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// 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:math' as math;
import 'package:flutter/foundation.dart';
import 'package:flutter/painting.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';
import 'button.dart';
import 'floating_action_button_theme.dart';
import 'scaffold.dart';
import 'theme.dart';
import 'theme_data.dart';
import 'tooltip.dart';
const BoxConstraints _kSizeConstraints = BoxConstraints.tightFor(
width: 56.0,
height: 56.0,
);
const BoxConstraints _kMiniSizeConstraints = BoxConstraints.tightFor(
width: 40.0,
height: 40.0,
);
const BoxConstraints _kExtendedSizeConstraints = BoxConstraints(
minHeight: 48.0,
maxHeight: 48.0,
);
class _DefaultHeroTag {
const _DefaultHeroTag();
@override
String toString() => '<default FloatingActionButton tag>';
}
/// A material design floating action button.
///
/// A floating action button is a circular icon button that hovers over content
/// to promote a primary action in the application. Floating action buttons are
/// most commonly used in the [Scaffold.floatingActionButton] field.
///
/// {@youtube 560 315 https://www.youtube.com/watch?v=2uaoEDOgk_I}
///
/// Use at most a single floating action button per screen. Floating action
/// buttons should be used for positive actions such as "create", "share", or
/// "navigate". (If more than one floating action button is used within a
/// [Route], then make sure that each button has a unique [heroTag], otherwise
/// an exception will be thrown.)
///
/// If the [onPressed] callback is null, then the button will be disabled and
/// will not react to touch. It is highly discouraged to disable a floating
/// action button as there is no indication to the user that the button is
/// disabled. Consider changing the [backgroundColor] if disabling the floating
/// action button.
///
/// {@tool snippet --template=stateless_widget_material}
/// This example shows how to display a [FloatingActionButton] in a
/// [Scaffold], with a pink [backgroundColor] and a thumbs up [Icon].
///
/// ![](https://flutter.github.io/assets-for-api-docs/assets/material/floating_action_button.png)
///
/// ```dart
/// Widget build(BuildContext context) {
/// return Scaffold(
/// appBar: AppBar(
/// title: const Text('Floating Action Button'),
/// ),
/// body: Center(
/// child: const Text('Press the button below!')
/// ),
/// floatingActionButton: FloatingActionButton(
/// onPressed: () {
/// // Add your onPressed code here!
/// },
/// child: Icon(Icons.navigation),
/// backgroundColor: Colors.green,
/// ),
/// );
/// }
/// ```
/// {@end-tool}
///
/// {@tool snippet --template=stateless_widget_material}
/// This example shows how to make an extended [FloatingActionButton] in a
/// [Scaffold], with a pink [backgroundColor], a thumbs up [Icon] and a
/// [Text] label that reads "Approve".
///
/// ![](https://flutter.github.io/assets-for-api-docs/assets/material/floating_action_button_label.png)
///
/// ```dart
/// Widget build(BuildContext context) {
/// return Scaffold(
/// appBar: AppBar(
/// title: const Text('Floating Action Button Label'),
/// ),
/// body: Center(
/// child: const Text('Press the button with a label below!'),
/// ),
/// floatingActionButton: FloatingActionButton.extended(
/// onPressed: () {
/// // Add your onPressed code here!
/// },
/// label: Text('Approve'),
/// icon: Icon(Icons.thumb_up),
/// backgroundColor: Colors.pink,
/// ),
/// );
/// }
/// ```
/// {@end-tool}
///
/// See also:
///
/// * [Scaffold], in which floating action buttons typically live.
/// * [RaisedButton], another kind of button that appears to float above the
/// content.
/// * <https://material.io/design/components/buttons-floating-action-button.html>
class FloatingActionButton extends StatelessWidget {
/// Creates a circular floating action button.
///
/// The [mini] and [clipBehavior] arguments must not be null. Additionally,
/// [elevation], [highlightElevation], and [disabledElevation] (if specified)
/// must be non-negative.
const FloatingActionButton({
Key key,
this.child,
this.tooltip,
this.foregroundColor,
this.backgroundColor,
this.focusColor,
this.hoverColor,
this.splashColor,
this.heroTag = const _DefaultHeroTag(),
this.elevation,
this.focusElevation,
this.hoverElevation,
this.highlightElevation,
this.disabledElevation,
@required this.onPressed,
this.mini = false,
this.shape,
this.clipBehavior = Clip.none,
this.focusNode,
this.autofocus = false,
this.materialTapTargetSize,
this.isExtended = false,
}) : assert(elevation == null || elevation >= 0.0),
assert(focusElevation == null || focusElevation >= 0.0),
assert(hoverElevation == null || hoverElevation >= 0.0),
assert(highlightElevation == null || highlightElevation >= 0.0),
assert(disabledElevation == null || disabledElevation >= 0.0),
assert(mini != null),
assert(clipBehavior != null),
assert(isExtended != null),
assert(autofocus != null),
_sizeConstraints = mini ? _kMiniSizeConstraints : _kSizeConstraints,
super(key: key);
/// Creates a wider [StadiumBorder]-shaped floating action button with
/// an optional [icon] and a [label].
