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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/cupertino.dart';
import 'checkbox_theme.dart';
import 'color_scheme.dart';
import 'colors.dart';
import 'constants.dart';
import 'debug.dart';
import 'material_state.dart';
import 'theme.dart';
import 'theme_data.dart';
import 'toggleable.dart';
// Examples can assume:
// bool _throwShotAway = false;
// late StateSetter setState;
enum _CheckboxType { material, adaptive }
/// A Material Design checkbox.
///
/// The checkbox itself does not maintain any state. Instead, when the state of
/// the checkbox changes, the widget calls the [onChanged] callback. Most
/// widgets that use a checkbox will listen for the [onChanged] callback and
/// rebuild the checkbox with a new [value] to update the visual appearance of
/// the checkbox.
///
/// The checkbox can optionally display three values - true, false, and null -
/// if [tristate] is true. When [value] is null a dash is displayed. By default
/// [tristate] is false and the checkbox's [value] must be true or false.
///
/// Requires one of its ancestors to be a [Material] widget.
///
/// {@tool dartpad}
/// This example shows how you can override the default theme of
/// a [Checkbox] with a [MaterialStateProperty].
/// In this example, the checkbox's color will be `Colors.blue` when the [Checkbox]
/// is being pressed, hovered, or focused. Otherwise, the checkbox's color will
/// be `Colors.red`.
///
/// ** See code in examples/api/lib/material/checkbox/checkbox.0.dart **
/// {@end-tool}
///
/// {@tool dartpad}
/// This example shows what the checkbox error state looks like.
///
/// ** See code in examples/api/lib/material/checkbox/checkbox.1.dart **
/// {@end-tool}
///
/// See also:
///
/// * [CheckboxListTile], which combines this widget with a [ListTile] so that
/// you can give the checkbox a label.
/// * [Switch], a widget with semantics similar to [Checkbox].
/// * [Radio], for selecting among a set of explicit values.
/// * [Slider], for selecting a value in a range.
/// * <https://material.io/design/components/selection-controls.html#checkboxes>
/// * <https://material.io/design/components/lists.html#types>
class Checkbox extends StatefulWidget {
/// Creates a Material Design checkbox.
///
/// The checkbox itself does not maintain any state. Instead, when the state of
/// the checkbox changes, the widget calls the [onChanged] callback. Most
/// widgets that use a checkbox will listen for the [onChanged] callback and
/// rebuild the checkbox with a new [value] to update the visual appearance of
/// the checkbox.
///
/// The following arguments are required:
///
/// * [value], which determines whether the checkbox is checked. The [value]
/// can only be null if [tristate] is true.
/// * [onChanged], which is called when the value of the checkbox should
/// change. It can be set to null to disable the checkbox.
///
/// The values of [tristate] and [autofocus] must not be null.
const Checkbox({
super.key,
required this.value,
this.tristate = false,
required this.onChanged,
this.mouseCursor,
this.activeColor,
this.fillColor,
this.checkColor,
this.focusColor,
this.hoverColor,
this.overlayColor,
this.splashRadius,
this.materialTapTargetSize,
this.visualDensity,
this.focusNode,
this.autofocus = false,
this.shape,
this.side,
this.isError = false,
this.semanticLabel,
}) : _checkboxType = _CheckboxType.material,
assert(tristate || value != null);
/// Creates an adaptive [Checkbox] based on whether the target platform is iOS
/// or macOS, following Material design's
/// [Cross-platform guidelines](https://material.io/design/platform-guidance/cross-platform-adaptation.html).
///
/// On iOS and macOS, this constructor creates a [CupertinoCheckbox], which has
/// matching functionality and presentation as Material checkboxes, and are the
/// graphics expected on iOS. On other platforms, this creates a Material
/// design [Checkbox].
///
/// If a [CupertinoCheckbox] is created, the following parameters are ignored:
/// [mouseCursor], [fillColor], [hoverColor], [overlayColor], [splashRadius],
/// [materialTapTargetSize], [visualDensity], [isError]. However, [shape] and
/// [side] will still affect the [CupertinoCheckbox] and should be handled if
/// native fidelity is important.
///
/// The target platform is based on the current [Theme]: [ThemeData.platform].
const Checkbox.adaptive({
super.key,
required this.value,
this.tristate = false,
required this.onChanged,
this.mouseCursor,
this.activeColor,
this.fillColor,
this.checkColor,
this.focusColor,
this.hoverColor,
this.overlayColor,
this.splashRadius,
this.materialTapTargetSize,
this.visualDensity,
this.focusNode,
this.autofocus = false,
this.shape,
this.side,
this.isError = false,
this.semanticLabel,
}) : _checkboxType = _CheckboxType.adaptive,
assert(tristate || value != null);
/// Whether this checkbox is checked.
