Make SlottedMultiChildRenderObjectWidgetMixin a concrete class (#126108)
This is a proof of concept for renaming SlottedMultiChildRenderObjectWidgetMixin to SlottedMultiChildRenderObjectWidget and making it a concrete class.
I also made SlottedContainerRenderObjectMixin generic instead of being specialized to RenderBox.
I don't think this is something we can easily automigrate, but we may not need to, I don't know how common this is...
diff --git a/examples/api/lib/widgets/slotted_render_object_widget/slotted_multi_child_render_object_widget_mixin.0.dart b/examples/api/lib/widgets/slotted_render_object_widget/slotted_multi_child_render_object_widget_mixin.0.dart
index e93e5f9..7105802 100644
--- a/examples/api/lib/widgets/slotted_render_object_widget/slotted_multi_child_render_object_widget_mixin.0.dart
+++ b/examples/api/lib/widgets/slotted_render_object_widget/slotted_multi_child_render_object_widget_mixin.0.dart
@@ -5,7 +5,7 @@
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
-/// Flutter code sample for [SlottedMultiChildRenderObjectWidgetMixin].
+/// Flutter code sample for [SlottedMultiChildRenderObjectWidget].
/// Slots used for the children of [Diagonal] and [RenderDiagonal].
enum DiagonalSlot {
@@ -14,9 +14,9 @@
}
/// A widget that demonstrates the usage of
-/// [SlottedMultiChildRenderObjectWidgetMixin] by providing slots for two
+/// [SlottedMultiChildRenderObjectWidget] by providing slots for two
/// children that will be arranged diagonally.
-class Diagonal extends RenderObjectWidget with SlottedMultiChildRenderObjectWidgetMixin<DiagonalSlot> {
+class Diagonal extends SlottedMultiChildRenderObjectWidget<DiagonalSlot, RenderBox> {
const Diagonal({
super.key,
this.topLeft,
@@ -49,7 +49,7 @@
// [SlottedRenderObjectElement.update].
@override
- SlottedContainerRenderObjectMixin<DiagonalSlot> createRenderObject(
+ SlottedContainerRenderObjectMixin<DiagonalSlot, RenderBox> createRenderObject(
BuildContext context,
) {
return RenderDiagonal(
@@ -60,7 +60,7 @@
@override
void updateRenderObject(
BuildContext context,
- SlottedContainerRenderObjectMixin<DiagonalSlot> renderObject,
+ SlottedContainerRenderObjectMixin<DiagonalSlot, RenderBox> renderObject,
) {
(renderObject as RenderDiagonal).backgroundColor = backgroundColor;
}
@@ -70,7 +70,7 @@
/// [SlottedContainerRenderObjectMixin] by providing slots for two children that
/// will be arranged diagonally.
class RenderDiagonal extends RenderBox
- with SlottedContainerRenderObjectMixin<DiagonalSlot>, DebugOverflowIndicatorMixin {
+ with SlottedContainerRenderObjectMixin<DiagonalSlot, RenderBox>, DebugOverflowIndicatorMixin {
RenderDiagonal({Color? backgroundColor}) : _backgroundColor = backgroundColor;
// Getters and setters to configure the [RenderObject] with the configuration
diff --git a/packages/flutter/lib/src/material/chip.dart b/packages/flutter/lib/src/material/chip.dart
index e794ef3..f6b3510 100644
--- a/packages/flutter/lib/src/material/chip.dart
+++ b/packages/flutter/lib/src/material/chip.dart
@@ -1342,7 +1342,7 @@
}
}
-class _ChipRenderWidget extends RenderObjectWidget with SlottedMultiChildRenderObjectWidgetMixin<_ChipSlot> {
+class _ChipRenderWidget extends SlottedMultiChildRenderObjectWidget<_ChipSlot, RenderBox> {
const _ChipRenderWidget({
required this.theme,
this.value,
@@ -1393,7 +1393,7 @@
}
@override
- SlottedContainerRenderObjectMixin<_ChipSlot> createRenderObject(BuildContext context) {
+ SlottedContainerRenderObjectMixin<_ChipSlot, RenderBox> createRenderObject(BuildContext context) {
return _RenderChip(
theme: theme,
textDirection: Directionality.of(context),
@@ -1478,7 +1478,7 @@
);
}
-class _RenderChip extends RenderBox with SlottedContainerRenderObjectMixin<_ChipSlot> {
+class _RenderChip extends RenderBox with SlottedContainerRenderObjectMixin<_ChipSlot, RenderBox> {
_RenderChip({
required _ChipRenderTheme theme,
required TextDirection textDirection,
diff --git a/packages/flutter/lib/src/material/input_decorator.dart b/packages/flutter/lib/src/material/input_decorator.dart
index 39f0185..18f8ffd 100644
--- a/packages/flutter/lib/src/material/input_decorator.dart
+++ b/packages/flutter/lib/src/material/input_decorator.dart
@@ -693,7 +693,7 @@
}
// The workhorse: layout and paint a _Decorator widget's _Decoration.
