// 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.
import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:flutter/widgets.dart';
import 'button_bar.dart';
import 'colors.dart';
import 'debug.dart';
import 'dialog_theme.dart';
import 'ink_well.dart';
import 'material.dart';
import 'material_localizations.dart';
import 'theme.dart';
// Examples can assume:
// enum Department { treasury, state }
// BuildContext context;
/// 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.io/design/components/dialogs.html>
class Dialog extends StatelessWidget {
/// Creates a dialog.
///
/// Typically used in conjunction with [showDialog].
const Dialog({
Key key,
this.backgroundColor,
this.elevation,
this.insetAnimationDuration = const Duration(milliseconds: 100),
this.insetAnimationCurve = Curves.decelerate,
this.shape,
this.child,
}) : super(key: key);
/// {@template flutter.material.dialog.backgroundColor}
/// The background color of the surface of this [Dialog].
///
/// This sets the [Material.color] on this [Dialog]'s [Material].
///
/// If `null`, [ThemeData.cardColor] is used.
/// {@endtemplate}
final Color backgroundColor;
/// {@template flutter.material.dialog.elevation}
/// The z-coordinate of this [Dialog].
///
/// If null then [DialogTheme.elevation] is used, and if that's null then the
/// dialog's elevation is 24.0.
/// {@endtemplate}
/// {@macro flutter.material.material.elevation}
final double elevation;
/// 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;
/// {@template flutter.material.dialog.shape}
/// The shape of this dialog's border.
///
/// Defines the dialog's [Material.shape].
///
/// The default shape is a [RoundedRectangleBorder] with a radius of 2.0.
/// {@endtemplate}
final ShapeBorder shape;
/// The widget below this widget in the tree.
///
/// {@macro flutter.widgets.child}
final Widget child;
// TODO(johnsonmh): Update default dialog border radius to 4.0 to match material spec.
static const RoundedRectangleBorder _defaultDialogShape =
RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(2.0)));
static const double _defaultElevation = 24.0;
@override
Widget build(BuildContext context) {
final DialogTheme dialogTheme = DialogTheme.of(context);
return AnimatedPadding(
padding: MediaQuery.of(context).viewInsets + const EdgeInsets.symmetric(horizontal: 40.0, vertical: 24.0),
duration: insetAnimationDuration,
curve: insetAnimationCurve,
child: MediaQuery.removeViewInsets(
removeLeft: true,
removeTop: true,
removeRight: true,
removeBottom: true,
context: context,
child: Center(
child: ConstrainedBox(
constraints: const BoxConstraints(minWidth: 280.0),
child: Material(
color: backgroundColor ?? dialogTheme.backgroundColor ?? Theme.of(context).dialogBackgroundColor,
elevation: elevation ?? dialogTheme.elevation ?? _defaultElevation,
shape: shape ?? dialogTheme.shape ?? _defaultDialogShape,
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, which is
/// rarely desired. Consider using a scrolling widget for [content], such as
/// [SingleChildScrollView], to avoid overflow. (However, be aware that since
/// [AlertDialog] tries to size itself using the intrinsic dimensions of its
/// children, widgets such as [ListView], [GridView], and [CustomScrollView],
/// which use lazy viewports, will not work. If this is a problem, consider
/// using [Dialog] directly.)
///
/// 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.
///
/// {@tool sample}
///
/// 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<void> _neverSatisfied() async {
/// return showDialog<void>(
/// context: context,
/// barrierDismissible: false, // user must tap button!
/// builder: (BuildContext context) {
/// return AlertDialog(
/// title: Text('Rewind and remember'),
/// content: SingleChildScrollView(
/// child: ListBody(
/// children: <Widget>[
/// Text('You will never be satisfied.'),
/// Text('You\’re like me. I’m never satisfied.'),
/// ],
/// ),
/// ),
/// actions: <Widget>[
/// FlatButton(
/// child: Text('Regret'),
/// onPressed: () {
/// Navigator.of(context).pop();
/// },
/// ),
/// ],
/// );
/// },
/// );
/// }
/// ```
/// {@end-tool}
///
/// See also:
///
/// * [SimpleDialog], which handles the scrolling of the contents but has no [actions].