///
/// When [tristate] is true, a value of null corresponds to the mixed state.
/// When [tristate] is false, this value must not be null.
final bool? value;
/// Called when the value of the checkbox should change.
///
/// The checkbox passes the new value to the callback but does not actually
/// change state until the parent widget rebuilds the checkbox with the new
/// value.
///
/// If this callback is null, the checkbox will be displayed as disabled
/// and will not respond to input gestures.
///
/// When the checkbox is tapped, if [tristate] is false (the default) then
/// the [onChanged] callback will be applied to `!value`. If [tristate] is
/// true this callback cycle from false to true to null.
///
/// The callback provided to [onChanged] should update the state of the parent
/// [StatefulWidget] using the [State.setState] method, so that the parent
/// gets rebuilt; for example:
///
/// ```dart
/// Checkbox(
/// value: _throwShotAway,
/// onChanged: (bool? newValue) {
/// setState(() {
/// _throwShotAway = newValue!;
/// });
/// },
/// )
/// ```
final ValueChanged<bool?>? onChanged;
/// {@template flutter.material.checkbox.mouseCursor}
/// The cursor for a mouse pointer when it enters or is hovering over the
/// widget.
///
/// If [mouseCursor] is a [MaterialStateProperty<MouseCursor>],
/// [MaterialStateProperty.resolve] is used for the following [MaterialState]s:
///
/// * [MaterialState.selected].
/// * [MaterialState.hovered].
/// * [MaterialState.focused].
/// * [MaterialState.disabled].
/// {@endtemplate}
///
/// When [value] is null and [tristate] is true, [MaterialState.selected] is
/// included as a state.
///
/// If null, then the value of [CheckboxThemeData.mouseCursor] is used. If
/// that is also null, then [MaterialStateMouseCursor.clickable] is used.
///
/// See also:
///
/// * [MaterialStateMouseCursor], a [MouseCursor] that implements
/// `MaterialStateProperty` which is used in APIs that need to accept
/// either a [MouseCursor] or a [MaterialStateProperty<MouseCursor>].
final MouseCursor? mouseCursor;
/// The color to use when this checkbox is checked.
///
/// Defaults to [ColorScheme.secondary].
///
/// If [fillColor] returns a non-null color in the [MaterialState.selected]
/// state, it will be used instead of this color.
final Color? activeColor;
/// {@template flutter.material.checkbox.fillColor}
/// The color that fills the checkbox, in all [MaterialState]s.
///
/// Resolves in the following states:
/// * [MaterialState.selected].
/// * [MaterialState.hovered].
/// * [MaterialState.focused].
/// * [MaterialState.disabled].
///
/// {@tool snippet}
/// This example resolves the [fillColor] based on the current [MaterialState]
/// of the [Checkbox], providing a different [Color] when it is
/// [MaterialState.disabled].
///
/// ```dart
/// Checkbox(
/// value: true,
/// onChanged: (_){},
/// fillColor: MaterialStateProperty.resolveWith<Color>((Set<MaterialState> states) {
/// if (states.contains(MaterialState.disabled)) {
/// return Colors.orange.withOpacity(.32);
/// }
/// return Colors.orange;
/// })
/// )
/// ```
/// {@end-tool}
/// {@endtemplate}
///
/// If null, then the value of [activeColor] is used in the selected
/// state. If that is also null, the value of [CheckboxThemeData.fillColor]
/// is used. If that is also null, then [ThemeData.disabledColor] is used in
/// the disabled state, [ColorScheme.secondary] is used in the
/// selected state, and [ThemeData.unselectedWidgetColor] is used in the
/// default state.
final MaterialStateProperty<Color?>? fillColor;
/// {@template flutter.material.checkbox.checkColor}
/// The color to use for the check icon when this checkbox is checked.
/// {@endtemplate}
///
/// If null, then the value of [CheckboxThemeData.checkColor] is used. If
/// that is also null, then Color(0xFFFFFFFF) is used.
final Color? checkColor;
/// If true the checkbox's [value] can be true, false, or null.
///
/// [Checkbox] displays a dash when its value is null.
