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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:flute/foundation.dart';
import 'package:flute/gestures.dart';
import 'package:flute/scheduler.dart';
import 'package:flute/semantics.dart';
import 'package:flute/services.dart';
import 'box.dart';
import 'layer.dart';
import 'object.dart';
/// How an embedded platform view behave during hit tests.
enum PlatformViewHitTestBehavior {
/// Opaque targets can be hit by hit tests, causing them to both receive
/// events within their bounds and prevent targets visually behind them from
/// also receiving events.
opaque,
/// Translucent targets both receive events within their bounds and permit
/// targets visually behind them to also receive events.
translucent,
/// Transparent targets don't receive events within their bounds and permit
/// targets visually behind them to receive events.
transparent,
}
enum _PlatformViewState {
uninitialized,
resizing,
ready,
}
bool _factoryTypesSetEquals<T>(Set<Factory<T>>? a, Set<Factory<T>>? b) {
if (a == b) {
return true;
}
if (a == null || b == null) {
return false;
}
return setEquals(_factoriesTypeSet(a), _factoriesTypeSet(b));
}
Set<Type> _factoriesTypeSet<T>(Set<Factory<T>> factories) {
return factories.map<Type>((Factory<T> factory) => factory.type).toSet();
}
/// A render object for an Android view.
///
/// Requires Android API level 23 or greater.
///
/// [RenderAndroidView] is responsible for sizing, displaying and passing touch events to an
/// Android [View](https://developer.android.com/reference/android/view/View).
///
/// {@template flutter.rendering.RenderAndroidView.layout}
/// The render object's layout behavior is to fill all available space, the parent of this object must
/// provide bounded layout constraints.
/// {@endtemplate}
///
/// {@template flutter.rendering.RenderAndroidView.gestures}
/// The render object participates in Flutter's gesture arenas, and dispatches touch events to the
/// platform view iff it won the arena. Specific gestures that should be dispatched to the platform
/// view can be specified with factories in the `gestureRecognizers` constructor parameter or
/// by calling `updateGestureRecognizers`. If the set of gesture recognizers is empty, the gesture
/// will be dispatched to the platform view iff it was not claimed by any other gesture recognizer.
/// {@endtemplate}
///
/// See also:
///
/// * [AndroidView] which is a widget that is used to show an Android view.
/// * [PlatformViewsService] which is a service for controlling platform views.
class RenderAndroidView extends PlatformViewRenderBox {
/// Creates a render object for an Android view.
RenderAndroidView({
required AndroidViewController viewController,
required PlatformViewHitTestBehavior hitTestBehavior,
required Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers,
Clip clipBehavior = Clip.hardEdge,
}) : _viewController = viewController,
_clipBehavior = clipBehavior,
super(controller: viewController, hitTestBehavior: hitTestBehavior, gestureRecognizers: gestureRecognizers) {
_viewController.pointTransformer = (Offset offset) => globalToLocal(offset);
updateGestureRecognizers(gestureRecognizers);
_viewController.addOnPlatformViewCreatedListener(_onPlatformViewCreated);
this.hitTestBehavior = hitTestBehavior;
_setOffset();
}
_PlatformViewState _state = _PlatformViewState.uninitialized;
Size? _currentTextureSize;
bool _isDisposed = false;
/// The Android view controller for the Android view associated with this render object.
@override
AndroidViewController get controller => _viewController;
AndroidViewController _viewController;
/// Sets a new Android view controller.
@override
set controller(AndroidViewController controller) {
assert(!_isDisposed);
if (_viewController == controller) {
return;
}
_viewController.removeOnPlatformViewCreatedListener(_onPlatformViewCreated);
super.controller = controller;
_viewController = controller;
_viewController.pointTransformer = (Offset offset) => globalToLocal(offset);
_sizePlatformView();
if (_viewController.isCreated) {
markNeedsSemanticsUpdate();
}
_viewController.addOnPlatformViewCreatedListener(_onPlatformViewCreated);
}
/// {@macro flutter.material.Material.clipBehavior}
///
/// Defaults to [Clip.hardEdge], and must not be null.
