blob: c0258122363e9570e3e9f8226f25b557c28d5549 [file] [log] [blame]
// Copyright 2014 The Flutter 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:ui' show ImageFilter;
import 'package:flutter/foundation.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';
import 'colors.dart';
import 'interface_level.dart';
import 'scrollbar.dart';
import 'theme.dart';
const TextStyle _kActionSheetActionStyle = TextStyle(
fontFamily: '.SF UI Text',
inherit: false,
fontSize: 20.0,
fontWeight: FontWeight.w400,
textBaseline: TextBaseline.alphabetic,
);
const TextStyle _kActionSheetContentStyle = TextStyle(
fontFamily: '.SF UI Text',
inherit: false,
fontSize: 13.0,
fontWeight: FontWeight.w400,
color: _kContentTextColor,
textBaseline: TextBaseline.alphabetic,
);
// Translucent, very light gray that is painted on top of the blurred backdrop
// as the action sheet's background color.
// TODO(LongCatIsLooong): https://github.com/flutter/flutter/issues/39272. Use
// System Materials once we have them.
// Extracted from https://developer.apple.com/design/resources/.
const Color _kBackgroundColor = CupertinoDynamicColor.withBrightness(
color: Color(0xC7F9F9F9),
darkColor: Color(0xC7252525),
);
// Translucent, light gray that is painted on top of the blurred backdrop as
// the background color of a pressed button.
// Eye-balled from iOS 13 beta simulator.
const Color _kPressedColor = CupertinoDynamicColor.withBrightness(
color: Color(0xFFE1E1E1),
darkColor: Color(0xFF2E2E2E),
);
const Color _kCancelPressedColor = CupertinoDynamicColor.withBrightness(
color: Color(0xFFECECEC),
darkColor: Color(0xFF49494B),
);
// The gray color used for text that appears in the title area.
// Extracted from https://developer.apple.com/design/resources/.
const Color _kContentTextColor = Color(0xFF8F8F8F);
// Translucent gray that is painted on top of the blurred backdrop in the gap
// areas between the content section and actions section, as well as between
// buttons.
// Eye-balled from iOS 13 beta simulator.
const Color _kButtonDividerColor = _kContentTextColor;
const double _kBlurAmount = 20.0;
const double _kEdgeHorizontalPadding = 8.0;
const double _kCancelButtonPadding = 8.0;
const double _kEdgeVerticalPadding = 10.0;
const double _kContentHorizontalPadding = 40.0;
const double _kContentVerticalPadding = 14.0;
const double _kButtonHeight = 56.0;
const double _kCornerRadius = 14.0;
const double _kDividerThickness = 1.0;
/// An iOS-style action sheet.
///
/// An action sheet is a specific style of alert that presents the user
/// with a set of two or more choices related to the current context.
/// An action sheet can have a title, an additional message, and a list
/// of actions. The title is displayed above the message and the actions
/// are displayed below this content.
///
/// This action sheet styles its title and message to match standard iOS action
/// sheet title and message text style.
///
/// To display action buttons that look like standard iOS action sheet buttons,
/// provide [CupertinoActionSheetAction]s for the [actions] given to this action
/// sheet.
///
/// To include a iOS-style cancel button separate from the other buttons,
/// provide an [CupertinoActionSheetAction] for the [cancelButton] given to this
/// action sheet.
///
/// An action sheet is typically passed as the child widget to
/// [showCupertinoModalPopup], which displays the action sheet by sliding it up
/// from the bottom of the screen.
///
/// See also:
///
/// * [CupertinoActionSheetAction], which is an iOS-style action sheet button.
/// * <https://developer.apple.com/design/human-interface-guidelines/ios/views/action-sheets/>
class CupertinoActionSheet extends StatelessWidget {
/// Creates an iOS-style action sheet.
///
/// An action sheet must have a non-null value for at least one of the
/// following arguments: [actions], [title], [message], or [cancelButton].
///
/// Generally, action sheets are used to give the user a choice between
/// two or more choices for the current context.
const CupertinoActionSheet({
Key key,
this.title,
this.message,
this.actions,
this.messageScrollController,
this.actionScrollController,
this.cancelButton,
}) : assert(actions != null || title != null || message != null || cancelButton != null,
'An action sheet must have a non-null value for at least one of the following arguments: '
'actions, title, message, or cancelButton'),
super(key: key);
/// An optional title of the action sheet. When the [message] is non-null,
/// the font of the [title] is bold.
///
/// Typically a [Text] widget.
final Widget title;
/// An optional descriptive message that provides more details about the
/// reason for the alert.
///
/// Typically a [Text] widget.
final Widget message;
/// The set of actions that are displayed for the user to select.
///
/// Typically this is a list of [CupertinoActionSheetAction] widgets.
final List<Widget> actions;
/// A scroll controller that can be used to control the scrolling of the
/// [message] in the action sheet.
///
/// This attribute is typically not needed, as alert messages should be
/// short.
final ScrollController messageScrollController;
/// A scroll controller that can be used to control the scrolling of the
/// [actions] in the action sheet.