-class _RenderDecoration extends RenderBox with SlottedContainerRenderObjectMixin<_DecorationSlot> {
+class _RenderDecoration extends RenderBox with SlottedContainerRenderObjectMixin<_DecorationSlot, RenderBox> {
_RenderDecoration({
required _Decoration decoration,
required TextDirection textDirection,
@@ -1637,7 +1637,7 @@
}
}
-class _Decorator extends RenderObjectWidget with SlottedMultiChildRenderObjectWidgetMixin<_DecorationSlot> {
+class _Decorator extends SlottedMultiChildRenderObjectWidget<_DecorationSlot, RenderBox> {
const _Decorator({
required this.textAlignVertical,
required this.decoration,
diff --git a/packages/flutter/lib/src/material/list_tile.dart b/packages/flutter/lib/src/material/list_tile.dart
index 1b0abbe..e96ea52 100644
--- a/packages/flutter/lib/src/material/list_tile.dart
+++ b/packages/flutter/lib/src/material/list_tile.dart
@@ -967,7 +967,7 @@
trailing,
}
-class _ListTile extends RenderObjectWidget with SlottedMultiChildRenderObjectWidgetMixin<_ListTileSlot> {
+class _ListTile extends SlottedMultiChildRenderObjectWidget<_ListTileSlot, RenderBox> {
const _ListTile({
this.leading,
required this.title,
@@ -1049,7 +1049,7 @@
}
}
-class _RenderListTile extends RenderBox with SlottedContainerRenderObjectMixin<_ListTileSlot> {
+class _RenderListTile extends RenderBox with SlottedContainerRenderObjectMixin<_ListTileSlot, RenderBox> {
_RenderListTile({
required bool isDense,
required VisualDensity visualDensity,
diff --git a/packages/flutter/lib/src/widgets/framework.dart b/packages/flutter/lib/src/widgets/framework.dart
index 92874bd..50eb6ca 100644
--- a/packages/flutter/lib/src/widgets/framework.dart
+++ b/packages/flutter/lib/src/widgets/framework.dart
@@ -1760,7 +1760,7 @@
///
/// * [MultiChildRenderObjectWidget], which configures a [RenderObject] with
/// a single list of children.
-/// * [SlottedMultiChildRenderObjectWidgetMixin], which configures a
+/// * [SlottedMultiChildRenderObjectWidget], which configures a
/// [RenderObject] that organizes its children in different named slots.
abstract class RenderObjectWidget extends Widget {
/// Abstract const constructor. This constructor enables subclasses to provide
@@ -1854,7 +1854,7 @@
/// * [Stack], which uses [MultiChildRenderObjectWidget].
/// * [RenderStack], for an example implementation of the associated render
/// object.
-/// * [SlottedMultiChildRenderObjectWidgetMixin], which configures a
+/// * [SlottedMultiChildRenderObjectWidget], which configures a
/// [RenderObject] that instead of having a single list of children organizes
/// its children in named slots.
abstract class MultiChildRenderObjectWidget extends RenderObjectWidget {
diff --git a/packages/flutter/lib/src/widgets/slotted_render_object_widget.dart b/packages/flutter/lib/src/widgets/slotted_render_object_widget.dart
index d3bd339..1318c04 100644
--- a/packages/flutter/lib/src/widgets/slotted_render_object_widget.dart
+++ b/packages/flutter/lib/src/widgets/slotted_render_object_widget.dart
@@ -7,8 +7,8 @@
import 'framework.dart';
-/// A mixin for a [RenderObjectWidget] that configures a [RenderObject]
-/// subclass, which organizes its children in different slots.
