [ListView] containing the contents of the dialog.
/// Using a [ListView] ensures that the contents can scroll if they are too
/// big to fit on the display.
final Widget content;
/// Padding around the content.
///
/// If there is no content, no padding will be provided. Otherwise, padding of
/// 20 pixels is provided above the content to separate the content from the
/// title, and padding of 24 pixels is provided on the left, right, and bottom
/// to separate the content from the other edges of the dialog.
final EdgeInsetsGeometry contentPadding;
/// The (optional) set of actions that are displayed at the bottom of the
/// dialog.
///
/// Typically this is a list of [FlatButton] widgets.
///
/// These widgets will be wrapped in a [ButtonBar], which introduces 8 pixels
/// of padding on each side.
///
/// If the [title] is not null but the [content] _is_ null, then an extra 20
/// pixels of padding is added above the [ButtonBar] to separate the [title]
/// from the [actions].
final List<Widget> actions;
/// The semantic label of the dialog used by accessibility frameworks to
/// announce screen transitions when the dialog is opened and closed.
///
/// If this label is not provided, a semantic label will be infered from the
/// [title] if it is not null. If there is no title, the label will be taken
/// from [MaterialLocalizations.alertDialogLabel].
///
/// See also:
///
/// * [SemanticsConfiguration.isRouteName], for a description of how this
/// value is used.
final String semanticLabel;
@override
Widget build(BuildContext context) {
final List<Widget> children = <Widget>[];
String label = semanticLabel;
if (title != null) {
children.add(new Padding(
padding: titlePadding ??
new EdgeInsets.fromLTRB(
24.0, 24.0, 24.0, content == null ? 20.0 : 0.0),
child: new DefaultTextStyle(
style: Theme.of(context).textTheme.title,
child: new Semantics(child: title, namesRoute: true),
),
));
} else {
switch (defaultTargetPlatform) {
case TargetPlatform.iOS:
label = semanticLabel;
break;
case TargetPlatform.android:
case TargetPlatform.fuchsia:
label = semanticLabel ??
MaterialLocalizations.of(context)?.alertDialogLabel;
}
}
if (content != null) {
children.add(new Flexible(
child: new Padding(
padding: contentPadding,
child: new DefaultTextStyle(
style: Theme.of(context).textTheme.subhead,
child: content,
),
),
));
}
if (actions != null) {
children.add(new ButtonTheme.bar(
child: new ButtonBar(
children: actions,
),
));
}
Widget dialogChild = new IntrinsicWidth(
child: new Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: children,
),
);
if (label != null)
dialogChild =
new Semantics(namesRoute: true, label: label, child: dialogChild);
return new Dialog(child: dialogChild);
}
}
/// An option used in a [SimpleDialog].
///
/// A simple dialog offers the user a choice between several options. This
/// widget is commonly used to represent each of the options. If the user
/// selects this option, the widget will call the [onPressed] callback, which
/// typically uses [Navigator.pop] to close the dialog.
///
/// The padding on a [SimpleDialogOption] is configured to combine with the
/// default [SimpleDialog.contentPadding] so that each option ends up 8 pixels
/// from the other vertically, with 20 pixels of spacing between the dialog's
/// title and the first option, and 24 pixels of spacing between the last option
/// and the bottom of the dialog.
///
/// ## Sample code
///
/// ```dart
/// new SimpleDialogOption(
/// onPressed: () { Navigator.pop(context, Department.treasury); },
/// child: const Text('Treasury department'),
/// )
/// ```
///
/// See also:
///
/// * [SimpleDialog], for a dialog in which to use this widget.
/// * [showDialog], which actually displays the dialog and returns its result.
/// * [FlatButton], which are commonly used as actions in other kinds of
/// dialogs, such as [AlertDialog]s.
/// * <https://material.google.com/components/dialogs.html#dialogs-simple-dialogs>
class SimpleDialogOption extends StatelessWidget {
/// Creates an option for a [SimpleDialog].
const SimpleDialogOption({
Key key,
this.onPressed,
this.child,
}) : super(key: key);
/// The callback that is called when this option is selected.
///
/// If this is set to null, the option cannot be selected.
///
/// When used in a [SimpleDialog], this will typically call [Navigator.pop]
/// with a value for [showDialog] to complete its future with.
final VoidCallback onPressed;
/// The widget below this widget in the tree.
///
/// Typically a [Text] widget.
final Widget child;
@override
Widget build(BuildContext context) {
return new InkWell(
onTap: onPressed,
child: new Padding(
padding: const EdgeInsets.symmetric(vertical: 8.0, horizontal: 24.0),
child: child),
);
}
}
/// A simple material design dialog.