///
/// This attribute is typically not needed.
final ScrollController actionScrollController;
/// The optional cancel button that is grouped separately from the other
/// actions.
///
/// Typically this is an [CupertinoActionSheetAction] widget.
final Widget cancelButton;
Widget _buildContent(BuildContext context) {
final List<Widget> content = <Widget>[];
if (title != null || message != null) {
final Widget titleSection = _CupertinoAlertContentSection(
title: title,
message: message,
scrollController: messageScrollController,
);
content.add(Flexible(child: titleSection));
}
return Container(
color: CupertinoDynamicColor.resolve(_kBackgroundColor, context),
child: Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: content,
),
);
}
Widget _buildActions() {
if (actions == null || actions.isEmpty) {
return Container(
height: 0.0,
);
}
return Container(
child: _CupertinoAlertActionSection(
children: actions,
scrollController: actionScrollController,
hasCancelButton: cancelButton != null,
),
);
}
Widget _buildCancelButton() {
final double cancelPadding = (actions != null || message != null || title != null)
? _kCancelButtonPadding : 0.0;
return Padding(
padding: EdgeInsets.only(top: cancelPadding),
child: _CupertinoActionSheetCancelButton(
child: cancelButton,
),
);
}
@override
Widget build(BuildContext context) {
final List<Widget> children = <Widget>[
Flexible(child: ClipRRect(
borderRadius: BorderRadius.circular(12.0),
child: BackdropFilter(
filter: ImageFilter.blur(sigmaX: _kBlurAmount, sigmaY: _kBlurAmount),
child: _CupertinoAlertRenderWidget(
contentSection: Builder(builder: _buildContent),
actionsSection: _buildActions(),
),
),
),
),
if (cancelButton != null) _buildCancelButton(),
];
final Orientation orientation = MediaQuery.of(context).orientation;
double actionSheetWidth;
if (orientation == Orientation.portrait) {
actionSheetWidth = MediaQuery.of(context).size.width - (_kEdgeHorizontalPadding * 2);
} else {
actionSheetWidth = MediaQuery.of(context).size.height - (_kEdgeHorizontalPadding * 2);
}
return SafeArea(
child: Semantics(
namesRoute: true,
scopesRoute: true,
explicitChildNodes: true,
label: 'Alert',
child: CupertinoUserInterfaceLevel(
data: CupertinoUserInterfaceLevelData.elevated,
child: Container(
width: actionSheetWidth,
margin: const EdgeInsets.symmetric(
horizontal: _kEdgeHorizontalPadding,
vertical: _kEdgeVerticalPadding,
),
child: Column(
children: children,
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.stretch,
),
),
),
),
);
}
}
/// A button typically used in a [CupertinoActionSheet].
///
/// See also:
///
/// * [CupertinoActionSheet], an alert that presents the user with a set of two or
/// more choices related to the current context.
class CupertinoActionSheetAction extends StatelessWidget {
/// Creates an action for an iOS-style action sheet.
///
/// The [child] and [onPressed] arguments must not be null.
const CupertinoActionSheetAction({
Key key,
@required this.onPressed,
this.isDefaultAction = false,
this.isDestructiveAction = false,
@required this.child,
}) : assert(child != null),
assert(onPressed != null),
super(key: key);
/// The callback that is called when the button is tapped.
///
/// This attribute must not be null.
final VoidCallback onPressed;
/// Whether this action is the default choice in the action sheet.
///
/// Default buttons have bold text.
final bool isDefaultAction;
/// Whether this action might change or delete data.
///
/// Destructive buttons have red text.
final bool isDestructiveAction;
/// The widget below this widget in the tree.
///
/// Typically a [Text] widget.
