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Unverified Commit 2aa9bb2b authored by Hans Muller's avatar Hans Muller Committed by GitHub
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Tri-state Checkbox (#14611)

parent 8507b72a
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Showing with 275 additions and 71 deletions
packages/flutter/lib/src/material/checkbox.dart
View file @ 2aa9bb2b
......@@ -21,6 +21,10 @@ import 'toggleable.dart';
/// 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.
///
/// See also:
......@@ -43,16 +47,20 @@ class Checkbox extends StatefulWidget {
///
/// The following arguments are required:
///
/// * [value], which determines whether the checkbox is checked, and must not
/// be null.
/// * [value], which determines whether the checkbox is checked. The [value]
/// can only be 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 value of [tristate] must not be null.
const Checkbox({
Key key,
@required this.value,
this.tristate: false,
@required this.onChanged,
this.activeColor,
}) : assert(value != null),
}) : assert(tristate != null),
assert(tristate || value != null),
super(key: key);
/// Whether this checkbox is checked.
......@@ -66,7 +74,12 @@ class Checkbox extends StatefulWidget {
/// change state until the parent widget rebuilds the checkbox with the new
/// value.
///
/// If null, the checkbox will be displayed as disabled.
/// 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
......@@ -89,6 +102,18 @@ class Checkbox extends StatefulWidget {
/// Defaults to accent color of the current [Theme].
final Color activeColor;
/// 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 is tapped its [onChanged] callback will be
/// applied to true if the current value is null or false, false otherwise.
/// Typically tri-state checkboxes are disabled (the onChanged callback is
/// null) so they don't respond to taps.
///
/// If tristate is false (the default), [value] must not be null.
final bool tristate;
/// The width of a checkbox widget.
static const double width = 18.0;
......@@ -103,6 +128,7 @@ class _CheckboxState extends State<Checkbox> with TickerProviderStateMixin {
final ThemeData themeData = Theme.of(context);
return new _CheckboxRenderObjectWidget(
value: widget.value,
tristate: widget.tristate,
activeColor: widget.activeColor ?? themeData.accentColor,
inactiveColor: widget.onChanged != null ? themeData.unselectedWidgetColor : themeData.disabledColor,
onChanged: widget.onChanged,
......@@ -115,17 +141,20 @@ class _CheckboxRenderObjectWidget extends LeafRenderObjectWidget {
const _CheckboxRenderObjectWidget({
Key key,
@required this.value,
@required this.tristate,
@required this.activeColor,
@required this.inactiveColor,
@required this.onChanged,
@required this.vsync,
}) : assert(value != null),
}) : assert(tristate != null),
assert(tristate || value != null),
assert(activeColor != null),
assert(inactiveColor != null),
assert(vsync != null),
super(key: key);
final bool value;
final bool tristate;
final Color activeColor;
final Color inactiveColor;
final ValueChanged<bool> onChanged;
......@@ -134,6 +163,7 @@ class _CheckboxRenderObjectWidget extends LeafRenderObjectWidget {
@override
_RenderCheckbox createRenderObject(BuildContext context) => new _RenderCheckbox(
value: value,
tristate: tristate,
activeColor: activeColor,
inactiveColor: inactiveColor,
onChanged: onChanged,
......@@ -144,6 +174,7 @@ class _CheckboxRenderObjectWidget extends LeafRenderObjectWidget {
void updateRenderObject(BuildContext context, _RenderCheckbox renderObject) {
renderObject
..value = value
..tristate = tristate
..activeColor = activeColor
..inactiveColor = inactiveColor
..onChanged = onChanged
......@@ -158,12 +189,15 @@ const double _kStrokeWidth = 2.0;
class _RenderCheckbox extends RenderToggleable {
_RenderCheckbox({
bool value,
bool tristate,
Color activeColor,
Color inactiveColor,
ValueChanged<bool> onChanged,
@required TickerProvider vsync,
}): super(
}): _oldValue = value,
super(
value: value,
tristate: tristate,
activeColor: activeColor,
inactiveColor: inactiveColor,
onChanged: onChanged,
......@@ -171,54 +205,135 @@ class _RenderCheckbox extends RenderToggleable {
vsync: vsync,
);
@override
void paint(PaintingContext context, Offset offset) {
final Canvas canvas = context.canvas;
final double offsetX = offset.dx + (size.width - _kEdgeSize) / 2.0;
final double offsetY = offset.dy + (size.height - _kEdgeSize) / 2.0;
paintRadialReaction(canvas, offset, size.center(Offset.zero));
final double t = position.value;