+/// A superclass for [RenderObjectWidget]s that configure [RenderObject]
+/// subclasses that organize their children in different slots.
///
/// Implementers of this mixin have to provide the list of available slots by
/// overriding [slots]. The list of slots must never change for a given class
@@ -20,14 +20,19 @@
/// widget configuration for a given slot.
///
/// The [RenderObject] returned by [createRenderObject] and updated by
-/// [updateRenderObject] must implement the [SlottedContainerRenderObjectMixin].
+/// [updateRenderObject] must implement [SlottedContainerRenderObjectMixin].
///
-/// The type parameter `S` is the type for the slots to be used by this
+/// The type parameter `SlotType` is the type for the slots to be used by this
/// [RenderObjectWidget] and the [RenderObject] it configures. In the typical
-/// case, `S` is an [Enum] type.
+/// case, `SlotType` is an [Enum] type.
+///
+/// The type parameter `ChildType` is the type used for the [RenderObject] children
+/// (e.g. [RenderBox] or [RenderSliver]). In the typical case, `ChildType` is
+/// [RenderBox]. This class does not support having different kinds of children
+/// for different slots.
///
/// {@tool dartpad}
-/// This example uses the [SlottedMultiChildRenderObjectWidgetMixin] in
+/// This example uses the [SlottedMultiChildRenderObjectWidget] in
/// combination with the [SlottedContainerRenderObjectMixin] to implement a
/// widget that provides two slots: topLeft and bottomRight. The widget arranges
/// the children in those slots diagonally.
@@ -39,9 +44,25 @@
///
/// * [MultiChildRenderObjectWidget], which configures a [RenderObject]
/// with a single list of children.
-/// * [ListTile], which uses [SlottedMultiChildRenderObjectWidgetMixin] in its
+/// * [ListTile], which uses [SlottedMultiChildRenderObjectWidget] in its
/// internal (private) implementation.
-mixin SlottedMultiChildRenderObjectWidgetMixin<S> on RenderObjectWidget {
+abstract class SlottedMultiChildRenderObjectWidget<SlotType, ChildType extends RenderObject> extends RenderObjectWidget with SlottedMultiChildRenderObjectWidgetMixin<SlotType, ChildType> {
+ /// Abstract const constructor. This constructor enables subclasses to provide
+ /// const constructors so that they can be used in const expressions.
+ const SlottedMultiChildRenderObjectWidget({ super.key });
+}
+
+/// A mixin version of [SlottedMultiChildRenderObjectWidget].
+///
+/// This mixin provides the same logic as extending
+/// [SlottedMultiChildRenderObjectWidget] directly.
+///
+/// It was deprecated to simplify the process of creating slotted widgets.
+@Deprecated(
+ 'Extend SlottedMultiChildRenderObjectWidget instead of mixing in SlottedMultiChildRenderObjectWidgetMixin. '
+ 'This feature was deprecated after v3.10.0-1.5.pre.'
+)
+mixin SlottedMultiChildRenderObjectWidgetMixin<SlotType, ChildType extends RenderObject> on RenderObjectWidget {
/// Returns a list of all available slots.
///
/// The list of slots must be static and must never change for a given class
@@ -51,7 +72,7 @@
/// this getter can be implemented by returning what the `values` getter
/// of the enum used returns.
@protected
- Iterable<S> get slots;
+ Iterable<SlotType> get slots;
/// Returns the widget that is currently occupying the provided `slot`.
///
@@ -59,56 +80,60 @@
/// the [RenderObject] produced by the returned [Widget] in the provided
/// `slot`.
@protected
- Widget? childForSlot(S slot);
+ Widget? childForSlot(SlotType slot);
@override
- SlottedContainerRenderObjectMixin<S> createRenderObject(BuildContext context);
+ SlottedContainerRenderObjectMixin<SlotType, ChildType> createRenderObject(BuildContext context);
@override
- void updateRenderObject(BuildContext context, SlottedContainerRenderObjectMixin<S> renderObject);
+ void updateRenderObject(BuildContext context, SlottedContainerRenderObjectMixin<SlotType, ChildType> renderObject);
@override
- SlottedRenderObjectElement<S> createElement() => SlottedRenderObjectElement<S>(this);
+ SlottedRenderObjectElement<SlotType, ChildType> createElement() => SlottedRenderObjectElement<SlotType, ChildType>(this);
}
-/// Mixin for a [RenderBox] configured by a [SlottedMultiChildRenderObjectWidgetMixin].