/// * [Dialog], on which [AlertDialog] and [SimpleDialog] are based.
/// * [CupertinoAlertDialog], an iOS-styled alert dialog.
/// * [showDialog], which actually displays the dialog and returns its result.
/// * <https://material.io/design/components/dialogs.html#alert-dialog>
class AlertDialog 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 AlertDialog({
Key key,
this.title,
this.titlePadding,
this.titleTextStyle,
this.content,
this.contentPadding = const EdgeInsets.fromLTRB(24.0, 20.0, 24.0, 24.0),
this.contentTextStyle,
this.actions,
this.backgroundColor,
this.elevation,
this.semanticLabel,
this.shape,
}) : 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;
/// Style for the text in the [title] of this [AlertDialog].
///
/// If null, [DialogTheme.titleTextStyle] is used, if that's null, defaults to
/// [ThemeData.textTheme.title].
final TextStyle titleTextStyle;
/// The (optional) content of the dialog is displayed in the center of the
/// dialog in a lighter font.
///
/// Typically this is a [SingleChildScrollView] that contains the dialog's
/// message. As noted in the [AlertDialog] documentation, it's important
/// to use a [SingleChildScrollView] if there's any risk that the content
/// will not fit.
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;
/// Style for the text in the [content] of this [AlertDialog].
///
/// If null, [DialogTheme.contentTextStyle] is used, if that's null, defaults
/// to [ThemeData.textTheme.subhead].
final TextStyle contentTextStyle;
/// 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;
/// {@macro flutter.material.dialog.backgroundColor}
final Color backgroundColor;
/// {@macro flutter.material.dialog.elevation}
/// {@macro flutter.material.material.elevation}
final double elevation;
/// 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 inferred 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;
/// {@macro flutter.material.dialog.shape}
final ShapeBorder shape;
@override
Widget build(BuildContext context) {
assert(debugCheckHasMaterialLocalizations(context));
final ThemeData theme = Theme.of(context);
final DialogTheme dialogTheme = DialogTheme.of(context);
final List<Widget> children = <Widget>[];
String label = semanticLabel;
if (title != null) {
children.add(Padding(
padding: titlePadding ?? EdgeInsets.fromLTRB(24.0, 24.0, 24.0, content == null ? 20.0 : 0.0),
child: DefaultTextStyle(
style: titleTextStyle ?? dialogTheme.titleTextStyle ?? theme.textTheme.title,
child: Semantics(
child: title,
namesRoute: true,
container: true,
),
),
));
} else {
switch (theme.platform) {
case TargetPlatform.iOS:
label = semanticLabel;
break;
case TargetPlatform.android:
case TargetPlatform.fuchsia:
label = semanticLabel ?? MaterialLocalizations.of(context)?.alertDialogLabel;
}
}
if (content != null) {
children.add(Flexible(
child: Padding(
padding: contentPadding,
child: DefaultTextStyle(
style: contentTextStyle ?? dialogTheme.contentTextStyle ?? theme.textTheme.subhead,
child: content,
),
),
));
}
if (actions != null) {
children.add(ButtonBar(
children: actions,
));
}
Widget dialogChild = IntrinsicWidth(
child: Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: children,
),
);
if (label != null)
dialogChild = Semantics(
namesRoute: true,
label: label,
child: dialogChild,
);
return Dialog(
backgroundColor: backgroundColor,
elevation: elevation,
shape: shape,
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.
///
/// {@tool sample}
///
/// ```dart
/// SimpleDialogOption(
/// onPressed: () { Navigator.pop(context, Department.treasury); },
/// child: const Text('Treasury department'),
/// )
/// ```
/// {@end-tool}
///
/// 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.io/design/components/dialogs.html#simple-dialog>
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 InkWell(
onTap: onPressed,
child: 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.