final Widget child;
@override
Widget build(BuildContext context) {
TextStyle style = _kActionSheetActionStyle.copyWith(
color: isDestructiveAction
? CupertinoDynamicColor.resolve(CupertinoColors.systemRed, context)
: CupertinoTheme.of(context).primaryColor,
);
if (isDefaultAction) {
style = style.copyWith(fontWeight: FontWeight.w600);
}
return GestureDetector(
onTap: onPressed,
behavior: HitTestBehavior.opaque,
child: ConstrainedBox(
constraints: const BoxConstraints(
minHeight: _kButtonHeight,
),
child: Semantics(
button: true,
child: Container(
alignment: Alignment.center,
padding: const EdgeInsets.symmetric(
vertical: 16.0,
horizontal: 10.0,
),
child: DefaultTextStyle(
style: style,
child: child,
textAlign: TextAlign.center,
),
),
),
),
);
}
}
class _CupertinoActionSheetCancelButton extends StatefulWidget {
const _CupertinoActionSheetCancelButton({
Key key,
this.child,
}) : super(key: key);
final Widget child;
@override
_CupertinoActionSheetCancelButtonState createState() => _CupertinoActionSheetCancelButtonState();
}
class _CupertinoActionSheetCancelButtonState extends State<_CupertinoActionSheetCancelButton> {
bool isBeingPressed = false;
void _onTapDown(TapDownDetails event) {
setState(() { isBeingPressed = true; });
}
void _onTapUp(TapUpDetails event) {
setState(() { isBeingPressed = false; });
}
void _onTapCancel() {
setState(() { isBeingPressed = false; });
}
@override
Widget build(BuildContext context) {
final Color backgroundColor = isBeingPressed
? _kCancelPressedColor
: CupertinoColors.secondarySystemGroupedBackground;
return GestureDetector(
excludeFromSemantics: true,
onTapDown: _onTapDown,
onTapUp: _onTapUp,
onTapCancel: _onTapCancel,
child: Container(
decoration: BoxDecoration(
color: CupertinoDynamicColor.resolve(backgroundColor, context),
borderRadius: BorderRadius.circular(_kCornerRadius),
),
child: widget.child,
),
);
}
}
class _CupertinoAlertRenderWidget extends RenderObjectWidget {
const _CupertinoAlertRenderWidget({
Key key,
@required this.contentSection,
@required this.actionsSection,
}) : super(key: key);
final Widget contentSection;
final Widget actionsSection;
@override
RenderObject createRenderObject(BuildContext context) {
return _RenderCupertinoAlert(
dividerThickness: _kDividerThickness / MediaQuery.of(context).devicePixelRatio,
dividerColor: CupertinoDynamicColor.resolve(_kButtonDividerColor, context),
);
}
@override
void updateRenderObject(BuildContext context, _RenderCupertinoAlert renderObject) {
super.updateRenderObject(context, renderObject);
renderObject.dividerColor = CupertinoDynamicColor.resolve(_kButtonDividerColor, context);
}
@override
RenderObjectElement createElement() {
return _CupertinoAlertRenderElement(this);
}
}
class _CupertinoAlertRenderElement extends RenderObjectElement {
_CupertinoAlertRenderElement(_CupertinoAlertRenderWidget widget) : super(widget);
Element _contentElement;
Element _actionsElement;
@override
_CupertinoAlertRenderWidget get widget => super.widget as _CupertinoAlertRenderWidget;
@override
_RenderCupertinoAlert get renderObject => super.renderObject as _RenderCupertinoAlert;
@override
void visitChildren(ElementVisitor visitor) {
if (_contentElement != null) {
visitor(_contentElement);
}
if (_actionsElement != null) {
visitor(_actionsElement);
}
}
@override
void mount(Element parent, dynamic newSlot) {
super.mount(parent, newSlot);
_contentElement = updateChild(_contentElement,
widget.contentSection, _AlertSections.contentSection);
_actionsElement = updateChild(_actionsElement,
widget.actionsSection, _AlertSections.actionsSection);
}
@override
void insertChildRenderObject(RenderObject child, _AlertSections slot) {
_placeChildInSlot(child, slot);
}
@override
void moveChildRenderObject(RenderObject child, _AlertSections slot) {
_placeChildInSlot(child, slot);
}
@override
void update(RenderObjectWidget newWidget) {
super.update(newWidget);
_contentElement = updateChild(_contentElement,
widget.contentSection, _AlertSections.contentSection);
_actionsElement = updateChild(_actionsElement,
widget.actionsSection, _AlertSections.actionsSection);
}
@override
void forgetChild(Element child) {
assert(child == _contentElement || child == _actionsElement);
if (_contentElement == child) {
_contentElement = null;
} else if (_actionsElement == child) {
_actionsElement = null;
}
super.forgetChild(child);
}
@override
void removeChildRenderObject(RenderObject child) {
assert(child == renderObject.contentSection || child == renderObject.actionsSection);
if (renderObject.contentSection == child) {
renderObject.contentSection = null;
} else if (renderObject.actionsSection == child) {
renderObject.actionsSection = null;
}
}
void _placeChildInSlot(RenderObject child, _AlertSections slot) {
assert(slot != null);
switch (slot) {
case _AlertSections.contentSection:
renderObject.contentSection = child as RenderBox;
break;
case _AlertSections.actionsSection:
renderObject.actionsSection = child as RenderBox;
break;
}
}
}
// An iOS-style layout policy for sizing an alert's content section and action
// button section.
//
// The policy is as follows:
//
// If all content and buttons fit on the screen:
// The content section and action button section are sized intrinsically.
//
// If all content and buttons do not fit on the screen:
// A minimum height for the action button section is calculated. The action
// button section will not be rendered shorter than this minimum. See
// _RenderCupertinoAlertActions for the minimum height calculation.
//
// With the minimum action button section calculated, the content section can
// take up as much of the remaining space as it needs.