+/// Mixin for a [RenderObject] configured by a [SlottedMultiChildRenderObjectWidget].
///
-/// The [RenderBox] child currently occupying a given slot can be obtained by
+/// The [RenderObject] child currently occupying a given slot can be obtained by
/// calling [childForSlot].
///
/// Implementers may consider overriding [children] to return the children
/// of this render object in a consistent order (e.g. hit test order).
///
-/// The type parameter `S` is the type for the slots to be used by this
-/// [RenderObject] and the [SlottedMultiChildRenderObjectWidgetMixin] it was
-/// configured by. In the typical case, `S` is an [Enum] type.
+/// The type parameter `SlotType` is the type for the slots to be used by this
+/// [RenderObject] and the [SlottedMultiChildRenderObjectWidget] it was
+/// configured by. In the typical case, `SlotType` is an [Enum] type.
///
-/// See [SlottedMultiChildRenderObjectWidgetMixin] for example code showcasing
-/// how this mixin is used in combination with the
-/// [SlottedMultiChildRenderObjectWidgetMixin].
+/// The type parameter `ChildType` is the type of [RenderObject] used for the children
+/// (e.g. [RenderBox] or [RenderSliver]). In the typical case, `ChildType` is
+/// [RenderBox]. This mixin does not support having different kinds of children
+/// for different slots.
+///
+/// See [SlottedMultiChildRenderObjectWidget] for example code showcasing how
+/// this mixin is used in combination with [SlottedMultiChildRenderObjectWidget].
///
/// See also:
///
/// * [ContainerRenderObjectMixin], which organizes its children in a single
/// list.
-mixin SlottedContainerRenderObjectMixin<S> on RenderBox {
- /// Returns the [RenderBox] child that is currently occupying the provided
+mixin SlottedContainerRenderObjectMixin<SlotType, ChildType extends RenderObject> on RenderObject {
+ /// Returns the [RenderObject] child that is currently occupying the provided
/// `slot`.
///
- /// Returns null if no [RenderBox] is configured for the given slot.
+ /// Returns null if no [RenderObject] is configured for the given slot.
@protected
- RenderBox? childForSlot(S slot) => _slotToChild[slot];
+ ChildType? childForSlot(SlotType slot) => _slotToChild[slot];
/// Returns an [Iterable] of all non-null children.
///
/// This getter is used by the default implementation of [attach], [detach],
/// [redepthChildren], [visitChildren], and [debugDescribeChildren] to iterate
- /// over the children of this [RenderBox]. The base implementation makes no
- /// guarantee about the order in which the children are returned. Subclasses,
+ /// over the children of this [RenderObject]. The base implementation makes no
+ /// guarantee about the order in which the children are returned. Subclasses
/// for which the child order is important should override this getter and
/// return the children in the desired order.
@protected
- Iterable<RenderBox> get children => _slotToChild.values;
+ Iterable<ChildType> get children => _slotToChild.values;
/// Returns the debug name for a given `slot`.
///
@@ -119,7 +144,7 @@
/// The default implementation calls [EnumName.name] on `slot` if it is an
/// [Enum] value and `toString` if it is not.