///
/// {@tool sample}
///
/// 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<void> _askedToLead() async {
/// switch (await showDialog<Department>(
/// context: context,
/// builder: (BuildContext context) {
/// return SimpleDialog(
/// title: const Text('Select assignment'),
/// children: <Widget>[
/// SimpleDialogOption(
/// onPressed: () { Navigator.pop(context, Department.treasury); },
/// child: const Text('Treasury department'),
/// ),
/// SimpleDialogOption(
/// onPressed: () { Navigator.pop(context, Department.state); },
/// child: const Text('State department'),
/// ),
/// ],
/// );
/// }
/// )) {
/// case Department.treasury:
/// // Let's go.
/// // ...
/// break;
/// case Department.state:
/// // ...
/// break;
/// }
/// }
/// ```
/// {@end-tool}
///
/// 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.io/design/components/dialogs.html#simple-dialog>
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.backgroundColor,
this.elevation,
this.semanticLabel,
this.shape,
}) : 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;
/// {@macro flutter.material.dialog.backgroundColor}
final Color backgroundColor;
/// {@macro flutter.material.dialog.elevation}
/// {@macro flutter.material.material.elevation}
final double elevation;
/// 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 inferred 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;
/// {@macro flutter.material.dialog.shape}
final ShapeBorder shape;
@override
Widget build(BuildContext context) {
assert(debugCheckHasMaterialLocalizations(context));
final List<Widget> body = <Widget>[];
String label = semanticLabel;
final ThemeData theme = Theme.of(context);
if (title != null) {
body.add(Padding(
padding: titlePadding,
child: DefaultTextStyle(
style: theme.textTheme.title,
child: Semantics(namesRoute: true, child: title),
),
));
} else {
switch (theme.platform) {
case TargetPlatform.iOS:
label = semanticLabel;
break;
case TargetPlatform.android:
case TargetPlatform.fuchsia:
label = semanticLabel ?? MaterialLocalizations.of(context)?.dialogLabel;
}
}
if (children != null) {
body.add(Flexible(
child: SingleChildScrollView(
padding: contentPadding,
child: ListBody(children: children),
),
));
}
Widget dialogChild = IntrinsicWidth(
stepWidth: 56.0,
child: ConstrainedBox(
constraints: const BoxConstraints(minWidth: 280.0),
child: Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: body,
),
),
);
if (label != null)
dialogChild = Semantics(
namesRoute: true,
label: label,
child: dialogChild,
);
return Dialog(
backgroundColor: backgroundColor,
elevation: elevation,
shape: shape,
child: dialogChild,
);
}
}
Widget _buildMaterialDialogTransitions(BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation, Widget child) {
return FadeTransition(
opacity: CurvedAnimation(
parent: animation,
curve: Curves.easeOut,
),
child: child,
);
}
/// Displays a Material dialog above the current contents of the app, with
/// Material entrance and exit animations, modal barrier color, and modal
/// barrier behavior (dialog is dismissible with a tap on the barrier).
///
/// This function takes a `builder` which typically builds a [Dialog] widget.
/// Content below the dialog is dimmed with a [ModalBarrier]. The widget
/// returned by the `builder` 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 than 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.
/// * [showCupertinoDialog], which displays an iOS-style dialog.
/// * [showGeneralDialog], which allows for customization of the dialog popup.
/// * <https://material.io/design/components/dialogs.html>
Future<T> showDialog<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);
assert(debugCheckHasMaterialLocalizations(context));
final ThemeData theme = Theme.of(context, shadowThemeOnly: true);
return showGeneralDialog(
context: context,
pageBuilder: (BuildContext buildContext, Animation<double> animation, Animation<double> secondaryAnimation) {
final Widget pageChild = child ?? Builder(builder: builder);
return SafeArea(
child: Builder(
builder: (BuildContext context) {
return theme != null
? Theme(data: theme, child: pageChild)
: pageChild;
}
),
);
},
barrierDismissible: barrierDismissible,
barrierLabel: MaterialLocalizations.of(context).modalBarrierDismissLabel,
barrierColor: Colors.black54,
transitionDuration: const Duration(milliseconds: 150),
transitionBuilder: _buildMaterialDialogTransitions,
);
}