///
/// A simple dialog offers the user a choice between several options. A simple
/// dialog has an optional title that is displayed above the choices.
///
/// Choices are normally represented using [SimpleDialogOption] widgets. If
/// other widgets are used, see [contentPadding] for notes regarding the
/// conventions for obtaining the spacing expected by Material Design.
///
/// For dialogs that inform the user about a situation, consider using an
/// [AlertDialog].
///
/// Typically passed as the child widget to [showDialog], which displays the
/// dialog.
///
/// ## Sample code
///
/// In this example, the user is asked to select between two options. These
/// options are represented as an enum. The [showDialog] method here returns
/// a [Future] that completes to a value of that enum. If the user cancels
/// the dialog (e.g. by hitting the back button on Android, or tapping on the
/// mask behind the dialog) then the future completes with the null value.
///
/// The return value in this example is used as the index for a switch statement.
/// One advantage of using an enum as the return value and then using that to
/// drive a switch statement is that the analyzer will flag any switch statement
/// that doesn't mention every value in the enum.
///
/// ```dart
/// Future<Null> _askedToLead() async {
/// switch (await showDialog<Department>(
/// context: context,
/// builder: (BuildContext context) {
/// return new SimpleDialog(
/// title: const Text('Select assignment'),
/// children: <Widget>[
/// new SimpleDialogOption(
/// onPressed: () { Navigator.pop(context, Department.treasury); },
/// child: const Text('Treasury department'),
/// ),
/// new SimpleDialogOption(
/// onPressed: () { Navigator.pop(context, Department.state); },
/// child: const Text('State department'),
/// ),
/// ],
/// );
/// }
/// )) {
/// case Department.treasury:
/// // Let's go.
/// // ...
/// break;
/// case Department.state:
/// // ...
/// break;
/// }
/// }
/// ```
///
/// See also:
///
/// * [SimpleDialogOption], which are options used in this type of dialog.
/// * [AlertDialog], for dialogs that have a row of buttons below the body.
/// * [Dialog], on which [SimpleDialog] and [AlertDialog] are based.
/// * [showDialog], which actually displays the dialog and returns its result.
/// * <https://material.google.com/components/dialogs.html#dialogs-simple-dialogs>
class SimpleDialog extends StatelessWidget {
/// Creates a simple dialog.
///
/// Typically used in conjunction with [showDialog].
///
/// The [titlePadding] and [contentPadding] arguments must not be null.
const SimpleDialog({
Key key,
this.title,
this.titlePadding: const EdgeInsets.fromLTRB(24.0, 24.0, 24.0, 0.0),
this.children,
this.contentPadding: const EdgeInsets.fromLTRB(0.0, 12.0, 0.0, 16.0),
this.semanticLabel,
}) : assert(titlePadding != null),
assert(contentPadding != null),
super(key: key);
/// The (optional) title of the dialog is displayed in a large font at the top
/// of the dialog.
///
/// Typically a [Text] widget.
final Widget title;
/// Padding around the title.
///
/// If there is no title, no padding will be provided.
///
/// By default, this provides the recommend Material Design padding of 24
/// pixels around the left, top, and right edges of the title.
///
/// See [contentPadding] for the conventions regarding padding between the
/// [title] and the [children].
final EdgeInsetsGeometry titlePadding;
/// The (optional) content of the dialog is displayed in a
/// [SingleChildScrollView] underneath the title.
///
/// Typically a list of [SimpleDialogOption]s.
final List<Widget> children;
/// Padding around the content.
///
/// By default, this is 12 pixels on the top and 16 pixels on the bottom. This
/// is intended to be combined with children that have 24 pixels of padding on
/// the left and right, and 8 pixels of padding on the top and bottom, so that
/// the content ends up being indented 20 pixels from the title, 24 pixels
/// from the bottom, and 24 pixels from the sides.
///
/// The [SimpleDialogOption] widget uses such padding.
///
/// If there is no [title], the [contentPadding] should be adjusted so that
/// the top padding ends up being 24 pixels.
final EdgeInsetsGeometry contentPadding;
/// The semantic label of the dialog used by accessibility frameworks to
/// announce screen transitions when the dialog is opened and closed.
///
/// If this label is not provided, a semantic label will be infered from the
/// [title] if it is not null. If there is no title, the label will be taken
/// from [MaterialLocalizations.dialogLabel].