//
// After the content section is laid out, the action button section is allowed
// to take up any remaining space that was not consumed by the content section.
class _RenderCupertinoAlert extends RenderBox {
_RenderCupertinoAlert({
RenderBox contentSection,
RenderBox actionsSection,
double dividerThickness = 0.0,
@required Color dividerColor,
}) : assert(dividerColor != null),
_contentSection = contentSection,
_actionsSection = actionsSection,
_dividerThickness = dividerThickness,
_dividerPaint = Paint()
..color = dividerColor
..style = PaintingStyle.fill;
RenderBox get contentSection => _contentSection;
RenderBox _contentSection;
set contentSection(RenderBox newContentSection) {
if (newContentSection != _contentSection) {
if (null != _contentSection) {
dropChild(_contentSection);
}
_contentSection = newContentSection;
if (null != _contentSection) {
adoptChild(_contentSection);
}
}
}
RenderBox get actionsSection => _actionsSection;
RenderBox _actionsSection;
set actionsSection(RenderBox newActionsSection) {
if (newActionsSection != _actionsSection) {
if (null != _actionsSection) {
dropChild(_actionsSection);
}
_actionsSection = newActionsSection;
if (null != _actionsSection) {
adoptChild(_actionsSection);
}
}
}
Color get dividerColor => _dividerPaint.color;
set dividerColor(Color value) {
if (value == _dividerPaint.color)
return;
_dividerPaint.color = value;
markNeedsPaint();
}
final double _dividerThickness;
final Paint _dividerPaint;
@override
void attach(PipelineOwner owner) {
super.attach(owner);
if (null != contentSection) {
contentSection.attach(owner);
}
if (null != actionsSection) {
actionsSection.attach(owner);
}
}
@override
void detach() {
super.detach();
if (null != contentSection) {
contentSection.detach();
}
if (null != actionsSection) {
actionsSection.detach();
}
}
@override
void redepthChildren() {
if (null != contentSection) {
redepthChild(contentSection);
}
if (null != actionsSection) {
redepthChild(actionsSection);
}
}
@override
void setupParentData(RenderBox child) {
if (child.parentData is! MultiChildLayoutParentData) {
child.parentData = MultiChildLayoutParentData();
}
}
@override
void visitChildren(RenderObjectVisitor visitor) {
if (contentSection != null) {
visitor(contentSection);
}
if (actionsSection != null) {
visitor(actionsSection);
}
}
@override
List<DiagnosticsNode> debugDescribeChildren() {
final List<DiagnosticsNode> value = <DiagnosticsNode>[];
if (contentSection != null) {
value.add(contentSection.toDiagnosticsNode(name: 'content'));
}
if (actionsSection != null) {
value.add(actionsSection.toDiagnosticsNode(name: 'actions'));
}
return value;
}
@override
double computeMinIntrinsicWidth(double height) {
return constraints.minWidth;
}
@override
double computeMaxIntrinsicWidth(double height) {
return constraints.maxWidth;
}
@override
double computeMinIntrinsicHeight(double width) {
final double contentHeight = contentSection.getMinIntrinsicHeight(width);
final double actionsHeight = actionsSection.getMinIntrinsicHeight(width);
final bool hasDivider = contentHeight > 0.0 && actionsHeight > 0.0;
double height = contentHeight + (hasDivider ? _dividerThickness : 0.0) + actionsHeight;
if (actionsHeight > 0 || contentHeight > 0)
height -= 2 * _kEdgeVerticalPadding;
if (height.isFinite)
return height;
return 0.0;
}
@override
double computeMaxIntrinsicHeight(double width) {
final double contentHeight = contentSection.getMaxIntrinsicHeight(width);
final double actionsHeight = actionsSection.getMaxIntrinsicHeight(width);
final bool hasDivider = contentHeight > 0.0 && actionsHeight > 0.0;
double height = contentHeight + (hasDivider ? _dividerThickness : 0.0) + actionsHeight;
if (actionsHeight > 0 || contentHeight > 0)
height -= 2 * _kEdgeVerticalPadding;
if (height.isFinite)
return height;
return 0.0;
}
@override
void performLayout() {
final BoxConstraints constraints = this.constraints;
final bool hasDivider = contentSection.getMaxIntrinsicHeight(constraints.maxWidth) > 0.0
&& actionsSection.getMaxIntrinsicHeight(constraints.maxWidth) > 0.0;
final double dividerThickness = hasDivider ? _dividerThickness : 0.0;
final double minActionsHeight = actionsSection.getMinIntrinsicHeight(constraints.maxWidth);
// Size alert content.
contentSection.layout(
constraints.deflate(EdgeInsets.only(bottom: minActionsHeight + dividerThickness)),
parentUsesSize: true,
);
final Size contentSize = contentSection.size;
// Size alert actions.
actionsSection.layout(
constraints.deflate(EdgeInsets.only(top: contentSize.height + dividerThickness)),
parentUsesSize: true,
);
final Size actionsSize = actionsSection.size;
// Calculate overall alert height.
final double actionSheetHeight = contentSize.height + dividerThickness + actionsSize.height;
// Set our size now that layout calculations are complete.
size = Size(constraints.maxWidth, actionSheetHeight);
// Set the position of the actions box to sit at the bottom of the alert.