///
/// When a tri-state checkbox ([tristate] is true) is tapped, its [onChanged]
/// callback will be applied to true if the current value is false, to null if
/// value is true, and to false if value is null (i.e. it cycles through false
/// => true => null => false when tapped).
///
/// If tristate is false (the default), [value] must not be null.
final bool tristate;
/// {@template flutter.material.checkbox.materialTapTargetSize}
/// Configures the minimum size of the tap target.
/// {@endtemplate}
///
/// If null, then the value of [CheckboxThemeData.materialTapTargetSize] is
/// used. If that is also null, then the value of
/// [ThemeData.materialTapTargetSize] is used.
///
/// See also:
///
/// * [MaterialTapTargetSize], for a description of how this affects tap targets.
final MaterialTapTargetSize? materialTapTargetSize;
/// {@template flutter.material.checkbox.visualDensity}
/// Defines how compact the checkbox's layout will be.
/// {@endtemplate}
///
/// {@macro flutter.material.themedata.visualDensity}
///
/// If null, then the value of [CheckboxThemeData.visualDensity] is used. If
/// that is also null, then the value of [ThemeData.visualDensity] is used.
///
/// See also:
///
/// * [ThemeData.visualDensity], which specifies the [visualDensity] for all
/// widgets within a [Theme].
final VisualDensity? visualDensity;
/// The color for the checkbox's [Material] when it has the input focus.
///
/// If [overlayColor] returns a non-null color in the [MaterialState.focused]
/// state, it will be used instead.
///
/// If null, then the value of [CheckboxThemeData.overlayColor] is used in the
/// focused state. If that is also null, then the value of
/// [ThemeData.focusColor] is used.
final Color? focusColor;
/// {@template flutter.material.checkbox.hoverColor}
/// The color for the checkbox's [Material] when a pointer is hovering over it.
///
/// If [overlayColor] returns a non-null color in the [MaterialState.hovered]
/// state, it will be used instead.
/// {@endtemplate}
///
/// If null, then the value of [CheckboxThemeData.overlayColor] is used in the
/// hovered state. If that is also null, then the value of
/// [ThemeData.hoverColor] is used.
final Color? hoverColor;
/// {@template flutter.material.checkbox.overlayColor}
/// The color for the checkbox's [Material].
///
/// Resolves in the following states:
/// * [MaterialState.pressed].
/// * [MaterialState.selected].
/// * [MaterialState.hovered].
/// * [MaterialState.focused].
/// {@endtemplate}
///
/// If null, then the value of [activeColor] with alpha
/// [kRadialReactionAlpha], [focusColor] and [hoverColor] is used in the
/// pressed, focused and hovered state. If that is also null,
/// the value of [CheckboxThemeData.overlayColor] is used. If that is
/// also null, then the value of [ColorScheme.secondary] with alpha
/// [kRadialReactionAlpha], [ThemeData.focusColor] and [ThemeData.hoverColor]
/// is used in the pressed, focused and hovered state.
final MaterialStateProperty<Color?>? overlayColor;
/// {@template flutter.material.checkbox.splashRadius}
/// The splash radius of the circular [Material] ink response.
/// {@endtemplate}
///
/// If null, then the value of [CheckboxThemeData.splashRadius] is used. If
/// that is also null, then [kRadialReactionRadius] is used.
final double? splashRadius;
/// {@macro flutter.widgets.Focus.focusNode}
final FocusNode? focusNode;
/// {@macro flutter.widgets.Focus.autofocus}
final bool autofocus;
/// {@template flutter.material.checkbox.shape}
/// The shape of the checkbox's [Material].
/// {@endtemplate}
///
/// If this property is null then [CheckboxThemeData.shape] of [ThemeData.checkboxTheme]
/// is used. If that's null then the shape will be a [RoundedRectangleBorder]
/// with a circular corner radius of 1.0 in Material 2, and 2.0 in Material 3.
final OutlinedBorder? shape;
/// {@template flutter.material.checkbox.side}
/// The color and width of the checkbox's border.
///
/// This property can be a [MaterialStateBorderSide] that can
/// specify different border color and widths depending on the
/// checkbox's state.
///
/// Resolves in the following states:
/// * [MaterialState.pressed].
/// * [MaterialState.selected].
/// * [MaterialState.hovered].
/// * [MaterialState.focused].
/// * [MaterialState.disabled].
/// * [MaterialState.error].
///
/// If this property is not a [MaterialStateBorderSide] and it is
/// non-null, then it is only rendered when the checkbox's value is
/// false. The difference in interpretation is for backwards
/// compatibility.
