can I cancel the timer within the function I use with timer.performWithDelay?

Solar2D General Questions/Discussion
#1

Is it ok to cancel a timer like this?   (i.e. from a memory managmeent point of view)

&nbsp;&nbsp;&nbsp;&nbsp;local t = timer.performWithDelay(200, &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;function(event) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;local x = 123 &nbsp;-- do stuff &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;timer.cancel(t) -- \<== IS THIS OK HERE? -- Do I need either of these lines? t:removeSelf() t = nil &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;end &nbsp;&nbsp;&nbsp;&nbsp;) &nbsp;

Also do I need:

 - a “removeSelf” here also?

 - a “= nil” here also?

#2

oh, that doesn’t seem to work - I think it would need to be like this:

&nbsp;&nbsp;&nbsp;&nbsp;local t = timer.performWithDelay(200, startPhysicsListener) &nbsp;&nbsp;&nbsp;&nbsp;local function startPhysicsListener(event) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;physics.start() &nbsp;-- i.e. do stuff &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;timer.cancel(t) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;t:removeSelf() &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;t = nil &nbsp;&nbsp;&nbsp;&nbsp;end &nbsp;

So again is this acceptable / best practice re memory management for timers?

#3

damm, that doesn’t seem to work either as “startPhysicsListener” isn’t defined at the time of the 1st line…

Any suggestions re how to cancel a timer in the same “area/block” of code you create it in?  i.e. trying to avoid having to put them all into a table to come back at a later time (e.g. scene:exitScene()) to cancel them…

#4

First of all, you can call object:removeSelf() only on display objects and NOT on timers.

For deleting timers just call timer.cancel(timer_name) and timer_name = nil.

Also you don’t need to cancel a timer after it ran out. I mean when the timer did his job, there is nothing to cancel :wink:

To your problem, try something like this:

local t &nbsp; local function startPhysicsListener() &nbsp;&nbsp; physics.start() &nbsp;-- i.e. do stuff &nbsp;&nbsp; timer.cancel(t)&nbsp; --if you really need it, but I don't see for what &nbsp;&nbsp; t = nil end &nbsp; t = timer.performWithDelay(200, startPhysicsListener)
#5

ok thanks - do you know what the “t=nil” does?  does that just ensure the garbage collector is triggered straight away to recover the memory vs later on?

#6

It frees that part of memory, so the garbage collector knows it can be deleted (or overwritten), as far as I know.

#7

oh, that doesn’t seem to work - I think it would need to be like this:

&nbsp;&nbsp;&nbsp;&nbsp;local t = timer.performWithDelay(200, startPhysicsListener) &nbsp;&nbsp;&nbsp;&nbsp;local function startPhysicsListener(event) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;physics.start() &nbsp;-- i.e. do stuff &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;timer.cancel(t) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;t:removeSelf() &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;t = nil &nbsp;&nbsp;&nbsp;&nbsp;end &nbsp;

So again is this acceptable / best practice re memory management for timers?

#8

damm, that doesn’t seem to work either as “startPhysicsListener” isn’t defined at the time of the 1st line…

Any suggestions re how to cancel a timer in the same “area/block” of code you create it in?  i.e. trying to avoid having to put them all into a table to come back at a later time (e.g. scene:exitScene()) to cancel them…

#9

First of all, you can call object:removeSelf() only on display objects and NOT on timers.

For deleting timers just call timer.cancel(timer_name) and timer_name = nil.

Also you don’t need to cancel a timer after it ran out. I mean when the timer did his job, there is nothing to cancel :wink:

To your problem, try something like this:

local t &nbsp; local function startPhysicsListener() &nbsp;&nbsp; physics.start() &nbsp;-- i.e. do stuff &nbsp;&nbsp; timer.cancel(t)&nbsp; --if you really need it, but I don't see for what &nbsp;&nbsp; t = nil end &nbsp; t = timer.performWithDelay(200, startPhysicsListener)
#10

ok thanks - do you know what the “t=nil” does?  does that just ensure the garbage collector is triggered straight away to recover the memory vs later on?

#11

It frees that part of memory, so the garbage collector knows it can be deleted (or overwritten), as far as I know.