WidgetsBinding mixin

The glue between the widgets layer and the Flutter engine.

Superclass Constraints
Implemented by

Constructors

WidgetsBinding()

Properties

buildOwner → BuildOwner
The BuildOwner in charge of executing the build pipeline for the widget tree rooted at this binding.
read-only
debugBuildingDirtyElements ↔ bool
Whether we are currently in a frame. This is used to verify that frames are not scheduled redundantly. [...]
@protected, read / write
debugDidSendFirstFrameEvent → bool
Whether the first frame has finished rendering. [...]
read-only
focusManager → FocusManager
The object in charge of the focus tree. [...]
read-only
renderViewElement → Element
The Element that is at the root of the hierarchy (and which wraps the RenderView object at the root of the rendering hierarchy). [...]
read-only
accessibilityFeatures → AccessibilityFeatures
The currently active set of AccessibilityFeatures. [...]
read-only, inherited
currentFrameTimeStamp → Duration
The time stamp for the frame currently being processed. [...]
read-only, inherited
disableAnimations → bool
The platform is requesting that animations be disabled or simplified. [...]
read-only, inherited
endOfFrame → Future<void>
Returns a Future that completes after the frame completes. [...]
read-only, inherited
framesEnabled → bool
Whether frames are currently being scheduled when scheduleFrame is called. [...]
read-only, inherited
gestureArena → GestureArenaManager
The gesture arenas used for disambiguating the meaning of sequences of pointer events.
final, inherited
hashCode → int
The hash code for this object. [...]
read-only, inherited
hasScheduledFrame → bool
Whether this scheduler has requested that handleBeginFrame be called soon.
read-only, inherited
lifecycleState → AppLifecycleState
Whether the application is visible, and if so, whether it is currently interactive. [...]
read-only, inherited
locked → bool
Whether lockEvents is currently locking events. [...]
@protected, read-only, inherited
pipelineOwner → PipelineOwner
The render tree's owner, which maintains dirty state for layout, composite, paint, and accessibility semantics
read-only, inherited
pointerRouter → PointerRouter
A router that routes all pointer events received from the engine.
final, inherited
renderView ↔ RenderView
The render tree that's attached to the output surface.
read / write, inherited
runtimeType → Type
A representation of the runtime type of the object.
read-only, inherited
schedulerPhase → SchedulerPhase
The phase that the scheduler is currently operating under.
read-only, inherited
schedulingStrategy ↔ SchedulingStrategy
The strategy to use when deciding whether to run a task or not. [...]
read / write, inherited
transientCallbackCount → int
The current number of transient frame callbacks scheduled. [...]
read-only, inherited