///
/// The [label], [autofocus], and [clipBehavior] arguments must not be null.
/// Additionally, [elevation], [highlightElevation], and [disabledElevation]
/// (if specified) must be non-negative.
FloatingActionButton.extended({
Key key,
this.tooltip,
this.foregroundColor,
this.backgroundColor,
this.focusColor,
this.hoverColor,
this.heroTag = const _DefaultHeroTag(),
this.elevation,
this.focusElevation,
this.hoverElevation,
this.splashColor,
this.highlightElevation,
this.disabledElevation,
@required this.onPressed,
this.shape,
this.isExtended = true,
this.materialTapTargetSize,
this.clipBehavior = Clip.none,
this.focusNode,
this.autofocus = false,
Widget icon,
@required Widget label,
}) : assert(elevation == null || elevation >= 0.0),
assert(focusElevation == null || focusElevation >= 0.0),
assert(hoverElevation == null || hoverElevation >= 0.0),
assert(highlightElevation == null || highlightElevation >= 0.0),
assert(disabledElevation == null || disabledElevation >= 0.0),
assert(isExtended != null),
assert(clipBehavior != null),
assert(autofocus != null),
_sizeConstraints = _kExtendedSizeConstraints,
mini = false,
child = _ChildOverflowBox(
child: Row(
mainAxisSize: MainAxisSize.min,
children: icon == null
? <Widget>[
const SizedBox(width: 20.0),
label,
const SizedBox(width: 20.0),
]
: <Widget>[
const SizedBox(width: 16.0),
icon,
const SizedBox(width: 8.0),
label,
const SizedBox(width: 20.0),
],
),
),
super(key: key);
/// The widget below this widget in the tree.
///
/// Typically an [Icon].
final Widget child;
/// Text that describes the action that will occur when the button is pressed.
///
/// This text is displayed when the user long-presses on the button and is
/// used for accessibility.
final String tooltip;
/// The default icon and text color.
///
/// Defaults to [ThemeData.accentIconTheme.color] for the current theme.
final Color foregroundColor;
/// The color to use when filling the button.
///
/// Defaults to [ThemeData.accentColor] for the current theme.
final Color backgroundColor;
/// The color to use for filling the button when the button has input focus.
///
/// Defaults to [ThemeData.focusColor] for the current theme.
final Color focusColor;
/// The color to use for filling the button when the button has a pointer
/// hovering over it.
///
/// Defaults to [ThemeData.hoverColor] for the current theme.
final Color hoverColor;
/// The splash color for this [FloatingActionButton]'s [InkWell].
///
/// If null, [FloatingActionButtonThemeData.splashColor] is used, if that is
/// null, [ThemeData.splashColor] is used.
final Color splashColor;
/// The tag to apply to the button's [Hero] widget.
///
/// Defaults to a tag that matches other floating action buttons.
///
/// Set this to null explicitly if you don't want the floating action button to
/// have a hero tag.
///
/// If this is not explicitly set, then there can only be one
/// [FloatingActionButton] per route (that is, per screen), since otherwise
/// there would be a tag conflict (multiple heroes on one route can't have the
/// same tag). The material design specification recommends only using one
/// floating action button per screen.
final Object heroTag;
/// The callback that is called when the button is tapped or otherwise activated.
///
/// If this is set to null, the button will be disabled.
final VoidCallback onPressed;
/// The z-coordinate at which to place this button relative to its parent.
///
/// This controls the size of the shadow below the floating action button.
///
/// Defaults to 6, the appropriate elevation for floating action buttons. The
/// value is always non-negative.
///
/// See also:
///
/// * [highlightElevation], the elevation when the button is pressed.
/// * [disabledElevation], the elevation when the button is disabled.
final double elevation;
/// The z-coordinate at which to place this button relative to its parent when
/// the button has the input focus.
///
/// This controls the size of the shadow below the floating action button.
///
/// Defaults to 8, the appropriate elevation for floating action buttons
/// while they have focus. The value is always non-negative.
///
/// See also:
///
/// * [elevation], the default elevation.
/// * [highlightElevation], the elevation when the button is pressed.