Clip get clipBehavior => _clipBehavior;
Clip _clipBehavior = Clip.hardEdge;
set clipBehavior(Clip value) {
if (value != _clipBehavior) {
_clipBehavior = value;
markNeedsPaint();
markNeedsSemanticsUpdate();
}
}
void _onPlatformViewCreated(int id) {
assert(!_isDisposed);
markNeedsSemanticsUpdate();
}
@override
bool get sizedByParent => true;
@override
bool get alwaysNeedsCompositing => true;
@override
bool get isRepaintBoundary => true;
@override
Size computeDryLayout(BoxConstraints constraints) {
return constraints.biggest;
}
@override
void performResize() {
super.performResize();
_sizePlatformView();
}
Future<void> _sizePlatformView() async {
// Android virtual displays cannot have a zero size.
// Trying to size it to 0 crashes the app, which was happening when starting the app
// with a locked screen (see: https://github.com/flutter/flutter/issues/20456).
if (_state == _PlatformViewState.resizing || size.isEmpty) {
return;
}
_state = _PlatformViewState.resizing;
markNeedsPaint();
Size targetSize;
do {
targetSize = size;
_currentTextureSize = await _viewController.setSize(targetSize);
if (_isDisposed) {
return;
}
// We've resized the platform view to targetSize, but it is possible that
// while we were resizing the render object's size was changed again.
// In that case we will resize the platform view again.
} while (size != targetSize);
_state = _PlatformViewState.ready;
markNeedsPaint();
}
// Sets the offset of the underlying platform view on the platform side.
//
// This allows the Android native view to draw the a11y highlights in the same
// location on the screen as the platform view widget in the Flutter framework.
//
// It also allows platform code to obtain the correct position of the Android
// native view on the screen.
void _setOffset() {
SchedulerBinding.instance.addPostFrameCallback((_) async {
if (!_isDisposed) {
if (attached) {
await _viewController.setOffset(localToGlobal(Offset.zero));
}
// Schedule a new post frame callback.
_setOffset();
}
});
}
@override
void paint(PaintingContext context, Offset offset) {
if (_viewController.textureId == null || _currentTextureSize == null) {
return;
}
// As resizing the Android view happens asynchronously we don't know exactly when is a
// texture frame with the new size is ready for consumption.
// TextureLayer is unaware of the texture frame's size and always maps it to the
// specified rect. If the rect we provide has a different size from the current texture frame's
// size the texture frame will be scaled.
// To prevent unwanted scaling artifacts while resizing, clip the texture.
// This guarantees that the size of the texture frame we're painting is always
// _currentAndroidTextureSize.
final bool isTextureLargerThanWidget = _currentTextureSize!.width > size.width ||
_currentTextureSize!.height > size.height;
if (isTextureLargerThanWidget && clipBehavior != Clip.none) {
_clipRectLayer.layer = context.pushClipRect(
true,
offset,
offset & size,
_paintTexture,
clipBehavior: clipBehavior,
oldLayer: _clipRectLayer.layer,
);
return;
}
_clipRectLayer.layer = null;
_paintTexture(context, offset);
}
final LayerHandle<ClipRectLayer> _clipRectLayer = LayerHandle<ClipRectLayer>();
@override
void dispose() {
_isDisposed = true;
_clipRectLayer.layer = null;
_viewController.removeOnPlatformViewCreatedListener(_onPlatformViewCreated);
super.dispose();
}
void _paintTexture(PaintingContext context, Offset offset) {
if (_currentTextureSize == null) {
return;
}
context.addLayer(TextureLayer(
rect: offset & _currentTextureSize!,
textureId: _viewController.textureId!,
));
}
@override
void describeSemanticsConfiguration(SemanticsConfiguration config) {
// Don't call the super implementation since `platformViewId` should
// be set only when the platform view is created, but the concept of
// a "created" platform view belongs to this subclass.
config.isSemanticBoundary = true;
if (_viewController.isCreated) {
config.platformViewId = _viewController.viewId;
}
}
}
/// A render object for an iOS UIKit UIView.
///
/// [RenderUiKitView] is responsible for sizing and displaying an iOS
/// [UIView](https://developer.apple.com/documentation/uikit/uiview).