///
/// See also:
///
/// * [SemanticsConfiguration.isRouteName], for a description of how this
/// value is used.
final String semanticLabel;
@override
Widget build(BuildContext context) {
final List<Widget> body = <Widget>[];
String label = semanticLabel;
if (title != null) {
body.add(new Padding(
padding: titlePadding,
child: new DefaultTextStyle(
style: Theme.of(context).textTheme.title,
child: new Semantics(namesRoute: true, child: title),
)));
} else {
switch (defaultTargetPlatform) {
case TargetPlatform.iOS:
label = semanticLabel;
break;
case TargetPlatform.android:
case TargetPlatform.fuchsia:
label =
semanticLabel ?? MaterialLocalizations.of(context)?.dialogLabel;
}
}
if (children != null) {
body.add(new Flexible(
child: new SingleChildScrollView(
padding: contentPadding,
child: new ListBody(children: children),
)));
}
Widget dialogChild = new IntrinsicWidth(
stepWidth: 56.0,
child: new ConstrainedBox(
constraints: const BoxConstraints(minWidth: 280.0),
child: new Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: body,
),
),
);
if (label != null)
dialogChild = new Semantics(
namesRoute: true,
label: label,
child: dialogChild,
);
return new Dialog(child: dialogChild);
}
}
class _DialogRoute<T> extends PopupRoute<T> {
_DialogRoute({
@required this.theme,
bool barrierDismissible: true,
this.barrierLabel,
@required this.child,
RouteSettings settings,
}) : assert(barrierDismissible != null),
_barrierDismissible = barrierDismissible,
super(settings: settings);
final Widget child;
final ThemeData theme;
@override
Duration get transitionDuration => const Duration(milliseconds: 150);
@override
bool get barrierDismissible => _barrierDismissible;
final bool _barrierDismissible;
@override
Color get barrierColor => Colors.black54;
@override
final String barrierLabel;
@override
Widget buildPage(BuildContext context, Animation<double> animation,
Animation<double> secondaryAnimation) {
return new SafeArea(
child: new Builder(builder: (BuildContext context) {
final Widget annotatedChild = new Semantics(
child: child,
scopesRoute: true,
explicitChildNodes: true,
);
return theme != null
? new Theme(data: theme, child: annotatedChild)
: annotatedChild;
}),
);
}
@override
Widget buildTransitions(BuildContext context, Animation<double> animation,
Animation<double> secondaryAnimation, Widget child) {
return new FadeTransition(
opacity: new CurvedAnimation(parent: animation, curve: Curves.easeOut),
child: child);
}
}
/// Displays a dialog above the current contents of the app.
///
/// This function takes a `builder` which typically builds a [Dialog] widget.
/// Content below the dialog is dimmed with a [ModalBarrier]. This widget does
/// not share a context with the location that `showDialog` is originally
/// called from. Use a [StatefulBuilder] or a custom [StatefulWidget] if the
/// dialog needs to update dynamically.
///
/// The `context` argument is used to look up the [Navigator] and [Theme] for
/// the dialog. It is only used when the method is called. Its corresponding
/// widget can be safely removed from the tree before the dialog is closed.
///
/// The `child` argument is deprecated, and should be replaced with `builder`.
///
/// Returns a [Future] that resolves to the value (if any) that was passed to
/// [Navigator.pop] when the dialog was closed.
///
/// The dialog route created by this method is pushed to the root navigator.
/// If the application has multiple [Navigator] objects, it may be necessary to
/// call `Navigator.of(context, rootNavigator: true).pop(result)` to close the
/// dialog rather just 'Navigator.pop(context, result)`.
///
/// See also:
/// * [AlertDialog], for dialogs that have a row of buttons below a body.
/// * [SimpleDialog], which handles the scrolling of the contents and does
/// not show buttons below its body.
/// * [Dialog], on which [SimpleDialog] and [AlertDialog] are based.
/// * <https://material.google.com/components/dialogs.html>
Future<T> customShowDialog<T>({
@required
BuildContext context,
bool barrierDismissible: true,
@Deprecated(
'Instead of using the "child" argument, return the child from a closure '
'provided to the "builder" argument. This will ensure that the BuildContext '
'is appropriate for widgets built in the dialog.')
Widget child,
WidgetBuilder builder,
}) {
assert(child == null || builder == null);
return Navigator.of(context, rootNavigator: true).push(new _DialogRoute<T>(
child: child ?? new Builder(builder: builder),
theme: Theme.of(context, shadowThemeOnly: true),
barrierDismissible: barrierDismissible,
barrierLabel:
MaterialLocalizations.of(context).modalBarrierDismissLabel,
));
}