// The content box defaults to the top left, which is where we want it.
assert(actionsSection.parentData is MultiChildLayoutParentData);
final MultiChildLayoutParentData actionParentData = actionsSection.parentData as MultiChildLayoutParentData;
actionParentData.offset = Offset(0.0, contentSize.height + dividerThickness);
}
@override
void paint(PaintingContext context, Offset offset) {
final MultiChildLayoutParentData contentParentData = contentSection.parentData as MultiChildLayoutParentData;
contentSection.paint(context, offset + contentParentData.offset);
final bool hasDivider = contentSection.size.height > 0.0 && actionsSection.size.height > 0.0;
if (hasDivider) {
_paintDividerBetweenContentAndActions(context.canvas, offset);
}
final MultiChildLayoutParentData actionsParentData = actionsSection.parentData as MultiChildLayoutParentData;
actionsSection.paint(context, offset + actionsParentData.offset);
}
void _paintDividerBetweenContentAndActions(Canvas canvas, Offset offset) {
canvas.drawRect(
Rect.fromLTWH(
offset.dx,
offset.dy + contentSection.size.height,
size.width,
_dividerThickness,
),
_dividerPaint,
);
}
@override
bool hitTestChildren(BoxHitTestResult result, { Offset position }) {
final MultiChildLayoutParentData contentSectionParentData = contentSection.parentData as MultiChildLayoutParentData;
final MultiChildLayoutParentData actionsSectionParentData = actionsSection.parentData as MultiChildLayoutParentData;
return result.addWithPaintOffset(
offset: contentSectionParentData.offset,
position: position,
hitTest: (BoxHitTestResult result, Offset transformed) {
assert(transformed == position - contentSectionParentData.offset);
return contentSection.hitTest(result, position: transformed);
},
)
|| result.addWithPaintOffset(
offset: actionsSectionParentData.offset,
position: position,
hitTest: (BoxHitTestResult result, Offset transformed) {
assert(transformed == position - actionsSectionParentData.offset);
return actionsSection.hitTest(result, position: transformed);
},
);
}
}
// Visual components of an alert that need to be explicitly sized and
// laid out at runtime.
enum _AlertSections {
contentSection,
actionsSection,
}
// The "content section" of a CupertinoActionSheet.
//
// If title is missing, then only content is added. If content is
// missing, then only a title is added. If both are missing, then it returns
// a SingleChildScrollView with a zero-sized Container.
class _CupertinoAlertContentSection extends StatelessWidget {
const _CupertinoAlertContentSection({
Key key,
this.title,
this.message,
this.scrollController,
}) : super(key: key);
// An optional title of the action sheet. When the message is non-null,
// the font of the title is bold.
//
// Typically a Text widget.
final Widget title;
// An optional descriptive message that provides more details about the
// reason for the alert.
//
// Typically a Text widget.
final Widget message;
// A scroll controller that can be used to control the scrolling of the
// content in the action sheet.
//
// Defaults to null, and is typically not needed, since most alert contents
// are short.
final ScrollController scrollController;
@override
Widget build(BuildContext context) {
final List<Widget> titleContentGroup = <Widget>[];
if (title != null) {
titleContentGroup.add(Padding(
padding: const EdgeInsets.only(
left: _kContentHorizontalPadding,
right: _kContentHorizontalPadding,
bottom: _kContentVerticalPadding,
top: _kContentVerticalPadding,
),
child: DefaultTextStyle(
style: message == null ? _kActionSheetContentStyle
: _kActionSheetContentStyle.copyWith(fontWeight: FontWeight.w600),
textAlign: TextAlign.center,
child: title,
),
));
}
if (message != null) {
titleContentGroup.add(
Padding(
padding: EdgeInsets.only(
left: _kContentHorizontalPadding,
right: _kContentHorizontalPadding,
bottom: title == null ? _kContentVerticalPadding : 22.0,
top: title == null ? _kContentVerticalPadding : 0.0,
),
child: DefaultTextStyle(
style: title == null ? _kActionSheetContentStyle.copyWith(fontWeight: FontWeight.w600)
: _kActionSheetContentStyle,
textAlign: TextAlign.center,
child: message,
),
),
);
}
if (titleContentGroup.isEmpty) {
return SingleChildScrollView(
controller: scrollController,
child: const SizedBox(
width: 0.0,
height: 0.0,
),
);
}
// Add padding between the widgets if necessary.
if (titleContentGroup.length > 1) {
titleContentGroup.insert(1, const Padding(padding: EdgeInsets.only(top: 8.0)));
}
return CupertinoScrollbar(
child: SingleChildScrollView(
controller: scrollController,
child: Column(
mainAxisSize: MainAxisSize.max,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: titleContentGroup,
),
),
);
}
}
// The "actions section" of a CupertinoActionSheet.