/// {@endtemplate}
///
/// If this property is null, then [CheckboxThemeData.side] of
/// [ThemeData.checkboxTheme] is used. If that is also null, then the side
/// will be width 2.
final BorderSide? side;
/// {@template flutter.material.checkbox.isError}
/// True if this checkbox wants to show an error state.
///
/// The checkbox will have different default container color and check color when
/// this is true. This is only used when [ThemeData.useMaterial3] is set to true.
/// {@endtemplate}
///
/// Must not be null. Defaults to false.
final bool isError;
/// {@template flutter.material.checkbox.semanticLabel}
/// The semantic label for the checkobox that will be announced by screen readers.
///
/// This is announced in accessibility modes (e.g TalkBack/VoiceOver).
///
/// This label does not show in the UI.
/// {@endtemplate}
final String? semanticLabel;
/// The width of a checkbox widget.
static const double width = 18.0;
final _CheckboxType _checkboxType;
@override
State<Checkbox> createState() => _CheckboxState();
}
class _CheckboxState extends State<Checkbox> with TickerProviderStateMixin, ToggleableStateMixin {
final _CheckboxPainter _painter = _CheckboxPainter();
bool? _previousValue;
@override
void initState() {
super.initState();
_previousValue = widget.value;
}
@override
void didUpdateWidget(Checkbox oldWidget) {
super.didUpdateWidget(oldWidget);
if (oldWidget.value != widget.value) {
_previousValue = oldWidget.value;
animateToValue();
}
}
@override
void dispose() {
_painter.dispose();
super.dispose();
}
@override
ValueChanged<bool?>? get onChanged => widget.onChanged;
@override
bool get tristate => widget.tristate;
@override
bool? get value => widget.value;
MaterialStateProperty<Color?> get _widgetFillColor {
return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
if (states.contains(MaterialState.disabled)) {
return null;
}
if (states.contains(MaterialState.selected)) {
return widget.activeColor;
}
return null;
});
}
BorderSide? _resolveSide(BorderSide? side, Set<MaterialState> states) {
if (side is MaterialStateBorderSide) {
return MaterialStateProperty.resolveAs<BorderSide?>(side, states);
}
if (!states.contains(MaterialState.selected)) {
return side;
}
return null;
}
@override
Widget build(BuildContext context) {
switch (widget._checkboxType) {
case _CheckboxType.material:
break;
case _CheckboxType.adaptive:
final ThemeData theme = Theme.of(context);
switch (theme.platform) {
case TargetPlatform.android:
case TargetPlatform.fuchsia:
case TargetPlatform.linux:
case TargetPlatform.windows:
break;
case TargetPlatform.iOS:
case TargetPlatform.macOS:
return CupertinoCheckbox(
value: value,
tristate: tristate,
onChanged: onChanged,
activeColor: widget.activeColor,
checkColor: widget.checkColor,
focusColor: widget.focusColor,
focusNode: widget.focusNode,
autofocus: widget.autofocus,
side: widget.side,
shape: widget.shape,
);
}
}
assert(debugCheckHasMaterial(context));
final CheckboxThemeData checkboxTheme = CheckboxTheme.of(context);
final CheckboxThemeData defaults = Theme.of(context).useMaterial3
? _CheckboxDefaultsM3(context)
: _CheckboxDefaultsM2(context);
final MaterialTapTargetSize effectiveMaterialTapTargetSize = widget.materialTapTargetSize
?? checkboxTheme.materialTapTargetSize
?? defaults.materialTapTargetSize!;
final VisualDensity effectiveVisualDensity = widget.visualDensity
?? checkboxTheme.visualDensity
?? defaults.visualDensity!;
Size size;
switch (effectiveMaterialTapTargetSize) {
case MaterialTapTargetSize.padded:
size = const Size(kMinInteractiveDimension, kMinInteractiveDimension);
case MaterialTapTargetSize.shrinkWrap:
size = const Size(kMinInteractiveDimension - 8.0, kMinInteractiveDimension - 8.0);
}
size += effectiveVisualDensity.baseSizeAdjustment;
final MaterialStateProperty<MouseCursor> effectiveMouseCursor = MaterialStateProperty.resolveWith<MouseCursor>((Set<MaterialState> states) {
return MaterialStateProperty.resolveAs<MouseCursor?>(widget.mouseCursor, states)
?? checkboxTheme.mouseCursor?.resolve(states)
?? MaterialStateMouseCursor.clickable.resolve(states);
});
// Colors need to be resolved in selected and non selected states separately
