Calls its callback once per animation frame, when enabled.
To obtain a ticker, consider TickerProvider.
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 (for example, an AnimationController), and the muted property is controlled by the TickerProvider that created the ticker (for example, a State that uses TickerProviderStateMixin to silence the ticker when the state's subtree is disabled as defined by TickerMode).
See also:
- TickerProvider, for obtaining a ticker.
- SchedulerBinding.scheduleFrameCallback, which drives tickers.
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
- forceFrames ↔ bool
-
If true, this ticker will request frames using
SchedulerBinding.scheduleForcedFrame instead of SchedulerBinding.scheduleFrame.
getter/setter pair
- hashCode → int
-
The hash code for this object.
no setterinherited
- isActive → bool
-
Whether time is elapsing for this Ticker. Becomes true when start is
called and false when stop is called.
no setter
- isTicking → bool
-
Whether this Ticker has scheduled a call to call its callback
on the next frame.
no setter
- muted ↔ bool
-
Whether this ticker has been silenced.
getter/setter pair
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- scheduled → bool
-
Whether this Ticker has already scheduled a frame callback.
no setter
- shouldScheduleTick → bool
-
Whether a tick should be scheduled.
no setter
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.
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
scheduleTick(
{bool rescheduling = false}) → void - Schedules a tick for the next frame.
-
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.
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited