Ticker class Null safety

Calls its callback once per animation frame.

When created, a ticker is initially disabled. Call start to enable the ticker.

A Ticker can be silenced by setting muted to true. While silenced, time still elapses, and start and stop can still be called, but no callbacks are called.

By convention, the start and stop methods are used by the ticker's consumer, and the muted property is controlled by the TickerProvider that created the ticker.

Tickers are driven by the SchedulerBinding. See SchedulerBinding.scheduleFrameCallback.

Constructors

Ticker(TickerCallback _onTick, {String? debugLabel})
Creates a ticker that will call the provided callback once per frame while running.

Properties

debugLabel String?
An optional label can be provided for debugging purposes.
final
hashCode int
The hash code for this object.
read-onlyinherited
isActive bool
Whether time is elapsing for this Ticker. Becomes true when start is called and false when stop is called.
read-only
isTicking bool
Whether this Ticker has scheduled a call to call its callback on the next frame.
read-only
muted bool
Whether this ticker has been silenced.
read / write
runtimeType Type
A representation of the runtime type of the object.
read-onlyinherited
scheduled bool
Whether this Ticker has already scheduled a frame callback.
protected">@protectedread-only
shouldScheduleTick bool
Whether a tick should be scheduled.
protected">@protectedread-only

Methods

absorbTicker(Ticker originalTicker) → void
Makes this Ticker take the state of another ticker, and disposes the other ticker.
describeForError(String name) DiagnosticsNode
Adds a debug representation of a Ticker optimized for including in error messages.
dispose() → void
Release the resources used by this object. The object is no longer usable after this method is called.
mustCallSuper">@mustCallSuper
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
inherited
scheduleTick({bool rescheduling = false}) → void
Schedules a tick for the next frame.
protected">@protected
start() TickerFuture
Starts the clock for this Ticker. If the ticker is not muted, then this also starts calling the ticker's callback once per animation frame.
stop({bool canceled = false}) → void
Stops calling this Ticker's callback.
toString({bool debugIncludeStack = false}) String
A string representation of this object.
override
unscheduleTick() → void
Cancels the frame callback that was requested by scheduleTick, if any.
protected">@protected

Operators

operator ==(Object other) bool
The equality operator.
inherited