final Set<MaterialState> activeStates = states..add(MaterialState.selected);
final Set<MaterialState> inactiveStates = states..remove(MaterialState.selected);
if (widget.isError) {
activeStates.add(MaterialState.error);
inactiveStates.add(MaterialState.error);
}
final Color? activeColor = widget.fillColor?.resolve(activeStates)
?? _widgetFillColor.resolve(activeStates)
?? checkboxTheme.fillColor?.resolve(activeStates);
final Color effectiveActiveColor = activeColor
?? defaults.fillColor!.resolve(activeStates)!;
final Color? inactiveColor = widget.fillColor?.resolve(inactiveStates)
?? _widgetFillColor.resolve(inactiveStates)
?? checkboxTheme.fillColor?.resolve(inactiveStates);
final Color effectiveInactiveColor = inactiveColor
?? defaults.fillColor!.resolve(inactiveStates)!;
final BorderSide activeSide = _resolveSide(widget.side, activeStates)
?? _resolveSide(checkboxTheme.side, activeStates)
?? _resolveSide(defaults.side, activeStates)!;
final BorderSide inactiveSide = _resolveSide(widget.side, inactiveStates)
?? _resolveSide(checkboxTheme.side, inactiveStates)
?? _resolveSide(defaults.side, inactiveStates)!;
final Set<MaterialState> focusedStates = states..add(MaterialState.focused);
if (widget.isError) {
focusedStates.add(MaterialState.error);
}
Color effectiveFocusOverlayColor = widget.overlayColor?.resolve(focusedStates)
?? widget.focusColor
?? checkboxTheme.overlayColor?.resolve(focusedStates)
?? defaults.overlayColor!.resolve(focusedStates)!;
final Set<MaterialState> hoveredStates = states..add(MaterialState.hovered);
if (widget.isError) {
hoveredStates.add(MaterialState.error);
}
Color effectiveHoverOverlayColor = widget.overlayColor?.resolve(hoveredStates)
?? widget.hoverColor
?? checkboxTheme.overlayColor?.resolve(hoveredStates)
?? defaults.overlayColor!.resolve(hoveredStates)!;
final Set<MaterialState> activePressedStates = activeStates..add(MaterialState.pressed);
final Color effectiveActivePressedOverlayColor = widget.overlayColor?.resolve(activePressedStates)
?? checkboxTheme.overlayColor?.resolve(activePressedStates)
?? activeColor?.withAlpha(kRadialReactionAlpha)
?? defaults.overlayColor!.resolve(activePressedStates)!;
final Set<MaterialState> inactivePressedStates = inactiveStates..add(MaterialState.pressed);
final Color effectiveInactivePressedOverlayColor = widget.overlayColor?.resolve(inactivePressedStates)
?? checkboxTheme.overlayColor?.resolve(inactivePressedStates)
?? inactiveColor?.withAlpha(kRadialReactionAlpha)
?? defaults.overlayColor!.resolve(inactivePressedStates)!;
if (downPosition != null) {
effectiveHoverOverlayColor = states.contains(MaterialState.selected)
? effectiveActivePressedOverlayColor
: effectiveInactivePressedOverlayColor;
effectiveFocusOverlayColor = states.contains(MaterialState.selected)
? effectiveActivePressedOverlayColor
: effectiveInactivePressedOverlayColor;
}
final Set<MaterialState> checkStates = widget.isError ? (states..add(MaterialState.error)) : states;
final Color effectiveCheckColor = widget.checkColor
?? checkboxTheme.checkColor?.resolve(checkStates)
?? defaults.checkColor!.resolve(checkStates)!;
final double effectiveSplashRadius = widget.splashRadius
?? checkboxTheme.splashRadius
?? defaults.splashRadius!;
return Semantics(
label: widget.semanticLabel,
checked: widget.value ?? false,
mixed: widget.tristate ? widget.value == null : null,
child: buildToggleable(
mouseCursor: effectiveMouseCursor,
focusNode: widget.focusNode,
autofocus: widget.autofocus,
size: size,
painter: _painter
..position = position
..reaction = reaction
..reactionFocusFade = reactionFocusFade
..reactionHoverFade = reactionHoverFade
..inactiveReactionColor = effectiveInactivePressedOverlayColor
..reactionColor = effectiveActivePressedOverlayColor
..hoverColor = effectiveHoverOverlayColor
..focusColor = effectiveFocusOverlayColor
..splashRadius = effectiveSplashRadius
..downPosition = downPosition
..isFocused = states.contains(MaterialState.focused)
..isHovered = states.contains(MaterialState.hovered)
..activeColor = effectiveActiveColor
..inactiveColor = effectiveInactiveColor
..checkColor = effectiveCheckColor
..value = value
..previousValue = _previousValue
..shape = widget.shape ?? checkboxTheme.shape ?? defaults.shape!
