Timer with random seconds ¿How to update the random seconds?

Question

I have a timer "tmr_sendCesta" which must be called each x seconds between 1 and 3 seconds. The problem is the timer "tmr_sendCesta" is called only one time, and the random seconds is never updated. I need to call the function "createCesta" each x seconds randomly.

Any idea how to do it?

function createCesta()
    cesta = display.newImageRect("cesta.png", 100, 55)
    cesta.x = -110
    cesta.y = screenH - 110
    cesta.name = "cesta"
    physics.addBody( cesta, physicsData:get("cestaSmall")) 
    grupoCesta:insert(cesta)
    transition.to(cesta, {time = 4000, x = screenW + 110})
end


function scene:enterScene( event )
    local group = self.view
    physics.start()
    Runtime:addEventListener("touch", touchScreen)
    Runtime:addEventListener( "collision", onCollision )

    tmr_sendCesta = timer.performWithDelay(math.random(1000, 3000), createCesta, 0)
end

Answer 1

If you want call createCesta (or randomCesta, not sure if that's a typo or you didn't show the correct function) at random intervals, than you have to re-evaluate math.random every time. So you cannot use a looped timer, since the delay will be the same every time. You have to reschedule a new timer that computes a new random number and creates a new timer:

local function randomDelay() return math.random(1000, 3000) end

local function randomCesta()
    cesta = display.newImageRect("cesta.png", 100, 55)
    ...
    grupoCesta:insert(cesta)
    transition.to(cesta, {time = 4000, x = screenW + 110})

    # reschedule at new random time:
    timer.performWithDelay(randomDelay(), randomCesta)
end

function scene:enterScene( event )
    ...

    timer.performWithDelay(randomDelay(), randomCesta)
end

Presumably, you only need the return value of timer.performWithDelay and transition.to if you are going to cancel/resume/pause the timer or transition.