//
// See _RenderCupertinoAlertActions for details about action button sizing
// and layout.
class _CupertinoAlertActionSection extends StatefulWidget {
const _CupertinoAlertActionSection({
Key key,
@required this.children,
this.scrollController,
this.hasCancelButton,
}) : assert(children != null),
super(key: key);
final List<Widget> children;
// A scroll controller that can be used to control the scrolling of the
// actions in the action sheet.
//
// Defaults to null, and is typically not needed, since most alerts
// don't have many actions.
final ScrollController scrollController;
final bool hasCancelButton;
@override
_CupertinoAlertActionSectionState createState() => _CupertinoAlertActionSectionState();
}
class _CupertinoAlertActionSectionState extends State<_CupertinoAlertActionSection> {
@override
Widget build(BuildContext context) {
final double devicePixelRatio = MediaQuery.of(context).devicePixelRatio;
final List<Widget> interactiveButtons = <Widget>[];
for (int i = 0; i < widget.children.length; i += 1) {
interactiveButtons.add(
_PressableActionButton(
child: widget.children[i],
),
);
}
return CupertinoScrollbar(
child: SingleChildScrollView(
controller: widget.scrollController,
child: _CupertinoAlertActionsRenderWidget(
actionButtons: interactiveButtons,
dividerThickness: _kDividerThickness / devicePixelRatio,
hasCancelButton: widget.hasCancelButton,
),
),
);
}
}
// A button that updates its render state when pressed.
//
// The pressed state is forwarded to an _ActionButtonParentDataWidget. The
// corresponding _ActionButtonParentData is then interpreted and rendered
// appropriately by _RenderCupertinoAlertActions.
class _PressableActionButton extends StatefulWidget {
const _PressableActionButton({
@required this.child,
});
final Widget child;
@override
_PressableActionButtonState createState() => _PressableActionButtonState();
}
class _PressableActionButtonState extends State<_PressableActionButton> {
bool _isPressed = false;
@override
Widget build(BuildContext context) {
return _ActionButtonParentDataWidget(
isPressed: _isPressed,
// TODO(mattcarroll): Button press dynamics need overhaul for iOS:
// https://github.com/flutter/flutter/issues/19786
child: GestureDetector(
excludeFromSemantics: true,
behavior: HitTestBehavior.opaque,
onTapDown: (TapDownDetails details) => setState(() => _isPressed = true),
onTapUp: (TapUpDetails details) => setState(() => _isPressed = false),
// TODO(mattcarroll): Cancel is currently triggered when user moves past
// slop instead of off button: https://github.com/flutter/flutter/issues/19783
onTapCancel: () => setState(() => _isPressed = false),
child: widget.child,
),
);
}
}
// ParentDataWidget that updates _ActionButtonParentData for an action button.
//
// Each action button requires knowledge of whether or not it is pressed so that
// the alert can correctly render the button. The pressed state is held within
// _ActionButtonParentData. _ActionButtonParentDataWidget is responsible for
// updating the pressed state of an _ActionButtonParentData based on the
// incoming isPressed property.
class _ActionButtonParentDataWidget extends ParentDataWidget<_ActionButtonParentData> {
const _ActionButtonParentDataWidget({
Key key,
this.isPressed,
@required Widget child,
}) : super(key: key, child: child);
final bool isPressed;
@override
void applyParentData(RenderObject renderObject) {
assert(renderObject.parentData is _ActionButtonParentData);
final _ActionButtonParentData parentData = renderObject.parentData as _ActionButtonParentData;
if (parentData.isPressed != isPressed) {
parentData.isPressed = isPressed;
// Force a repaint.
final AbstractNode targetParent = renderObject.parent;
if (targetParent is RenderObject)
targetParent.markNeedsPaint();
}
}
@override
Type get debugTypicalAncestorWidgetClass => _CupertinoAlertActionsRenderWidget;
}
// ParentData applied to individual action buttons that report whether or not
// that button is currently pressed by the user.
class _ActionButtonParentData extends MultiChildLayoutParentData {
_ActionButtonParentData({
this.isPressed = false,
});
bool isPressed;
}
// An iOS-style alert action button layout.
//
// See _RenderCupertinoAlertActions for specific layout policy details.
class _CupertinoAlertActionsRenderWidget extends MultiChildRenderObjectWidget {
_CupertinoAlertActionsRenderWidget({
Key key,
@required List<Widget> actionButtons,
double dividerThickness = 0.0,
bool hasCancelButton = false,
}) : _dividerThickness = dividerThickness,
_hasCancelButton = hasCancelButton,
super(key: key, children: actionButtons);
final double _dividerThickness;
final bool _hasCancelButton;
@override
RenderObject createRenderObject(BuildContext context) {
return _RenderCupertinoAlertActions(
dividerThickness: _dividerThickness,
dividerColor: CupertinoDynamicColor.resolve(_kButtonDividerColor, context),
hasCancelButton: _hasCancelButton,
backgroundColor: CupertinoDynamicColor.resolve(_kBackgroundColor, context),
pressedColor: CupertinoDynamicColor.resolve(_kPressedColor, context),
);
}
@override
void updateRenderObject(BuildContext context, _RenderCupertinoAlertActions renderObject) {
renderObject
..dividerThickness = _dividerThickness
..dividerColor = CupertinoDynamicColor.resolve(_kButtonDividerColor, context)
..hasCancelButton = _hasCancelButton
..backgroundColor = CupertinoDynamicColor.resolve(_kBackgroundColor, context)
..pressedColor = CupertinoDynamicColor.resolve(_kPressedColor, context);
}
}
// An iOS-style layout policy for sizing and positioning an action sheet's
// buttons.