///
/// UIViews are added as sub views of the FlutterView and are composited by Quartz.
///
/// {@macro flutter.rendering.RenderAndroidView.layout}
///
/// {@macro flutter.rendering.RenderAndroidView.gestures}
///
/// See also:
///
/// * [UiKitView] which is a widget that is used to show a UIView.
/// * [PlatformViewsService] which is a service for controlling platform views.
class RenderUiKitView extends RenderBox {
/// Creates a render object for an iOS UIView.
///
/// The `viewId`, `hitTestBehavior`, and `gestureRecognizers` parameters must not be null.
RenderUiKitView({
required UiKitViewController viewController,
required this.hitTestBehavior,
required Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers,
}) : _viewController = viewController {
updateGestureRecognizers(gestureRecognizers);
}
/// The unique identifier of the UIView controlled by this controller.
///
/// Typically generated by [PlatformViewsRegistry.getNextPlatformViewId], the UIView
/// must have been created by calling [PlatformViewsService.initUiKitView].
UiKitViewController get viewController => _viewController;
UiKitViewController _viewController;
set viewController(UiKitViewController value) {
if (_viewController == value) {
return;
}
final bool needsSemanticsUpdate = _viewController.id != value.id;
_viewController = value;
markNeedsPaint();
if (needsSemanticsUpdate) {
markNeedsSemanticsUpdate();
}
}
/// How to behave during hit testing.
// The implicit setter is enough here as changing this value will just affect
// any newly arriving events there's nothing we need to invalidate.
PlatformViewHitTestBehavior hitTestBehavior;
/// {@macro flutter.rendering.PlatformViewRenderBox.updateGestureRecognizers}
void updateGestureRecognizers(Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers) {
assert(
_factoriesTypeSet(gestureRecognizers).length == gestureRecognizers.length,
'There were multiple gesture recognizer factories for the same type, there must only be a single '
'gesture recognizer factory for each gesture recognizer type.',
);
if (_factoryTypesSetEquals(gestureRecognizers, _gestureRecognizer?.gestureRecognizerFactories)) {
return;
}
_gestureRecognizer?.dispose();
_gestureRecognizer = _UiKitViewGestureRecognizer(viewController, gestureRecognizers);
}
@override
bool get sizedByParent => true;
@override
bool get alwaysNeedsCompositing => true;
@override
bool get isRepaintBoundary => true;
_UiKitViewGestureRecognizer? _gestureRecognizer;
PointerEvent? _lastPointerDownEvent;
@override
Size computeDryLayout(BoxConstraints constraints) {
return constraints.biggest;
}
@override
void paint(PaintingContext context, Offset offset) {
context.addLayer(PlatformViewLayer(
rect: offset & size,
viewId: _viewController.id,
));
}
@override
bool hitTest(BoxHitTestResult result, { Offset? position }) {
if (hitTestBehavior == PlatformViewHitTestBehavior.transparent || !size.contains(position!)) {
return false;
}
result.add(BoxHitTestEntry(this, position));
return hitTestBehavior == PlatformViewHitTestBehavior.opaque;
}
@override
bool hitTestSelf(Offset position) => hitTestBehavior != PlatformViewHitTestBehavior.transparent;
@override
void handleEvent(PointerEvent event, HitTestEntry entry) {
if (event is! PointerDownEvent) {
return;
}
_gestureRecognizer!.addPointer(event);
_lastPointerDownEvent = event.original ?? event;
}
// This is registered as a global PointerRoute while the render object is attached.
void _handleGlobalPointerEvent(PointerEvent event) {
if (event is! PointerDownEvent) {
return;
}
if (!(Offset.zero & size).contains(globalToLocal(event.position))) {
return;
}
if ((event.original ?? event) != _lastPointerDownEvent) {
// The pointer event is in the bounds of this render box, but we didn't get it in handleEvent.
// This means that the pointer event was absorbed by a different render object.
// Since on the platform side the FlutterTouchIntercepting view is seeing all events that are
// within its bounds we need to tell it to reject the current touch sequence.