..activeSide = activeSide
..inactiveSide = inactiveSide,
),
);
}
}
const double _kEdgeSize = Checkbox.width;
const double _kStrokeWidth = 2.0;
class _CheckboxPainter extends ToggleablePainter {
Color get checkColor => _checkColor!;
Color? _checkColor;
set checkColor(Color value) {
if (_checkColor == value) {
return;
}
_checkColor = value;
notifyListeners();
}
bool? get value => _value;
bool? _value;
set value(bool? value) {
if (_value == value) {
return;
}
_value = value;
notifyListeners();
}
bool? get previousValue => _previousValue;
bool? _previousValue;
set previousValue(bool? value) {
if (_previousValue == value) {
return;
}
_previousValue = value;
notifyListeners();
}
OutlinedBorder get shape => _shape!;
OutlinedBorder? _shape;
set shape(OutlinedBorder value) {
if (_shape == value) {
return;
}
_shape = value;
notifyListeners();
}
BorderSide get activeSide => _activeSide!;
BorderSide? _activeSide;
set activeSide(BorderSide value) {
if (_activeSide == value) {
return;
}
_activeSide = value;
notifyListeners();
}
BorderSide get inactiveSide => _inactiveSide!;
BorderSide? _inactiveSide;
set inactiveSide(BorderSide value) {
if (_inactiveSide == value) {
return;
}
_inactiveSide = value;
notifyListeners();
}
// The square outer bounds of the checkbox at t, with the specified origin.
// At t == 0.0, the outer rect's size is _kEdgeSize (Checkbox.width)
// At t == 0.5, .. is _kEdgeSize - _kStrokeWidth
// At t == 1.0, .. is _kEdgeSize
Rect _outerRectAt(Offset origin, double t) {
final double inset = 1.0 - (t - 0.5).abs() * 2.0;
final double size = _kEdgeSize - inset * _kStrokeWidth;
final Rect rect = Rect.fromLTWH(origin.dx + inset, origin.dy + inset, size, size);
return rect;
}
// The checkbox's fill color
Color _colorAt(double t) {
// As t goes from 0.0 to 0.25, animate from the inactiveColor to activeColor.
return t >= 0.25 ? activeColor : Color.lerp(inactiveColor, activeColor, t * 4.0)!;
}
// White stroke used to paint the check and dash.
Paint _createStrokePaint() {
return Paint()
..color = checkColor
..style = PaintingStyle.stroke
..strokeWidth = _kStrokeWidth;
}
void _drawBox(Canvas canvas, Rect outer, Paint paint, BorderSide? side) {
canvas.drawPath(shape.getOuterPath(outer), paint);
if (side != null) {
shape.copyWith(side: side).paint(canvas, outer);
}
}
void _drawCheck(Canvas canvas, Offset origin, double t, Paint paint) {
assert(t >= 0.0 && t <= 1.0);
// As t goes from 0.0 to 1.0, animate the two check mark strokes from the
// short side to the long side.
final Path path = Path();
const Offset start = Offset(_kEdgeSize * 0.15, _kEdgeSize * 0.45);
const Offset mid = Offset(_kEdgeSize * 0.4, _kEdgeSize * 0.7);
const Offset end = Offset(_kEdgeSize * 0.85, _kEdgeSize * 0.25);
if (t < 0.5) {
final double strokeT = t * 2.0;
final Offset drawMid = Offset.lerp(start, mid, strokeT)!;
path.moveTo(origin.dx + start.dx, origin.dy + start.dy);
path.lineTo(origin.dx + drawMid.dx, origin.dy + drawMid.dy);
} else {
final double strokeT = (t - 0.5) * 2.0;
final Offset drawEnd = Offset.lerp(mid, end, strokeT)!;
path.moveTo(origin.dx + start.dx, origin.dy + start.dy);
path.lineTo(origin.dx + mid.dx, origin.dy + mid.dy);
path.lineTo(origin.dx + drawEnd.dx, origin.dy + drawEnd.dy);
}
canvas.drawPath(path, paint);
}
void _drawDash(Canvas canvas, Offset origin, double t, Paint paint) {
assert(t >= 0.0 && t <= 1.0);
// As t goes from 0.0 to 1.0, animate the horizontal line from the
// mid point outwards.