//
// The policy is as follows:
//
// Action sheet buttons are always stacked vertically. In the case where the
// content section and the action section combined can not fit on the screen
// without scrolling, the height of the action section is determined as
// follows.
//
// If the user has included a separate cancel button, the height of the action
// section can be up to the height of 3 action buttons (i.e., the user can
// include 1, 2, or 3 action buttons and they will appear without needing to
// be scrolled). If 4+ action buttons are provided, the height of the action
// section shrinks to 1.5 buttons tall, and is scrollable.
//
// If the user has not included a separate cancel button, the height of the
// action section is at most 1.5 buttons tall.
class _RenderCupertinoAlertActions extends RenderBox
with ContainerRenderObjectMixin<RenderBox, MultiChildLayoutParentData>,
RenderBoxContainerDefaultsMixin<RenderBox, MultiChildLayoutParentData> {
_RenderCupertinoAlertActions({
List<RenderBox> children,
double dividerThickness = 0.0,
@required Color dividerColor,
bool hasCancelButton = false,
Color backgroundColor,
Color pressedColor,
}) : _dividerThickness = dividerThickness,
_hasCancelButton = hasCancelButton,
_buttonBackgroundPaint = Paint()
..style = PaintingStyle.fill
..color = backgroundColor,
_pressedButtonBackgroundPaint = Paint()
..style = PaintingStyle.fill
..color = pressedColor,
_dividerPaint = Paint()
..color = dividerColor
..style = PaintingStyle.fill {
addAll(children);
}
// The thickness of the divider between buttons.
double get dividerThickness => _dividerThickness;
double _dividerThickness;
set dividerThickness(double newValue) {
if (newValue == _dividerThickness) {
return;
}
_dividerThickness = newValue;
markNeedsLayout();
}
Color get backgroundColor => _buttonBackgroundPaint.color;
set backgroundColor(Color newValue) {
if (newValue == _buttonBackgroundPaint.color) {
return;
}
_buttonBackgroundPaint.color = newValue;
markNeedsPaint();
}
Color get pressedColor => _pressedButtonBackgroundPaint.color;
set pressedColor(Color newValue) {
if (newValue == _pressedButtonBackgroundPaint.color) {
return;
}
_pressedButtonBackgroundPaint.color = newValue;
markNeedsPaint();
}
Color get dividerColor => _dividerPaint.color;
set dividerColor(Color value) {
if (value == _dividerPaint.color) {
return;
}
_dividerPaint.color = value;
markNeedsPaint();
}
bool _hasCancelButton;
bool get hasCancelButton => _hasCancelButton;
set hasCancelButton(bool newValue) {
if (newValue == _hasCancelButton) {
return;
}
_hasCancelButton = newValue;
markNeedsLayout();
}
final Paint _buttonBackgroundPaint;
final Paint _pressedButtonBackgroundPaint;
final Paint _dividerPaint;
@override
void setupParentData(RenderBox child) {
if (child.parentData is! _ActionButtonParentData)
child.parentData = _ActionButtonParentData();
}
@override
double computeMinIntrinsicWidth(double height) {
return constraints.minWidth;
}
@override
double computeMaxIntrinsicWidth(double height) {
return constraints.maxWidth;
}
@override
double computeMinIntrinsicHeight(double width) {
if (childCount == 0)
return 0.0;
if (childCount == 1)
return firstChild.computeMaxIntrinsicHeight(width) + dividerThickness;
if (hasCancelButton && childCount < 4)
return _computeMinIntrinsicHeightWithCancel(width);
return _computeMinIntrinsicHeightWithoutCancel(width);
}
// The minimum height for more than 2-3 buttons when a cancel button is
// included is the full height of button stack.
double _computeMinIntrinsicHeightWithCancel(double width) {
assert(childCount == 2 || childCount == 3);
if (childCount == 2) {
return firstChild.getMinIntrinsicHeight(width)
+ childAfter(firstChild).getMinIntrinsicHeight(width)
+ dividerThickness;
}
return firstChild.getMinIntrinsicHeight(width)
+ childAfter(firstChild).getMinIntrinsicHeight(width)
+ childAfter(childAfter(firstChild)).getMinIntrinsicHeight(width)
+ (dividerThickness * 2);
}
// The minimum height for more than 2 buttons when no cancel button or 4+
// buttons when a cancel button is included is the height of the 1st button
// + 50% the height of the 2nd button + 2 dividers.