_viewController.rejectGesture();
}
_lastPointerDownEvent = null;
}
@override
void describeSemanticsConfiguration (SemanticsConfiguration config) {
super.describeSemanticsConfiguration(config);
config.isSemanticBoundary = true;
config.platformViewId = _viewController.id;
}
@override
void attach(PipelineOwner owner) {
super.attach(owner);
GestureBinding.instance.pointerRouter.addGlobalRoute(_handleGlobalPointerEvent);
}
@override
void detach() {
GestureBinding.instance.pointerRouter.removeGlobalRoute(_handleGlobalPointerEvent);
_gestureRecognizer!.reset();
super.detach();
}
}
// This recognizer constructs gesture recognizers from a set of gesture recognizer factories
// it was give, adds all of them to a gesture arena team with the _UiKitViewGestureRecognizer
// as the team captain.
// When the team wins a gesture the recognizer notifies the engine that it should release
// the touch sequence to the embedded UIView.
class _UiKitViewGestureRecognizer extends OneSequenceGestureRecognizer {
_UiKitViewGestureRecognizer(
this.controller,
this.gestureRecognizerFactories
) {
team = GestureArenaTeam()
..captain = this;
_gestureRecognizers = gestureRecognizerFactories.map(
(Factory<OneSequenceGestureRecognizer> recognizerFactory) {
final OneSequenceGestureRecognizer gestureRecognizer = recognizerFactory.constructor();
gestureRecognizer.team = team;
// The below gesture recognizers requires at least one non-empty callback to
// compete in the gesture arena.
// https://github.com/flutter/flutter/issues/35394#issuecomment-562285087
if (gestureRecognizer is LongPressGestureRecognizer) {
gestureRecognizer.onLongPress ??= (){};
} else if (gestureRecognizer is DragGestureRecognizer) {
gestureRecognizer.onDown ??= (_){};
} else if (gestureRecognizer is TapGestureRecognizer) {
gestureRecognizer.onTapDown ??= (_){};
}
return gestureRecognizer;
},
).toSet();
}
// We use OneSequenceGestureRecognizers as they support gesture arena teams.
// TODO(amirh): get a list of GestureRecognizers here.
// https://github.com/flutter/flutter/issues/20953
final Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizerFactories;
late Set<OneSequenceGestureRecognizer> _gestureRecognizers;
final UiKitViewController controller;
@override
void addAllowedPointer(PointerDownEvent event) {
super.addAllowedPointer(event);
for (final OneSequenceGestureRecognizer recognizer in _gestureRecognizers) {
recognizer.addPointer(event);
}
}
@override
String get debugDescription => 'UIKit view';
@override
void didStopTrackingLastPointer(int pointer) { }
@override
void handleEvent(PointerEvent event) {
stopTrackingIfPointerNoLongerDown(event);
}
@override
void acceptGesture(int pointer) {
controller.acceptGesture();
}
@override
void rejectGesture(int pointer) {
controller.rejectGesture();
}
void reset() {
resolve(GestureDisposition.rejected);
}
}
typedef _HandlePointerEvent = Future<void> Function(PointerEvent event);
// This recognizer constructs gesture recognizers from a set of gesture recognizer factories
// it was give, adds all of them to a gesture arena team with the _PlatformViewGestureRecognizer
// as the team captain.
// As long as the gesture arena is unresolved, the recognizer caches all pointer events.
// When the team wins, the recognizer sends all the cached pointer events to `_handlePointerEvent`, and
// sets itself to a "forwarding mode" where it will forward any new pointer event to `_handlePointerEvent`.
class _PlatformViewGestureRecognizer extends OneSequenceGestureRecognizer {
_PlatformViewGestureRecognizer(
_HandlePointerEvent handlePointerEvent,
this.gestureRecognizerFactories
) {
team = GestureArenaTeam()
..captain = this;
_gestureRecognizers = gestureRecognizerFactories.map(
(Factory<OneSequenceGestureRecognizer> recognizerFactory) {
final OneSequenceGestureRecognizer gestureRecognizer = recognizerFactory.constructor();
gestureRecognizer.team = team;
// The below gesture recognizers requires at least one non-empty callback to
// compete in the gesture arena.