bool _oldValue;
Color borderColor = inactiveColor;
if (onChanged != null)
borderColor = t >= 0.25 ? activeColor : Color.lerp(inactiveColor, activeColor, t * 4.0);
final Paint paint = new Paint()
..color = borderColor;
@override
set value(bool newValue) {
if (newValue == value)
return;
_oldValue = value;
super.value = newValue;
}
// 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
RRect _outerRectAt(Offset origin, double t) {
final double inset = 1.0 - (t - 0.5).abs() * 2.0;
final double rectSize = _kEdgeSize - inset * _kStrokeWidth;
final Rect rect = new Rect.fromLTWH(offsetX + inset, offsetY + inset, rectSize, rectSize);
final double size = _kEdgeSize - inset * _kStrokeWidth;
final Rect rect = new Rect.fromLTWH(origin.dx + inset, origin.dy + inset, size, size);
return new RRect.fromRectAndRadius(rect, _kEdgeRadius);
}
final RRect outer = new RRect.fromRectAndRadius(rect, _kEdgeRadius);
if (t <= 0.5) {
// Outline
final RRect inner = outer.deflate(math.min(rectSize / 2.0, _kStrokeWidth + rectSize * t));
canvas.drawDRRect(outer, inner, paint);
} else {
// Background
canvas.drawRRect(outer, paint);
// The checkbox's border color if value == false, or its fill color when
// value == true or null.
Color _colorAt(double t) {
// As t goes from 0.0 to 0.25, animate from the inactiveColor to activeColor.
return onChanged == null
? inactiveColor
: (t >= 0.25 ? activeColor : Color.lerp(inactiveColor, activeColor, t * 4.0));
}
// White inner check
final double value = (t - 0.5) * 2.0;
// White stroke used to paint the check and dash.
void _initStrokePaint(Paint paint) {
paint
..color = const Color(0xFFFFFFFF)
..style = PaintingStyle.stroke
..strokeWidth = _kStrokeWidth;
}
void _drawBorder(Canvas canvas, RRect outer, double t, Paint paint) {
assert(t >= 0.0 && t <= 0.5);
final double size = outer.width;
// As t goes from 0.0 to 1.0, gradually fill the outer RRect.
final RRect inner = outer.deflate(math.min(size / 2.0, _kStrokeWidth + size * t));
canvas.drawDRRect(outer, inner, paint);
}
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 checkmark strokes from the
// mid point outwards.
final Path path = new Path();
const Offset start = const Offset(_kEdgeSize * 0.15, _kEdgeSize * 0.45);
const Offset mid = const Offset(_kEdgeSize * 0.4, _kEdgeSize * 0.7);
const Offset end = const Offset(_kEdgeSize * 0.85, _kEdgeSize * 0.25);
final Offset drawStart = Offset.lerp(start, mid, 1.0 - value);
final Offset drawEnd = Offset.lerp(mid, end, value);
path.moveTo(offsetX + drawStart.dx, offsetY + drawStart.dy);
path.lineTo(offsetX + mid.dx, offsetY + mid.dy);
path.lineTo(offsetX + drawEnd.dx, offsetY + drawEnd.dy);
final Offset drawStart = Offset.lerp(start, mid, 1.0 - t);
final Offset drawEnd = Offset.lerp(mid, end, t);
path.moveTo(origin.dx + drawStart.dx, origin.dy + drawStart.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 = const Offset(_kEdgeSize * 0.2, _kEdgeSize * 0.5);
const Offset mid = const Offset(_kEdgeSize * 0.5, _kEdgeSize * 0.5);
const Offset end = const 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(PaintingContext context, Offset offset) {
final Canvas canvas = context.canvas;
paintRadialReaction(canvas, offset, size.center(Offset.zero));
final Offset origin = offset + (size / 2.0 - const Size.square(_kEdgeSize) / 2.0);
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 (_oldValue == false || value == false) {
final double t = value == false ? 1.0 - tNormalized : tNormalized;
final RRect outer = _outerRectAt(origin, t);
final Paint paint = new Paint()..color = _colorAt(t);
if (t <= 0.5) {
_drawBorder(canvas, outer, t, paint);
} else {
canvas.drawRRect(outer, paint);
_initStrokePaint(paint);
final double tShrink = (t - 0.5) * 2.0;
if (_oldValue == null)
_drawDash(canvas, origin, tShrink, paint);
else
_drawCheck(canvas, origin, tShrink, paint);
}
} else { // Two cases: null to true, true to null
final RRect outer = _outerRectAt(origin, 1.0);
final Paint paint = new Paint() ..color = _colorAt(1.0);
canvas.drawRRect(outer, paint);
_initStrokePaint(paint);
if (tNormalized <= 0.5) {
final double tShrink = 1.0 - tNormalized * 2.0;
if (_oldValue == true)
_drawCheck(canvas, origin, tShrink, paint);
else
_drawDash(canvas, origin, tShrink, paint);
} else {
final double tExpand = (tNormalized - 0.5) * 2.0;
if (value == true)
_drawCheck(canvas, origin, tExpand, paint);
else
_drawDash(canvas, origin, tExpand, paint);
}
}
}
// TODO(hmuller): smooth segues for cases where the value changes
// in the middle of position's animation cycle.