Methods

addObserver(WidgetsBindingObserver observer) → void
Registers the given object as a binding observer. Binding observers are notified when various application events occur, for example when the system locale changes. Generally, one widget in the widget tree registers itself as a binding observer, and converts the system state into inherited widgets. [...]
allowFirstFrameReport() → void
When called after deferFirstFrameReport: tell the framework to report the frame it is building as a "useful" first frame. [...]
attachRootWidget(Widget rootWidget) → void
Takes a widget and attaches it to the renderViewElement, creating it if necessary. [...]
deferFirstFrameReport() → void
Tell the framework not to report the frame it is building as a "useful" first frame until there is a corresponding call to allowFirstFrameReport. [...]
dispatchAccessibilityFeaturesChanged() → void
Notify all the observers that the active set of AccessibilityFeatures has changed (using WidgetsBindingObserver.didChangeAccessibilityFeatures), giving them the features argument. [...]
@mustCallSuper, @protected
dispatchLocalesChanged(List<Locale> locales) → void
Notify all the observers that the locale has changed (using WidgetsBindingObserver.didChangeLocales), giving them the locales argument. [...]
@mustCallSuper, @protected
drawFrame() → void
Pump the build and rendering pipeline to generate a frame. [...]
override
handleAccessibilityFeaturesChanged() → void
Called when the platform accessibility features change. [...]
override
handleAppLifecycleStateChanged(AppLifecycleState state) → void
Called when the application lifecycle state changes. [...]
override
handleLocaleChanged() → void
Called when the system locale changes. [...]
@mustCallSuper, @protected
handleMemoryPressure() → void
Called when the operating system notifies the application of a memory pressure situation. [...]
handleMetricsChanged() → void
Called when the system metrics change. [...]
override
handlePopRoute() → Future<void>
Called when the system pops the current route. [...]
@protected
handlePushRoute(String route) → Future<void>
Called when the host tells the app to push a new route onto the navigator. [...]
@mustCallSuper, @protected
handleTextScaleFactorChanged() → void
Called when the platform text scale factor changes. [...]
override
initInstances() → void
The initialization method. Subclasses override this method to hook into the platform and otherwise configure their services. Subclasses must call "super.initInstances()". [...]
override
initServiceExtensions() → void
Called when the binding is initialized, to register service extensions. [...]
override
performReassemble() → Future<void>
This method is called by reassembleApplication to actually cause the application to reassemble, e.g. after a hot reload. [...]
override
removeObserver(WidgetsBindingObserver observer) → bool
Unregisters the given observer. This should be used sparingly as it is relatively expensive (O(N) in the number of registered observers). [...]
addPersistentFrameCallback(FrameCallback callback) → void
Adds a persistent frame callback. [...]
inherited
addPostFrameCallback(FrameCallback callback) → void
Schedule a callback for the end of this frame. [...]
inherited
cancelFrameCallbackWithId(int id) → void
Cancels the transient frame callback with the given id. [...]
inherited
cancelPointer(int pointer) → void
Dispatch a PointerCancelEvent for the given pointer soon. [...]
inherited
createViewConfiguration() → ViewConfiguration
Returns a ViewConfiguration configured for the RenderView based on the current environment. [...]
inherited
debugAssertNoTransientCallbacks(String reason) → bool
Asserts that there are no registered transient callbacks; if there are, prints their locations and throws an exception. [...]
inherited
dispatchEvent(PointerEvent event, HitTestResult result) → void
Dispatch an event to a hit test result's path. [...]
inherited
ensureVisualUpdate() → void
Schedules a new frame using scheduleFrame if this object is not currently producing a frame. [...]
inherited
evict(String asset) → void
Called in response to the ext.flutter.evict service extension. [...]
@mustCallSuper, @protected, inherited
handleBeginFrame(Duration rawTimeStamp) → void
Called by the engine to prepare the framework to produce a new frame. [...]
inherited
handleDrawFrame() → void
Called by the engine to produce a new frame. [...]
inherited
handleEvent(PointerEvent event, HitTestEntry entry) → void
Override this method to receive events.
inherited
handleEventLoopCallback() → bool
Execute the highest-priority task, if it is of a high enough priority. [...]
@visibleForTesting, inherited
hitTest(HitTestResult result, Offset position) → void
Check whether the given position hits this object. [...]
inherited
initLicenses() → void
Adds relevant licenses to the LicenseRegistry. [...]
@mustCallSuper, @protected, inherited
initRenderView() → void
Creates a RenderView object to be the root of the RenderObject rendering tree, and initializes it so that it will be rendered when the engine is next ready to display a frame. [...]
inherited
lockEvents(Future<void> callback()) → Future<void>
Locks the dispatching of asynchronous events and callbacks until the callback's future completes. [...]
@protected, inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed. [...]
inherited
reassembleApplication() → Future<void>
Cause the entire application to redraw, e.g. after a hot reload. [...]
inherited
registerBoolServiceExtension({String name, AsyncValueGetter<bool> getter, AsyncValueSetter<bool> setter }) → void
Registers a service extension method with the given name (full name "ext.flutter.name"), which takes a single argument "enabled" which can have the value "true" or the value "false" or can be omitted to read the current value. (Any value other than "true" is considered equivalent to "false". Other arguments are ignored.) [...]
@protected, inherited
registerNumericServiceExtension({String name, AsyncValueGetter<double> getter, AsyncValueSetter<double> setter }) → void
Registers a service extension method with the given name (full name "ext.flutter.name"), which takes a single argument with the same name as the method which, if present, must have a value that can be parsed by double.parse, and can be omitted to read the current value. (Other arguments are ignored.) [...]
@protected, inherited
registerServiceExtension({String name, ServiceExtensionCallback callback }) → void
Registers a service extension method with the given name (full name "ext.flutter.name"). [...]
@protected, inherited
registerSignalServiceExtension({String name, AsyncCallback callback }) → void
Registers a service extension method with the given name (full name "ext.flutter.name"), which takes no arguments and returns no value. [...]
@protected, inherited
registerStringServiceExtension({String name, AsyncValueGetter<String> getter, AsyncValueSetter<String> setter }) → void
Registers a service extension method with the given name (full name "ext.flutter.name"), which optionally takes a single argument with the name "value". If the argument is omitted, the value is to be read, otherwise it is to be set. Returns the current value. [...]
@protected, inherited
resetEpoch() → void
Prepares the scheduler for a non-monotonic change to how time stamps are calculated. [...]
inherited
scheduleForcedFrame() → void
Schedules a new frame by calling Window.scheduleFrame. [...]
inherited
scheduleFrame() → void
If necessary, schedules a new frame by calling Window.scheduleFrame. [...]
inherited
scheduleFrameCallback(FrameCallback callback, { bool rescheduling: false }) → int
Schedules the given transient frame callback. [...]
inherited
scheduleTask<T>(TaskCallback<T> task, Priority priority, { String debugLabel, Flow flow }) → Future<T>
Schedules the given task with the given priority and returns a Future that completes to the task's eventual return value. [...]
inherited
scheduleWarmUpFrame() → void
Schedule a frame to run as soon as possible, rather than waiting for the engine to request a frame in response to a system "Vsync" signal. [...]
inherited
setSemanticsEnabled(bool enabled) → void
Whether the render tree associated with this binding should produce a tree of SemanticsNode objects.
inherited
toString() → String
Returns a string representation of this object.
inherited
unlocked() → void
Called by lockEvents when events get unlocked. [...]
@mustCallSuper, @protected, inherited

Operators

operator ==(dynamic other) → bool
The equality operator. [...]
inherited

Static Properties

instance → WidgetsBinding
The current WidgetsBinding, if one has been created. [...]
read-only