const Offset start = Offset(_kEdgeSize * 0.2, _kEdgeSize * 0.5);
const Offset mid = Offset(_kEdgeSize * 0.5, _kEdgeSize * 0.5);
const Offset end = Offset(_kEdgeSize * 0.8, _kEdgeSize * 0.5);
final Offset drawStart = Offset.lerp(start, mid, 1.0 - t)!;
final Offset drawEnd = Offset.lerp(mid, end, t)!;
canvas.drawLine(origin + drawStart, origin + drawEnd, paint);
}
@override
void paint(Canvas canvas, Size size) {
paintRadialReaction(canvas: canvas, origin: size.center(Offset.zero));
final Paint strokePaint = _createStrokePaint();
final Offset origin = size / 2.0 - const Size.square(_kEdgeSize) / 2.0 as Offset;
final AnimationStatus status = position.status;
final double tNormalized = status == AnimationStatus.forward || status == AnimationStatus.completed
? position.value
: 1.0 - position.value;
// Four cases: false to null, false to true, null to false, true to false
if (previousValue == false || value == false) {
final double t = value == false ? 1.0 - tNormalized : tNormalized;
final Rect outer = _outerRectAt(origin, t);
final Paint paint = Paint()..color = _colorAt(t);
if (t <= 0.5) {
final BorderSide border = BorderSide.lerp(inactiveSide, activeSide, t);
_drawBox(canvas, outer, paint, border);
} else {
_drawBox(canvas, outer, paint, activeSide);
final double tShrink = (t - 0.5) * 2.0;
if (previousValue == null || value == null) {
_drawDash(canvas, origin, tShrink, strokePaint);
} else {
_drawCheck(canvas, origin, tShrink, strokePaint);
}
}
} else { // Two cases: null to true, true to null
final Rect outer = _outerRectAt(origin, 1.0);
final Paint paint = Paint() ..color = _colorAt(1.0);
_drawBox(canvas, outer, paint, activeSide);
if (tNormalized <= 0.5) {
final double tShrink = 1.0 - tNormalized * 2.0;
if (previousValue ?? false) {
_drawCheck(canvas, origin, tShrink, strokePaint);
} else {
_drawDash(canvas, origin, tShrink, strokePaint);
}
} else {
final double tExpand = (tNormalized - 0.5) * 2.0;
if (value ?? false) {
_drawCheck(canvas, origin, tExpand, strokePaint);
} else {
_drawDash(canvas, origin, tExpand, strokePaint);
}
}
}
}
}
// Hand coded defaults based on Material Design 2.
class _CheckboxDefaultsM2 extends CheckboxThemeData {
_CheckboxDefaultsM2(BuildContext context)
: _theme = Theme.of(context),
_colors = Theme.of(context).colorScheme;
final ThemeData _theme;
final ColorScheme _colors;
@override
MaterialStateBorderSide? get side {
return MaterialStateBorderSide.resolveWith((Set<MaterialState> states) {
if (states.contains(MaterialState.disabled)) {
if (states.contains(MaterialState.selected)) {
return const BorderSide(width: 2.0, color: Colors.transparent);
}
return BorderSide(width: 2.0, color: _theme.disabledColor);
}
if (states.contains(MaterialState.selected)) {
return const BorderSide(width: 2.0, color: Colors.transparent);
}
return BorderSide(width: 2.0, color: _theme.unselectedWidgetColor);
});
}
@override
MaterialStateProperty<Color> get fillColor {
return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
if (states.contains(MaterialState.disabled)) {
if (states.contains(MaterialState.selected)) {
return _theme.disabledColor;
}
return Colors.transparent;
}
if (states.contains(MaterialState.selected)) {
return _colors.secondary;
}
return Colors.transparent;
});
}
@override
MaterialStateProperty<Color> get checkColor {
return MaterialStateProperty.all<Color>(const Color(0xFFFFFFFF));
}
@override
MaterialStateProperty<Color?> get overlayColor {
return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
if (states.contains(MaterialState.pressed)) {
return fillColor.resolve(states).withAlpha(kRadialReactionAlpha);
}
if (states.contains(MaterialState.hovered)) {
return _theme.hoverColor;
}
if (states.contains(MaterialState.focused)) {
return _theme.focusColor;
}
return Colors.transparent;
});
}
@override
double get splashRadius => kRadialReactionRadius;
@override
MaterialTapTargetSize get materialTapTargetSize => _theme.materialTapTargetSize;
@override
VisualDensity get visualDensity => _theme.visualDensity;
@override
OutlinedBorder get shape => const RoundedRectangleBorder(
borderRadius: BorderRadius.all(Radius.circular(1.0)),
);
}
// BEGIN GENERATED TOKEN PROPERTIES - Checkbox
// Do not edit by hand. The code between the "BEGIN GENERATED" and
// "END GENERATED" comments are generated from data in the Material
// Design token database by the script:
// dev/tools/gen_defaults/bin/gen_defaults.dart.