double _computeMinIntrinsicHeightWithoutCancel(double width) {
assert(childCount >= 2);
return firstChild.getMinIntrinsicHeight(width)
+ dividerThickness
+ (0.5 * childAfter(firstChild).getMinIntrinsicHeight(width));
}
@override
double computeMaxIntrinsicHeight(double width) {
if (childCount == 0)
return 0.0;
if (childCount == 1)
return firstChild.computeMaxIntrinsicHeight(width) + dividerThickness;
return _computeMaxIntrinsicHeightStacked(width);
}
// Max height of a stack of buttons is the sum of all button heights + a
// divider for each button.
double _computeMaxIntrinsicHeightStacked(double width) {
assert(childCount >= 2);
final double allDividersHeight = (childCount - 1) * dividerThickness;
double heightAccumulation = allDividersHeight;
RenderBox button = firstChild;
while (button != null) {
heightAccumulation += button.getMaxIntrinsicHeight(width);
button = childAfter(button);
}
return heightAccumulation;
}
@override
void performLayout() {
final BoxConstraints perButtonConstraints = constraints.copyWith(
minHeight: 0.0,
maxHeight: double.infinity,
);
RenderBox child = firstChild;
int index = 0;
double verticalOffset = 0.0;
while (child != null) {
child.layout(
perButtonConstraints,
parentUsesSize: true,
);
assert(child.parentData is MultiChildLayoutParentData);
final MultiChildLayoutParentData parentData = child.parentData as MultiChildLayoutParentData;
parentData.offset = Offset(0.0, verticalOffset);
verticalOffset += child.size.height;
if (index < childCount - 1) {
// Add a gap for the next divider.
verticalOffset += dividerThickness;
}
index += 1;
child = childAfter(child);
}
size = constraints.constrain(
Size(constraints.maxWidth, verticalOffset)
);
}
@override
void paint(PaintingContext context, Offset offset) {
final Canvas canvas = context.canvas;
_drawButtonBackgroundsAndDividersStacked(canvas, offset);
_drawButtons(context, offset);
}
void _drawButtonBackgroundsAndDividersStacked(Canvas canvas, Offset offset) {
final Offset dividerOffset = Offset(0.0, dividerThickness);
final Path backgroundFillPath = Path()
..fillType = PathFillType.evenOdd
..addRect(Rect.fromLTWH(0.0, 0.0, size.width, size.height));
final Path pressedBackgroundFillPath = Path();
final Path dividersPath = Path();
Offset accumulatingOffset = offset;
RenderBox child = firstChild;
RenderBox prevChild;
while (child != null) {
assert(child.parentData is _ActionButtonParentData);
final _ActionButtonParentData currentButtonParentData = child.parentData as _ActionButtonParentData;
final bool isButtonPressed = currentButtonParentData.isPressed;
bool isPrevButtonPressed = false;
if (prevChild != null) {
assert(prevChild.parentData is _ActionButtonParentData);
final _ActionButtonParentData previousButtonParentData = prevChild.parentData as _ActionButtonParentData;
isPrevButtonPressed = previousButtonParentData.isPressed;
}
final bool isDividerPresent = child != firstChild;
final bool isDividerPainted = isDividerPresent && !(isButtonPressed || isPrevButtonPressed);
final Rect dividerRect = Rect.fromLTWH(
accumulatingOffset.dx,
accumulatingOffset.dy,
size.width,
_dividerThickness,
);
final Rect buttonBackgroundRect = Rect.fromLTWH(
accumulatingOffset.dx,
accumulatingOffset.dy + (isDividerPresent ? dividerThickness : 0.0),
size.width,
child.size.height,
);
// If this button is pressed, then we don't want a white background to be
// painted, so we erase this button from the background path.
if (isButtonPressed) {
backgroundFillPath.addRect(buttonBackgroundRect);
pressedBackgroundFillPath.addRect(buttonBackgroundRect);
}
// If this divider is needed, then we erase the divider area from the
// background path, and on top of that we paint a translucent gray to
// darken the divider area.
if (isDividerPainted) {
backgroundFillPath.addRect(dividerRect);
dividersPath.addRect(dividerRect);
}
accumulatingOffset += (isDividerPresent ? dividerOffset : Offset.zero)
+ Offset(0.0, child.size.height);
prevChild = child;
child = childAfter(child);
}
canvas.drawPath(backgroundFillPath, _buttonBackgroundPaint);
canvas.drawPath(pressedBackgroundFillPath, _pressedButtonBackgroundPaint);
canvas.drawPath(dividersPath, _dividerPaint);
}
void _drawButtons(PaintingContext context, Offset offset) {
RenderBox child = firstChild;
while (child != null) {
final MultiChildLayoutParentData childParentData = child.parentData as MultiChildLayoutParentData;
context.paintChild(child, childParentData.offset + offset);
child = childAfter(child);
}
}
@override
bool hitTestChildren(BoxHitTestResult result, { Offset position }) {
return defaultHitTestChildren(result, position: position);
}
}