The value of timed functions

Using a function that can be called at a later time can be helpful when organizing the timing of your game objects' appearance in an application. The timer library will allow us to handle our functions in a timely manner.

Timers

The timer function enables you to trigger events at a specific delay (in milliseconds) of your choosing.

• timer.performWithDelay(delay, listener [, iterations]): This invokes the listener after a delay in milliseconds and returns a handle to an object that you can pass to timer.cancel() in order to cancel the timer before it invokes the listener. For example:

  local function myEvent()
    print( "myEvent called" )
  end
  timer.performWithDelay( 1000, myEvent )

• timer.cancel(timerId): This cancels a timer operation initiated with timer.performWithDelay(). The parameter is as follows:
  • timerId: This is an object handle returned by the call to timer.performWithDelay(). For example:

    local count = 0
    
    local function myEvent()
      count = count + 1
      print( count )
    
      if count >= 3 then
        timer.cancel( myTimerID ) -- Cancels myTimerID
        end
      end

• timer.pause(timerId): This pauses a timer object started with timer.performWithDelay(). The parameter is:
  • timerId: This is the timer ID object from timer.performWithDelay(). For example:

    local count = 0
    
    local function myEvent()
      count = count + 1
      print( count )
    
      if count >= 5 then
        timer.pause( myTimerID ) -- Pauses myTimerID
        end
    end
    
    myTimerID = timer.performWithDelay(1000, myEvent, 0)

• timer.resume(timerId): This resumes a timer that was paused with timer.pause(timerId). The parameter is as follows:
  • timerID: This the timer ID from timer.performWithDelay(). For example:

    local function myEvent()
      print( "myEvent called" )
    end
    
    myTimerID = timer.performWithDelay( 3000, myEvent )  -- wait 3 seconds
    
    result = timer.pause( myTimerID ) -- Pauses myTimerID
    print( "Time paused at " .. result )
    
    result = timer.resume( myTimerID ) -- Resumes myTimerID
    print( "Time resumed at " .. result )