/// * [disabledElevation], the elevation when the button is disabled.
final double focusElevation;
/// The z-coordinate at which to place this button relative to its parent when
/// the button is enabled and has a pointer hovering over it.
///
/// This controls the size of the shadow below the floating action button.
///
/// Defaults to 8, the appropriate elevation for floating action buttons while
/// they have a pointer hovering over them. The value is always non-negative.
///
/// See also:
///
/// * [elevation], the default elevation.
/// * [highlightElevation], the elevation when the button is pressed.
/// * [disabledElevation], the elevation when the button is disabled.
final double hoverElevation;
/// The z-coordinate at which to place this button relative to its parent when
/// the user is touching the button.
///
/// This controls the size of the shadow below the floating action button.
///
/// Defaults to 12, the appropriate elevation for floating action buttons
/// while they are being touched. The value is always non-negative.
///
/// See also:
///
/// * [elevation], the default elevation.
final double highlightElevation;
/// The z-coordinate at which to place this button when the button is disabled
/// ([onPressed] is null).
///
/// This controls the size of the shadow below the floating action button.
///
/// Defaults to the same value as [elevation]. Setting this to zero makes the
/// floating action button work similar to a [RaisedButton] but the titular
/// "floating" effect is lost. The value is always non-negative.
///
/// See also:
///
/// * [elevation], the default elevation.
/// * [highlightElevation], the elevation when the button is pressed.
final double disabledElevation;
/// Controls the size of this button.
///
/// By default, floating action buttons are non-mini and have a height and
/// width of 56.0 logical pixels. Mini floating action buttons have a height
/// and width of 40.0 logical pixels with a layout width and height of 48.0
/// logical pixels. (The extra 4 pixels of padding on each side are added as a
/// result of the floating action button having [MaterialTapTargetSize.padded]
/// set on the underlying [RawMaterialButton.materialTapTargetSize].)
final bool mini;
/// The shape of the button's [Material].
///
/// The button's highlight and splash are clipped to this shape. If the
/// button has an elevation, then its drop shadow is defined by this
/// shape as well.
final ShapeBorder shape;
/// {@macro flutter.widgets.Clip}
///
/// Defaults to [Clip.none], and must not be null.
final Clip clipBehavior;
/// True if this is an "extended" floating action button.
///
/// Typically [extended] buttons have a [StadiumBorder] [shape]
/// and have been created with the [FloatingActionButton.extended]
/// constructor.
///
/// The [Scaffold] animates the appearance of ordinary floating
/// action buttons with scale and rotation transitions. Extended
/// floating action buttons are scaled and faded in.
final bool isExtended;
/// {@macro flutter.widgets.Focus.focusNode}
final FocusNode focusNode;
/// {@macro flutter.widgets.Focus.autofocus}
final bool autofocus;
/// Configures the minimum size of the tap target.
///
/// Defaults to [ThemeData.materialTapTargetSize].
///
/// See also:
///
/// * [MaterialTapTargetSize], for a description of how this affects tap targets.
final MaterialTapTargetSize materialTapTargetSize;
final BoxConstraints _sizeConstraints;
static const double _defaultElevation = 6;
// TODO(gspencer): verify focus and hover elevation values are correct
// according to spec.
static const double _defaultFocusElevation = 8;
static const double _defaultHoverElevation = 10;
static const double _defaultHighlightElevation = 12;
static const ShapeBorder _defaultShape = CircleBorder();
static const ShapeBorder _defaultExtendedShape = StadiumBorder();
@override
Widget build(BuildContext context) {
final ThemeData theme = Theme.of(context);
final FloatingActionButtonThemeData floatingActionButtonTheme = theme.floatingActionButtonTheme;
final Color foregroundColor = this.foregroundColor
?? floatingActionButtonTheme.foregroundColor
?? theme.accentIconTheme.color
?? theme.colorScheme.onSecondary;
final Color backgroundColor = this.backgroundColor
?? floatingActionButtonTheme.backgroundColor
?? theme.colorScheme.secondary;
final Color focusColor = this.focusColor
?? floatingActionButtonTheme.focusColor
?? theme.focusColor;
final Color hoverColor = this.hoverColor
?? floatingActionButtonTheme.hoverColor
?? theme.hoverColor;
final Color splashColor = this.splashColor
?? floatingActionButtonTheme.splashColor
?? theme.splashColor;
final double elevation = this.elevation