class _CheckboxDefaultsM3 extends CheckboxThemeData {
_CheckboxDefaultsM3(BuildContext context)
: _theme = Theme.of(context),
_colors = Theme.of(context).colorScheme;
final ThemeData _theme;
final ColorScheme _colors;
@override
MaterialStateBorderSide? get side {
return MaterialStateBorderSide.resolveWith((Set<MaterialState> states) {
if (states.contains(MaterialState.disabled)) {
if (states.contains(MaterialState.selected)) {
return const BorderSide(width: 2.0, color: Colors.transparent);
}
return BorderSide(width: 2.0, color: _colors.onSurface.withOpacity(0.38));
}
if (states.contains(MaterialState.selected)) {
return const BorderSide(width: 0.0, color: Colors.transparent);
}
if (states.contains(MaterialState.error)) {
return BorderSide(width: 2.0, color: _colors.error);
}
if (states.contains(MaterialState.pressed)) {
return BorderSide(width: 2.0, color: _colors.onSurface);
}
if (states.contains(MaterialState.hovered)) {
return BorderSide(width: 2.0, color: _colors.onSurface);
}
if (states.contains(MaterialState.focused)) {
return BorderSide(width: 2.0, color: _colors.onSurface);
}
return BorderSide(width: 2.0, color: _colors.onSurfaceVariant);
});
}
@override
MaterialStateProperty<Color> get fillColor {
return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
if (states.contains(MaterialState.disabled)) {
if (states.contains(MaterialState.selected)) {
return _colors.onSurface.withOpacity(0.38);
}
return Colors.transparent;
}
if (states.contains(MaterialState.selected)) {
if (states.contains(MaterialState.error)) {
return _colors.error;
}
return _colors.primary;
}
return Colors.transparent;
});
}
@override
MaterialStateProperty<Color> get checkColor {
return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
if (states.contains(MaterialState.disabled)) {
if (states.contains(MaterialState.selected)) {
return _colors.surface;
}
return Colors.transparent; // No icons available when the checkbox is unselected.
}
if (states.contains(MaterialState.selected)) {
if (states.contains(MaterialState.error)) {
return _colors.onError;
}
return _colors.onPrimary;
}
return Colors.transparent; // No icons available when the checkbox is unselected.
});
}
@override
MaterialStateProperty<Color> get overlayColor {
return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
if (states.contains(MaterialState.error)) {
if (states.contains(MaterialState.pressed)) {
return _colors.error.withOpacity(0.12);
}
if (states.contains(MaterialState.hovered)) {
return _colors.error.withOpacity(0.08);
}
if (states.contains(MaterialState.focused)) {
return _colors.error.withOpacity(0.12);
}
}
if (states.contains(MaterialState.selected)) {
if (states.contains(MaterialState.pressed)) {
return _colors.onSurface.withOpacity(0.12);
}
if (states.contains(MaterialState.hovered)) {
return _colors.primary.withOpacity(0.08);
}
if (states.contains(MaterialState.focused)) {
return _colors.primary.withOpacity(0.12);
}
return Colors.transparent;
}
if (states.contains(MaterialState.pressed)) {
return _colors.primary.withOpacity(0.12);
}
if (states.contains(MaterialState.hovered)) {
return _colors.onSurface.withOpacity(0.08);
}
if (states.contains(MaterialState.focused)) {
return _colors.onSurface.withOpacity(0.12);
}
return Colors.transparent;
});
}
@override
double get splashRadius => 40.0 / 2;
@override
MaterialTapTargetSize get materialTapTargetSize => _theme.materialTapTargetSize;
@override
VisualDensity get visualDensity => _theme.visualDensity;
@override
OutlinedBorder get shape => const RoundedRectangleBorder(
borderRadius: BorderRadius.all(Radius.circular(2.0)),
);
}
// END GENERATED TOKEN PROPERTIES - Checkbox