@protected
- String debugNameForSlot(S slot) {
+ String debugNameForSlot(SlotType slot) {
if (slot is Enum) {
return slot.name;
}
@@ -129,7 +154,7 @@
@override
void attach(PipelineOwner owner) {
super.attach(owner);
- for (final RenderBox child in children) {
+ for (final ChildType child in children) {
child.attach(owner);
}
}
@@ -137,7 +162,7 @@
@override
void detach() {
super.detach();
- for (final RenderBox child in children) {
+ for (final ChildType child in children) {
child.detach();
}
}
@@ -155,24 +180,24 @@
@override
List<DiagnosticsNode> debugDescribeChildren() {
final List<DiagnosticsNode> value = <DiagnosticsNode>[];
- final Map<RenderBox, S> childToSlot = Map<RenderBox, S>.fromIterables(
+ final Map<ChildType, SlotType> childToSlot = Map<ChildType, SlotType>.fromIterables(
_slotToChild.values,
_slotToChild.keys,
);
- for (final RenderBox child in children) {
- _addDiagnostics(child, value, debugNameForSlot(childToSlot[child] as S));
+ for (final ChildType child in children) {
+ _addDiagnostics(child, value, debugNameForSlot(childToSlot[child] as SlotType));
}
return value;
}
- void _addDiagnostics(RenderBox child, List<DiagnosticsNode> value, String name) {
+ void _addDiagnostics(ChildType child, List<DiagnosticsNode> value, String name) {
value.add(child.toDiagnosticsNode(name: name));
}
- final Map<S, RenderBox> _slotToChild = <S, RenderBox>{};
+ final Map<SlotType, ChildType> _slotToChild = <SlotType, ChildType>{};
- void _setChild(RenderBox? child, S slot) {
- final RenderBox? oldChild = _slotToChild[slot];
+ void _setChild(ChildType? child, SlotType slot) {
+ final ChildType? oldChild = _slotToChild[slot];
if (oldChild != null) {
dropChild(oldChild);
_slotToChild.remove(slot);
@@ -183,9 +208,9 @@
}
}
- void _moveChild(RenderBox child, S slot, S oldSlot) {
+ void _moveChild(ChildType child, SlotType slot, SlotType oldSlot) {
assert(slot != oldSlot);
- final RenderBox? oldChild = _slotToChild[oldSlot];
+ final ChildType? oldChild = _slotToChild[oldSlot];
if (oldChild == child) {
_setChild(null, oldSlot);
}
@@ -193,16 +218,16 @@
}
}
-/// Element used by the [SlottedMultiChildRenderObjectWidgetMixin].
-class SlottedRenderObjectElement<S> extends RenderObjectElement {
+/// Element used by the [SlottedMultiChildRenderObjectWidget].
+class SlottedRenderObjectElement<SlotType, ChildType extends RenderObject> extends RenderObjectElement {
/// Creates an element that uses the given widget as its configuration.
- SlottedRenderObjectElement(SlottedMultiChildRenderObjectWidgetMixin<S> super.widget);
+ SlottedRenderObjectElement(SlottedMultiChildRenderObjectWidgetMixin<SlotType, ChildType> super.widget);
- Map<S, Element> _slotToChild = <S, Element>{};
+ Map<SlotType, Element> _slotToChild = <SlotType, Element>{};
Map<Key, Element> _keyedChildren = <Key, Element>{};
@override
- SlottedContainerRenderObjectMixin<S> get renderObject => super.renderObject as SlottedContainerRenderObjectMixin<S>;
+ SlottedContainerRenderObjectMixin<SlotType, ChildType> get renderObject => super.renderObject as SlottedContainerRenderObjectMixin<SlotType, ChildType>;
@override
void visitChildren(ElementVisitor visitor) {
@@ -212,7 +237,7 @@
@override
void forgetChild(Element child) {
assert(_slotToChild.containsValue(child));
- assert(child.slot is S);
+ assert(child.slot is SlotType);
assert(_slotToChild.containsKey(child.slot));
_slotToChild.remove(child.slot);
super.forgetChild(child);
@@ -225,16 +250,16 @@
}
@override
- void update(SlottedMultiChildRenderObjectWidgetMixin<S> newWidget) {
+ void update(SlottedMultiChildRenderObjectWidgetMixin<SlotType, ChildType> newWidget) {
super.update(newWidget);
assert(widget == newWidget);
_updateChildren();
}
- List<S>? _debugPreviousSlots;
+ List<SlotType>? _debugPreviousSlots;
void _updateChildren() {
- final SlottedMultiChildRenderObjectWidgetMixin<S> slottedMultiChildRenderObjectWidgetMixin = widget as SlottedMultiChildRenderObjectWidgetMixin<S>;
+ final SlottedMultiChildRenderObjectWidgetMixin<SlotType, ChildType> slottedMultiChildRenderObjectWidgetMixin = widget as SlottedMultiChildRenderObjectWidgetMixin<SlotType, ChildType>;
assert(() {
_debugPreviousSlots ??= slottedMultiChildRenderObjectWidgetMixin.slots.toList();
return listEquals(_debugPreviousSlots, slottedMultiChildRenderObjectWidgetMixin.slots.toList());
@@ -243,12 +268,12 @@
final Map<Key, Element> oldKeyedElements = _keyedChildren;
_keyedChildren = <Key, Element>{};
- final Map<S, Element> oldSlotToChild = _slotToChild;
- _slotToChild = <S, Element>{};
+ final Map<SlotType, Element> oldSlotToChild = _slotToChild;
+ _slotToChild = <SlotType, Element>{};
Map<Key, List<Element>>? debugDuplicateKeys;
- for (final S slot in slottedMultiChildRenderObjectWidgetMixin.slots) {
+ for (final SlotType slot in slottedMultiChildRenderObjectWidgetMixin.slots) {
final Widget? widget = slottedMultiChildRenderObjectWidgetMixin.childForSlot(slot);
final Key? newWidgetKey = widget?.key;
@@ -259,7 +284,7 @@
// If key matching fails, resort to `oldSlotChild` from the same slot.
