CODEWITHSUNDEEP
timerluacomposer-phpcoronasdkcancellation
james42
james42

Reputation: 1

Lua : timer.cancel --> 'Attempt to index a nil value'

I'm fairly new to Lua, and one particular command in my code has been causing me some major problems.

I've been trying to cancel the timer:

currentPuddleDelay = timer.performWithDelay(puddleDelay, createPuddle);

The error that I am shown is:

Attempt to index a nil value

File: ?

stack traceback:
?: in function 'cancel'
game.lua:534: in function '?'
?: in function 'dispatchEvent'
?: in function '_saveSceneAndHide'
?: in function 'gotoScene'
game.lua:452: in function '?'
?: in function <?:182>

From what I've researched already, this problem can occur when the timer is within a function and is local, however, the timer in my code is global, so I don't think that that is the problem.

Below is the bit of code with the issue:

local function createPuddle()
    local function constantDelay()

        local puddle = display.newImage( sceneGroup, "images/puddle.png" )
        puddle.x = puddleLane
        puddle.y = -200

        physics.addBody( puddle, "dynamic", {density=0, filter=puddleCollisionFilter} )
        puddle:applyForce( 0, puddleSpeed, puddle.x, puddle.y )
        sceneGroup:insert(3,puddle)

        local function onPuddleCollision( self, event )
            if ( event.phase == "began" ) then
                print('puddle collision')
                puddle:removeSelf( )
                puddle = nil
                composer.gotoScene( "menu" )
            end
        end
        puddle.collision = onPuddleCollision
        puddle:addEventListener( "collision" )
    end

    local constantDelayTimer = timer.performWithDelay(puddleDelay/2,constantDelay,1)
    currentPuddleDelayHold = timer.performWithDelay(puddleDelay, createPuddle);
end

currentPuddleDelay = timer.performWithDelay(puddleDelay, createPuddle);

And then later on in the program:

timer.cancel(currentPuddleDelay)

Any help would be greatly appreciated.

Upvotes: 0

Views: 637

Answers (1)

Piglet
Piglet

Reputation: 28974

I can only guess as you most likely did not provide all relevant code.

It obviously doesn't make sense to cancel a non-existing timer so for the start just do

if currentPuddleDelay then timer.cancel(currentPuddleDelay) end

If there is any reason why currentPuddleDelay should still exist you should find out why it is nil.

Upvotes: 1

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