// https://github.com/flutter/flutter/issues/14674
// TODO(hmuller): accessibility support for tristate checkboxes.
// https://github.com/flutter/flutter/issues/14677
}
packages/flutter/lib/src/material/radio.dart
View file @ 2aa9bb2b
......@@ -176,6 +176,7 @@ class _RenderRadio extends RenderToggleable {
@required TickerProvider vsync,
}): super(
value: value,
tristate: false,
activeColor: activeColor,
inactiveColor: inactiveColor,
onChanged: onChanged,
......
packages/flutter/lib/src/material/switch.dart
View file @ 2aa9bb2b
......@@ -247,6 +247,7 @@ class _RenderSwitch extends RenderToggleable {
_textDirection = textDirection,
super(
value: value,
tristate: false,
activeColor: activeColor,
inactiveColor: inactiveColor,
onChanged: onChanged,
......
packages/flutter/lib/src/material/toggleable.dart
View file @ 2aa9bb2b
......@@ -21,20 +21,23 @@ final Tween<double> _kRadialReactionRadiusTween = new Tween<double>(begin: 0.0,
abstract class RenderToggleable extends RenderConstrainedBox {
/// Creates a toggleable render object.
///
/// The [value], [activeColor], and [inactiveColor] arguments must not be
/// null.
/// The [activeColor], and [inactiveColor] arguments must not be
/// null. The [value] can only be null if tristate is true.
RenderToggleable({
@required bool value,
bool tristate: false,
Size size,
@required Color activeColor,
@required Color inactiveColor,
ValueChanged<bool> onChanged,
@required TickerProvider vsync,
}) : assert(value != null),
}) : assert(tristate != null),
assert(tristate || value != null),
assert(activeColor != null),
assert(inactiveColor != null),
assert(vsync != null),
_value = value,
_tristate = tristate,
_activeColor = activeColor,
_inactiveColor = inactiveColor,
_onChanged = onChanged,
......@@ -47,7 +50,7 @@ abstract class RenderToggleable extends RenderConstrainedBox {
..onTapCancel = _handleTapCancel;
_positionController = new AnimationController(
duration: _kToggleDuration,
value: value ? 1.0 : 0.0,
value: value == false ? 0.0 : 1.0,
vsync: vsync,
);
_position = new CurvedAnimation(
......@@ -79,8 +82,9 @@ abstract class RenderToggleable extends RenderConstrainedBox {
/// The visual value of the control.
///
/// When the control is inactive, the [value] is false and this animation has
/// the value 0.0. When the control is active, the value is true and this
/// animation has the value 1.0. When the control is changing from inactive
/// the value 0.0. When the control is active, the value either true or tristate
/// is true and the value is null. When the control is active the animation
/// has a value of 1.0. When the control is changing from inactive
/// to active (or vice versa), [value] is the target value and this animation
/// gradually updates from 0.0 to 1.0 (or vice versa).
CurvedAnimation get position => _position;
......@@ -110,7 +114,11 @@ abstract class RenderToggleable extends RenderConstrainedBox {
reactionController.resync(vsync);
}
/// Whether this control is current "active" (checked, on, selected) or "inactive" (unchecked, off, not selected).
/// False if this control is "inactive" (not checked, off, or unselected).
///
/// If value is true then the control "active" (checked, on, or selected). If
/// tristate is true and value is null, then the control is considered to be
/// in its third or "indeterminate" state.
