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// 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 'package:flutter/widgets.dart';
import '../color_scheme.dart';
import '../icon_button.dart';
import '../text_theme.dart';
import '../theme.dart';
// NOTE: This is an internal implementation file. Even though there are public
// classes and functions defined here, they are only meant to be used by the
// date picker implementation and are not exported as part of the Material library.
// See pickers.dart for exactly what is considered part of the public API.
const double _datePickerHeaderLandscapeWidth = 152.0;
const double _datePickerHeaderPortraitHeight = 120.0;
const double _headerPaddingLandscape = 16.0;
/// Re-usable widget that displays the selected date (in large font) and the
/// help text above it.
///
/// These types include:
///
/// * Single Date picker with calendar mode.
/// * Single Date picker with manual input mode.
///
/// [helpText], [orientation], [icon], [onIconPressed] are required and must be
/// non-null.
class DatePickerHeader extends StatelessWidget {
/// Creates a header for use in a date picker dialog.
const DatePickerHeader({
Key key,
@required this.helpText,
@required this.titleText,
this.titleSemanticsLabel,
@required this.titleStyle,
@required this.orientation,
this.isShort = false,
@required this.icon,
@required this.iconTooltip,
@required this.onIconPressed,
}) : assert(helpText != null),
assert(orientation != null),
assert(isShort != null),
super(key: key);
/// The text that is displayed at the top of the header.
///
/// This is used to indicate to the user what they are selecting a date for.
final String helpText;
/// The text that is displayed at the center of the header.
final String titleText;
/// The semantic label associated with the [titleText].
final String titleSemanticsLabel;
/// The [TextStyle] that the title text is displayed with.
final TextStyle titleStyle;
/// The orientation is used to decide how to layout its children.
final Orientation orientation;
/// Indicates the header is being displayed in a shorter/narrower context.
///
/// This will be used to tighten up the space between the help text and date
/// text if `true`. Additionally, it will use a smaller typography style if
/// `true`.
///
/// This is necessary for displaying the manual input mode in
/// landscape orientation, in order to account for the keyboard height.
final bool isShort;
/// The mode-switching icon that will be displayed in the lower right
/// in portrait, and lower left in landscape.
///
/// The available icons are described in [Icons].
final IconData icon;
/// The text that is displayed for the tooltip of the icon.
final String iconTooltip;
/// Callback when the user taps the icon in the header.
///
/// The picker will use this to toggle between entry modes.
final VoidCallback onIconPressed;
@override
Widget build(BuildContext context) {
final ThemeData theme = Theme.of(context);
final ColorScheme colorScheme = theme.colorScheme;
final TextTheme textTheme = theme.textTheme;
// The header should use the primary color in light themes and surface color in dark
final bool isDark = colorScheme.brightness == Brightness.dark;
final Color primarySurfaceColor = isDark ? colorScheme.surface : colorScheme.primary;
final Color onPrimarySurfaceColor = isDark ? colorScheme.onSurface : colorScheme.onPrimary;
final TextStyle helpStyle = textTheme.overline?.copyWith(
color: onPrimarySurfaceColor,
);
final Text help = Text(
helpText,
style: helpStyle,
maxLines: 1,
overflow: TextOverflow.ellipsis,
);
final Text title = Text(
titleText,
semanticsLabel: titleSemanticsLabel ?? titleText,
style: titleStyle,
maxLines: (isShort || orientation == Orientation.portrait) ? 1 : 2,
overflow: TextOverflow.ellipsis,
);
final IconButton icon = IconButton(
icon: Icon(this.icon),
color: onPrimarySurfaceColor,
tooltip: iconTooltip,
onPressed: onIconPressed,
);
switch (orientation) {
case Orientation.portrait:
return Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Container(
height: _datePickerHeaderPortraitHeight,
color: primarySurfaceColor,
padding: const EdgeInsetsDirectional.only(
start: 24,
end: 12,
),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
const SizedBox(height: 16),
Flexible(child: help),
const SizedBox(height: 38),
Row(
children: <Widget>[
Expanded(child: title),
icon,
],
),
],
),
),
],
);
case Orientation.landscape:
return Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Container(
width: _datePickerHeaderLandscapeWidth,
color: primarySurfaceColor,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
const SizedBox(height: 16),
Padding(
padding: const EdgeInsets.symmetric(
horizontal: _headerPaddingLandscape,
),
child: help,
),
SizedBox(height: isShort ? 16 : 56),
Padding(
padding: const EdgeInsets.symmetric(
horizontal: _headerPaddingLandscape,
),
child: title,
),
const Spacer(),
Padding(
padding: const EdgeInsets.symmetric(
horizontal: 4,
),
child: icon,
),
],
),
),
],
);
}
return null;
}
}