Android Question timer interval?

[Michael Gasperi]

If a timer interval is 10ms and the code in the tick takes 5ms, does the timer event happen every 10ms or every 15ms?

 

[DonManfred]

10ms i believe unless you stop the timer on timer_tick sub start and start the timer again just before timer_tick sub ends...

 

[Erel]

@DonManfred is correct. However remember that timers are not 100% accurate. The timer sends a message to the message queue. Only when the message queue is processed then the timer event will be raised.

 

[Michael Gasperi]

Thanks. Now what happens if the code takes longer, say 15ms? Does the rate become 15ms?

 

[Erel]

As I wrote the timer sends messages to the message queue. The event will only be raised when your code completes the execution and the main thread is free to process the message queue.

 

[DonManfred]

Thanks. Now what happens if the code takes longer, say 15ms? Does the rate become 15ms?

As i already stated i would suggest

sub timer_tick
  timer.enable = false ' Stop timer
  ' do your stuff here
  timer.enable = true  ' restart timer
end sub

 

[lemonisdead]

Sorry to hijack the question but it is also about timers.

What is the best for a long delay : have the timer internal for example datetime.TicksPerHour or store the targeted time and check regularly if this target is reached ?
Many thanks

 

[DonManfred]

probably it is better to use a service (StartServiceAt) instead of a timer for a longer distance.
Your app must be active to get the timer tick event

 

[Michael Gasperi]

Thanks again for your help.

DonManfred, I don't think the enable toggle is necessary since the task will not try to restart again till it is done.

I tested the timing variation using DateTime.Now and found the following:
Timers greater than about 20ms will "on average" give you the interval time you want.
However, the time interval you get for a given tick can vary about -20ms to +35ms off this average.
A really short timer interval, like 10ms, averages 17ms and can be as short as essentially 0ms and as long as 45ms.