Timer class Null safety

A countdown timer that can be configured to fire once or repeatedly.

The timer counts down from the specified duration to 0. When the timer reaches 0, the timer invokes the specified callback function. Use a periodic timer to repeatedly count down the same interval.

A negative duration is treated the same as a duration of 0. If the duration is statically known to be 0, consider using run.

Frequently the duration is either a constant or computed as in the following example (taking advantage of the multiplication operator of the Duration class):

void main() {
  scheduleTimeout(5 * 1000); // 5 seconds.

Timer scheduleTimeout([int milliseconds = 10000]) =>
    Timer(Duration(milliseconds: milliseconds), handleTimeout);

void handleTimeout() {  // callback function
  // Do some work.

Note: If Dart code using Timer is compiled to JavaScript, the finest granularity available in the browser is 4 milliseconds.

See also:


Timer(Duration duration, void callback())
Creates a new timer.
Timer.periodic(Duration duration, void callback(Timer timer))
Creates a new repeating timer.


hashCode int
The hash code for this object.
read-only, inherited
isActive bool
Returns whether the timer is still active.
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited
tick int
The number of durations preceding the most recent timer event.


cancel() → void
Cancels the timer.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
toString() String
A string representation of this object.


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

Static Methods

run(void callback()) → void
Runs the given callback asynchronously as soon as possible.