// https://github.com/flutter/flutter/issues/35394#issuecomment-562285087
if (gestureRecognizer is LongPressGestureRecognizer) {
gestureRecognizer.onLongPress ??= (){};
} else if (gestureRecognizer is DragGestureRecognizer) {
gestureRecognizer.onDown ??= (_){};
} else if (gestureRecognizer is TapGestureRecognizer) {
gestureRecognizer.onTapDown ??= (_){};
}
return gestureRecognizer;
},
).toSet();
_handlePointerEvent = handlePointerEvent;
}
late _HandlePointerEvent _handlePointerEvent;
// Maps a pointer to a list of its cached pointer events.
// Before the arena for a pointer is resolved all events are cached here, if we win the arena
// the cached events are dispatched to `_handlePointerEvent`, if we lose the arena we clear the cache for
// the pointer.
final Map<int, List<PointerEvent>> cachedEvents = <int, List<PointerEvent>>{};
// Pointer for which we have already won the arena, events for pointers in this set are
// immediately dispatched to `_handlePointerEvent`.
final Set<int> forwardedPointers = <int>{};
// We use OneSequenceGestureRecognizers as they support gesture arena teams.
// TODO(amirh): get a list of GestureRecognizers here.
// https://github.com/flutter/flutter/issues/20953
final Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizerFactories;
late Set<OneSequenceGestureRecognizer> _gestureRecognizers;
@override
void addAllowedPointer(PointerDownEvent event) {
super.addAllowedPointer(event);
for (final OneSequenceGestureRecognizer recognizer in _gestureRecognizers) {
recognizer.addPointer(event);
}
}
@override
String get debugDescription => 'Platform view';
@override
void didStopTrackingLastPointer(int pointer) { }
@override
void handleEvent(PointerEvent event) {
if (!forwardedPointers.contains(event.pointer)) {
_cacheEvent(event);
} else {
_handlePointerEvent(event);
}
stopTrackingIfPointerNoLongerDown(event);
}
@override
void acceptGesture(int pointer) {
_flushPointerCache(pointer);
forwardedPointers.add(pointer);
}
@override
void rejectGesture(int pointer) {
stopTrackingPointer(pointer);
cachedEvents.remove(pointer);
}
void _cacheEvent(PointerEvent event) {
if (!cachedEvents.containsKey(event.pointer)) {
cachedEvents[event.pointer] = <PointerEvent> [];
}
cachedEvents[event.pointer]!.add(event);
}
void _flushPointerCache(int pointer) {
cachedEvents.remove(pointer)?.forEach(_handlePointerEvent);
}
@override
void stopTrackingPointer(int pointer) {
super.stopTrackingPointer(pointer);
forwardedPointers.remove(pointer);
}
void reset() {
forwardedPointers.forEach(super.stopTrackingPointer);
forwardedPointers.clear();
cachedEvents.keys.forEach(super.stopTrackingPointer);
cachedEvents.clear();
resolve(GestureDisposition.rejected);
}
}
/// A render object for embedding a platform view.
///
/// [PlatformViewRenderBox] presents a platform view by adding a [PlatformViewLayer] layer,
/// integrates it with the gesture arenas system and adds relevant semantic nodes to the semantics tree.
class PlatformViewRenderBox extends RenderBox with _PlatformViewGestureMixin {
/// Creating a render object for a [PlatformViewSurface].
///
/// The `controller` parameter must not be null.
PlatformViewRenderBox({
required PlatformViewController controller,
required PlatformViewHitTestBehavior hitTestBehavior,
required Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers,
}) : assert(controller.viewId > -1),
_controller = controller {
this.hitTestBehavior = hitTestBehavior;
updateGestureRecognizers(gestureRecognizers);
}
/// The controller for this render object.
PlatformViewController get controller => _controller;
PlatformViewController _controller;
/// This value must not be null, and setting it to a new value will result in a repaint.
set controller(covariant PlatformViewController controller) {
assert(controller.viewId > -1);
if (_controller == controller) {
return;
}
final bool needsSemanticsUpdate = _controller.viewId != controller.viewId;
_controller = controller;
markNeedsPaint();
if (needsSemanticsUpdate) {
markNeedsSemanticsUpdate();
}
}
/// {@template flutter.rendering.PlatformViewRenderBox.updateGestureRecognizers}
/// Updates which gestures should be forwarded to the platform view.
///
/// Gesture recognizers created by factories in this set participate in the gesture arena for each
/// pointer that was put down on the render box. If any of the recognizers on this list wins the
/// gesture arena, the entire pointer event sequence starting from the pointer down event
/// will be dispatched to the Android view.
///
/// The `gestureRecognizers` property must not contain more than one factory with the same [Factory.type].
///
/// Setting a new set of gesture recognizer factories with the same [Factory.type]s as the current
/// set has no effect, because the factories' constructors would have already been called with the previous set.
/// {@endtemplate}
///
/// Any active gesture arena the `PlatformView` participates in is rejected when the
/// set of gesture recognizers is changed.
void updateGestureRecognizers(Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers) {
_updateGestureRecognizersWithCallBack(gestureRecognizers, _controller.dispatchPointerEvent);
}
@override
bool get sizedByParent => true;
@override
bool get alwaysNeedsCompositing => true;
@override
bool get isRepaintBoundary => true;
@override
Size computeDryLayout(BoxConstraints constraints) {
return constraints.biggest;
}
@override
void paint(PaintingContext context, Offset offset) {
context.addLayer(PlatformViewLayer(
rect: offset & size,
viewId: _controller.viewId,
));
}
@override
void describeSemanticsConfiguration(SemanticsConfiguration config) {
super.describeSemanticsConfiguration(config);
config.isSemanticBoundary = true;
config.platformViewId = _controller.viewId;
}
}
/// The Mixin handling the pointer events and gestures of a platform view render box.
mixin _PlatformViewGestureMixin on RenderBox implements MouseTrackerAnnotation {
/// How to behave during hit testing.
// Changing _hitTestBehavior might affect which objects are considered hovered over.
set hitTestBehavior(PlatformViewHitTestBehavior value) {
if (value != _hitTestBehavior) {
_hitTestBehavior = value;
if (owner != null) {
markNeedsPaint();
}
}
}
PlatformViewHitTestBehavior? _hitTestBehavior;
_HandlePointerEvent? _handlePointerEvent;
/// {@macro flutter.rendering.RenderAndroidView.updateGestureRecognizers}
///
/// Any active gesture arena the `PlatformView` participates in is rejected when the
/// set of gesture recognizers is changed.
void _updateGestureRecognizersWithCallBack(Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers, _HandlePointerEvent handlePointerEvent) {
assert(
_factoriesTypeSet(gestureRecognizers).length == gestureRecognizers.length,
'There were multiple gesture recognizer factories for the same type, there must only be a single '
'gesture recognizer factory for each gesture recognizer type.',
);
if (_factoryTypesSetEquals(gestureRecognizers, _gestureRecognizer?.gestureRecognizerFactories)) {
return;
}
_gestureRecognizer?.dispose();
_gestureRecognizer = _PlatformViewGestureRecognizer(handlePointerEvent, gestureRecognizers);
_handlePointerEvent = handlePointerEvent;
}
_PlatformViewGestureRecognizer? _gestureRecognizer;
@override
bool hitTest(BoxHitTestResult result, { required Offset position }) {
if (_hitTestBehavior == PlatformViewHitTestBehavior.transparent || !size.contains(position)) {
return false;
}
result.add(BoxHitTestEntry(this, position));
return _hitTestBehavior == PlatformViewHitTestBehavior.opaque;
}
@override
bool hitTestSelf(Offset position) => _hitTestBehavior != PlatformViewHitTestBehavior.transparent;
@override
PointerEnterEventListener? get onEnter => null;
@override
PointerExitEventListener? get onExit => null;
@override
MouseCursor get cursor => MouseCursor.uncontrolled;
@override
bool get validForMouseTracker => true;
@override
void handleEvent(PointerEvent event, HitTestEntry entry) {
if (event is PointerDownEvent) {
_gestureRecognizer!.addPointer(event);
}
if (event is PointerHoverEvent) {
_handlePointerEvent?.call(event);
}
}
@override
void detach() {
_gestureRecognizer!.reset();
super.detach();
}
}