?? floatingActionButtonTheme.elevation
?? _defaultElevation;
final double focusElevation = this.focusElevation
?? floatingActionButtonTheme.focusElevation
?? _defaultFocusElevation;
final double hoverElevation = this.hoverElevation
?? floatingActionButtonTheme.hoverElevation
?? _defaultHoverElevation;
final double disabledElevation = this.disabledElevation
?? floatingActionButtonTheme.disabledElevation
?? elevation;
final double highlightElevation = this.highlightElevation
?? floatingActionButtonTheme.highlightElevation
?? _defaultHighlightElevation;
final MaterialTapTargetSize materialTapTargetSize = this.materialTapTargetSize
?? theme.materialTapTargetSize;
final TextStyle textStyle = theme.accentTextTheme.button.copyWith(
color: foregroundColor,
letterSpacing: 1.2,
);
final ShapeBorder shape = this.shape
?? floatingActionButtonTheme.shape
?? (isExtended ? _defaultExtendedShape : _defaultShape);
Widget result = RawMaterialButton(
onPressed: onPressed,
elevation: elevation,
focusElevation: focusElevation,
hoverElevation: hoverElevation,
highlightElevation: highlightElevation,
disabledElevation: disabledElevation,
constraints: _sizeConstraints,
materialTapTargetSize: materialTapTargetSize,
fillColor: backgroundColor,
focusColor: focusColor,
hoverColor: hoverColor,
splashColor: splashColor,
textStyle: textStyle,
shape: shape,
clipBehavior: clipBehavior,
focusNode: focusNode,
autofocus: autofocus,
child: child,
);
if (tooltip != null) {
result = Tooltip(
message: tooltip,
child: result,
);
}
if (heroTag != null) {
result = Hero(
tag: heroTag,
child: result,
);
}
return MergeSemantics(child: result);
}
@override
void debugFillProperties(DiagnosticPropertiesBuilder properties) {
super.debugFillProperties(properties);
properties.add(ObjectFlagProperty<VoidCallback>('onPressed', onPressed, ifNull: 'disabled'));
properties.add(StringProperty('tooltip', tooltip, defaultValue: null));
properties.add(ColorProperty('foregroundColor', foregroundColor, defaultValue: null));
properties.add(ColorProperty('backgroundColor', backgroundColor, defaultValue: null));
properties.add(ColorProperty('focusColor', focusColor, defaultValue: null));
properties.add(ColorProperty('hoverColor', hoverColor, defaultValue: null));
properties.add(ColorProperty('splashColor', splashColor, defaultValue: null));
properties.add(ObjectFlagProperty<Object>('heroTag', heroTag, ifPresent: 'hero'));
properties.add(DoubleProperty('elevation', elevation, defaultValue: null));
properties.add(DoubleProperty('focusElevation', focusElevation, defaultValue: null));
properties.add(DoubleProperty('hoverElevation', hoverElevation, defaultValue: null));
properties.add(DoubleProperty('highlightElevation', highlightElevation, defaultValue: null));
properties.add(DoubleProperty('disabledElevation', disabledElevation, defaultValue: null));
properties.add(DiagnosticsProperty<ShapeBorder>('shape', shape, defaultValue: null));
properties.add(DiagnosticsProperty<FocusNode>('focusNode', focusNode, defaultValue: null));
properties.add(FlagProperty('isExtended', value: isExtended, ifTrue: 'extended'));
properties.add(DiagnosticsProperty<MaterialTapTargetSize>('materialTapTargetSize', materialTapTargetSize, defaultValue: null));
}
}
// This widget's size matches its child's size unless its constraints
// force it to be larger or smaller. The child is centered.
//
// Used to encapsulate extended FABs whose size is fixed, using Row
// and MainAxisSize.min, to be as wide as their label and icon.
class _ChildOverflowBox extends SingleChildRenderObjectWidget {
const _ChildOverflowBox({
Key key,
Widget child,
}) : super(key: key, child: child);
@override
_RenderChildOverflowBox createRenderObject(BuildContext context) {
return _RenderChildOverflowBox(
textDirection: Directionality.of(context),
);
}
@override
void updateRenderObject(BuildContext context, _RenderChildOverflowBox renderObject) {
renderObject
..textDirection = Directionality.of(context);
}
}
class _RenderChildOverflowBox extends RenderAligningShiftedBox {
_RenderChildOverflowBox({
RenderBox child,
TextDirection textDirection,
}) : super(child: child, alignment: Alignment.center, textDirection: textDirection);
@override
double computeMinIntrinsicWidth(double height) => 0.0;
@override
double computeMinIntrinsicHeight(double width) => 0.0;
@override
void performLayout() {
if (child != null) {
child.layout(const BoxConstraints(), parentUsesSize: true);
size = Size(
math.max(constraints.minWidth, math.min(constraints.maxWidth, child.size.width)),
math.max(constraints.minHeight, math.min(constraints.maxHeight, child.size.height)),
);
alignChild();
} else {
size = constraints.biggest;
}
}
}
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