final Element? fromElement;
if (oldKeyChild != null) {
- fromElement = oldSlotToChild.remove(oldKeyChild.slot as S);
+ fromElement = oldSlotToChild.remove(oldKeyChild.slot as SlotType);
} else if (oldSlotChild?.widget.key == null) {
fromElement = oldSlotToChild.remove(slot);
} else {
@@ -311,13 +336,13 @@
}
@override
- void insertRenderObjectChild(RenderBox child, S slot) {
+ void insertRenderObjectChild(ChildType child, SlotType slot) {
renderObject._setChild(child, slot);
assert(renderObject._slotToChild[slot] == child);
}
@override
- void removeRenderObjectChild(RenderBox child, S slot) {
+ void removeRenderObjectChild(ChildType child, SlotType slot) {
if (renderObject._slotToChild[slot] == child) {
renderObject._setChild(null, slot);
assert(renderObject._slotToChild[slot] == null);
@@ -325,7 +350,7 @@
}
@override
- void moveRenderObjectChild(RenderBox child, S oldSlot, S newSlot) {
+ void moveRenderObjectChild(ChildType child, SlotType oldSlot, SlotType newSlot) {
renderObject._moveChild(child, newSlot, oldSlot);
}
}
diff --git a/packages/flutter/test/widgets/slotted_render_object_widget_test.dart b/packages/flutter/test/widgets/slotted_render_object_widget_test.dart
index e5ba7a5..7d61f84 100644
--- a/packages/flutter/test/widgets/slotted_render_object_widget_test.dart
+++ b/packages/flutter/test/widgets/slotted_render_object_widget_test.dart
@@ -269,7 +269,7 @@
bottomRight,
}
-class _Diagonal extends RenderObjectWidget with SlottedMultiChildRenderObjectWidgetMixin<_DiagonalSlot?> {
+class _Diagonal extends RenderObjectWidget with SlottedMultiChildRenderObjectWidgetMixin<_DiagonalSlot?, RenderBox> {
const _Diagonal({
this.topLeft,
this.bottomRight,
@@ -296,14 +296,14 @@
}
@override
- SlottedContainerRenderObjectMixin<_DiagonalSlot?> createRenderObject(
+ SlottedContainerRenderObjectMixin<_DiagonalSlot?, RenderBox> createRenderObject(
BuildContext context,
) {
return _RenderDiagonal();
}
}
-class _RenderDiagonal extends RenderBox with SlottedContainerRenderObjectMixin<_DiagonalSlot?> {
+class _RenderDiagonal extends RenderBox with SlottedContainerRenderObjectMixin<_DiagonalSlot?, RenderBox> {
RenderBox? get _topLeft => childForSlot(_DiagonalSlot.topLeft);
RenderBox? get _bottomRight => childForSlot(_DiagonalSlot.bottomRight);
RenderBox? get _nullSlot => childForSlot(null);
@@ -370,6 +370,6 @@
String toString() => describeIdentity(this);
}
-class _RenderTest extends RenderBox with SlottedContainerRenderObjectMixin<_Slot> {
+class _RenderTest extends RenderBox with SlottedContainerRenderObjectMixin<_Slot, RenderBox> {
String publicNameForSlot(_Slot slot) => debugNameForSlot(slot);
}