///
/// When the value changes, this object starts the [positionController] and
/// [position] animations to animate the visual appearance of the control to
......@@ -118,7 +126,7 @@ abstract class RenderToggleable extends RenderConstrainedBox {
bool get value => _value;
bool _value;
set value(bool value) {
assert(value != null);
assert(tristate || value != null);
if (value == _value)
return;
_value = value;
......@@ -126,10 +134,29 @@ abstract class RenderToggleable extends RenderConstrainedBox {
_position
..curve = Curves.easeIn
..reverseCurve = Curves.easeOut;
if (value)
_positionController.forward();
else
switch (_positionController.status) {
case AnimationStatus.forward:
case AnimationStatus.completed:
_positionController.reverse();
break;
default:
_positionController.forward();
}
}
/// If true, [value] can be true, false, or null, otherwise [value] must
/// be true or false.
///
/// When [tristate] is true and [value] is null, then the control is
/// considered to be in its third or "indeterminate" state.
bool get tristate => _tristate;
bool _tristate;
set tristate(bool value) {
assert(tristate != null);
if (value == _tristate)
return;
_tristate = value;
markNeedsSemanticsUpdate();
}
/// The color that should be used in the active state (i.e., when [value] is true).
......@@ -196,10 +223,10 @@ abstract class RenderToggleable extends RenderConstrainedBox {
@override
void attach(PipelineOwner owner) {
super.attach(owner);
if (value)
_positionController.forward();
else
if (value == false)
_positionController.reverse();
else
_positionController.forward();
if (isInteractive) {
switch (_reactionController.status) {
case AnimationStatus.forward:
......@@ -223,14 +250,19 @@ abstract class RenderToggleable extends RenderConstrainedBox {
super.detach();
}
// Handle the case where the _positionController's value changes because
// the user dragged the toggleable: we may reach 0.0 or 1.0 without
// seeing a tap. The Switch does this.
void _handlePositionStateChanged(AnimationStatus status) {
if (isInteractive) {
if (status == AnimationStatus.completed && !_value)
if (isInteractive && !tristate) {
if (status == AnimationStatus.completed && _value == false) {
onChanged(true);
else if (status == AnimationStatus.dismissed && _value)
}
else if (status == AnimationStatus.dismissed && _value != false) {
onChanged(false);
}
}
}
void _handleTapDown(TapDownDetails details) {
if (isInteractive) {
......@@ -240,8 +272,19 @@ abstract class RenderToggleable extends RenderConstrainedBox {
}
void _handleTap() {
if (isInteractive)
onChanged(!_value);
if (!isInteractive)
return;
switch (value) {
case false:
onChanged(true);
break;
case true:
onChanged(tristate ? null : false);
break;
default: // case null:
onChanged(false);
break;
}
}
void _handleTapUp(TapUpDetails details) {
......@@ -290,7 +333,7 @@ abstract class RenderToggleable extends RenderConstrainedBox {
config.isEnabled = isInteractive;
if (isInteractive)
config.onTap = _handleTap;
config.isChecked = _value;
config.isChecked = _value != false;
}
@override
......
packages/flutter/test/material/checkbox_test.dart
View file @ 2aa9bb2b
......@@ -102,4 +102,48 @@ void main() {
semantics.dispose();
});
testWidgets('CheckBox tristate: true', (WidgetTester tester) async {
bool checkBoxValue;
await tester.pumpWidget(
new Material(
child: new StatefulBuilder(
builder: (BuildContext context, StateSetter setState) {
return new Checkbox(
tristate: true,
value: checkBoxValue,
onChanged: (bool value) {
setState(() {
checkBoxValue = value;
});
},
);
},
),
),
);
expect(tester.widget<Checkbox>(find.byType(Checkbox)).value, null);
await tester.tap(find.byType(Checkbox));
await tester.pumpAndSettle();
expect(checkBoxValue, false);
await tester.tap(find.byType(Checkbox));
await tester.pumpAndSettle();
expect(checkBoxValue, true);
await tester.tap(find.byType(Checkbox));
await tester.pumpAndSettle();
expect(checkBoxValue, null);
checkBoxValue = true;
await tester.pumpAndSettle();
expect(checkBoxValue, true);
checkBoxValue = null;
await tester.pumpAndSettle();
expect(checkBoxValue, null);
});
}
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