Class Scheduler

java.lang.Object
org.robolectric.util.Scheduler
Direct Known Subclasses:
LooperDelegatingScheduler

public class Scheduler
extends Object
Class that manages a queue of Runnables that are scheduled to run now (or at some time in the future). Runnables that are scheduled to run on the UI thread (tasks, animations, etc) eventually get routed to a Scheduler instance.

The execution of a scheduler can be in one of three states:

  • paused (pause()): if paused, then no posted events will be run unless the Scheduler is explicitly instructed to do so, correctly matching Android's behavior.
  • normal (unPause()): if not paused but not set to idle constantly, then the Scheduler will automatically run any Runnables that are scheduled to run at or before the Scheduler's current time, but it won't automatically run any future events. To run future events the Scheduler needs to have its clock advanced.
  • idling constantly: if idleConstantly(boolean) is called with true, then the Scheduler will continue looping through posted events (including future events), advancing its clock as it goes.
  • Constructor Details

  • Method Details

    • getIdleState

      public Scheduler.IdleState getIdleState()
      Retrieves the current idling state of this Scheduler.
      Returns:
      The current idle state of this Scheduler.
      See Also:
      setIdleState(IdleState), isPaused()
    • setIdleState

      public void setIdleState​(Scheduler.IdleState idleState)
      Sets the current idling state of this Scheduler. If transitioning to the Scheduler.IdleState.UNPAUSED state any tasks scheduled to be run at or before the current time will be run, and if transitioning to the Scheduler.IdleState.CONSTANT_IDLE state all scheduled tasks will be run and the clock advanced to the time of the last runnable.
      Parameters:
      idleState - The new idle state of this Scheduler.
      See Also:
      setIdleState(IdleState), isPaused()
    • getCurrentTime

      public long getCurrentTime()
      Get the current time (as seen by the scheduler), in milliseconds.
      Returns:
      Current time in milliseconds.
    • pause

      public void pause()
      Pause the scheduler. Equivalent to setIdleState(PAUSED).
      See Also:
      unPause(), setIdleState(IdleState)
    • unPause

      public void unPause()
      Un-pause the scheduler. Equivalent to setIdleState(UNPAUSED).
      See Also:
      pause(), setIdleState(IdleState)
    • isPaused

      public boolean isPaused()
      Determine if the scheduler is paused.
      Returns:
      true if it is paused.
    • post

      public void post​(Runnable runnable)
      Add a runnable to the queue.
      Parameters:
      runnable - Runnable to add.
    • postDelayed

      public void postDelayed​(Runnable runnable, long delayMillis)
      Add a runnable to the queue to be run after a delay.
      Parameters:
      runnable - Runnable to add.
      delayMillis - Delay in millis.
    • postDelayed

      public void postDelayed​(Runnable runnable, long delay, TimeUnit unit)
      Add a runnable to the queue to be run after a delay.
    • postAtFrontOfQueue

      public void postAtFrontOfQueue​(Runnable runnable)
      Add a runnable to the head of the queue.
      Parameters:
      runnable - Runnable to add.
    • remove

      public void remove​(Runnable runnable)
      Remove a runnable from the queue.
      Parameters:
      runnable - Runnable to remove.
    • advanceToLastPostedRunnable

      public boolean advanceToLastPostedRunnable()
      Run all runnables in the queue, and any additional runnables they schedule that are scheduled before the latest scheduled runnable currently in the queue.
      Returns:
      True if a runnable was executed.
    • advanceToNextPostedRunnable

      public boolean advanceToNextPostedRunnable()
      Run the next runnable in the queue.
      Returns:
      True if a runnable was executed.
    • advanceBy

      @Deprecated public boolean advanceBy​(long interval)
      Deprecated.
      Run all runnables that are scheduled to run in the next time interval.
      Parameters:
      interval - Time interval (in millis).
      Returns:
      True if a runnable was executed.
    • advanceBy

      public boolean advanceBy​(long amount, TimeUnit unit)
      Run all runnables that are scheduled to run in the next time interval.
      Returns:
      True if a runnable was executed.
    • advanceTo

      public boolean advanceTo​(long endTime)
      Run all runnables that are scheduled before the endTime.
      Parameters:
      endTime - Future time.
      Returns:
      True if a runnable was executed.
    • runOneTask

      public boolean runOneTask()
      Run the next runnable in the queue.
      Returns:
      True if a runnable was executed.
    • areAnyRunnable

      public boolean areAnyRunnable()
      Determine if any enqueued runnables are enqueued before the current time.
      Returns:
      True if any runnables can be executed.
    • reset

      public void reset()
      Reset the internal state of the Scheduler.
    • size

      public int size()
      Return the number of enqueued runnables.
      Returns:
      Number of enqueues runnables.
    • getNextScheduledTaskTime

      public Duration getNextScheduledTaskTime()
    • getLastScheduledTaskTime

      public Duration getLastScheduledTaskTime()
    • idleConstantly

      @Deprecated public void idleConstantly​(boolean shouldIdleConstantly)
      Deprecated.
      This method is ambiguous in how it should behave when turning off constant idle. Use setIdleState(IdleState) instead to explicitly set the state.
      Set the idle state of the Scheduler. If necessary, the clock will be advanced and runnables executed as required by the newly-set state.
      Parameters:
      shouldIdleConstantly - If true the idle state will be set to Scheduler.IdleState.CONSTANT_IDLE, otherwise it will be set to Scheduler.IdleState.UNPAUSED.